diff --git a/src/ifcopenshell-python/ifcopenshell/util/doc.py b/src/ifcopenshell-python/ifcopenshell/util/doc.py
index b0443f6117..be780c0bd8 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/doc.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/doc.py
@@ -265,6 +265,33 @@ class DocExtractor:
         description = description.strip()
         return description
 
+    def extract_full_description(self, html: str) -> str:
+        """Extract the full definition text from markdown-derived HTML.
+
+        Entity/type documentation often introduces a bulleted list mid-definition
+        (e.g. "... may include:" followed by a `<ul>`), or continues with another
+        paragraph after it. Naively taking only the first `<p>` silently drops
+        that content (see #4624). Instead, walk all top-level paragraph/list
+        elements in document order, stopping before any `<blockquote>` (which in
+        these docs holds the HISTORY/NOTE remarks).
+        """
+        soup = BeautifulSoup(html, features="lxml")
+        body = soup.body or soup
+        parts = []
+        for child in body.find_all(["p", "ul", "ol"], recursive=False):
+            if child.name in ("ul", "ol"):
+                items = [li.get_text() for li in child.find_all("li", recursive=False)]
+                parts.append(" ".join(f"- {item}" for item in items))
+            else:
+                parts.append(child.get_text())
+        text = " ".join(parts)
+        # strip inline kramdown/pandoc attribute-list markers that survive as literal
+        # text once we're no longer limited to the first paragraph, e.g.
+        # "{ .change-ifc2x4}", "{ .note}", "{: .extDef}".
+        text = re.sub(r"\{[^{}]*\}", "", text)
+        text = re.sub(r"\s+", " ", text).strip()
+        return text
+
     def extract_ifc2x3(self):
         print("Parsing data for Ifc2.3.0.1")
         if not IFC2x3_DOCS_LOCATION.is_dir():
@@ -337,7 +364,7 @@ class DocExtractor:
                 with open(md_path, "r", encoding="utf-8-sig") as fi:
                     # convert markdown to html for easier parsing
                     html = markdown(fi.read())
-                    entity_description = BeautifulSoup(html, features="lxml").find("p").text
+                    entity_description = self.extract_full_description(html)
                     entity_description = entity_description.replace("\n", " ")
                     entity_description = entity_description.replace("\u00a0", " ")
 
@@ -550,7 +577,7 @@ class DocExtractor:
                 with open(md_path, "r", encoding="utf-8-sig") as fi:
                     # convert markdown to html for easier parsing
                     html = markdown(fi.read())
-                    type_description = BeautifulSoup(html, features="lxml").find("p").text
+                    type_description = self.extract_full_description(html)
                     type_description = type_description.replace("\n", " ")
                     type_description = type_description.replace("\u00a0", " ")
                     type_description = type_description.replace("Definition from ISO/CD 10303-46:1992: ", "")
@@ -662,7 +689,7 @@ class DocExtractor:
                 with open(md_path, "r", encoding="utf-8-sig") as fi:
                     # convert markdown to html for easier parsing
                     html = markdown(fi.read())
-                    entity_description = BeautifulSoup(html, features="lxml").find("p").text
+                    entity_description = self.extract_full_description(html)
                     entity_description = entity_description.replace("\n", " ")
                     entity_description = entity_description.replace("\u00a0", " ")
                     entity_description = entity_description.replace("{ .extDef}", "")
@@ -888,7 +915,7 @@ class DocExtractor:
                 with open(md_path, "r", encoding="utf-8-sig") as fi:
                     # convert markdown to html for easier parsing
                     html = markdown(fi.read().replace("{ .extDef}", ""))
-                    type_description = BeautifulSoup(html, features="lxml").find("p").text
+                    type_description = self.extract_full_description(html)
                     type_description = type_description.replace("\n", " ")
                     type_description = type_description.replace("\u00a0", " ")
                     type_description = type_description.replace("{ .extDef}", "")
diff --git a/src/ifcopenshell-python/ifcopenshell/util/schema/ifc2x3_entities.json b/src/ifcopenshell-python/ifcopenshell/util/schema/ifc2x3_entities.json
index 3d3bb81afb..f9b3740ce8 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/schema/ifc2x3_entities.json
+++ b/src/ifcopenshell-python/ifcopenshell/util/schema/ifc2x3_entities.json
@@ -7,7 +7,7 @@
         "attributes": {
             "RequestID": "A unique identifier assigned to the request on receipt."
         },
-        "description": "An IfcActionRequest is a request for an action to fulfill a need.",
+        "description": "An IfcActionRequest is a request for an action to fulfill a need. *Use Definitions* Requests may take many forms depending on the need including fault reports for maintenance, requests for small works, purchase requests (where these are to be made through a help desk or buying function) etc. A request may call for several actions and an action may refer to several requests. IfcRelAssignsToControl is used to relate one or more requests to an action. *Property Set Use Definition*: The property sets relating to an IfcActionRequest_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcActionRequest are part of this IFC release: - Pset_ActionRequest: property set for the properties of a request for a facilities management action, if available",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcactionrequest.htm"
     },
     "IfcActor": {
@@ -15,7 +15,7 @@
             "IsActingUpon": "Reference to the relationship that associates the actor to an object.",
             "TheActor": "Information about the actor."
         },
-        "description": "The IfcActor defines all actors or human agents involved in a project during its full life cycle. It facilitates the use of person and organization definitions in the resource part of the IFC object model.",
+        "description": "The IfcActor defines all actors or human agents involved in a project during its full life cycle. It facilitates the use of person and organization definitions in the resource part of the IFC object model. *Property Set Use Definition*: The property sets relating to the IfcActor are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcActor are part of this IFC release: - Pset_ActorCommon: common property set for all actor occurrences",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcactor.htm"
     },
     "IfcActorRole": {
@@ -28,7 +28,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcactorrole.htm"
     },
     "IfcActuatorType": {
-        "description": "An IfcActuatorType defines a particular type of actuating device that is typically used in a control system such as a building automation control system.",
+        "description": "An IfcActuatorType defines a particular type of actuating device that is typically used in a control system such as a building automation control system. *Use Definitions* An IfcActuatorType provides for all forms of actuator. Usage of IfcActuatorType defines the parameters for one or more occurrences of IfcDistributionControlElement. Parameters may be specified through property sets that are enumerated in the IfcActuatorTypeEnum data type. *Property Set Use Definition*: The property sets relating to the IfcActuatorType defined by the IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcActuatorType are part of this IFC release: - Pset_ActuatorTypeCommon: property set for the properties common to all types of actuator, if available - Pset_ActuatorTypeLinearActuation: specific property set for the properties of a linear actuator, if available - Pset_ActuatorTypeRotationalActuation: specific property set for the properties of a rotational actuator, if available - Pset_ActuatorTypeElectricActuator: specific property set for the properties of an electrical actuator, if available - Pset_ActuatorTypeHydraulicActuator: specific property set for the properties of an hydraulic actuator, if available - Pset_ActuatorTypePneumaticActuator: specific property set for the properties of a pneumatic actuator, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "ELECTRICACTUATOR": "A device that electrically actuates a control element.",
             "HANDOPERATEDACTUATOR": "A device that manually actuates a control element.",
@@ -52,7 +52,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcaddress.htm"
     },
     "IfcAirTerminalBoxType": {
-        "description": "The element type IfcAirTerminalBoxType defines a list of commonly shared property set definitions of an air termainal box and an optional set of product representations. It is used to define an air terminal box specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcAirTerminalBoxType defines a list of commonly shared property set definitions of an air termainal box and an optional set of product representations. It is used to define an air terminal box specification (i.e. the specific product information, that is common to all occurrences of that product type). An air terminal box type is used to define the common properties of an air terminal box that may be applied to many occurrences of that type. An air terminal box typically participates in an HVAC duct distribution system and is used to control or modulate the amount of air delivered to its downstream ductwork. Air terminal box types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcAirTerminalBoxType are represented by instances of IfcFlowController or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_AirTerminalBoxTypeCommon: common property set for all air terminal box types",
         "predefined_types": {
             "CONSTANTFLOW": "Terminal box does not include a means to reset the volume automatically to an outside signal such as thermostat.",
             "NOTDEFINED": "Undefined terminal box.",
@@ -63,7 +63,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcairterminalboxtype.htm"
     },
     "IfcAirTerminalType": {
-        "description": "The element type IfcAirTerminalType defines a list of commonly shared property set definitions of an air terminal and an optional set of product representations. It is used to define an air terminal specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcAirTerminalType defines a list of commonly shared property set definitions of an air terminal and an optional set of product representations. It is used to define an air terminal specification (i.e. the specific product information, that is common to all occurrences of that product type). A air terminal type is used to define the common properties of a air terminal that may be applied to many occurrences of that type. An air terminal is a mechanical device used to control the characteristics air at the entrance or exit to an open system, such as a room or space. Air terminal types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcAirTerminalType are represented by instances of IfcFlowTerminal or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_AirTerminalTypeCommon: common property set for all air terminal types Pset_AirTerminalTypeRectangular: property set for rectangular shaped air terminal types Pset_AirTerminalTypeRound: property set for round shaped air terminal types Pset_AirTerminalTypeSlot: property set for slot air terminal types Pset_AirTerminalTypeSquare: property set for square shaped air terminal types",
         "predefined_types": {
             "DIFFUSER": "An outlet discharging supply air in various directions and planes.",
             "EYEBALL": "",
@@ -78,7 +78,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcairterminaltype.htm"
     },
     "IfcAirToAirHeatRecoveryType": {
-        "description": "The element type IfcAirToAirHeatRecoveryType defines a list of commonly shared property set definitions of an air-to-air heat recovery device and an optional set of product representations. It is used to define an air-to-air heat recovery device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcAirToAirHeatRecoveryType defines a list of commonly shared property set definitions of an air-to-air heat recovery device and an optional set of product representations. It is used to define an air-to-air heat recovery device specification (i.e. the specific product information, that is common to all occurrences of that product type). An air-to-air heat recovery type is used to define the common properties of an air-to-air heat recovery device that may be applied to many occurrences of that type. An air-to-air heat recovery device is typically used to transfer heat from warmer air in one chamber to cooler air in the second chamber (i.e., typically used to recover heat from the conditioned air being exhausted and the outside air being supplied to a building). Air-to-air heat recovery types may be exchanged without being already assigned to occurrences. The occurrences of the IfcAirToAirHeatRecoveryType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_AirToAirHeatRecoveryTypeCommon: common property set for all air-to-air heat recovery types",
         "predefined_types": {
             "FIXEDPLATECOUNTERFLOWEXCHANGER": "Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with primary air entering at secondary air outlet location and exiting at secondary air inlet location.",
             "FIXEDPLATECROSSFLOWEXCHANGER": "Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with secondary air flow in the direction perpendicular to primary air flow.",
@@ -95,7 +95,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcairtoairheatrecoverytype.htm"
     },
     "IfcAlarmType": {
-        "description": "The IfcAlarmType defines a device that signals the existence of a condition or situation that is outside the boundaries of normal expectation or that activates such a device.",
+        "description": "The IfcAlarmType defines a device that signals the existence of a condition or situation that is outside the boundaries of normal expectation or that activates such a device. *Use Definitions* An IfcAlarmType may be included into the spatial context of the building model through an (or multiple) instances of IfcDistributionControlElement. Usage of IfcAlarmType defines the parameters for one or more occurrences of IfcDistributionControlElement. Alarm types include the provision of break glass buttons and manual pull boxes that are used to activate alarms. These should be used for alarms rather than a 'user defined' type of IfcSwitchingDevice. *Property Set Use Definition*: There are no predefined property sets for IfcAlarmType in this release *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "BELL": "An audible alarm.",
             "BREAKGLASSBUTTON": "An alarm activation mechanism in which a protective glass has to be broken to enable a button to be pressed.",
@@ -109,18 +109,18 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcalarmtype.htm"
     },
     "IfcAngularDimension": {
-        "description": "The angular dimension is a draughting callout that presents the plane angle measure between two non parallel orientations. It consists of a dimension curve and may have projection curves.",
+        "description": "The angular dimension is a draughting callout that presents the plane angle measure between two non parallel orientations. It consists of a dimension curve and may have projection curves. Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcangulardimension.htm"
     },
     "IfcAnnotation": {
         "attributes": {
             "ContainedInStructure": "Relationship to a spatial structure element, to which the associate is primarily associated."
         },
-        "description": "An annotation is a graphical representation within the geometric (and spatial) context of a project, that adds a note or meaning to the objects which constitutes the project model. Annotations include additional line drawings, text, dimensioning, hatching and other forms of graphical notes.",
+        "description": "An annotation is a graphical representation within the geometric (and spatial) context of a project, that adds a note or meaning to the objects which constitutes the project model. Annotations include additional line drawings, text, dimensioning, hatching and other forms of graphical notes. If available, the annotation should be related to the spatial context of the project, by containing the annotation within the appropriate level of the building structure (site, building, storey, or space). This is handled by the IfcRelContainedInSpatialStructure relationship. *Geometry Use Definitions* The geometric representation of any IfcAnnotation is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. Local Placement The local placement for any IfcAnnotation is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representations The standard representation of IfcAnnotation is defined using 'GeometricCurveSet' or, when including surfaces, the 'GeometricSet' geometry. Styled items adding the style information assigned to the geometric representation items are grouped together with the geometric representation items within the set of Items at IfcShapeRepresentation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcannotation.htm"
     },
     "IfcAnnotationCurveOccurrence": {
-        "description": "Definition from ISO/CD 10303-46:1992: An annotation curve occurrence is a curve with a style assignment.",
+        "description": "Definition from ISO/CD 10303-46:1992: An annotation curve occurrence is a curve with a style assignment. The IfcAnnotationCurveOccurrence shall only be used within a material or paper space dependent representation (note: paper space is not yet supported within this IFC release). Styled curves within model space shall use IfcStyledItem as the instance to link the geometric curve representation item to the (shared) style information. An IfcAnnotationCurveOccurrence is a relation object, that assigns a (set of) styles to a representation item. It can be used without having a geometric representation item already assigned, e.g. within an IfcMaterialDefinitionRepresentation. If it has a geometric representation item already assigned than this is further restricted to be a subtype of IfcCurve. The applicable style information is restricted to be an IfcCurveStyle. For each instance of a styled curve, one instance of IfcAnnotationCurveOccurrence has to be created, that points, via an IfcPresentationStyleAssignment, to an IfcCurveStyle, that can be shared by many styled curves.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationcurveoccurrence.htm"
     },
     "IfcAnnotationFillArea": {
@@ -128,7 +128,7 @@
             "InnerBoundaries": "A set of inner curves that define the inner boundaries of the fill area. The areas defined by the inner boundaries are excluded from applying the fill area style.",
             "OuterBoundary": "A closed curve that defines the outer boundary of the fill area. The areas defined by the outer boundary (minus potentially defined inner boundaries) is filled by the fill area style."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: An annotation fill area is a set of curves that may be filled with hatching, colour or tiling. The annotation fill are is described by boundaries which consist of non-intersecting, non-self-intersecting closed curves. These curves form the boundary of planar areas to be filled according to the style for the annotation fill area.",
+        "description": "Definition from ISO/CD 10303-46:1992: An annotation fill area is a set of curves that may be filled with hatching, colour or tiling. The annotation fill are is described by boundaries which consist of non-intersecting, non-self-intersecting closed curves. These curves form the boundary of planar areas to be filled according to the style for the annotation fill area. Illustration from ISO 10303-46 The IfcAnnotationFillArea defines an area by a definite OuterBoundary, that might include InnerBoundaries. The areas defined by the InnerBoundaries are excluded from applying the fill area style. Informal Proposition: - Any curve that describes an inner boundary shall not intersect with, nor include, another curve defining an inner boundary. - The curve defining the outer boundary shall not intersect with any curve defining an inner boundary, nor shall it be surrounded by a curve defining an inner boundary.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationfillarea.htm"
     },
     "IfcAnnotationFillAreaOccurrence": {
@@ -140,7 +140,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationfillareaoccurrence.htm"
     },
     "IfcAnnotationOccurrence": {
-        "description": "Definition from ISO/CD 10303-46:1992: The annotation occurrence entity is a geometric representation item which has style for presentation. This entity shall be used for annotation purposes only.",
+        "description": "Definition from ISO/CD 10303-46:1992: The annotation occurrence entity is a geometric representation item which has style for presentation. This entity shall be used for annotation purposes only. The IfcAnnotationOccurrence, and its subtypes, shall only be used within a material or paper space dependent representation (note: paper space is not yet supported within this IFC release). Styled geometric representation items within model space shall use IfcStyledItem as the instance to link geometric representation items to style information.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationoccurrence.htm"
     },
     "IfcAnnotationSurface": {
@@ -148,15 +148,15 @@
             "Item": "Geometric representation item, providing the geometric definition of the annotated surface. It is further restricted to be a surface, surface model, or solid model.",
             "TextureCoordinates": "Texture coordinates, such as a texture map, that are associated with the textures for the surface style. It should only be given, if the _IfcSurfaceStyle_ associated to the _IfcAnnotationSurfaceOccurrence_ contains an _IfcSurfaceStyleWithTextures_."
         },
-        "description": "Definition from IAI: An IfcAnnotationSurface is a surface or solid with texture coordinates assigned. It provides the capabilities to assign",
+        "description": "Definition from IAI: An IfcAnnotationSurface is a surface or solid with texture coordinates assigned. It provides the capabilities to assign - surface shading information, - surface rendering information - surface lighting information - surface textures to a surface, or all surfaces of a face based surface model, a shell based surface model, or a solid model. If the assigned IfcSurfaceStyle defines textures by including an instance of IfcSurfaceStyleWithTextures, the attribute TextureCoordinates determines the mapping of the texture to the surface(s) of the Item. In case of vertex based geometry, texture maps may be used to define the texture coordinates for each face. The style information is linked by using the IfcStyledItem to the IfcAnnotationSurface instance.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationsurface.htm"
     },
     "IfcAnnotationSurfaceOccurrence": {
-        "description": "Definition from IAI: The IfcAnnotationSurfaceOccurrence shall only be used within a material or paper space dependent representation (note: paper space is not yet supported within this IFC release). Styled surfaces or solids within model space shall use IfcStyledItem as the instance to link the geometric surface, solid or annotation surface (for texture maps) representation item to the (shared) style information.",
+        "description": "Definition from IAI: The IfcAnnotationSurfaceOccurrence shall only be used within a material or paper space dependent representation (note: paper space is not yet supported within this IFC release). Styled surfaces or solids within model space shall use IfcStyledItem as the instance to link the geometric surface, solid or annotation surface (for texture maps) representation item to the (shared) style information. An IfcAnnotationSurfaceOccurrence is a relation object, that assigns a (set of) styles to a representation item. It can be used without having a geometric representation item already assigned, e.g. within an IfcMaterialDefinitionRepresentation. Each instance of IfcAnnotationSurfaceOccurrence points, via an IfcPresentationStyleAssignment, to an IfcSurfaceStyle, that can be shared by many styled surfaces, or solids.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationsurfaceoccurrence.htm"
     },
     "IfcAnnotationSymbolOccurrence": {
-        "description": "Definition from ISO/CD 10303-46:1992: An annotation symbol occurrence is a symbol with a style assignment.",
+        "description": "Definition from ISO/CD 10303-46:1992: An annotation symbol occurrence is a symbol with a style assignment. The IfcAnnotationSymbolOccurrence_shall only be used within a material or paper space dependent representation (note: paper space is not yet supported within this IFC release). Styled symbols within model space shall use _IfcStyledItem as the instance to link the geometric symbol representation item to the (shared) style information. An IfcAnnotationSymbolOccurrence_is a relation object, that assigns a (set of) styles to a representation item. It can be used without having a geometric representation item already assigned, e.g. within an _IfcMaterialDefinitionRepresentation. If it has a geometric representation item already assigned than this is further restricted to be a subtype of IfcDefinedSymbol. The applicable style information is restricted to be an IfcSymbolStyle. For each instance of a styled symbol, one instance of IfcAnnotationSymbolOccurrence has to be created, that points, via an IfcPresentationStyleAssignment, to an IfcSymbolStyle, that can be shared by many styled symbols.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationsymboloccurrence.htm"
     },
     "IfcAnnotationTextOccurrence": {
@@ -185,7 +185,7 @@
             "ValueOfComponents": "The total (or subtotal) value of the components within the applied value relationship expressed as a single applied value.",
             "ValuesReferenced": "Pointer to the IfcReferencesCostDocument relationship, which refer to a document from which the cost value is referenced."
         },
-        "description": "An IfcAppliedValue is an abstract supertype that specifies the common attributes for cost and environmental values that may be applied to objects within the IFC model.",
+        "description": "An IfcAppliedValue is an abstract supertype that specifies the common attributes for cost and environmental values that may be applied to objects within the IFC model. Use Definitions The extent of the IfcAppliedValue is determined by the AppliedValue attribute which may be defined either as an IfcMeasureWithUnit or as an IfcMonetaryMeasure or as an IfcRatioMeasure via the IfcAppliedValueSelect type. Optionally, an IfcAppliedValue may have an applicable date. This is intended to fix the date on which the value became relevant for use. It may be the date on which the value was set in the model or it may be a prior or future date when the value becomes operable. It should be noted that the datatype for IfcAppliedValue.ApplicableDate is IfcDateTimeSelect. This enables either a calendar date or a date and time to be selected. The option of selecting a time only without a date is also possible through this select mechanism but should not be used in the case of an applied value. Similarly, an IfcAppliedValue may have a 'fixed until' date. This is intended to fix the date on which the value ceases to be relevant for use. An instance of IfcAppliedValue may have a unit basis asserted. This is defined as an IfcMeasureWithUnit that determines the extent of the unit value for application purposes. It is assumed that when this attribute is asserted, then the value given to IfcAppliedValue is that for unit quantity. This is not enforced within the IFC schema and thus needs to be controlled within an application.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcappliedvalue.htm"
     },
     "IfcAppliedValueRelationship": {
@@ -196,7 +196,7 @@
             "Description": "A description that may apply additional information about an applied value relationship.",
             "Name": "A name used to identify or qualify the applied value relationship."
         },
-        "description": "An IfcAppliedValueRelationship is a relationship class that enables applied values of cost or environmental impact to be aggregated together as components of another applied value.",
+        "description": "An IfcAppliedValueRelationship is a relationship class that enables applied values of cost or environmental impact to be aggregated together as components of another applied value. Use Definitions Dependency relationships can exist between applied values on the basis that one particular value may be determined by operations on one or more other values. This is captured through the IfcAppliedValueRelationship entity. In this relationship, one instance of IfcAppliedValue acts as the principal (IfcAppliedValueRelationship.ComponentOf) whose value may be determined from the instances of IfcAppliedValue that are defined as its components (IfcAppliedValueRelationship.Components) An IfcAppliedValueRelationship has an ArithmeticOperator attribute that specifies the form of arithmetical operation implied by the relationship. A practical consideration when using the applied value relationship is that when the arithmetic operator is ADD, then the type of the IfcAppliedValue.AppliedValue attribute will be IfcMeasureWithUnit or IfcMonetaryMeasure while if the arithmetic operator is MULTIPLY, then the type of the IfcAppliedValue.AppliedValue attribute for one instance of IfcAppliedValue will be IfcMeasureWithUnit or IfcMonetaryMeasure while for other instances it will be IfcRatioMeasure. Example A relationship exists between applied value A and applied values B, C and D such that the value of A is determined by the addition of B, C and D such that: A = B + C + D It is possible to develop more complex applied value specifications by creating hierarchies of applied value relationships. In the diagram below, the development of a applied value is shown whereby, because B = E * F and D = G * H * J, then: A = ((E * F) + C + (G * H * J))",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcappliedvaluerelationship.htm"
     },
     "IfcApproval": {
@@ -246,21 +246,21 @@
         "attributes": {
             "OuterCurve": "Bounded curve, defining the outer boundaries of the arbitrary profile."
         },
-        "description": "Definition from IAI: The closed profile IfcArbitraryClosedProfileDef defines an arbitrary two-dimensional profile for the use within the swept surface geometry, the swept area solid or a sectioned spine. It is given by an outer boundary from which the surface or solid can be constructed.",
+        "description": "Definition from IAI: The closed profile IfcArbitraryClosedProfileDef defines an arbitrary two-dimensional profile for the use within the swept surface geometry, the swept area solid or a sectioned spine. It is given by an outer boundary from which the surface or solid can be constructed. Informal proposition: - The OuterCurve has to be a closed curve. - The OuterCurve shall not intersect. Illustration: Table: Definition of arbitrary closed profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcarbitraryclosedprofiledef.htm"
     },
     "IfcArbitraryOpenProfileDef": {
         "attributes": {
             "Curve": "Open bounded curve defining the profile."
         },
-        "description": "Definition from IAI: The open profile IfcArbitraryOpenProfileDef defines an arbitrary two-dimensional open profile for the use within the swept surface geometry. It is given by an open boundary from with the surface can be constructed.",
+        "description": "Definition from IAI: The open profile IfcArbitraryOpenProfileDef defines an arbitrary two-dimensional open profile for the use within the swept surface geometry. It is given by an open boundary from with the surface can be constructed. Informal proposition: - The Curve has to be an open curve. Illustration: Table: Definition of arbitrary open profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcarbitraryopenprofiledef.htm"
     },
     "IfcArbitraryProfileDefWithVoids": {
         "attributes": {
             "InnerCurves": "Set of bounded curves, defining the inner boundaries of the arbitrary profile."
         },
-        "description": "Definition from IAI: The IfcArbitraryProfileDefWithVoids defines an arbitrary closed two-dimensional profile with holes defined for the use for the swept area solid or a sectioned spine. It is given by an outer boundary and inner boundaries from with the solid the can be constructed.",
+        "description": "Definition from IAI: The IfcArbitraryProfileDefWithVoids defines an arbitrary closed two-dimensional profile with holes defined for the use for the swept area solid or a sectioned spine. It is given by an outer boundary and inner boundaries from with the solid the can be constructed. Informal propositions: - The outer curve and all inner curves shall be closed curves. - The outer curve shall enclose all inner curves. - No inner curve shall intersect with the outer curve or any other inner curve. - No inner curve may enclose another inner curve. Illustration: Table: Definition of arbitrary closed profile definition with voids",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcarbitraryprofiledefwithvoids.htm"
     },
     "IfcAsset": {
@@ -275,7 +275,7 @@
             "TotalReplacementCost": "The total cost of replacement of the asset.",
             "User": "The name of the person or organization that 'uses' the asset."
         },
-        "description": "An IfcAsset is a uniquely identifiable grouping of elements acting as a single entity that has a financial value",
+        "description": "An IfcAsset is a uniquely identifiable grouping of elements acting as a single entity that has a financial value *Use Definitions* An asset is generally the level of granularity at which maintenance operations are undertaken. An asset is a group that can contain one or more elements. While the value of a component or element can be defined, value is also defined for accounting purposes at the level of the asset. There are a number of actors that can be associated with an asset, each actor having a role. Principal actors are identified as attributes of the class. Additional actors can be specified through the relationship class IfcRelAssignsToActor in which case roles should be defined through the IfcActorRole class which must be asserted for each defined role. There are a number of costs that can be associated with an asset, each cost having a role. Principal costs are identified as attributes of the class. Additional costs can be specified through the relationship class IfcRelAssociatesCost in which case roles must be asserted. Service life data (expected life etc.) can be assigned for one or more assets as IfcServiceLife through the relationship class IfcRelAssignsToControl. The operating function of an asset within an organization may be particularly valuable in situations where one organization provides and maintains core services and another organization adds and maintains terminal services. It can classify who owns and is responsible for the asset. Operating function can be designated through the use of one or more classification notations which will be handled through the relationship class IfcRelAssociatesClassification. *Property Set Use Definition*: The property sets relating to an IfcAsset_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcAsset are part of this IFC release: - Pset_Asset: specific property set for the properties of an asset, if available - Pset_Reliability: specific property set for the properties defining risk that may be associated with an asset or any occurrence of a subtype of IfcProduct, if available - Pset_Risk: specific property set for the properties defining risk that may be associated with an asset or any occurrence of a subtype of IfcObject, if available - Pset_Warranty: specific property set for the properties relating to a warranty or guarantee that may be associated with an asset, any occurrence of IfcProduct or any occurrence of IfcSystem, if available *Geometry Use Definitions* The geometric representation of an IfcAsset is determined by the geometric representations of the products that comprise the asset (since an asset is a subtype of IfcGroup)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcasset.htm"
     },
     "IfcAsymmetricIShapeProfileDef": {
@@ -285,7 +285,7 @@
             "TopFlangeThickness": "Flange thickness of the top flange of the I-shape. If given, the upper and the lower flanges can have different thicknesses. If not given, the value of the inherited FlangeThickness attribute applies to both, the top and bottom flange thickness.",
             "TopFlangeWidth": "Extent of the top flange, defined parallel to the x axis of the position coordinate system."
         },
-        "description": "Definition from IAI: The IfcAsymmetricIShapeProfileDef defines a section profile that provides the defining parameters of an asymmetric I-shaped section to be used by the swept area solid. The bottom flange is always wider than the top flange. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the gravity bounding box.",
+        "description": "Definition from IAI: The IfcAsymmetricIShapeProfileDef defines a section profile that provides the defining parameters of an asymmetric I-shaped section to be used by the swept area solid. The bottom flange is always wider than the top flange. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the gravity bounding box. The centre of gravity, if given, is located in x direction within the center of the bounding box, and in y-direction along the negative y axis, the offset value is given by the offset parameter CentreOfGravityInY. Illustration: Table: Parameters of asymmetric I-shaped section definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcasymmetricishapeprofiledef.htm"
     },
     "IfcAxis1Placement": {
@@ -293,7 +293,7 @@
             "Axis": "The direction of the local Z axis.",
             "Z": "The normalized direction of the local Z axis. It is either identical with the Axis value, if given, or it defaults to [0.,0.,1.] NVL (IfcNormalise(Axis), IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcDirection([0.0,0.0,1.0]))"
         },
-        "description": "Definition from ISO/CD 10303-42:1992: The direction and location in three dimensional space of a single axis. An axis1_placement is defined in terms of a locating point (inherited from placement supertype) and an axis direction: this is either the direction of axis or defaults to (0.0,0.0,1.0). The actual direction for the axis placement is given by the derived attribute z (Z).",
+        "description": "Definition from ISO/CD 10303-42:1992: The direction and location in three dimensional space of a single axis. An axis1_placement is defined in terms of a locating point (inherited from placement supertype) and an axis direction: this is either the direction of axis or defaults to (0.0,0.0,1.0). The actual direction for the axis placement is given by the derived attribute z (Z). Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcaxis1placement.htm"
     },
     "IfcAxis2Placement2D": {
@@ -301,7 +301,7 @@
             "P": "P[1]: The normalized direction of the placement X Axis. This is (1.0,0.0,0.0) if RefDirection is omitted. P[2]: The normalized direction of the placement Y Axis. This is a derived attribute and is orthogonal to P[1]. IfcBuild2Axes(RefDirection)",
             "RefDirection": "The direction used to determine the direction of the local X Axis."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: The location and orientation in two dimensional space of two mutually perpendicular axes. An axis2_placement_2d is defined in terms of a point, (inherited from the placement supertype), and an axis. It can be used to locate and originate an object in two dimensional space and to define a placement coordinate system. The class includes a point which forms the origin of the placement coordinate system. A direction vector is required to complete the definition of the placement coordinate system. The reference direction defines the placement X axis direction, the placement Y axis is derived from this.",
+        "description": "Definition from ISO/CD 10303-42:1992: The location and orientation in two dimensional space of two mutually perpendicular axes. An axis2_placement_2d is defined in terms of a point, (inherited from the placement supertype), and an axis. It can be used to locate and originate an object in two dimensional space and to define a placement coordinate system. The class includes a point which forms the origin of the placement coordinate system. A direction vector is required to complete the definition of the placement coordinate system. The reference direction defines the placement X axis direction, the placement Y axis is derived from this. If the RefDirection attribute is not given, the placement defaults to P[1] (x-axis) as [1.,0.] and P[2] (y-axis) as [0.,1.]. Illustration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcaxis2placement2d.htm"
     },
     "IfcAxis2Placement3D": {
@@ -310,7 +310,7 @@
             "P": "The normalized directions of the placement X Axis (P[1]) and the placement Y Axis (P[2]) and the placement Z Axis (P[3]). IfcBuildAxes(Axis, RefDirection)",
             "RefDirection": "The direction used to determine the direction of the local X Axis. If necessary an adjustment is made to maintain orthogonality to the Axis direction. If Axis and/or RefDirection is omitted, these directions are taken from the geometric coordinate system."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: The location and orientation in three dimensional space of three mutually perpendicular axes. An axis2_placement_3D is defined in terms of a point (inherited from placement supertype) and two (ideally orthogonal) axes. It can be used to locate and originate an object in three dimensional space and to define a placement coordinate system. The entity includes a point which forms the origin of the placement coordinate system. Two direction vectors are required to complete the definition of the placement coordinate system. The axis is the placement Z axis direction and the ref_direction is an approximation to the placement X axis direction.",
+        "description": "Definition from ISO/CD 10303-42:1992: The location and orientation in three dimensional space of three mutually perpendicular axes. An axis2_placement_3D is defined in terms of a point (inherited from placement supertype) and two (ideally orthogonal) axes. It can be used to locate and originate an object in three dimensional space and to define a placement coordinate system. The entity includes a point which forms the origin of the placement coordinate system. Two direction vectors are required to complete the definition of the placement coordinate system. The axis is the placement Z axis direction and the ref_direction is an approximation to the placement X axis direction. If the attribute values for Axis and RefDirection are not given, the placement defaults to P[1] (x-axis) as [1.,0.,0.], P[2] (y-axis) as [0.,1.,0.] and P[3] (z-axis) as [0.,0.,1.]. Illustration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcaxis2placement3d.htm"
     },
     "IfcBSplineCurve": {
@@ -323,15 +323,15 @@
             "SelfIntersect": "Indication whether the curve self-intersects or not; it is for information only.",
             "UpperIndexOnControlPoints": "The upper index on the array of control points; the lower index is 0. This value is derived from the control points list. (SIZEOF(ControlPointsList) - 1)"
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A B-spline curve is a piecewise parametric polynomial or rational curve described in terms of control points and basis functions. The B-spline curve has been selected as the most stable format to represent all types of polynomial or rational parametric curves. With appropriate attribute values it is capable of representing single span or spline curves of explicit polynomial, rational, Bezier or B-spline type.",
+        "description": "Definition from ISO/CD 10303-42:1992: A B-spline curve is a piecewise parametric polynomial or rational curve described in terms of control points and basis functions. The B-spline curve has been selected as the most stable format to represent all types of polynomial or rational parametric curves. With appropriate attribute values it is capable of representing single span or spline curves of explicit polynomial, rational, Bezier or B-spline type. Interpretation of the data is as follows: - All weights shall be positive and the curve is given by k+1 = number of control points Pi = control points wi = weights d = degree The knot array is an array of (k+d+2) real numbers [u-d ... uk+1], such that for all indices j in [-d,k], uj <= uj+1. This array is obtained from the knot data list by repeating each multiple knot according to the multiplicity. N di, the ith normalized B-spline basis function of degree d, is defined on the subset [ui-d, ... , ui+1] of this array. - Let L denote the number of distinct values among the d+k+2 knots in the knot array; L will be referred to as the 'upper index on knots'. Let mj denote the multiplicity (i.e. number of repetitions) of the jth distinct knot. Then All knot multiplicities except the first and the last shall be in the range 1 ... degree; the first and last may have a maximum value of degree + 1. In evaluating the basis functions, a knot u of e.g. multiplicity 3 is interpreted as a string u, u, u, in the knot array. The B-spline curve has 3 special subtypes (IAI note: only 1, Bezier curve, included in this IFC release) where the knots and knot multiplicities are derived to provide simple default capabilities. - Logical flag is provided to indicate whether the curve self intersects or not. Illustration from ISO 10303-42:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcbsplinecurve.htm"
     },
     "IfcBeam": {
-        "description": "Definition from ISO 6707-1:1989: Structural member designed to carry loads between or beyond points of support, usually narrow in relation to its length and horizontal or nearly so.",
+        "description": "Definition from ISO 6707-1:1989: Structural member designed to carry loads between or beyond points of support, usually narrow in relation to its length and horizontal or nearly so. An IfcBeam is a horizontal, or nearly horizontal, structural member. It represents such a member from an architectural point of view. It is not required to be load bearing. *Type Use Definition* IfcBeam defines the occurrence of any beam, common information about beam types (or styles) is handled by IfcBeamType. The IfcBeamType (if present) may establish the common type name, usage (or predefined) type, common material layer set, common set of properties and common shape representations (using IfcRepresentationMap). The IfcBeamType is attached using the IfcRelDefinedByType.RelatingType objectified relationship and is accessible by the inverse IsDefinedBy attribute. If no IfcBeamType is attached (i.e. if only occurrence information is given) the predefined type may be given by using the ObjectType attribute. Recommended values are 'beam' (the default), 'brace', 'joist', 'rafter', 'stringer'. *Property Set Use Definition*: The property sets relating to the IfcBeam are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcBeam are part of this IFC release: - Pset_BeamCommon: common property set for all beam occurrences *Material Use Definition* The material of the IfcBeam is defined by the IfcMaterial or IfcMaterialList and attached by the IfcRelAssociatesMaterial.RelatingMaterial. It is accessible by the inverse HasAssociations relationship. Material information can also be given at the IfcBeamType, defining the common attribute data for all occurrences of the same type. It is then accessible by the inverse IsDefinedBy relationship pointing to_IfcBeamType.HasAssociations_ and via IfcRelAssociatesMaterial.RelatingMaterial to IfcMaterial or IfcMaterialList. If both are given, then the material directly assigned to IfcBeam overrides the material assigned to IfcBeamType. *Quantity Use Definition*: The quantities relating to the IfcBeam are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following quantities are foreseen, but will be subjected to the local standard of measurement used: *Containment Use Definition* The IfcBeam, as any subtype of IfcBuildingElement, may participate in two different containment relationships. The first (and in most implementation scenarios mandatory) relationship is the hierachical spatial containment, the second (optional) relationship is the aggregation within an element assembly. - The IfcBeam is places within the project spatial hierarchy using the objectified relationship IfcRelContainedInSpatialStructure, referring to it by its inverse attribute SELF\\IfcElement.ContainedInStructure. Subtypes of IfcSpatialStructureElement are valid spatial containers, with IfcBuildingStorey being the default container. - The IfcBeam_may be aggregated into an element assembly using the objectified relationship _IfcRelAggregates, referring to it by its inverse attribute SELF\\IfcObjectDefinition.Decomposes. Any subtype of IfcElement can be an element assembly, with IfcElementAssembly as a special focus subtype. In this case it should not be additionally contained in the project spatial hierarchy, i.e. SELF\\IfcElement.ContainedInStructure_should be _NIL. *Geometry Use Definitions*: The geometric representation of IfcBeam is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The local placement for IfcBeam is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representations Currently, the use of 'SweptSolid', 'Clipping' and 'MappedRepresentation' representations is supported. In addition the general representation types 'SurfaceModel', 'Brep', and 'BoundingBox' are allowed. The geometry use definition for 'BoundingBox', 'SurfaceModel' and 'Brep' is explained at IfcBuildingElement. SweptSolid Representation The standard geometric representation of IfcBeam is defined using the 'SweptSolid' representation. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'SweptSolid' The following additional constraints apply to the 'SweptSolid' representation: - Solid: IfcExtrudedAreaSolid shall be supported - Profile: IfcRectangleProfileDef, IfcCircleProfileDef, IfcEllipseProfileDef, and IfcArbitraryClosedProfileDef (including the subtype IfcArbitraryProfileDefWithVoids) shall be supported, in addition the support of basic steel profiles, such as IfcIShapeProfileDef, IfcLShapeProfileDef, IfcUShapeProfileDef, IfcCShapeProfileDef, IfcZShapeProfileDef, and IfcTShapeProfileDef can be agreed. - Extrusion: All extrusion directions shall be supported. Clipping Representation The advanced geometric representation of IfcBeam is defined using the 'Clipping' geometry. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'Clipping' The following constraints apply to the advanced representation: - Solid: see 'SweptSolid' geometric representation - Profile: see 'SweptSolid' geometric representation - Extrusion: see 'SweptSolid' geometric representation - Boolean result: The IfcBooleanClippingResult shall be supported, allowing for Boolean differences between the swept solid (here IfcExtrudedAreaSolid) and one or several IfcHalfSpaceSolid (or its subtypes). MappedRepresentation In addition to the standard and advanced geometric representation of IfcBeam that is defined using the SweptSolid or Clipping geometry, also the MappedRepresentation, shall be supported as it allows for reusing the geometry definition of the beam type at all occurrences of the same type. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'MappedRepresentation' The same constraints, as given for the 'SweptSolid' and 'Clipping' geometric representation, shall apply to the MappedRepresentation of the IfcRepresentationMap.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcbeam.htm"
     },
     "IfcBeamType": {
-        "description": "The element type (IfcBeamType) defines a list of commonly shared property set definitions of a beam and an optional set of product representations. It is used to define a beam specification (i.e. the specific product information that is common to all occurrences of that product type).",
+        "description": "The element type (IfcBeamType) defines a list of commonly shared property set definitions of a beam and an optional set of product representations. It is used to define a beam specification (i.e. the specific product information that is common to all occurrences of that product type). A beam type is used to define the common properties of a certain type of beam that may be applied to many instances of that type to assign a specific style. Beam types may be exchanged without being already assigned to occurrences. The occurrences of the IfcBeamType are represented by instances of IfcBeam.",
         "predefined_types": {
             "BEAM": "A standard beam usually used horizontally.",
             "JOIST": "A beam used to support a floor or ceiling.",
@@ -343,7 +343,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcbeamtype.htm"
     },
     "IfcBezierCurve": {
-        "description": "Definition from ISO/CD 10303-42:1992: This is a special type of curve which can be represented as a type of B-spline curve in which the knots are evenly spaced and have high multiplicities. Suitable default values for the knots and knot multiplicities are derived in this case.",
+        "description": "Definition from ISO/CD 10303-42:1992: This is a special type of curve which can be represented as a type of B-spline curve in which the knots are evenly spaced and have high multiplicities. Suitable default values for the knots and knot multiplicities are derived in this case. A B-spline curve is a piecewise Bezier curve if it is quasi-uniform except that the interior knots have multiplicity degree rather than having multiplicity one. In this subtype the knot spacing is 1.0, starting at 0.0. A piecewise Bezier curve which has only two knots, 0.0 and 1.0, each of multiplicity (degree+1), is a simple Bezier curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcbeziercurve.htm"
     },
     "IfcBlobTexture": {
@@ -351,7 +351,7 @@
             "RasterCode": "Blob, given as a single binary, to capture the texture within one popular file (compression) format.",
             "RasterFormat": "The format of the _RasterCode_ often using a compression."
         },
-        "description": "An IfcBlobTexture provides a 2-dimensional distribution of the lighting parameters of a surface onto which it is mapped. The texture itself is given as a single binary, representing the content of a pixel format. The file format of the pixel file is given by the RasterFormat attribute and allowable formats are guided by where rule WR41.",
+        "description": "An IfcBlobTexture provides a 2-dimensional distribution of the lighting parameters of a surface onto which it is mapped. The texture itself is given as a single binary, representing the content of a pixel format. The file format of the pixel file is given by the RasterFormat attribute and allowable formats are guided by where rule WR41. For interpretation of the texture nodes see IfcImageTexture definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcblobtexture.htm"
     },
     "IfcBlock": {
@@ -360,11 +360,11 @@
             "YLength": "The size of the block along the placement Y axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[2]_.",
             "ZLength": "The size of the block along the placement Z axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[3]_."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A block is a solid rectangular parallelepiped, defined with a location and placement coordinate system. The block is specified by the positive lengths x, y, and z along the axes of the placement coordinate system, and has one vertex at the origin of the placement coordinate system.",
+        "description": "Definition from ISO/CD 10303-42:1992: A block is a solid rectangular parallelepiped, defined with a location and placement coordinate system. The block is specified by the positive lengths x, y, and z along the axes of the placement coordinate system, and has one vertex at the origin of the placement coordinate system. The inherited Position attribute defines the IfcAxis2Placement3D and provides: - SELF\\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcCsgPrimitive3D.Position.Location: The block has one vertex at location and the edges are aligned with the placement axes in the positive sense.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcblock.htm"
     },
     "IfcBoilerType": {
-        "description": "The element type IfcBoilerType defines a list of commonly shared property set definitions of a boiler and an optional set of product representations. It is used to define a boiler specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcBoilerType defines a list of commonly shared property set definitions of a boiler and an optional set of product representations. It is used to define a boiler specification (i.e. the specific product information, that is common to all occurrences of that product type). A boiler type is used to define the common properties of a boiler that may be applied to many occurrences of that type. A boiler is a device which converts stored energy to heat which is added to a fluid; typically used to heat water. Boiler types may be exchanged without being already assigned to occurrences. The occurrences of the IfcBoilerType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_BoilerTypeCommon: common property set for all boiler types Pset_BoilerTypeSteam: property set for steam boiler types",
         "predefined_types": {
             "NOTDEFINED": "Undefined Boiler type.",
             "STEAM": "Steam boiler.",
@@ -374,7 +374,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcboilertype.htm"
     },
     "IfcBooleanClippingResult": {
-        "description": "A clipping result is defined as a special subtype of the general Boolean result (IfcBooleanResult). It constrains the operands and the operator of the Boolean result.",
+        "description": "A clipping result is defined as a special subtype of the general Boolean result (IfcBooleanResult). It constrains the operands and the operator of the Boolean result. A clipping result is the Boolean difference between a solid (restricted to swept area solid) and a half space solid, whereas more than one difference operation can be applied to the Boolean result.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcbooleanclippingresult.htm"
     },
     "IfcBooleanResult": {
@@ -384,7 +384,7 @@
             "Operator": "The Boolean operator used in the operation to create the result.",
             "SecondOperand": "The second operand specified for the operation."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A Boolean result is the result of a regularized operation on two solids to create a new solid. Valid operations are regularized union, regularized intersection, and regularized difference. For purpose of Boolean operations, a solid is considered to be a regularized set of points. The final Boolean result depends upon the operation and the two operands. In the case of the difference operator the order of the operands is also significant. The operator can be either union, intersection or difference. The effect of these operators is described below:",
+        "description": "Definition from ISO/CD 10303-42:1992: A Boolean result is the result of a regularized operation on two solids to create a new solid. Valid operations are regularized union, regularized intersection, and regularized difference. For purpose of Boolean operations, a solid is considered to be a regularized set of points. The final Boolean result depends upon the operation and the two operands. In the case of the difference operator the order of the operands is also significant. The operator can be either union, intersection or difference. The effect of these operators is described below: - Union on two solids is the new solid that is the regularization of the set of all points that are in either the first operand or the second operand or in both. - Intersection on two solids is the new solid that is the regularization of the set of all points that are in both the first operand and the second operand. - The result of the difference operation on two solids is the regularization of the set of all points which are in the first operand, but not in the second operand.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcbooleanresult.htm"
     },
     "IfcBoundaryCondition": {
@@ -412,7 +412,7 @@
             "LinearStiffnessByAreaY": "Linear stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.",
             "LinearStiffnessByAreaZ": "Linear stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object."
         },
-        "description": "Definition from IAI: The entity IfcBoundaryFaceCondition describes boundary conditions that can be applied to structural face connections, either directly for the connection (e.g. the connecting face) or for the relation between a structural member and the connection.",
+        "description": "Definition from IAI: The entity IfcBoundaryFaceCondition describes boundary conditions that can be applied to structural face connections, either directly for the connection (e.g. the connecting face) or for the relation between a structural member and the connection. The following conventions to the values of the LinearStiffnessByArea[X,Y,Z] apply: - value (-1.) represents an infinitive large value \u2013 or a fixed connectivity with infinitive stiffness - value zero (0.), represents no stiffness or a free connectivity - any other value represents a finitive stiffness or spring connectivity in that direction or rotation - value NIL ($) represents an unknown connectivity condition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcboundaryfacecondition.htm"
     },
     "IfcBoundaryNodeCondition": {
@@ -424,22 +424,22 @@
             "RotationalStiffnessY": "Rotational stiffness value about the y-axis of the coordinate system defined by the instance which uses this resource object.",
             "RotationalStiffnessZ": "Rotational stiffness value about the z-axis of the coordinate system defined by the instance which uses this resource object."
         },
-        "description": "Definition from IAI: The entity IfcBoundaryNodeCondition describes boundary conditions that can be applied to structural point connections, either directly for the connection (e.g. the joint) or for the relation between a structural member and the connection. ",
+        "description": "Definition from IAI: The entity IfcBoundaryNodeCondition describes boundary conditions that can be applied to structural point connections, either directly for the connection (e.g. the joint) or for the relation between a structural member and the connection. The following conventions to the values of the LinearStiffness[X,Y,Z] and RotationalStiffness[X,Y,Z] apply: - value (-1.) represents an infinitely large value \u2013 or a fixed connectivity with infinitive stiffness - value zero (0.), represents no stiffness or a free connectivity - any other value represents a finitive stiffness or spring connectivity in that direction or rotation - value NIL ($) represents an unknown connectivity condition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcboundarynodecondition.htm"
     },
     "IfcBoundaryNodeConditionWarping": {
         "attributes": {
             "WarpingStiffness": "Defines the warping stiffness value."
         },
-        "description": "IfcBoundaryNodeConditionWarping inherits all attributes from IfcBoundaryNodeCondition and includes additionally the possibility to define a value describing the warping stiffness.",
+        "description": "IfcBoundaryNodeConditionWarping inherits all attributes from IfcBoundaryNodeCondition and includes additionally the possibility to define a value describing the warping stiffness. If a warping stiffness value is needed, an instance of this entity must be used. Otherwise, an instance of IfcBoundaryNodeCondition is adequate.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcboundarynodeconditionwarping.htm"
     },
     "IfcBoundedCurve": {
-        "description": "Definition from ISO/CD 10303-42:1992: A bounded curve is a curve of finite arc length with identifiable end points.",
+        "description": "Definition from ISO/CD 10303-42:1992: A bounded curve is a curve of finite arc length with identifiable end points. Informal propositions: - A bounded curve has finite arc length. - A bounded curve has a start point and an end point.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcboundedcurve.htm"
     },
     "IfcBoundedSurface": {
-        "description": "Definition from ISO/CD 10303-42:1992: A bounded surface is a surface of finite area with identifiable boundaries.",
+        "description": "Definition from ISO/CD 10303-42:1992: A bounded surface is a surface of finite area with identifiable boundaries. Informal propositions: - A bounded surface has finite non-zero surface area. - A bounded surface has boundary curves.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcboundedsurface.htm"
     },
     "IfcBoundingBox": {
@@ -450,14 +450,14 @@
             "YDim": "Width attribute (measured along the edge parallel to the Y Axis)",
             "ZDim": "Height attribute (measured along the edge parallel to the Z Axis)."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A box domain is an orthogonal box parallel to the axes of the geometric coordinate system which may be used to limit the domain of a half space solid. A box domain is specified by the coordinates of the bottom left corner, and the lengths of the sides measured in the directions of the coordinate axes.",
+        "description": "Definition from ISO/CD 10303-42:1992: A box domain is an orthogonal box parallel to the axes of the geometric coordinate system which may be used to limit the domain of a half space solid. A box domain is specified by the coordinates of the bottom left corner, and the lengths of the sides measured in the directions of the coordinate axes. Every semantic object having a physical extent might have a minimum default representation of a bounding box. The bounding box is therefore also used as minimal geometric representation for any geometrically represented object. Therefore the IfcBoundingBox is subtyped from IfcGeometricRepresentationItem. Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcboundingbox.htm"
     },
     "IfcBoxedHalfSpace": {
         "attributes": {
             "Enclosure": "The box which bounds the half space for computational purposes only."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: This entity is a subtype of the half space solid which is trimmed by a surrounding rectangular box. The box has its edges parallel to the coordinate axes of the geometric coordinate system.",
+        "description": "Definition from ISO/CD 10303-42:1992: This entity is a subtype of the half space solid which is trimmed by a surrounding rectangular box. The box has its edges parallel to the coordinate axes of the geometric coordinate system. The IfcBoxedHalfSpace (from ISO 10303-42:1994 boxed_half_space) is used (as its supertype IfcHalfSpaceSolid) only within Boolean operations. It divides the domain into exactly two subsets, where the domain in question is that of the attribute Enclosure. Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcboxedhalfspace.htm"
     },
     "IfcBuilding": {
@@ -466,30 +466,30 @@
             "ElevationOfRefHeight": "Elevation above sea level of the reference height used for all storey elevation measures, equals to height 0.0. It is usually the ground floor level.",
             "ElevationOfTerrain": "Elevation above the minimal terrain level around the foot print of the building, given in elevation above sea level."
         },
-        "description": "Definition from ISO 6707-1:1989: Construction work that has the provision of shelter for its occupants or contents as one of its main purpose and is normally designed to stand permanently in one place.",
+        "description": "Definition from ISO 6707-1:1989: Construction work that has the provision of shelter for its occupants or contents as one of its main purpose and is normally designed to stand permanently in one place. A building represents a structure that provides shelter for its occupants or contents and stands in one place. The building is also used to provide a basic element within the spatial structure hierarchy for the components of a building project (together with site, storey, and space). A building is (if specified) associated to a site. A building may span over several connected or disconnected buildings. Therefore building complex provides for a collection of buildings included in a site. A building can also be decomposed in (vertical) parts, where each part defines a building section. This is defined by the composition type attribute of the supertype IfcSpatialStructureElements which is interpreted as follow: - COMPLEX = building complex - ELEMENT = building - PARTIAL = building section *Property Set Use Definition*: The property sets relating to the IfcBuilding are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcBuilding are part of this IFC release: - Pset_BuildingCommon: common property set for all types of buildings - Pset_BuildingWaterStorage: specific property set for buildings to capture the water supply requirements - Pset_BuildingUse: specific property set for buildings to capture the current and anticipated real estate context. - Pset_BuildingUseAdjacent: specific property set for buildings to capture the use information about the adjacent buildings. *Quantity Use Definition*: The quantities relating to the IfcBuilding are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. The following quantities are foreseen, but will be subjected to the local standard of measurement: *Spatial Structure Use Definition* The IfcBuilding is used to build the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). The spatial structure elements are linked together by using the objectified relationship IfcRelAggregates. The IfcBuilding references them by its inverse relationships: - IfcBuilding.Decomposes -- referencing (IfcSite || IfcBuilding) by IfcRelAggregates.RelatingObject, If it refers to another instance of IfcBuilding, the referenced IfcBuilding needs to have a different and higher CompositionType, i.e. COMPLEX (if the other IfcBuilding has ELEMENT), or ELEMENT (if the other IfcBuilding has PARTIAL). - IfcBuilding.IsDecomposedBy -- referencing (IfcBuilding || IfcBuildingStorey) by IfcRelAggregates.RelatedObjects. If it refers to another instance of IfcBuilding, the referenced IfcBuilding needs to have a different and lower CompositionType, i.e. ELEMENT (if the other IfcBuilding has COMPLEX), or PARTIAL (if the other IfcBuilding has ELEMENT). If there are building elements and/or other elements directly related to the IfcBuilding (like a curtain wall spanning several stories), they are associated with the IfcBuilding by using the objectified relationship IfcRelContainedInSpatialStructure. The IfcBuilding references them by its inverse relationship: * IfcBuilding.ContainsElements -- referencing any subtype of IfcProduct (with the exception of other spatial structure element) by IfcRelContainedInSpatialStructure.RelatedElements. *Attribute Use Definition*: *Geometry Use Definitions*: The geometric representation of IfcBuilding is given by the IfcProductDefinitionShape and IfcLocalPlacement, allowing multiple geometric representation. Local Placement The local placement for IfcBuilding is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if relative placement is used) to the IfcSpatialStructureElement of type IfcSite, or of type IfcBuilding (e.g. to position a building relative to a building complex, or a building section to a building). - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representations Currently, the use of a 2D 'FootPrint' representation of type 'GeometricCurveSet' and a 3D 'Body' representation of type 'Brep' is supported. Foot Print Representation The foot print representation of IfcBuilding is given by either a single 2D curve (such as IfcPolyline or IfcCompositeCurve), or by a list of 2D curves (in case of inner boundaries), if the building has an independent geometric representation. The representation identifier and type of this geometric representation of IfcBuilding is: - IfcShapeRepresentation.RepresentationIdentifier = 'FootPrint' - IfcShapeRepresentation.RepresentationType = 'GeometricCurveSet' Body Representation The body (or solid model) geometric representation (if the building has an independent geometric representation) of IfcBuilding is defined using faceted B-Rep capabilities (with or without voids), based on the IfcFacetedBrep or on the IfcFacetedBrepWithVoids. The representation identifier and type of this representation of IfcBuilding is: - IfcShapeRepresentation.RepresentationIdentifier = 'Body' - IfcShapeRepresentation.RepresentationType = 'Brep' Since the building shape is usually described by the exterior building elements, an independent shape representation shall only be given, if the building is exposed independently from its constituting elements.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuilding.htm"
     },
     "IfcBuildingElement": {
-        "description": "Definition from ISO 6707-1:1989: Major functional part of a building, examples are foundation, floor, roof, wall.",
+        "description": "Definition from ISO 6707-1:1989: Major functional part of a building, examples are foundation, floor, roof, wall. The building element comprises all elements that are primarily part of the construction of a building, i.e., its structural and space separating system. The IfcBuildingElement utilizes the following capabilities mainly through inverse attributes referencing objectified relationships: - Grouping - being part of a logical group of objects objectified relationship: IfcRelAssignsToGroup inverse attribute: HasAssignment - Work processes - reference to work tasks, in which this building element is used objectified relationship: IfcRelAssignsToProcess inverse attribute: HasAssignments - Aggregation - aggregated together with other elements to form an aggregate objectified relationship: IfcRelAggregates inverse attribute (for container): IsDecomposedBy inverse attribute (for contained parts): Decomposes - Material - assignment of material used by this building element objectified relationship: IfcRelAssociatesMaterial inverse attribute: HasAssociations - Classification - assigned reference to an external classification objectified relationship: IfcRelAssociatesClassification inverse attribute: HasAssociations - Documentation - assigned reference to an external documentation objectified relationship: IfcRelAssociatesDocumentation inverse attribute: HasAssociations - Type - reference to the common product type information for the element occurrence objectified relationship: IfcRelDefinesByType inverse attribute: IsDefinedBy - Properties - reference to all attached properties, including quantities objectified relationship: IfcRelDefinesByProperties inverse attribute: IsDefinedBy - Connection - connectivity to other elements, including the definition of the joint objectified relationship: IfcRelConnectsElements inverse attribute: ConnectedTo inverse attribute: ConnectedFrom - Realization - information, whether the building element is used to realize a connection (e.g. as a weld in a connection between two members) objectified relationship: IfcRelConnectsWithRealizingElements inverse attribute: IsConnectionRealization - Ports - information, whether the building element has ports for system connections (note: normally not used, this relationship is inherited from IfcElement and mainly applicable to IfcDistributionElement's) objectified relationship: IfcRelConnectsPortToElement inverse attribute: HasPorts - Assignment to spatial structure - hierarchical assignment to the right level within the spatial structure objectified relationship: IfcRelContainedInSpatialStructure inverse attribute: ContainedInStructure - Reference to spatial structure(s) - non hierarchical reference to one or more elements within the spatial structure (e.g. a curtain wall, being contained in the building, references several stories) objectified relationship: IfcRelContainedInSpatialStructure inverse attribute: ContainedInStructure - Boundary - provision of space boundaries by this building element objectified relationship: IfcRelSpaceBoundary inverse attribute: ProvidesBoundaries - Coverings - assignment of covering elements to this building element (note: normally covering elements are assigned to the space, only used for special cases) objectified relationship: IfcRelCoversBldgElements inverse attribute: HasCoverings - Voids - information, whether the building element includes openings, recesses or other voids objectified relationship: IfcRelVoidsElement inverse attribute: HasOpenings - Projection - information, whether the building element has projections (such as a fascia) objectified relationship: IfcRelProjectsElement inverse attribute: HasProjections - Filling - information whether the building element is used to fill openings objectified relationship: IfcRelFillsElement inverse attribute: FillsVoids - Structural member reference - information whether the building element is represented in a structural analysis model by a structural member objectified relationship: IfcRelConnectsStructuralElement inverse attribute: HasStructuralMember *Quantity Use Definition*: The quantities relating to the IfcBuildingElement are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. A detailed specification for individual quantities is introduced at the level of subtypes of IfcBuildingElement. *Geometry Use Definitions* The geometric representation of any IfcBuildingElement is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. Local Placement The local placement for any IfcBuildingElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. Further constraints are defined at the level of its subtypes. Geometric Representations Any IfcBuildingElement can be represented by one or several geometric representations. A detailed specification is introduced at the level of subtypes. Only the general representation types 'BoundingBox', 'SurfaceModel', 'Brep', and 'MappedRepresentation' are defined here. Bounding Box Representation Any IfcBuildingElement may be represented as a bounding box, which shows the maximum extend of the body within the coordinated system established by the IfcLocalPlacement. The bounding box representation is the simplest geometric representation available. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Box' ~~Body~~ - RepresentationType : 'BoundingBox' SurfaceModel Representation Any IfcBuildingElement (so far no further constraints are defined at the level of its subtypes) may be represented as a single or multiple surface models, based on either shell or face based models. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'SurfaceModel' In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. Brep Representation Any IfcBuildingElement (so far no further constraints are defined at the level of its subtypes) may be represented as a single or multiple Boundary Representation elements (which are restricted to faceted Brep with or without voids). The Brep representation allows for the representation of complex element shape. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'Brep' In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. MappedRepresentation Any IfcBuildingElement (so far no further constraints are defined at the level of its subtypes) may be represented using the MappedRepresentation. This shall be supported as it allows for reusing the geometry definition of a type at all occurrences of the same type. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'MappedRepresentation' The same constraints, as given for the 'SurfaceModel' and the 'Brep' geometric representation, shall apply to the MappedRepresentation of the IfcRepresentationMap.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingelement.htm"
     },
     "IfcBuildingElementComponent": {
-        "description": "A building element component represents items included in building elements, which usually are not of interest from the overall building structure viewpoint. Contrary to accessories these components form a significant part of the building elements they belong to and usually have a vital and load carrying function within the structure. Typical examples of _IfcBuildingElementComponent_s include different kinds of reinforcing elements, layers of sandwich wall panels, and plates as parts of structural members.",
+        "description": "A building element component represents items included in building elements, which usually are not of interest from the overall building structure viewpoint. Contrary to accessories these components form a significant part of the building elements they belong to and usually have a vital and load carrying function within the structure. Typical examples of _IfcBuildingElementComponent_s include different kinds of reinforcing elements, layers of sandwich wall panels, and plates as parts of structural members. Geometry Use Definitions: The geometric representation of IfcBuildingElementComponent is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The local placement for IfcBuildingElementComponent is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcBuildingElement or IfcElementAssembly, which is used in the Decomposes inverse attribute, i.e. the local placement is defined relative to the local placement of the building element or element assembly in which the component is contained. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. SurfaceModel Representation Any IfcBuildingElementComponent (if no further constraints are defined at the level of its subtypes) may be represented as a single or multiple surface models, based on either shell or face based models. It is ensured by assigning the value 'SurfaceModel' to the RepresentationType attribute of IfcShapeRepresentation. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. Brep Representation Any IfcBuildingElementComponent (if no further constraints are defined at the level of its subtypes) may be represented as a single or multiple Boundary Representation elements (which are restricted to faceted Brep with or without voids). The Brep representation allows for the representation of complex element shape. It is ensured by assigning the value 'Brep' to the RepresentationType attribute of IfcShapeRepresentation. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. MappedRepresentation The mapped item, IfcMappedItem, should be used if appropriate as it allows for reusing the geometry definition of the equipment type at occurrences of the same equipment type. In this case the IfcShapeRepresentation.RepresentationType = 'MappedRepresentation' is used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcbuildingelementcomponent.htm"
     },
     "IfcBuildingElementPart": {
-        "description": "Layers or major components as subordinate parts of a building element. Typical usage examples include precast concrete sandwich walls, where the layers may have different geometry representations. In this case the layered material representation does not sufficiently describe the element. Each layer is represented by an own instance of the IfcBuildingElementPart with its own geometry description.",
+        "description": "Layers or major components as subordinate parts of a building element. Typical usage examples include precast concrete sandwich walls, where the layers may have different geometry representations. In this case the layered material representation does not sufficiently describe the element. Each layer is represented by an own instance of the IfcBuildingElementPart with its own geometry description. General usage The exact type information of the IfcBuildingElementPart is given in the ObjectType attribute inherited from IfcObject. Standard type designations are provided for guideline below. Other object type values may be defined in local agreements. *Property Set Use Definition*: The property sets relating to the IfcBuildingElementPart are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcBuildingElementPart are part of this IFC release: - Pset_ConcreteElementSurfaceFinishQuantityGeneral: common property set for all IfcBuildingElementPart occurrences related to concrete construction. (Note: this is a general property set, which relates to many IFC classes, e.g. subtypes of IfcBuildingElement). - Pset_PrecastConcreteElementGeneral: common property set for all IfcBuildingElementPart occurrences related to precast concrete construction. (Note: this is a general property set, which relates to many IFC classes, e.g. subtypes of IfcBuildingElement). Geometry Use Definitions: The geometric representation of IfcBuildingElementPart is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcBuildingElementComponent. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcBuildingElementComponent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcbuildingelementpart.htm"
     },
     "IfcBuildingElementProxy": {
         "attributes": {
             "CompositionType": "Indication, whether the proxy is intended to form an aggregation (COMPLEX), an integral element (ELEMENT), or a part in an aggregation (PARTIAL)."
         },
-        "description": "The IfcBuildingElementProxy is a proxy definition that provides the same functionality as an IfcBuildingElement, but without having a defined meaning of the special type of building element, it represents.",
+        "description": "The IfcBuildingElementProxy is a proxy definition that provides the same functionality as an IfcBuildingElement, but without having a defined meaning of the special type of building element, it represents. *Type Use Definition* The IfcBuildingElementProxy defines the occurrence of any building element, common information about the types (or styles) is handled by IfcBuildingElementProxyType. The IfcBuildingElementProxyType (if present) may establish the common type name, usage (or predefined) type, common material, common set of properties and common shape representations (using IfcRepresentationMap). The IfcBuildingElementProxyType is attached using the IfcRelDefinedByType.RelatingType objectified relationship and is accessible by the inverse IsDefinedBy attribute. If no IfcBuildingElementProxyType is attached (i.e. if only occurrence information is given) the predefined type may be given by using the ObjectType attribute. *Property Set Use Definition*: The property sets relating to the IfcBuildingElementProxy are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcBuildingElementProxy/i> are part of this IFC release: - Pset_BuildingElementProxyCommon: common property set for all occurrences of building element proxies. *Geometry Use Definitions* The geometric representation of any IfcBuildingElementProxy is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. The representation types defined at the supertype IfcBuildingElement also apply. Local Placement The local placement for any IfcBuildingElementProxy is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. The local placement can be given relatively. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. *Geometric Representation* Currently, the use of the representation types 'BoundingBox', 'GeometricSet', 'GeometricCurveSet', 'SweptSolid', 'SurfaceModel', 'Brep', and 'MappedRepresentation' are allowed. The geometry use definitions for 'BoundingBox', 'SurfaceModel', 'Brep', and 'MappedRepresentation' are explained at the supertype IfcBuildingElement. GeometricCurveSet Representation Any building element proxy may be represented by a geometric curve set, given by a collection of 2D points and curves. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier: 'FootPrint' - RepresentationType: 'GeometricCurveSet' GeometricSet Representation Any building element proxy may be represented by a geometric set, given by a collection of 2D and 3D points, curves, and surfaces. It represents the body of the proxy object, when no topological structure is available. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier: 'Body' - RepresentationType: 'GeometricSet' Swept Solid Representation Any building element proxy may be represented by swept solid geometry (either by extrusion or by revolution). The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier: 'Body' - RepresentationType: 'SweptSolid' No further restrictions (e.g., for the profile or extrusion direction) are defined at this level. A single or multiple swept area solid(s) can be the Items of the IfcShapeRepresentation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingelementproxy.htm"
     },
     "IfcBuildingElementProxyType": {
-        "description": "The IfcBuildingElementProxyType defines a list of commonly shared property set definitions of a building element proxy and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The IfcBuildingElementProxyType defines a list of commonly shared property set definitions of a building element proxy and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A building element proxy type is used to define the common properties of a certain type of a building element proxy that may be applied to many instances of that type to assign a specific style. Building element proxy types may be exchanged without being already assigned to occurrences. The occurrences of the IfcBuildingElementProxyType are represented by instances of IfcBuildingElementProxy.",
         "predefined_types": {
             "NOTDEFINED": "Undefined building element proxy.",
             "USERDEFINED": "User-defined building element proxy."
@@ -497,14 +497,14 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingelementproxytype.htm"
     },
     "IfcBuildingElementType": {
-        "description": "The element type (IfcBuildingElementType) defines a list of commonly shared property set definitions of a building element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type (IfcBuildingElementType) defines a list of commonly shared property set definitions of a building element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A building element type is used to define the common properties of a certain type of a building element that may be applied to many instances of that feature type to assign a specific style. Building element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The IfcBuildingElementType is an abstract type. Occurrences of subtypes of the IfcBuildingElementType are represented by instances of the appropriate subtypes of IfcBuildingElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingelementtype.htm"
     },
     "IfcBuildingStorey": {
         "attributes": {
             "Elevation": "Elevation of the base of this storey, relative to the 0,00 internal reference height of the building. The 0.00 level is given by the absolute above sea level height by the ElevationOfRefHeight attribute given at IfcBuilding."
         },
-        "description": "The building storey has an elevation and typically represents a (nearly) horizontal aggregation of spaces that are vertically bound.",
+        "description": "The building storey has an elevation and typically represents a (nearly) horizontal aggregation of spaces that are vertically bound. A storey is (if specified) associated to a building. A storey may span over several connected storeys. Therefore storey complex provides for a collection of storeys included in a building. A storey can also be decomposed in (horizontal) parts, where each part defines a partial storey. This is defined by the composition type attribute of the supertype IfcSpatialStructureElements which is interpreted as follow: - COMPLEX = building storey complex - ELEMENT = building storey - PARTIAL = partial building storey *Property Set Use Definition* The property sets relating to the IfcBuildingStorey are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcBuildingStorey are part of this IFC release: - Pset_BuildingStoreyCommon: common property set for all types of building stories *Quantity Use Definition* The quantities relating to the building storey are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. The following quantities are foreseen, but will be subjected to the local standard of measurement: *Spatial Structure Use Definition* The IfcBuildingStorey is used to build the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). The spatial structure elements are linked together by using the objectified relationship IfcRelAggregates. The _IfcBuildingStorey_references them by its inverse relationships: - IfcBuildingStorey.Decomposes -- referencing (IfcBuilding || IfcBuildingStorey) by IfcRelAggregates.RelatingObject, If it refers to another instance of IfcBuildingStorey, the referenced IfcBuildingStorey needs to have a different and higher CompositionType, i.e. COMPLEX (if the other IfcBuildingStorey has ELEMENT), or ELEMENT (if the other IfcBuildingStorey has PARTIAL). - IfcBuildingStorey.IsDecomposedBy -- referencing (IfcBuildingStorey || IfcSpace) by IfcRelAggregates.RelatedObjects. If it refers to another instance of IfcBuildingStorey, the referenced IfcBuildingStorey needs to have a different and lower CompositionType, i.e. ELEMENT (if the other IfcBuildingStorey has COMPLEX), or PARTIAL (if the other IfcBuildingStorey has ELEMENT). If there are building elements and/or other elements directly related to the IfcBuildingStorey (like most building elements, such as walls, columns, etc.), they are associated with the IfcBuildingStorey by using the objectified relationship IfcRelContainedInSpatialStructure. The IfcBuildingStorey references them by its inverse relationship: * IfcBuildingStorey.ContainsElements -- referencing any subtype of IfcProduct (with the exception of other spatial structure element) by IfcRelContainedInSpatialStructure.RelatedElements. *Geometry Use Definitions* The geometric representation of IfcBuildingStorey is given by the IfcProductDefinitionShape and IfcLocalPlacement, allowing multiple geometric representation. Local Placement The local placement for IfcBuildingStorey is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if relative placement is used) to the IfcSpatialStructureElement of type IfcBuilding, or of type IfcBuildingStorey (e.g. to position a building storey relative to a building storey complex, or a partial building storey to a building storey). - If the relative placement is not used, the absolute placement is defined within the world coordinate system. *Geometric Representations* Currently, the use of a 2D 'FootPrint' representation of type 'GeometricCurveSet' and a 3D 'Body' representation of type 'Brep' is supported. Foot Print Representation The foot print representation of IfcBuildingStorey is given by either a single 2D curve (such as IfcPolyline or IfcCompositeCurve), or by a list of 2D curves (in case of inner boundaries), if the building storey has an independent geometric representation. The representation identifier and type of this geometric representation of IfcBuildingStorey is: - IfcShapeRepresentation.RepresentationIdentifier = 'FootPrint' - IfcShapeRepresentation.RepresentationType = 'GeometricCurveSet' Body Representation The body (or solid model) geometric representation (if the building storey has an independent geometric representation) of IfcBuildingStorey is defined using faceted B-Rep capabilities (with or without voids), based on the IfcFacetedBrep or on the IfcFacetedBrepWithVoids. The representation identifier and type of this representation of IfcBuildingStorey is: - IfcShapeRepresentation.RepresentationIdentifier = 'Body' - IfcShapeRepresentation.RepresentationType = 'Brep' Since the building storey shape is usually described by the exterior building elements, an independent shape representation shall only be given, if the building storey is exposed independently from its constituting elements.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingstorey.htm"
     },
     "IfcCShapeProfileDef": {
@@ -516,11 +516,11 @@
             "WallThickness": "Constant wall thickness of profile (= ts).",
             "Width": "Profile width, see illustration above (= b)."
         },
-        "description": "The IfcCShapeProfileDef defines a section profile that provides the defining parameters of a C-shaped section to be used by the swept area solid. This section is typically produced by cold forming steel. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
+        "description": "The IfcCShapeProfileDef defines a section profile that provides the defining parameters of a C-shaped section to be used by the swept area solid. This section is typically produced by cold forming steel. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box. The centre of gravity, if given, is located in y direction within the center of the bounding box, and in x-direction along the negative x axis, the offset value is given by the offset parameter CentreOfGravityInX. Illustration: Table: Parameters of C-shape profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccshapeprofiledef.htm"
     },
     "IfcCableCarrierFittingType": {
-        "description": "An IfcCableCarrierFittingType defines a particular type of cable carrier fitting which is a fitting that is placed at junction or transition in a cable carrier system.",
+        "description": "An IfcCableCarrierFittingType defines a particular type of cable carrier fitting which is a fitting that is placed at junction or transition in a cable carrier system. *Use Definitions* An IfcCableCarrierFittingType is a subtype of IfcFlowFittingType and provides for all forms of cable carrier fittings. Usage of IfcCableCarrierFittingType defines the parameters for one or more occurrences of IfcFlowFitting. Parameters are specified through property sets that are enumerated in the IfcCableCarrierFittingTypeEnum data type. *Property Set Use Definition*: There are no property sets currently defined for IfcCableCarrierFittingType. *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "BEND": "A fitting that changes the route of the cable carrier.",
             "CROSS": "A fitting at which two branches are taken from the main route of the cable carrier simultaneously.",
@@ -532,7 +532,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifccablecarrierfittingtype.htm"
     },
     "IfcCableCarrierSegmentType": {
-        "description": "The IfcCableCarrierSegmentType is a flow segment that is specifically used to carry and support cabling.",
+        "description": "The IfcCableCarrierSegmentType is a flow segment that is specifically used to carry and support cabling. *Use Definitions* An IfcCableCarrierSegmentType is used to define the common properties of a cable carrier segment that may be applied to many occurrences of that type. A cable carrier segment is used to carry and supports components of a cabling system. Cable carrier segment types may be exchanged without being already assigned to occurrences. The occurrences of the IfcCableCarrierSegmentType are represented by instances of IfcFlowSegment or its subtypes. *Property Set Use Definition:* The property sets relating to the IfcCableCarrierSegmentType are defined by the IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcCableCarrierSegmentType are part of this IFC release: - Pset_CableCarrierSegmentTypeCableLadderSegment: specific property set for the properties of a segment of a cable ladder, if available - Pset_CableCarrierSegmentTypeCableTraySegment: specific property set for the properties of a segment of cable tray, if available - Pset_CableCarrierSegmentTypeCableTrunkingSegment: specific property set for the properties of a segment of cable trunking, if available - Pset_CableCarrierSegmentTypeConduitSegment: : specific property set for the properties of a segment of electrical conduit, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "CABLELADDERSEGMENT": "An open carrier segment on which cables are carried on a ladder structure.",
             "CABLETRAYSEGMENT": "A (typically) open carrier segment onto which cables are laid.",
@@ -544,7 +544,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifccablecarriersegmenttype.htm"
     },
     "IfcCableSegmentType": {
-        "description": "An IfcCableSegmentType is a type of flow segment used to carry electrical power or communications signals.",
+        "description": "An IfcCableSegmentType is a type of flow segment used to carry electrical power or communications signals. *Use Definitions* A cable segment type is used to define the common properties of a cable segment that may be applied to many occurrences of that type. A cable segment is used to typically join two sections of an electrical network or a network of components carrying the electrical service. Cable segment types may be exchanged without being already assigned to occurrences. The occurrences of the IfcCableSegmentType are represented by instances of IfcFlowSegment or its subtypes. *Property Set Use Definition*: The property sets relating to the IfcCableSegmentType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the _IfcCableSegmentType_are part of this IFC release: - Pset_CableSegmentTypeCableSegment: specific property set for the properties of a whole cable (including the aggregation of conductors within the cable), if available - Pset_CableSegmentTypeConductorSegment: specific property set for the properties of an individual conductor within an electrical cable, if available. *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "CABLESEGMENT": "Cable with a specific purpose to lead electric current within a circuit or any other electric construction. Includes all types of electric cables, mainly several core segments or conductor segments wrapped together.",
             "CONDUCTORSEGMENT": "A single linear element within a cable or an exposed wire (such as for grounding) with the specific purpose to lead electric current, data, or a telecommunications signal.",
@@ -567,7 +567,7 @@
             "Coordinates": "The first, second, and third coordinate of the point location. If placed in a two or three dimensional rectangular Cartesian coordinate system, Coordinates[1] is the X coordinate, Coordinates[2] is the Y coordinate, and Coordinates[3] is the Z coordinate.",
             "Dim": "The space dimensionality of this class, determined by the number of coordinates in the List of Coordinates. HIINDEX(Coordinates)"
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A point defined by its coordinates in a two or three dimensional rectangular Cartesian coordinate system, or in a two dimensional parameter space. The entity is defined in a two or three dimensional space.",
+        "description": "Definition from ISO/CD 10303-42:1992: A point defined by its coordinates in a two or three dimensional rectangular Cartesian coordinate system, or in a two dimensional parameter space. The entity is defined in a two or three dimensional space. The derived attribute Dim has been added (see also note at IfcGeometricRepresentationItem). The WR1 was added to constrain the usage of IfcCartesianPoint in the context of IFC geometry. For the purpose of defining geometry in IFC only two and three dimensional Cartesian points are used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesianpoint.htm"
     },
     "IfcCartesianTransformationOperator": {
@@ -579,7 +579,7 @@
             "Scale": "The scaling value specified for the transformation.",
             "Scl": "The derived scale S of the transformation, equal to scale if that exists, or 1.0 otherwise. NVL(Scale, 1.0)"
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A Cartesian transformation operator defines a geometric transformation composed of translation, rotation, mirroring and uniform scaling. The list of normalized vectors u defines the columns of an orthogonal matrix T. These vectors are computed, by the base axis function, from the direction attributes axis1, axis2 and, in Cartesian transformation operator 3d, axis3. If |T|= -1, the transformation includes mirroring. The local origin point A, the scale value S and the matrix T together define a transformation.",
+        "description": "Definition from ISO/CD 10303-42:1992: A Cartesian transformation operator defines a geometric transformation composed of translation, rotation, mirroring and uniform scaling. The list of normalized vectors u defines the columns of an orthogonal matrix T. These vectors are computed, by the base axis function, from the direction attributes axis1, axis2 and, in Cartesian transformation operator 3d, axis3. If |T|= -1, the transformation includes mirroring. The local origin point A, the scale value S and the matrix T together define a transformation. The transformation for a point with position vector P is defined by For curves on surface the p curve.reference to curve will be unaffected by any transformation. The Cartesian transformation operator shall only be applied to geometry defined in a consistent system of units with the same units on each axis. With all optional attributes omitted, the transformation defaults to the identity transformation. The Cartesian transformation operator shall only be instantiated as one of its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesiantransformationoperator.htm"
     },
     "IfcCartesianTransformationOperator2D": {
@@ -594,7 +594,7 @@
             "Scale2": "The scaling value specified for the transformation along the axis 2. This is normally the y scale factor.",
             "Scl2": "The derived scale S(2) of the transformation along the axis 2 (normally the y axis), equal to Scale2 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. NVL(Scale2, SELF\\IfcCartesianTransformationOperator.Scl)"
         },
-        "description": "A Cartesian transformation operator 2d non uniform defines a geometric transformation in two-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by two different scaling factors:",
+        "description": "A Cartesian transformation operator 2d non uniform defines a geometric transformation in two-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by two different scaling factors: - SELF\\IfcCartesianTransformationOperator.Scale: the x axis scale factor - Scale2: the y axis scale factor If the Scale factor (at supertype IfcCartesianTransformationOperator) is omitted, it defaults to 1.0. If the Scale2 factor is omitted, it defaults to the value of Scale (the x axis scale factor).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesiantransformationoperator2dnonuniform.htm"
     },
     "IfcCartesianTransformationOperator3D": {
@@ -612,14 +612,14 @@
             "Scl2": "The derived scale S(2) of the transformation along the axis 2 (normally the y axis), equal to Scale2 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. NVL(Scale2, SELF\\IfcCartesianTransformationOperator.Scl)",
             "Scl3": "The derived scale S(3) of the transformation along the axis 3 (normally the z axis), equal to Scale3 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. NVL(Scale3, SELF\\IfcCartesianTransformationOperator.Scl)"
         },
-        "description": "A Cartesian transformation operator 3d non uniform defines a geometric transformation in three-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by three different scaling factors:",
+        "description": "A Cartesian transformation operator 3d non uniform defines a geometric transformation in three-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by three different scaling factors: - SELF\\IfcCartesianTransformationOperator.Scale: the x axis scale factor - Scale2: the y axis scale factor - Scale3: the z axis scale factor If the Scale factor (at supertype IfcCartesianTransformationOperator) is omitted, it defaults to 1.0. If the Scale2 or the Scale3 factor is omitted, it defaults to the value of Scale (the x axis scale factor).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesiantransformationoperator3dnonuniform.htm"
     },
     "IfcCenterLineProfileDef": {
         "attributes": {
             "Thickness": "Constant thickness applied along the center line."
         },
-        "description": "The profile IfcCenterLineProfileDef defines an arbitrary two-dimensional open, not self intersecting profile for the use within the swept solid geometry. It is given by an area defined by applying a constant thickness to a centerline, generating an area from which the solid can be constructed.",
+        "description": "The profile IfcCenterLineProfileDef defines an arbitrary two-dimensional open, not self intersecting profile for the use within the swept solid geometry. It is given by an area defined by applying a constant thickness to a centerline, generating an area from which the solid can be constructed. Informal proposition: - The Curve has to be an open curve. - The Curve has to be a non-intersecting curve. Illustration: Table: Definition of center line profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccenterlineprofiledef.htm"
     },
     "IfcChamferEdgeFeature": {
@@ -627,11 +627,11 @@
             "Height": "The height of the feature chamfer cross section.",
             "Width": "The width of the feature chamfer cross section."
         },
-        "description": "An edge feature with a chamfered cross section shape.",
+        "description": "An edge feature with a chamfered cross section shape. Geometry Use Definitions: The geometric representation of IfcChamferEdgeFeature is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined in the supertype IfcFeatureElementSubtraction. Standard Geometric Representation The use of Standard Geometric Representations is defined in the supertype IfcFeatureElementSubtraction.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcchamferedgefeature.htm"
     },
     "IfcChillerType": {
-        "description": "The element type IfcChillerType defines a list of commonly shared property set definitions of a chiller and an optional set of product representations. It is used to define a chiller specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcChillerType defines a list of commonly shared property set definitions of a chiller and an optional set of product representations. It is used to define a chiller specification (i.e. the specific product information, that is common to all occurrences of that product type). A chiller type is used to define the common properties of a chiller that may be applied to many occurrences of that type. A chiller is a device used to implement a refrigeration cycle for cooling a fluid, typically water or a mixture of water and glycol. The chilled water is then used to cool and dehumidify air in a building. Chiller types may be exchanged without being already assigned to occurrences. The occurrences of the IfcChillerType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_ChillerTypeCommon: common property set for all chiller types",
         "predefined_types": {
             "AIRCOOLED": "Air cooled chiller.",
             "HEATRECOVERY": "Heat recovery chiller.",
@@ -645,21 +645,21 @@
         "attributes": {
             "Radius": "The radius of the circle, which shall be greater than zero."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: An IfcCircle is defined by a radius and the location and orientation of the circle. Interpretation of data should be as follows:",
+        "description": "Definition from ISO/CD 10303-42:1992: An IfcCircle is defined by a radius and the location and orientation of the circle. Interpretation of data should be as follows: Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccircle.htm"
     },
     "IfcCircleHollowProfileDef": {
         "attributes": {
             "WallThickness": "Thickness of the material, it is the difference between the outer and inner radius."
         },
-        "description": "Definition from IAI: The IfcCircleHollowProfileDef defines a section profile that provides the defining parameters of a circular hollow section (tube) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profile's centre of the bounding box (for symmetric profiles identical with the centre of gravity).",
+        "description": "Definition from IAI: The IfcCircleHollowProfileDef defines a section profile that provides the defining parameters of a circular hollow section (tube) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profile's centre of the bounding box (for symmetric profiles identical with the centre of gravity). Illustration: Table: Parameters of circular hollow profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccirclehollowprofiledef.htm"
     },
     "IfcCircleProfileDef": {
         "attributes": {
             "Radius": "The radius of the circle."
         },
-        "description": "Definition from IAI: The IfcCircleProfileDef defines a circle as the profile definition used by the swept surface geometry or by the swept area solid. It is given by its Radius attribute and placed within the 2D position coordinate system, established by the Position attribute.",
+        "description": "Definition from IAI: The IfcCircleProfileDef defines a circle as the profile definition used by the swept surface geometry or by the swept area solid. It is given by its Radius attribute and placed within the 2D position coordinate system, established by the Position attribute. Illustration: Table: Parameter for circle profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccircleprofiledef.htm"
     },
     "IfcClassification": {
@@ -670,7 +670,7 @@
             "Name": "The name or label by which the classification used is normally known. NOTE: Examples of names include CI/SfB, Masterformat, BSAB, Uniclass, STABU etc.",
             "Source": "Source (or publisher) for this classification."
         },
-        "description": "An IfcClassification is used for the arrangement of objects into a class or category according to a common purpose or their possession of common characteristics.",
+        "description": "An IfcClassification is used for the arrangement of objects into a class or category according to a common purpose or their possession of common characteristics. IfcClassification identifies the classification system or source from which a classification notation is derived. The objective is to minimize the number of IfcClassification objects contained within an IFC model. Ideally, each classification system or source used should have only one IfcClassification object. However, because multiple classification is allowed, there may be many IfcClassification objects used, each identifying a different classification system or source.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassification.htm"
     },
     "IfcClassificationItem": {
@@ -681,7 +681,7 @@
             "Notation": "The notations from within a classification item that are used within the project. NOTE: In Uniclass this label is called the Code, in UDC it is called the Class Number.",
             "Title": "The name of the classification item. NOTE: Examples of the above attributes from Uniclass:  A classification item in Uniclass has a notation \"L6814\" which has the title \"Tanking\". It has a parent notation \"L681\" which has the title \"Proofings, insulation\"."
         },
-        "description": "An IfcClassificationItem is a class of classification notations used.",
+        "description": "An IfcClassificationItem is a class of classification notations used. The term 'classification item' is used in preference to the term 'table' for improved flexibility. For example, the classification item \"L681\" in Uniclass may be used to contain all subsequent notation facets within that class of classifications which has the title \"Proofings, insulation\" (e.g. L6811, L6812, L6813 etc.).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationitem.htm"
     },
     "IfcClassificationItemRelationship": {
@@ -689,36 +689,36 @@
             "RelatedItems": "The child level items in a classification structure that are related to the parent level item.",
             "RelatingItem": "The parent level item in a classification structure that is used for relating the child level items."
         },
-        "description": "An IfcClassificationItemRelationship is a relationship class that enables the hierarchical structure of a classification system to be exposed through its ability to contain related classification items and to be contained by a relating classification item.",
+        "description": "An IfcClassificationItemRelationship is a relationship class that enables the hierarchical structure of a classification system to be exposed through its ability to contain related classification items and to be contained by a relating classification item. IfcClassificationItem's can be progressively decomposed using the IfcClassificationItemRelationship such that the relationship always captures the information about the parent level (relating) item and the child level (related) items of which there can be many. The following example shows how this could be achieved for the Uniclass system. The inverse relationships from IfcClassificationItem to IfcClassificationRelationship enable information about the relationship to be recovered by the items concerned so that they are also aware of the decomposition. The cardinality of the inverse relationship is that an IfcClassificationItem can be the classifying item in only one relationship and can be a classified item in only one relationship. This implies that there is no overlap of IfcClassificationItem's. This reflects typical classification approaches which use strict hierarchical decomposition (or taxonomy) and do not have matrix relationships.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationitemrelationship.htm"
     },
     "IfcClassificationNotation": {
         "attributes": {
             "NotationFacets": "Alphanumeric characters in defined groups from which the classification notation is derived."
         },
-        "description": "An IfcClassificationNotation is a notation used from published reference (which may be either publicly available from a classification society or is published locally for the purposes of an organization, project or other purpose).",
+        "description": "An IfcClassificationNotation is a notation used from published reference (which may be either publicly available from a classification society or is published locally for the purposes of an organization, project or other purpose). A classification notation may be developed using various notation facets. A facet is a part of the actual notation but which has a specific meaning. For instance, it may be appropriate to classify an item by owning actor (represented by A=Architect) and by an entry from a classification table such as CI/SfB (represented by 210 for external wall). This gives a classification as A210. All classifications of an object that are contained within the IFC model are made through the IfcClassificationNotation class. For a given object, the IfcRelAssociatesClassification class makes the connection between the IfcObject and the IfcClassificationNotation. It is a requirement that a classification notation can only bring together facets from the same classification system or source. Bringing together notation facets from different sources within the same classification notation is not allowed. However, multiple classifications can be applied to a single object through the use of more than one instance of IfcRelAssociatesClassification. In this way it is possible to define multiple classification notations where each notation contains facets from a single source.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationnotation.htm"
     },
     "IfcClassificationNotationFacet": {
         "attributes": {
             "NotationValue": "The notation value that specifies the classification e.g. 'L781'"
         },
-        "description": "An IfcClassificationNotationFacet is a group of alphanumeric characters used within a classification notation.",
+        "description": "An IfcClassificationNotationFacet is a group of alphanumeric characters used within a classification notation. An IfcClassificationNotationFacet object holds an individual classification value that is to be assigned to an object through IfcClassificationNotation and IfcRelAssociatesClassification objects.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationnotationfacet.htm"
     },
     "IfcClassificationReference": {
         "attributes": {
             "ReferencedSource": "The classification system or source that is referenced."
         },
-        "description": "An IfcClassificationReference is a reference into a classification system or source (see IfcClassification). An optional inherited ItemReference key is also provided to allow more specific references to classification items (or tables) by type. The inherited Name attribute allows for a human interpretable designation of a classification notation (or code) - see use definition of \"Lightweight Classification\".",
+        "description": "An IfcClassificationReference is a reference into a classification system or source (see IfcClassification). An optional inherited ItemReference key is also provided to allow more specific references to classification items (or tables) by type. The inherited Name attribute allows for a human interpretable designation of a classification notation (or code) - see use definition of \"Lightweight Classification\". The IfcClassificationReference can be used as a form of 'lightweight' classification through the 'ItemReference' attribute inherited from the abstract IfcExternalReference class. In this case, the 'ItemReference' could take (for instance) the Uniclass notation \"L6814\" which, if the classification was well understood by all parties and was known to be taken from a particular classification source, would be sufficient. The Name attribute could be the title \"Tanking\". This would remove the need for the overhead of the more complete classification structure of the model. However, it is not recommended that this lightweight method be used in cases where more than one classification system is in use or where there may be uncertainty as to the origin or meaning of the classification. Classifications of an object may be referenced from an external source rather than being contained within the IFC model. This is done through the IfcClassificationReference class.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationreference.htm"
     },
     "IfcClosedShell": {
-        "description": "Definition from ISO/CD 10303-42:1992: A closed shell is a shell of the dimensionality 2 which typically serves as a bound for a region in R3. A closed shell has no boundary, and has non-zero finite extent. If the shell has a domain with coordinate space R3, it divides that space into two connected regions, one finite and the other infinite. In this case, the topological normal of the shell is defined as being directed from the finite to the infinite region.",
+        "description": "Definition from ISO/CD 10303-42:1992: A closed shell is a shell of the dimensionality 2 which typically serves as a bound for a region in R3. A closed shell has no boundary, and has non-zero finite extent. If the shell has a domain with coordinate space R3, it divides that space into two connected regions, one finite and the other infinite. In this case, the topological normal of the shell is defined as being directed from the finite to the infinite region. The shell is represented by a collection of faces. The domain of the shell, if present, contains all those faces, together with their bounds. Associated with each face in the shell is a logical value which indicates whether the face normal agrees with (TRUE) or is opposed to (FALSE) the shell normal. The logical value can be applied directly as a BOOLEAN attribute of an oriented face, or be defaulted to TRUE if the shell boundary attribute member is a face without the orientation attribute. The combinatorial restrictions on closed shells and geometrical restrictions on their domains are designed to ensure that any domain associated with a closed shell is a closed, orientable manifold. The domain of a closed shell, if present, is a connected, closed, oriented 2-manifold. It is always topologically equivalent to an H-fold torus for some H\u00b3 0. The number H is referred to as the surface genus of the shell. If a shell of genus H has a domain within coordinate space R^3^, then the finite region of space inside it is topologically equivalent to a solid ball with H tunnels drilled through it. The Euler equation (7) applies with B=0, because in this case there are no holes. As in the case of open shells, the surface genus H may not be known a priori, but shall be an integer \u00b3 0. Thus a necessary, but not sufficient, condition for a well-formed closed shell is the following: Informal propositions: - Every edge shall be referenced exactly twice by the loops of the face. - Each oriented edge shall be unique. - No edge shall be referenced by more than two faces. - Distinct faces of the shell do not intersect, but may share edges or vertices. - Distinct edges do not intersect but may share vertices. - Each face reference shall be unique. - The loops of the shell shall not be a mixture of poly loop and other loop types. Note: this is given, since only poly loop is defined as face bound definition. - The closed shell shall be an oriented arcwise connected 2-manifold. - The Euler equation shall be satisfied. Note: Please refer to ISO/IS 10303-42:1994, p.149 for the equation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcclosedshell.htm"
     },
     "IfcCoilType": {
-        "description": "The element type IfcCoilType defines a list of commonly shared property set definitions of a coil and an optional set of product representations. It is used to define a coil specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcCoilType defines a list of commonly shared property set definitions of a coil and an optional set of product representations. It is used to define a coil specification (i.e. the specific product information, that is common to all occurrences of that product type). A coil type is used to define the common properties of a coil that may be applied to many occurrences of that type. A coil is a device used to provide heat transfer between non-mixing media. A common example is a cooling coil, which utilizes a finned coil in which circulates chilled water, antifreeze, or refrigerant that is used to remove heat from air moving across the surface of the coil. Coil types may be exchanged without being already assigned to occurrences. The occurrences of the IfcCoilType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_CoilTypeCommon: common property set for all coil types Pset_CoilTypeHydronic: property set for hydronic coil types",
         "predefined_types": {
             "DXCOOLINGCOIL": "Cooling coil using a refrigerant to cool the air stream directly.",
             "ELECTRICHEATINGCOIL": "Heating coil using electricity as a heating source.",
@@ -752,7 +752,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifccolumn.htm"
     },
     "IfcColumnType": {
-        "description": "The element type (IfcColumnType) defines a list of commonly shared property set definitions of a column and an optional set of product representations. It is used to define a column specification (i.e. the specific product information that is common to all occurrences of that product type).",
+        "description": "The element type (IfcColumnType) defines a list of commonly shared property set definitions of a column and an optional set of product representations. It is used to define a column specification (i.e. the specific product information that is common to all occurrences of that product type). A column type is used to define the common properties of a certain type of column that may be applied to many instances of that type to assign a specific style. Column types may be exchanged without being already assigned to occurrences. The occurrences of the IfcColumnType are represented by instances of IfcColumn.",
         "predefined_types": {
             "COLUMN": "A standard member usually vertical and requiring resistance to vertical forces by compression but also sometimes to lateral forces.",
             "NOTDEFINED": "Undefined linear element.",
@@ -775,7 +775,7 @@
             "Segments": "The component bounded curves, their transitions and senses. The transition attribute for the last segment defines the transition between the end of the last segment and the start of the first; this transition attribute may take the value discontinuous, which indicates an open curve.",
             "SelfIntersect": "Indication of whether the curve intersects itself or not; this is for information only."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A composite curve (IfcCompositeCurve) is a collection of curves joined end-to-end. The individual segments of the curve are themselves defined as composite curve segments. The parameterization of the composite curve is an accumulation of the parametric ranges of the referenced bounded curves. The first segment is parameterized from 0 to l~1~~, and, for i\u00b3 2, the i^th^^ segment is parameterized from",
+        "description": "Definition from ISO/CD 10303-42:1992: A composite curve (IfcCompositeCurve) is a collection of curves joined end-to-end. The individual segments of the curve are themselves defined as composite curve segments. The parameterization of the composite curve is an accumulation of the parametric ranges of the referenced bounded curves. The first segment is parameterized from 0 to l~1~~, and, for i\u00b3 2, the i^th^^ segment is parameterized from Informal Propositions: - The SameSense attribute of each segment correctly specifies the senses of the component curves. When traversed in the direction indicated by SameSense, the segments shall join end-to-end.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccompositecurve.htm"
     },
     "IfcCompositeCurveSegment": {
@@ -786,7 +786,7 @@
             "Transition": "The state of transition (i.e., geometric continuity from the last point of this segment to the first point of the next segment) in a composite curve.",
             "UsingCurves": "The set of composite curves which use this composite curve segment as a segment. This set shall not be empty."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A composite curve segment (IfcCompositeCurveSegment) is a bounded curve together with transition information which is used to construct a composite curve (IfcCompositeCurve).",
+        "description": "Definition from ISO/CD 10303-42:1992: A composite curve segment (IfcCompositeCurveSegment) is a bounded curve together with transition information which is used to construct a composite curve (IfcCompositeCurve). The derived attribute Dim has been added (see also note at IfcGeometricRepresentationItem). The IfcCompositeCurveSegment is a subtype of IfcGeometricRepresentationItem (whereas in STEP P42 composite_curve_segment is not a subtype of geometric_representation_item, the proposed 2nd edition of P42 however proposes the subtype relationship).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccompositecurvesegment.htm"
     },
     "IfcCompositeProfileDef": {
@@ -794,11 +794,11 @@
             "Label": "The name by which the composition may be referred to. The actual meaning of the name has to be defined in the context of applications.",
             "Profiles": "The profiles which are used to define the composite profile."
         },
-        "description": "Definition from IAI: The IfcCompositeProfileDef defines the profile by composition of other profiles. The composition is given by a set of at least two other profile definitions. Any profile definition (except for another composite profile) can be used to construct the composite.",
+        "description": "Definition from IAI: The IfcCompositeProfileDef defines the profile by composition of other profiles. The composition is given by a set of at least two other profile definitions. Any profile definition (except for another composite profile) can be used to construct the composite. Illustration: Table: Definition of composite profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccompositeprofiledef.htm"
     },
     "IfcCompressorType": {
-        "description": "The element type IfcCompressorType defines a list of commonly shared property set definitions of a compressor and an optional set of product representations. It is used to define a compressor specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcCompressorType defines a list of commonly shared property set definitions of a compressor and an optional set of product representations. It is used to define a compressor specification (i.e. the specific product information, that is common to all occurrences of that product type). A compressor type is used to define the common properties of a Compressor that may be applied to many occurrences of that type. A compressor is a device that compresses a fluid typically used in a refrigeration circuit. Compressor types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcCompressorType are represented by instances of IfcFlowMovingDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_CompressorTypeCommon: common property set for all compressor types",
         "predefined_types": {
             "BOOSTER": "Positive-displacement reciprocating compressor where pressure is increased by a booster.",
             "DYNAMIC": "The pressure of refrigerant vapor is increased by a continuous transfer of angular momentum from a rotating member to the vapor followed by conversion of this momentum into static pressure.",
@@ -821,7 +821,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccompressortype.htm"
     },
     "IfcCondenserType": {
-        "description": "The element type IfcCondenserType defines a list of commonly shared property set definitions of a condenser and an optional set of product representations. It is used to define a condenser specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcCondenserType defines a list of commonly shared property set definitions of a condenser and an optional set of product representations. It is used to define a condenser specification (i.e. the specific product information, that is common to all occurrences of that product type). A condenser type is used to define the common properties of a condenser that may be applied to many occurrences of that type. A condenser is a device that is used to dissipate heat, typically by condensing a substance such as a refrigerant from its gaseous to its liquid state. Condenser types may be exchanged without being already assigned to occurrences. The occurrences of the IfcCondenserType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_CondenserTypeCommon: common property set for all condenser types",
         "predefined_types": {
             "AIRCOOLED": "A condenser in which heat is transferred to an air-stream.",
             "EVAPORATIVECOOLED": "A condenser that is cooled evaporatively.",
@@ -835,7 +835,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccondensertype.htm"
     },
     "IfcCondition": {
-        "description": "An IfcCondition determines the state or condition of an element at a particular point in time",
+        "description": "An IfcCondition determines the state or condition of an element at a particular point in time IfcCondition is a particular subtype of IfcGroup that can contain only instances of IfcConditionCriterion. The objectified relationship class IfcRelAssignsToGroup is used to assign the related instances of IfcConditionCriterion to the relating instance of IfcCondition. An IfcCondition is determined either from an observed or a measured state (see IfcConditionCriterion). The condition is determined at a particular point in time, the time being determined through the IfcRelAssociatesDateTime class with an appropriate designation for the value of the DateTimeType e.g. AssessmentDate. Note that other dates may be assigned to IfcCondition for relevant purposes e.g. to recommend the date for the next condition assessment. IfcRelAssignsToProduct is used to relate one or more instances of IfcCondition to an artifact that is an instance of a subtype of IfcProduct. For an instance of IfcAsset, condition is related through the use of IfcRelAssignsToGroup.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifccondition.htm"
     },
     "IfcConditionCriterion": {
@@ -843,7 +843,7 @@
             "Criterion": "The measured or assessed value of a criterion.",
             "CriterionDateTime": "The time and/or date at which the criterion is determined."
         },
-        "description": "An IfcConditionCriterion is a particular measured or assessed criterion that contributes to the overall condition of an artifact.",
+        "description": "An IfcConditionCriterion is a particular measured or assessed criterion that contributes to the overall condition of an artifact. An IfcConditionCriterion may be either an observed/assessed value or a measured value. This is determined by selection through the IfcConditionCriterionSelect type that has a datatype either of IfcLabel (for a numeric or alphanumeric scale observation e.g. on a scale of 1 to 10 where 1 represents 'as new' and 10 represents 'urgent replacement required') or of IfcMeasureWithUnit (for a measured criterion that also includes units of measure). Each criterion must be named and optionally, may also have a description. A description used for a condition should be persistent so that there is absolute consistency in condition recording.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcconditioncriterion.htm"
     },
     "IfcConic": {
@@ -857,7 +857,7 @@
         "attributes": {
             "CfsFaces": "The set of faces arcwise connected along common edges or vertices."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A connected_face_set is a set of faces such that the domain of faces together with their bounding edges and vertices is connected.",
+        "description": "Definition from ISO/CD 10303-42:1992: A connected_face_set is a set of faces such that the domain of faces together with their bounding edges and vertices is connected. Informal proposition: - The union of the domains of the faces and their bounding loops shall be arcwise connected.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcconnectedfaceset.htm"
     },
     "IfcConnectionCurveGeometry": {
@@ -865,11 +865,11 @@
             "CurveOnRelatedElement": "The bounded curve at which the connected objects are aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.",
             "CurveOnRelatingElement": "The bounded curve at which the connected objects are aligned at the relating element, given in the LCS of the relating element."
         },
-        "description": "The IfcConnectionCurveGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a curve or at an edge with curve geometry associated. It is envisioned as a control that applies to the element connection relationships.",
+        "description": "The IfcConnectionCurveGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a curve or at an edge with curve geometry associated. It is envisioned as a control that applies to the element connection relationships. The available geometry for the connection constraint may be further restricted to only allow straight segments by applying IfcPolyline only. Such an usage constraint is provided at the object definition of the IfcElement subtype, utilizing the element connection by referring to the subtype of IfcRelConnects with the associated IfcConnectionCurveGeometry. *Geometry Use Definitions*: The IfcCurve (or the IfcEdgeCurve with an associated IfcCurve) at the CurveOnRelatingElement attribute defines the curve where the basic geometry items of the connected elements connects. The curve geometry and coordinates are provided within the local coordinate system of the RelatingElement, as specified at the IfcRelConnects_Subtype that utilizes the _IfcConnectionCurveGeometry. Optionally, the same curve geometry and coordinates can also be provided within the local coordinate system of the RelatedElement by using the CurveOnRelatedElement attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectioncurvegeometry.htm"
     },
     "IfcConnectionGeometry": {
-        "description": "The IfcConnectionGeometry is used to describe the geometric and topological constraints that facilitate the physical connection of two objects. It is envisioned as a control that applies to the element connection relationships.",
+        "description": "The IfcConnectionGeometry is used to describe the geometric and topological constraints that facilitate the physical connection of two objects. It is envisioned as a control that applies to the element connection relationships. The IfcConnectionGeometry allows for the provision of connection constraints between geometric and topological elements, the following connection geometry/topology types are in scope: - point | vertex point, - curve | edge curve, - surface | face surface, - profile - NOTE the profile (or port) connection type is deprecated since Release IFC2x Edition 2.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectiongeometry.htm"
     },
     "IfcConnectionPointEccentricity": {
@@ -878,7 +878,7 @@
             "EccentricityInY": "Distance in y direction between the two points (or vertex points) engaged in the point connection.",
             "EccentricityInZ": "Distance in z direction between the two points (or vertex points) engaged in the point connection."
         },
-        "description": "The IfcConnectionPointEccentricity is used to describe the geometric constraints that facilitate the physical connection of two objects at a point or vertex point with associated point coordinates. There is a physical distance, or eccentricity, between the connection points of both object. The eccentricity can be either given by:",
+        "description": "The IfcConnectionPointEccentricity is used to describe the geometric constraints that facilitate the physical connection of two objects at a point or vertex point with associated point coordinates. There is a physical distance, or eccentricity, between the connection points of both object. The eccentricity can be either given by: - providing the PointOnRelatingElement_and the _PointOnRelatedElement, where both point coordinates are not identical within a common parent coordinate system (latestly within the world coordinate system), - providing the PointOnRelatingElement_and the three distance measures, _EccentricityInX, EccentricityInY, and_EccentricityInZ_(or only EccentricityInX, and EccentricityInY if the underlying coordinate system is two-dimensional), or - providing both. *Geometry Use Definitions*: The IfcPoint (or the IfcVertexPoint with an associated IfcPoint) at the PointOnRelatingElement attribute defines the point where the basic geometry items of the connected elements connects. The point coordinates are provided within the local coordinate system of the RelatingElement, as specified at the IfcRelConnectsSubtype that utilizes the IfcConnectionPointGeometry. Optionally, the same point coordinates can also be provided within the local coordinate system of the RelatedElement by using the PointOnRelatedElement attribute, otherwise the distance to the point at the RelatedElement has to be given by the three eccentricity values.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectionpointeccentricity.htm"
     },
     "IfcConnectionPointGeometry": {
@@ -886,7 +886,7 @@
             "PointOnRelatedElement": "Point at which connected objects are aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.",
             "PointOnRelatingElement": "Point at which the connected object is aligned at the relating element, given in the LCS of the relating element."
         },
-        "description": "The IfcConnectionPointGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a point (here IfcCartesianPoint) or at an vertex with point coordinates associated. It is envisioned as a control that applies to the element connection relationships.",
+        "description": "The IfcConnectionPointGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a point (here IfcCartesianPoint) or at an vertex with point coordinates associated. It is envisioned as a control that applies to the element connection relationships. *Geometry Use Definitions*: The IfcPoint (or the IfcVertexPoint with an associated IfcPoint) at the PointOnRelatingElement attribute defines the point where the basic geometry items of the connected elements connects. The point coordinates are provided within the local coordinate system of the RelatingElement, as specified at the IfcRelConnectsSubtype that utilizes the IfcConnectionPointGeometry. Optionally, the same point coordinates can also be provided within the local coordinate system of the RelatedElement by using the PointOnRelatedElement attribute. If both point coordinates are not identical within a common parent coordinate system (latestly within the world coordinate system), the subtype IfcConnectionPointEccentricity shall be used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectionpointgeometry.htm"
     },
     "IfcConnectionPortGeometry": {
@@ -895,7 +895,7 @@
             "LocationAtRelatingElement": "Local placement of the port relative to its distribution element's local placement. The element in question is that, which plays the role of the relating element in the connectivity relationship.",
             "ProfileOfPort": "Profile that defines the port connection geometry. It is placed inside the XY plane of the location, given at the relating and (optionally) related distribution element."
         },
-        "description": "The IfcConnectionPortGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a port having a profile geometry (here IfcProfile). It is envisioned as a control that applies to the element connection relationships.",
+        "description": "The IfcConnectionPortGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a port having a profile geometry (here IfcProfile). It is envisioned as a control that applies to the element connection relationships. This entity defines the geometric location and configuration of a port on a distribution element. This information can be used to determine how to physically connect distribution elements.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectionportgeometry.htm"
     },
     "IfcConnectionSurfaceGeometry": {
@@ -903,7 +903,7 @@
             "SurfaceOnRelatedElement": "Surface at which the relating element is aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.",
             "SurfaceOnRelatingElement": "Surface at which related object is aligned at the relating element, given in the LCS of the relating element."
         },
-        "description": "The IfcConnectionSurfaceGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a surface or at a face with surface geometry associated. It is envisioned as a control that applies to the element connection relationships.",
+        "description": "The IfcConnectionSurfaceGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a surface or at a face with surface geometry associated. It is envisioned as a control that applies to the element connection relationships. *Geometry Use Definitions*: The IfcSurface (or the IfcFaceSurface with an associated IfcSurface) at the SurfaceOnRelatingElement attribute defines the surface where the basic geometry items of the connected elements connects. The surface geometry and coordinates are provided within the local coordinate system of the RelatingElement, as specified at the IfcRelConnectsSubtype that utilizes the IfcConnectionSurfaceGeometry. Optionally, the same surface geometry and coordinates can also be provided within the local coordinate system of the RelatedElement by using the SurfaceOnRelatedElement attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectionsurfacegeometry.htm"
     },
     "IfcConstraint": {
@@ -922,7 +922,7 @@
             "RelatesConstraints": "References to the objectified relationships that relate other constraints with this constraint.",
             "UserDefinedGrade": "Allows for specification of user defined grade of the constraint  beyond the enumeration values (hard, soft, advisory) provided by ConstraintGrade attribute of type _IfcConstraintEnum_.  When a value is provided for attribute UserDefinedGrade in parallel the attribute ConstraintGrade shall have enumeration value USERDEFINED."
         },
-        "description": "An IfcConstraint is used to define a constraint or limiting value or boundary condition that may be applied to an object or to the value of a property.",
+        "description": "An IfcConstraint is used to define a constraint or limiting value or boundary condition that may be applied to an object or to the value of a property. IfcConstraint may be associated with any subtype of IfcObject through the IfcRelAssociatesConstraint relationship in the IfcControlExtension schema. A constraint may aggregate other constraints through the IfcConstraintAggregationRelationship through which a logical association between constraints may be applied. A constraint must have a name applied through the IfcConstraint.Name attribute and optionally, a description through IfcConstraint.Description. For instance, when undertaking a move (instantiated through the IfcMove class), a constraint may be named as a 'Move Start Constraint' or 'Move End Constraint' and described using one of a possible range of move constraints as shown in the table below. Application of constraints to moves as indicated by this example replaces the use of IfcActionTimeControl class which is now deleted. The constraint is instantiated as the class IfcMetric and uses a Date/Time value through IfcMetricValue. An appropriate benchmark is applied according to the requirement of the constraint (as indicated). The grade of the constraint (hard, soft, advisory) must be specified through IfcConstraint.ConstraintGrade whilst the time at which the constraint is created may be optionally asserted through IfcConstraint.ConstraintTime.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcconstraint.htm"
     },
     "IfcConstraintAggregationRelationship": {
@@ -933,7 +933,7 @@
             "RelatedConstraints": "Constraints that are aggregated in using the LogicalAggregator.",
             "RelatingConstraint": "Constraint to which the other Constraints are associated."
         },
-        "description": "An IfcConstraintAggregationRelationship is an objectified relationship that enables instances of IfcConstraint and its subtypes to be aggregated together logically.",
+        "description": "An IfcConstraintAggregationRelationship is an objectified relationship that enables instances of IfcConstraint and its subtypes to be aggregated together logically. The IfcConstraintAggregationRelationship allows the aggregation link between constraints to be logically defined (AND, OR). In this way, where an object or property has multiple constraints assigned, the linkage between them can be specified. Thus linked constraints might show as (> X AND < Y) which is useful for an allowed range or bounded value or as (A OR B OR C) which is valuable for an enumerated property where a selection is constrained to be one of A, B or C.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcconstraintaggregationrelationship.htm"
     },
     "IfcConstraintClassificationRelationship": {
@@ -963,11 +963,11 @@
             "Suppliers": "Possible suppliers of the type of materials.",
             "UsageRatio": "The ratio of the amount of a construction material used to the amount provided (determined as a quantity)"
         },
-        "description": "An IfcConstructionMaterialResource identifies a material resource type in a construction project.",
+        "description": "An IfcConstructionMaterialResource identifies a material resource type in a construction project. Occurrences of IfcConstructionMaterialResource are consumed (wholly or partially), or occupied during a construction work task (i.e. IfcTask). Similar to IfcConstructionProductResource, sometimes things such as 5000kg of gravel are already instantiated as an IfcProduct because it is a result of a work task e.g. \u2018transporting gravel\u2019. In this case, the instance of IfcConstructionMaterialResource can be associated with the product instance \u20185000kg of gravel\u2019 to provide more information for resource uses. Nevertheless, IfcConstructionMaterialResource should only be used to represent resource types, e.g. \u2018gravel\u2019, but not product substances, e.g. \u20185000kg of gravel\u2019. Note: This class is not the same as IfcMaterial; the former can typically represent the type of bulk materials such as sand, gravels, nails and so on (note these can be instantiated from IfcProduct as well depending their uses in the system) used in a construction process. The latter is about physical materials used in a physical building element typically with detailed positioning (e.g. offset) and layering information. The association of an actual material with an IfcConstructionMaterialResource is handled by IfcRelAssociatesMaterial. Quantities for an IfcConstructionMaterialResource are defined through IfcRelDefinesByProperty and use IfcElementQuantity.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifcconstructionmaterialresource.htm"
     },
     "IfcConstructionProductResource": {
-        "description": "An IfcConstructionProductResource defines the role of a product that is consumed (wholly or partially), or occupied (i.e. used) in the performance of construction.",
+        "description": "An IfcConstructionProductResource defines the role of a product that is consumed (wholly or partially), or occupied (i.e. used) in the performance of construction. Occurrences of products that are used as product resources are instances of IfcProduct (by reference) since they result from some processes. For instance, formworks can be instantiated as products resulting from the process \u2018constructing formwork\u2019. However, they are used as resources in the process \u2018pouring concrete\u2019 in a later stage of the project. The product that is used as a construction resource is referenced using the IfcRelAssignsToResource.RelatedObjects relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifcconstructionproductresource.htm"
     },
     "IfcConstructionResource": {
@@ -995,7 +995,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifccontrol.htm"
     },
     "IfcControllerType": {
-        "description": "An IfcControllerType defines a particular type of controller that interacts with other devices in a control system such as a building automation control system.",
+        "description": "An IfcControllerType defines a particular type of controller that interacts with other devices in a control system such as a building automation control system. *Use Definitions* An IfcControllerType provides for all forms of controller. Usage of IfcControllerType defines the parameters for one or more occurrences of IfcDistributionControlElement. Parameters are specified through property sets that may be enumerated in the IfcControllerTypeEnum data type. An IfcController typically has a relationship with an IfcSensor and/or an IfcActuator. These relationships can be handled either through aggregation (e.g., a unitized controller/actuator assembly) using IfcRelAggregates or simply as an arbitrary grouping of related devices using the IfcRelAssignsToGroup relationship. *Property Set Use Definition*: The property sets relating to the IfcControllerType defined by the IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcControllerType are part of this IFC release: - Pset_ControllerTypeCommon: property set for the properties common to all types of controller, if available - Pset_ControllerTypeProportional: specific property set for the properties of a proportional controller, if available - Pset_ControllerTypeTwoPosition: specific property set for the properties of a two position controller, if available In addition to the above, the following predefined property sets may be used for specification of input/output signal type for controllers: - Pset_AnalogInput: specific property set for the properties of an analog input, if available - Pset_AnalogOutput: specific property set for the properties of an analog output, if available - Pset_BinaryInput: specific property set for the properties of a binary input, if available - Pset_BinaryOutput: specific property set for the properties of a binary output, if available - Pset_MultiStateInput: specific property set for the properties of a multi-state input, if available - Pset_MultiStateOutput: specific property set for the properties of a multi-state output, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "FLOATING": "Output increases or decreases at a constant or accelerating rate.",
             "NOTDEFINED": "Undefined type.",
@@ -1013,11 +1013,11 @@
             "ConversionFactor": "The physical quantity from which the converted unit is derived.",
             "Name": "The word, or group of words, by which the conversion based unit is referred to."
         },
-        "description": "Definition from ISO/CD 10303-41:1992: A conversion based unit is a unit that is defined based on a measure with unit.",
+        "description": "Definition from ISO/CD 10303-41:1992: A conversion based unit is a unit that is defined based on a measure with unit. An inch is a converted unit. It is from the Imperial system, its name is \"inch\" and it can be related to the si unit, millimetre, through a measure with unit whose value is 25.4 millimetre. A foot is also a converted unit. It is from the Imperial system, its name is \"foot\" and it can be related to an si unit, millimetre, either directly or through the unit called \"inch\". To identify some commonly used conversion based units the standard designations (case insensitive) for the Name attribute include the following:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcconversionbasedunit.htm"
     },
     "IfcCooledBeamType": {
-        "description": "The element type IfcCooledBeamType defines a list of commonly shared property set definitions of a cooled beam and an optional set of product representations. It is used to define a cooled beam specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcCooledBeamType defines a list of commonly shared property set definitions of a cooled beam and an optional set of product representations. It is used to define a cooled beam specification (i.e. the specific product information, that is common to all occurrences of that product type). A cooled beam type is used to define the common properties of a cooled beam that may be applied to many occurrences of that type. A cooled beam is a device typically used to cool air by circulating a fluid such as chilled water through exposed finned tubes above a space. Cooled beam types may be exchanged without being already assigned to occurrences. The occurrences of the IfcCooledBeamType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_CooledBeamTypeCommon: common property set for all cooled beam types Pset_CooledBeamTypeActive: property set for all active or ventilated cooled beam types",
         "predefined_types": {
             "ACTIVE": "An active or ventilated cooled beam provides cooling (and heating) but can also function as an air terminal in a ventilation system.",
             "NOTDEFINED": "Undefined cooled beam type.",
@@ -1027,7 +1027,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccooledbeamtype.htm"
     },
     "IfcCoolingTowerType": {
-        "description": "The element type IfcCoolingTowerType defines a list of commonly shared property set definitions of a cooling tower and an optional set of product representations. It is used to define a cooling tower specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcCoolingTowerType defines a list of commonly shared property set definitions of a cooling tower and an optional set of product representations. It is used to define a cooling tower specification (i.e. the specific product information, that is common to all occurrences of that product type). A cooling tower type is used to define the common properties of a cooling tower that may be applied to many occurrences of that type. A cooling tower is a device which rejects heat to ambient air by circulating a fluid such as water through it to reduce its temperature by partial evaporation. Cooling tower types may be exchanged without being already assigned to occurrences. The occurrences of the IfcCoolingTowerType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_CoolingTowerTypeCommon: common property set for all cooling tower types",
         "predefined_types": {
             "MECHANICALFORCEDDRAFT": "Air flow is produced by a mechanical device, typically one or more fans, located on the inlet air side of the cooling tower.",
             "MECHANICALINDUCEDDRAFT": "Air flow is produced by a mechanical device, typically one or more fans, located on the air outlet side of the cooling tower.",
@@ -1047,7 +1047,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifccoordinateduniversaltimeoffset.htm"
     },
     "IfcCostItem": {
-        "description": "An IfcCostItem describes a cost or financial value together with descriptive information that describes its context in a form that enables it to be used within a cost schedule.",
+        "description": "An IfcCostItem describes a cost or financial value together with descriptive information that describes its context in a form that enables it to be used within a cost schedule. Use Definitions An IfcCostItem can be used to represent the cost of goods and services, the execution of works by a process, lifecycle cost and much more. IfcCostItem brings together the value and currency concepts available through the IfcCostResource schema with the identification, naming and descriptive powers that all non-resource entities in the model inherit from IfcRoot. Each instance of IfcCostItem may have a name and a description. Depending on the use for which the cost is intended, these values should be asserted on the basis of agreement. For instance, the name attribute could be used to provide a common value that enables distinct instances to be brought together in a nesting arrangement (see below) whilst the description attribute could be used to provide the typical text that would be used for item description in a costing schedule. An IfcCostItem can nest other instances of IfcCostItem through its relationships to IfcRelNests. This can be used to enable the development of complex groups of costs as may be found in cost schedules through to pages, sections and complete cost schedules. Instances of IfcCostItem can be assigned to an IfcCostSchedule through the IfcRelSchedulesCostItems relationship class. Instances of IfcCostItem are used for cost estimates, budgets, etc., where a variety of identification codes are used extensively to identify the meaning of the cost. Examples include project phase codes, CSI codes, takeoff sequence numbers, cost accounts, etc. The IFC model allows for all classes that are ultimately subtypes of IfcObject to inherit the ability to have one or more instances of IfcClassificationNotation to be assigned. Where identification codes are required, the generic IFC classification facility should be used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifccostitem.htm"
     },
     "IfcCostSchedule": {
@@ -1060,7 +1060,7 @@
             "TargetUsers": "The actors for whom the cost schedule was prepared.",
             "UpdateDate": "The date that this cost schedule is updated; this allows tracking the schedule history."
         },
-        "description": "An IfcCostSchedule brings together instances of IfcCostItem either for the purpose of identifying purely cost information as in an estimate for constructions costs, bill of quantities etc. or for including cost information within another presentation form such as an order (of whatever type)",
+        "description": "An IfcCostSchedule brings together instances of IfcCostItem either for the purpose of identifying purely cost information as in an estimate for constructions costs, bill of quantities etc. or for including cost information within another presentation form such as an order (of whatever type) Use Definitions An IfcCostSchedule is ultimately a subtype of IfcRoot and consequently inherits its identifying, naming and description attributes. In addition to the global unique identifier, an IfcCostSchedule may be assigned a specific local unique identifier. The name attribute may be used to give an overall title or name to the IfcCostSchedule. The description attribute may be used to provide further descriptive narrative. This may include specific comments that can be applied. An IfcCostSchedule may be assigned a status that determines its current level of development or agreement. In the case of an 'APPROVED' status, this should only be set after an approval has been given through the association of an instance of IfcApproval. An IfcCostSchedule may also be declared as being of a particular type. A number of predefined types are included through the IfcCostScheduleTypeEnum enumeration.",
         "predefined_types": {
             "BUDGET": "An allocation of money for a particular purpose.",
             "COSTPLAN": "An assessment of the amount of money needing to be expended for a defined purpose based on incomplete information about the goods and services required for a construction or installation.",
@@ -1079,7 +1079,7 @@
             "Condition": "The condition under which a cost value applies.",
             "CostType": "Specification of the type of cost type used.  > NOTE: There are many possible types of cost value that may be identified. Whilst there is a broad understanding of the meaning of names that may be assigned to different types of costs, there is no general standard for naming cost types nor are there any broadly defined classifications. To allow for any type of cost value, the IfcLabel datatype is assigned.     In the absence of any well defined standard, it is recommended that local agreements should be made to define allowable and understandable cost value types within a project or region."
         },
-        "description": "An IfcCostValue is an amount of money or a value that affects an amount of money.",
+        "description": "An IfcCostValue is an amount of money or a value that affects an amount of money. Use Definitions Each instance of IfcCostValue may also have a CostType. There are many possible types of cost value that may be identified. Whilst there is a broad understanding of the meaning of names that may be assigned to different types of costs, there is no general standard for naming cost types nor are there any broadly defined classifications. To allow for any type of cost value, the IfcLabel datatype is assigned. The following defines some cost types that might be applied: In the absence of any well-defined standard, it is recommended that local agreements should be made to define allowable and understandable cost value types within a project or region.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifccostvalue.htm"
     },
     "IfcCovering": {
@@ -1087,7 +1087,7 @@
             "Covers": "Reference to the objectified relationship that handles the relationship of the covering to the covered space.",
             "CoversSpaces": ""
         },
-        "description": "Definition from ISO 6707-1:1989: term used: Finishing - final coverings and treatments of surfaces and their intersections.",
+        "description": "Definition from ISO 6707-1:1989: term used: Finishing - final coverings and treatments of surfaces and their intersections. A covering is an element which covers some part of another element and is fully dependent on that other element. The IfcCovering defines the occurrence of a covering type, that (if given) is expressed by the IfcCoveringType. Coverings can be assigned to - a space represented by IfcSpace using the inverse relationship CoversSpaces pointing to IfcRelCoversSpaces. The space is then accessible via IfcRelCoversSpaces.RelatedSpace. - a space boundary represented by IfcRelSpaceBoundary using the inverse relationship ProvidesBoundaries pointing to IfcRelSpaceBoundary. The space is then accessible via IfcRelSpaceBoundary.RelatingSpace. - a building element represented by IfcBuildingElement using the inverse relationship Covers pointing to IfcRelCoversBldgElements. The building element is then accessible via IfcRelCoversBldgElements.RelatingBuildingElement. - a distribution element represented by IfcDistributionElement using the inverse relationship Covers pointing to IfcRelCoversBldgElements. The distribution element is then accessible via IfcRelCoversBldgElements.RelatingBuildingElement. Only IfcCovering's with a PredefinedType INSULATION, MEMBRANE, SLEEVING, or WRAPPING shall be used to cover distribution elements. The following guideline shall apply: - (default) if the space has coverings that may not have an own shape representation and no defined relationships to the building elements they cover, then the IfcCovering shall be assigned to IfcSpace using the IfcRelCoversSpaces relationship, - if the space has coverings that have an own shape representation and the space has defined space boundaries, then the covering, which relates to that space, may be assigned to the space boundaries using the link to IfcRelSpaceBoundary, - if the covering does not relate to a space, then the covering should be assigned to the building element or a distribution element using the IfcRelCoversBldgElements relationship. *Type Use Definition* The IfcCovering defines the occurrence of any covering, common information about covering types (or styles) is handled by IfcCoveringType. The IfcCoveringType (if present) may establish the common type name, usage (or predefined) type, common set of properties, common material layer set, and common shape representations (using IfcRepresentationMap). The IfcCoveringType is attached using the IfcRelDefinedByType.RelatingType objectified relationship and is accessible by the inverse IsDefinedBy attribute. As an additional use agreement for standard coverings (i.e. slabs with constant thickness along the extrusion direction), the IfcCoveringType should have a unique IfcMaterialLayerSet, that is referenced by the IfcMaterialLayerSetUsage assigned to all occurrences of this covering type. If an IfcCoveringType is assigned to the IfcCovering, the attribute PredefinedType shall not be assigned, or shall be identical to IfcCoveringType.PredefinedType. *Property Set Use Definition*: The property sets relating to the IfcCovering are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcCovering are part of this IFC release: - Pset_CoveringCommon: common property set for all covering occurrences Pset_CoveringCeiling: specific property set for all occurrences of coverings with the PredefinedType: CEILING Pset_CoveringFlooring: specific property set for all occurrences of coverings with the PredefinedType: FLOORING *Quantity Use Definition*: The quantities relating to the IfcCovering are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. The following quantities are foreseen, but will be subjected to the local standard of measurement: *Geometry Use Definitions* The geometric representation of IfcCovering is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Included are: Local Placement The local placement for IfcCovering is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the same IfcSpatialStructureElement , which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the IfcCovering, however, is assigned to an IfcBuildingElement, and this element defines its own local placement, than the PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the IfcBuildingElement. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representations The geometric representation of the IfcCovering depends on two criteria: - Does it define an area or a volume? - Is the base surface (either the IfcRelSpaceBoundary or the surface of the IfcBuildingElement it relates to) a planar surface or a cylindrical surface? GeometricSet Representation The 'GeometricSet' geometric representation of IfcCovering supports area definitions as 3D surfaces. - RepresentationIdentifier : 'Surface' - RepresentationType : 'GeometricSet' The following additional constraints apply to the 'GeometricSet' representation of IfcCovering: - for planar base surfaces - bounded surface representation - for cylindrical base surfaces - swept surface representation SweptSolid Representation The 'SweptSolid' geometric representation of IfcCovering supports volume definitions as 3D solids. - RepresentationIdentifier : 'Body' - RepresentationType : 'SweptSolid' The following additional constraints apply to the 'SweptSolid' representation of IfcCovering: - for planar base surfaces - swept area representation - for cylindrical base surfaces - swept area representation",
         "predefined_types": {
             "CEILING": "The covering is used torepresent a ceiling.",
             "CLADDING": "The covering is used to represent a cladding.",
@@ -1103,7 +1103,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifccovering.htm"
     },
     "IfcCoveringType": {
-        "description": "The IfcCoveringType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The IfcCoveringType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A covering type is used to define the common properties of a certain type of a covering that may be applied to many instances of that type to assign a specific style. Covering types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcCoveringType are represented by instances of IfcCovering (or its subtypes). Informal proposition - The material assignment, if provided using the IfcRelAssociatesMaterial relationship, shall not reference the IfcMaterialLayerSetUsage.",
         "predefined_types": {
             "CEILING": "The covering is used torepresent a ceiling.",
             "CLADDING": "The covering is used to represent a cladding.",
@@ -1133,7 +1133,7 @@
             "Radius": "Edge radius according the above illustration (= r1).",
             "WebThickness": "Thickness of the web of the A shape crane rail. See illustration above (= b3)."
         },
-        "description": "Definition from IAI: The IfcCraneRailAShapeProfileDef defines a section profile that provides the defining parameters of a crane rail to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
+        "description": "Definition from IAI: The IfcCraneRailAShapeProfileDef defines a section profile that provides the defining parameters of a crane rail to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box. The centre of gravity, if given, is located in x direction within the center of the bounding box, and in y-direction along the negative y axis, the offset value is given by the offset parameter CentreOfGravityInY. Illustration: Table: Parameters of crane rail A shape",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccranerailashapeprofiledef.htm"
     },
     "IfcCraneRailFShapeProfileDef": {
@@ -1148,11 +1148,11 @@
             "Radius": "Edge radius according the above illustration (= r1).",
             "WebThickness": "Thickness of the web of the F shape crane rail. See illustration above (= b3)"
         },
-        "description": "Definition from IAI: The IfcCraneRailFShapeProfileDef defines a section profile that provides the defining parameters of a crane rail to be used by the swept surface geometry or the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
+        "description": "Definition from IAI: The IfcCraneRailFShapeProfileDef defines a section profile that provides the defining parameters of a crane rail to be used by the swept surface geometry or the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box. The centre of gravity, if given, is located in x direction within the center of the bounding box, and in y-direction along the positive y axis, the offset value is given by the offset parameter CentreOfGravityInY. Illustration: Table: Parameters of crane rail F shape.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccranerailfshapeprofiledef.htm"
     },
     "IfcCrewResource": {
-        "description": "An IfcCrewResource represents a type of resource used in construction processes, i.e. construction crew resource.",
+        "description": "An IfcCrewResource represents a type of resource used in construction processes, i.e. construction crew resource. A construction crew resource typically includes labor resource, equipment resource, material resource, subcontractor resource, as well as other crew resources. Construction crew resources are partially or wholly consumed, or occupied in a construction process (i.e. IfcTask). Since IfcCrewResource represents the resource types, individual persons are not required to be identified and linked to the crew resource, while they can be associated if needed. The IfcCrewResource is enabled to contain other crew resource types (i.e. crew resource type nesting) through its relationship to IfcRelNests.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifccrewresource.htm"
     },
     "IfcCsgPrimitive3D": {
@@ -1160,14 +1160,14 @@
             "Dim": "The space dimensionality of this geometric representation item, it is always 3. 3",
             "Position": "The placement coordinate system to which the parameters of each individual CSG primitive apply."
         },
-        "description": "Definition from IAI:  Abstract supertype of all three dimensional primitives used as either tree root item, or as Boolean results within an CSG solid model. All 3D CSG primitives are defined within an three-dimensional placement coordinate system,.",
+        "description": "Definition from IAI: Abstract supertype of all three dimensional primitives used as either tree root item, or as Boolean results within an CSG solid model. All 3D CSG primitives are defined within an three-dimensional placement coordinate system,.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifccsgprimitive3d.htm"
     },
     "IfcCsgSolid": {
         "attributes": {
             "TreeRootExpression": "Boolean expression of regularized operators describing the solid. The root of the tree of Boolean expressions is given explicitly as an IfcBooleanResult (the only item in the Select IfcCsgSelect)."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A solid represented as a CSG model is defined by a collection of so-called primitive solids, combined using regularized Boolean operations. The allowed operations are intersection, union, and difference. As a special case a CSG solid can also consists of a single CSG primitive.",
+        "description": "Definition from ISO/CD 10303-42:1992: A solid represented as a CSG model is defined by a collection of so-called primitive solids, combined using regularized Boolean operations. The allowed operations are intersection, union, and difference. As a special case a CSG solid can also consists of a single CSG primitive. - A CSG solid requires two kinds of information for its complete definition: geometric and structural. The geometric information is conveyed by solid models. These typically primitive volumes such as cylinders, wedges and extrusions, but can include general B-Rep models. There can also be solid replicas (not in current IFC release) and half space solids. - The structural information is in a tree (strictly an acyclic directed graph) of Boolean result and CSG solids, which represent a \u2018recipe\u2019 for building the solid. The terminal nodes are the geometric primitives and other solids. Every CSG solid has precisely one Boolean result associated with it which is the root of the tree that defines the solid. (There may be further Boolean results within the tree as operands). The significance of a CSG solid entity is that the solid defined by the associated tree is thus identified as a significant object itself, and in this way it is distinguished from other Boolean result entities representing intermediate results during the construction process. The following primitive volumes can be parts of the CSG tree: solid models, i.e. faceted B-Rep (IfcFacetedBrep, IfcFacetedBrepWithVoids), swept area solid (IfcExtrudedAreaSolid, IfcRevolvedAreaSolid, IfcSurfaceCurveSweptAreaSolid), swept disk solids (IfcSweptDiskSolid) and half space solids (_IfcHalfSpaceSolid_and subtypes). CSG primitives are out of scope for current IFC Release.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifccsgsolid.htm"
     },
     "IfcCurrencyRelationship": {
@@ -1178,15 +1178,15 @@
             "RelatedMonetaryUnit": "The monetary unit to which an exchange results. For instance, in the case of a conversion from GBP to USD, the related monetary unit is USD.",
             "RelatingMonetaryUnit": "The monetary unit from which an exchange is derived. For instance, in the case of a conversion from GBP to USD, the relating monetary unit is GBP."
         },
-        "description": "An IfcCurrencyRelationship defines the rate of exchange that applies between two designated currencies at a particular time and as published by a particular source.",
+        "description": "An IfcCurrencyRelationship defines the rate of exchange that applies between two designated currencies at a particular time and as published by a particular source. An IfcCurrencyRelationship is used where there may be a need to reference an IfcCostValue in one currency to an IfcCostValue in another currency. It takes account of fact that currency exchange rates may vary by requiring the recording the date and time of the currency exchange rate used and the source that publishes the rate. There may be many sources and there are different strategies for currency conversion (spot rate, forward buying of currency at a fixed rate). The source for the currency exchange is defined as an instance of IfcLibraryInformation that includes a name and a location (typically a URL, since most rates are now published in reliable sources via the web, although it may be a string value defining a location of any type).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifccurrencyrelationship.htm"
     },
     "IfcCurtainWall": {
-        "description": "Definition from ISO 6707-1:1989: Non load bearing wall positioned on the outside of a building and enclosing it.",
+        "description": "Definition from ISO 6707-1:1989: Non load bearing wall positioned on the outside of a building and enclosing it. Definition of IAI: Exterior wall of a building which is an assembly of components, hung from the edge of the floor/roof structure rather than bearing on a floor. Curtain wall is represented as a building element assembly and implemented as a subtype of IfcBuildingElement that uses an IfcRelAggregates relationship. *Property Set Use Definition*: The property sets relating to the IfcCurtainWall are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcCurtainWall are part of this IFC release: - Pset_CurtainWallCommon: common property set for all curtain wall occurrences *Geometry Use Definitions*: The geometric representation of IfcCurtainWall is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Independent geometric representations, as described below, should only be used when the IfcCurtainWall is not defined as an aggregate. If defined as an aggregate, the geometric representation is the sum of the representations of the components within the aggregate. Local placement The local placement for IfcCurtainWall is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. If the IfcCurtainWall establishes an aggregate, then all contained elements (defined by the IsDecomposedBy inverse attribute) shall be placed relative to the IfcCurtainWall.ObjectPlacement. Geometric Representation Currently, the use of 'BoundingBox', 'SurfaceModel', 'Brep' and 'MappedRepresentation' representations of IfcCurtainWall are supported. The conventions to use these representations are given at the level of the supertype, IfcBuildingElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifccurtainwall.htm"
     },
     "IfcCurtainWallType": {
-        "description": "The element type (IfcCurtainWallType) defines a list of commonly shared property set definitions of a curtain wall element and an optional set of product representations. It is used to define a curtain wall specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type (IfcCurtainWallType) defines a list of commonly shared property set definitions of a curtain wall element and an optional set of product representations. It is used to define a curtain wall specification (i.e. the specific product information, that is common to all occurrences of that product type). A curtain wall type is used to define the common properties of a certain type of curtain wall that may be applied to many instances of that type to assign a specific style. Curtain wall types may be exchanged without being already assigned to occurrences. The occurrences of the IfcCurtainWallType are represented by instances of IfcCurtainWall.",
         "predefined_types": {
             "NOTDEFINED": "",
             "USERDEFINED": ""
@@ -1197,7 +1197,7 @@
         "attributes": {
             "Dim": "The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve. IfcCurveDim(SELF)"
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A curve can be envisioned as the path of a point moving in its coordinate space.",
+        "description": "Definition from ISO/CD 10303-42:1992: A curve can be envisioned as the path of a point moving in its coordinate space. Informal proposition: - A curve shall be arcwise connected - A curve shall have an arc length greater than zero.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccurve.htm"
     },
     "IfcCurveBoundedPlane": {
@@ -1207,7 +1207,7 @@
             "InnerBoundaries": "An optional set of inner boundaries. They shall not intersect each other or the outer boundary.",
             "OuterBoundary": "The outer boundary of the surface."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: The curve bounded surface is a parametric surface with curved boundaries defined by one or more boundary curves. The bounded surface is defined to be the portion of the basis surface in the direction of N x T from any point on the boundary, where N is the surface normal and T the boundary curve tangent vector at this point. The region so defined shall be arcwise connected.",
+        "description": "Definition from ISO/CD 10303-42:1992: The curve bounded surface is a parametric surface with curved boundaries defined by one or more boundary curves. The bounded surface is defined to be the portion of the basis surface in the direction of N x T from any point on the boundary, where N is the surface normal and T the boundary curve tangent vector at this point. The region so defined shall be arcwise connected. The IfcCurveBoundedPlane is a specialized bounded surface class that deals only with bounding basis plane surfaces. The definition varies from STEP as outer and inner boundaries are separated attributes and refer to IfcCurve. The only basis surface that is allowed is of type IfcPlane, and the implicit_outer attribute has not been incorporated, since only unbounded surfaces are used as basis surface. The BasisSurface is an IfcPlane that establishes the position coordinate system by SELF\\IfcElementarySurface.Position. The OuterBoundary and the InnerBoundaries (if provided) shall lie on the surface of IfcPlane. Therefore the IfcCurve's establishing the outer and inner boundaries shall be: - either a 2D curve within the XY plane of the position coordinate sytem of IfcPlane - or a 3D curve with all coordinates having a z value = 0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccurveboundedplane.htm"
     },
     "IfcCurveStyle": {
@@ -1216,7 +1216,7 @@
             "CurveFont": "A curve style font which is used to present a curve. It can either be a predefined curve font, or an explicitly defined curve font. Both may be scaled. If not given, then the curve font should be taken from the layer assignment with style, if that is not given either, then the default curve font applies.",
             "CurveWidth": "A positive length measure in units of the presentation area for the width of a presented curve. If not given, then the style should be taken from the layer assignment with style, if that is not given either, then the default style applies."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: A curve style specifies the visual appearance of curves.",
+        "description": "Definition from ISO/CD 10303-46:1992: A curve style specifies the visual appearance of curves. An IfcCurveStyle provides the style table for presentation information assigned to geometric curves. The style is defined by a color, a font and a width. The IfcCurveStyle defines curve patterns as model patterns, i.e. the distance between visible and invisible segments of curve patterns are given in model space dimensions (that have to be scaled using the target plot scale). Styles are intended to be shared by multiple IfcStyledItem's, assigning the style to occurrences of (subtypes of) IfcGeometricRepresentationItem's. Measures given to a font pattern or a curve width are given in global drawing length units. The measure values for font pattern and curve width apply to the model space with a target plot scale provided for the correct appearance in the default plot scale.. For different scale and projection dependent curve styles a different instance of IfcCurveStyle needs to be used by IfcPresentationStyleAssignment for different IfcGeometricRepresentationSubContext dependent representations. An IfcCurveStyle can be assigned to IfcGeometricRepresentationItem's via the IfcPresentationStyleAssignment through an intermediate IfcStyledItem or IfcAnnotationCurveOccurrence.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccurvestyle.htm"
     },
     "IfcCurveStyleFont": {
@@ -1233,7 +1233,7 @@
             "CurveFontScaling": "The scale factor.",
             "Name": "Name that may be assigned with the scaling of a curve font."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: A curve style font and scaling is a curve style font and a scalar factor for that font, so that a given curve style font may be applied at various scales.",
+        "description": "Definition from ISO/CD 10303-46:1992: A curve style font and scaling is a curve style font and a scalar factor for that font, so that a given curve style font may be applied at various scales. The IfcCurveStyleFontAndScaling allows for the reuse of the same curve style definition in several sizes. The definition of the CurveFontScale is the scaling of a base curve style pattern to be used as a new or derived curve style pattern. An example for IfcCurveStyleFontAndScaling is the sizing of a basic curve style dash pattern 'dash' (visible 0.01m, invisible 0.005m) into 'dash large' with CurveFontScale = 2 (resulting in visible 0.02m, invisible 0.01m), and into 'dash small' with CurveFontScale = 0.5 (resulting in visible 0.005m, invisible 0.0025m).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccurvestylefontandscaling.htm"
     },
     "IfcCurveStyleFontPattern": {
@@ -1245,7 +1245,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccurvestylefontpattern.htm"
     },
     "IfcDamperType": {
-        "description": "The element type IfcDamperType defines a list of commonly shared property set definitions of a damper and an optional set of product representations. It is used to define a damper specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcDamperType defines a list of commonly shared property set definitions of a damper and an optional set of product representations. It is used to define a damper specification (i.e. the specific product information, that is common to all occurrences of that product type). A damper type is used to define the common properties of a damper that may be applied to many occurrences of that type. A damper typically participates in an HVAC duct distribution system and is used to control or modulate the flow of air. Damper types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDamperType are represented by instances of IfcFlowController or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DamperTypeCommon: common property set for all damper types Pset_DamperTypeControlDamper: property set for all control damper types Pset_DamperTypeFireDamper: property set for all fire damper types Pset_DamperTypeFireSmokeDamper: property set for all combination fire and smoke damper types Pset_DamperTypeSmokeDamper: property set for all smoke damper types",
         "predefined_types": {
             "BACKDRAFTDAMPER": "Damper used for purposes of manually balancing pressure differences.  Commonly operated by mechanical adjustment.",
             "BALANCINGDAMPER": "Backdraft damper used to restrict the movement of air in one direction.  Commonly operated by mechanical spring.",
@@ -1285,7 +1285,7 @@
             "Operator": "Transformation operator applied to the parent profile.",
             "ParentProfile": "The parent profile provides the origin of the transformation."
         },
-        "description": "Definition from IAI: The IfcDerivedProfileDef defines the profile by transformation from the parent profile. The transformation is given by a two dimensional transformation operator. Transformation includes translation, rotation, mirror and scaling. The latter can be uniform or non uniform. The derived profiles may be used to define swept surfaces, swept area solids or sectioned spines.",
+        "description": "Definition from IAI: The IfcDerivedProfileDef defines the profile by transformation from the parent profile. The transformation is given by a two dimensional transformation operator. Transformation includes translation, rotation, mirror and scaling. The latter can be uniform or non uniform. The derived profiles may be used to define swept surfaces, swept area solids or sectioned spines. The transformation effects the position, rotation, mirroring or scale of the profile at the underlying coordinate system, i.e. the coordinate system defined by the swept surface or swept area solid that uses the profile definition. It is the xy plane of either: - IfcSweptSurface.Position - IfcSweptAreaSolid.Position or in case of sectioned spines the xy plane of each list member of IfcSectionedSpine.CrossSectionPositions. The position and potential rotation of the ParentProfile within the underlying coordinate system is taken into consideration before applying the Cartesian transformation operator. Illustration: Table: Derivation of derived profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcderivedprofiledef.htm"
     },
     "IfcDerivedUnit": {
@@ -1307,7 +1307,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcderivedunitelement.htm"
     },
     "IfcDiameterDimension": {
-        "description": "The diameter dimension is a draughting callout that presents the diameter extent of a conic element. It consists of a dimension curve and may have projection curves (but is often defined without projection curves).",
+        "description": "The diameter dimension is a draughting callout that presents the diameter extent of a conic element. It consists of a dimension curve and may have projection curves (but is often defined without projection curves). Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdiameterdimension.htm"
     },
     "IfcDimensionCalloutRelationship": {
@@ -1322,7 +1322,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdimensioncurve.htm"
     },
     "IfcDimensionCurveDirectedCallout": {
-        "description": "The dimension curve directed callout is a dimension callout, which includes a dimension line. It normally presents an extent and/or direction of the product shape. Subtypes are introduced to declare specific forms of dimension curve directed callouts, such as:",
+        "description": "The dimension curve directed callout is a dimension callout, which includes a dimension line. It normally presents an extent and/or direction of the product shape. Subtypes are introduced to declare specific forms of dimension curve directed callouts, such as: - linear dimension - radius dimension - diameter dimension - angular dimension",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdimensioncurvedirectedcallout.htm"
     },
     "IfcDimensionCurveTerminator": {
@@ -1358,19 +1358,19 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcdirection.htm"
     },
     "IfcDiscreteAccessory": {
-        "description": "Representation of different kinds of accessories included in or added to elements.",
+        "description": "Representation of different kinds of accessories included in or added to elements. General usage The exact type information of the IfcDiscreteAccessory is given in the ObjectType attribute inherited from IfcObject. Standard type designations are provided for guideline below. The list is not exhaustive and the list of definitions may be extended based on local national extensions. Geometry Use Definitions: The geometric representation of IfcDiscreteAccessory is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcElementComponent. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcElementComponent. If the accessory is composed from several individual components it is represented through the IfcShapeRepresentation.Items with multiple geometry items.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcdiscreteaccessory.htm"
     },
     "IfcDiscreteAccessoryType": {
-        "description": "The element type (IfcDiscreteAccessoryType) defines a list of commonly shared property set definitions of a discrete accessory and an optional set of product representations. It is used to define a supporting element mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type).",
+        "description": "The element type (IfcDiscreteAccessoryType) defines a list of commonly shared property set definitions of a discrete accessory and an optional set of product representations. It is used to define a supporting element mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type). The occurrences of the IfcDiscreteAccessoryType are represented by instances of IfcDiscreteAccessory. The IfcDiscreteAccessoryType is a specialization of the general building element component type to represent different type of structural and building service related auxiliary elements. General usage The exact type information of the IfcDiscreteAccessoryType is given in the ElementType attribute inherited from IfcElementType. Standard type designations are provided for guideline below. The list is not exhaustive and the list of definitions may be extended based on local national extensions.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcdiscreteaccessorytype.htm"
     },
     "IfcDistributionChamberElement": {
-        "description": "The IfcDistributionChamberElement defines a place at which distribution systems and their constituent elements may be inspected or through which they may travel.",
+        "description": "The IfcDistributionChamberElement defines a place at which distribution systems and their constituent elements may be inspected or through which they may travel. An IfcDistributionChamberElement is a formed volume used in a distribution system, such as a sump, trench or manhole. Instances of IfcSystem or IfcDistributionFlowElement may be related to the IfcDistributionChamberElement enabling their location in or at the chamber to be determined. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences Geometry Use Definitions The geometric representation of IfcDistributionChamberElement is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcDistributionFlowElement. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcDistributionFlowElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionchamberelement.htm"
     },
     "IfcDistributionChamberElementType": {
-        "description": "The element type IfcDistributionChamberElementType defines a list of commonly shared property set definitions of a distribution chamber element and an optional set of product representations. It is used to define a distribution chamber element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcDistributionChamberElementType defines a list of commonly shared property set definitions of a distribution chamber element and an optional set of product representations. It is used to define a distribution chamber element specification (i.e. the specific product information, that is common to all occurrences of that product type). A distribution chamber element type is used to define the common properties of a distribution chamber element that may be applied to many occurrences of that type. A distribution chamber element is a formed volume used in a distribution system, such as a sump, trench or manhole. Distribution chamber element types may be exchanged without being already assigned to occurrences. The occurrences of the IfcDistributionChamberElementType are represented by instances of IfcDistributionElement or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release:",
         "predefined_types": {
             "FORMEDDUCT": "Space formed in the ground for the passage of pipes, cables, ducts.",
             "INSPECTIONCHAMBER": "Chamber constructed on a drain, sewer or pipeline with a removable cover that permits visble inspection.",
@@ -1390,37 +1390,37 @@
             "AssignedToFlowElement": "Reference through the relationship object to related distribution flow elements.",
             "ControlElementId": "The ControlElement Point Identification assigned to this control element by the Building Automation System."
         },
-        "description": "The distribution element IfcDistributionControlElement defines occurrence elements of a building automation control system that are used to impart control over elements of a distribution system.",
+        "description": "The distribution element IfcDistributionControlElement defines occurrence elements of a building automation control system that are used to impart control over elements of a distribution system. This class defines elements of a building automation control system. These are typically used to control distribution system elements to maintain temperature, humidity, pressure, flow, power, lighting levels, etc., through the modulation, staging or sequencing of mechanical or electrical devices. The three general functional categories of ControlElements as defined for this release of the IFC model are as follows: - Impart control over flow control elements (IfcFlowController) in a distribution system such as dampers, valves, relays, etc., typically through the use of actuation (IfcActuator: See IfcHvacDomain schema). - Sensing elements (IfcSensor: See IfcHvacDomain schema) that measure changes in the controlled variable (e.g., temperature, humidity, pressure, flow, etc.). - Controllers (IfcController: See IfcHvacDomain schema) typically classified according to the control action they seek to perform and generally responsible for making decisions about the elements under control. Since this class and its subtypes typically relate to many different distribution flow elements (IfcDistributionFlowElement), the objectified relationship IfcRelFlowControlElements has been provided to relate control and flow elements as required. Geometry Use Definitions The geometric representation of IfcControlElement is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The local placement is defined in the supertype IfcProduct. It is defined by a subtype of IfcObjectPlacement which can define an absolute placement, relative placement, or grid reference, with each defining the local coordinate system referenced by all geometric representations. The PlacementRelTo relationship of IfcLocalPlacement, if given, shall point to the same IfcSpatialStructureElement which is used in the ContainedInStructure inverse attribute, or to a referenced spatial structure element at a higher level. If the relative placement is not used, the absolute placement is defined within the world coordinate system. Informal propositions for local placement: - If the LocalPlacement is specified, then all aggregated components should use this placement as their relative placement. Standard Geometric Representation Currently, the use of attribute driven geometry for this class is not supported. The standard geometric representation is defined using explicit geometry. B-Rep Representation The faceted B-Rep capabilities (with or without voids) shall be supported for B-Rep representation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributioncontrolelement.htm"
     },
     "IfcDistributionControlElementType": {
-        "description": "The element type IfcDistributionControlElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcDistributionControlElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A distribution control element type is used to define the common properties of a distribution control element that may be applied to many occurrences of that type. Distribution control element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDistributionControlElementType are represented by instances of IfcDistributionControlElement or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributioncontrolelementtype.htm"
     },
     "IfcDistributionElement": {
-        "description": "Generalization of all elements that participate in a distribution system. Typical examples of IfcDistributionElement are (among others):",
+        "description": "Generalization of all elements that participate in a distribution system. Typical examples of IfcDistributionElement are (among others): - building service elements within a heating systems - building service elements within a cooling system - building service elements within a ventilation system - sanitary elements - electrical elements - elements within a communication network The IfcDistributionElement is further specialized in the IFC model. Direct instantiation of IfcDistributionElement without an assigned subtype of IfcDistributionElementType provides the meaning of an distribution element proxy. *Type Use Definition* The IfcDistributionElement defines the occurrence of any HVAC, electrical, sanitary or other element within a distribution system. Common information about distribution element types (or styles) is handled by subtypes of IfcDistributionElementType. The IfcDistributionElementType (if present) may establish the common type name, usage (or predefined) type, common material, common set of properties and common shape representations (using IfcRepresentationMap). The IfcDistributionElementType is attached using the IfcRelDefinedByType.RelatingType objectified relationship and is accessible by the inverse IsDefinedBy attribute. The assignment of types to distribution element occurrences is vital for providing the additional meaning, or ontology, of the distribution element. Many specialized type are defined in other schemas of the IFC specification. *Quantity Use Definition* The quantities relating to the IfcDistributionElement are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. A detailed specification for individual quantities is introduced at the level of subtypes of IfcDistributionElement. *Geometry Use Definitions* The geometric representation of IfcDistributionElement is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Local Placement The local placement for IfcDistributionElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement , which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representations The geometric representation of IfcDistributionElement is defined using different geometric representation types for the various subtypes. Only general recommendations are given at the level of the supertype, further constraints are defined at the level of its subtypes. - all occurrences of IfcDistributionElement (and its subtypes) should (whenever possible) share a representation map established by the assigned type. The geometric representation of the occurrence is then an IfcMappedItem. The IfcShapeRepresentation has: RepresentationIdentifier : 'Body' RepresentationType : 'MappedRepresentation' The shared geometric representation of the distribution element type (or in some cases of the distribution element) should follow (if applicable) the the following guidelines: - all fixtures (all non distribution flow elements, i.e. everything which is not a duct, a pipe, a cable, or a cable carrier) should be defined by an b-rep geometry. This includes also the complex flow fitting elements (e.g. Y branch or T branch) or distribution flow elements with size changes (e.g. reducer). The IfcShapeRepresentation has: RepresentationIdentifier : 'Body' RepresentationType : 'Brep' - if the geometric model consistency of a b-rep shape representation can not be guaranteed (arcwise connected volume bounded by faces, each being connected, oriented, finite, closed 2-manifold), a surface representation based on open shells should be used. The IfcShapeRepresentation then has: RepresentationIdentifier : 'Body' RepresentationType : 'SurfaceModel' - all \"simple\" distribution flow elements (general ducts and pipes) are defined by sweep geometry. The IfcShapeRepresentation has: RepresentationIdentifier : 'Body' RepresentationType : 'SweptSolid' - an additional representation type for all \"simple\" distribution flow elements (general ducts and pipes) is the ability to have a simple line based representation. The IfcShapeRepresentation has: RepresentationIdentifier : 'FootPrint' RepresentationType : 'GeometricCurveSet' - if only the analytical shape is required for which the exact interpolation between the cross sections is not required, a sectioned spine can be used. RepresentationIdentifier : 'Body' RepresentationType : 'SectionedSpine'",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcdistributionelement.htm"
     },
     "IfcDistributionElementType": {
-        "description": "The IfcDistributionElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The IfcDistributionElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A distribution element type is used to define the common properties of a certain type of a distribution element that may be applied to many instances of that feature type to assign a specific style. Distribution element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDistributionElementType are represented by instances of IfcDistributionElement (or its subtypes).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcdistributionelementtype.htm"
     },
     "IfcDistributionFlowElement": {
         "attributes": {
             "HasControlElements": "Reference to the relationship object that relates control elements."
         },
-        "description": "The distribution element IfcDistributionFlowElement defines occurrence elements of a distribution system that facilitate the distribution of energy or matter, such as air, water or power.",
+        "description": "The distribution element IfcDistributionFlowElement defines occurrence elements of a distribution system that facilitate the distribution of energy or matter, such as air, water or power. The IfcDistributionFlowElement utilizes the following capabilities mainly through inverse references to objectified relationships: - Grouping - being part of a logical group of objects - Classification - assigned reference to an external classification - Documentation - assigned reference to an external documentation - Type - reference to the product type information for the element occurrence - Properties - reference to all attached properties, including quantities - Cost control - reference to cost elements associated with this distribution element - Work processes - reference to work tasks, in which this distribution element participates - Aggregation - aggregated together with other elements to form an aggregate - Connection - connectivity to other elements, including the definition of the connection or joint The IfcDistributionFlowElement defines the occurrence of a distribution element within the spatial context of a project. The parameters that define the type of the distribution element and/or its shape are defined by the IfcDistributionFlowElementType subtypes, which is related by the inverse relationship IsDefinedBy pointing to IfcRelDefinesByType. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences *Containment Use Definition* The IfcDistributionFlowElement, like any subtype of IfcBuildingElement, may participate in two different containment relationships. The first (and in most implementation scenarios mandatory) relationship is the hierachical spatial containment, the second (optional) relationship is the aggregation within an element assembly. - The IfcDistributionFlowElement is placed within the project spatial hierarchy using the objectified relationship IfcRelContainedInSpatialStructure, referring to it by its inverse attribute SELF\\IfcElement.ContainedInStructure. Subtypes of IfcSpatialStructureElement are valid spatial containers, with IfcBuildingStorey being the default container. - The IfcDistributionFlowElement may be aggregated into an element assembly using the objectified relationship IfcRelAggregates, referring to it by its inverse attribute SELF\\IfcObjectDefinition.Decomposes. Any subtype of IfcElement can be an element assembly, with IfcElementAssembly as a special focus subtype. In this case it should not be additionally contained in the project spatial hierarchy, i.e. SELF\\IfcElement.ContainedInStructure should be NIL. *Geometry Use Definitions* The geometric representation of IfcDistributionFlowElement is given by the IfcProductDefinitionShape, allowing multiple geometric representations. If an IfcRepresentationMap is defined for the IfcFlowElementType or one of its subtypes, then the IfcDistributionFlowELement utilizes it through the IfcMappedItem. Included geometric representations are: Local Placement The local placement is defined in the supertype IfcProduct. It is defined by the IfcLocalPlacement which can define an absolute placement, relative placement, or grid reference, with each defining the local coordinate system referenced by all geometric representations. If given, the PlacementRelTo relationship of IfcLocalPlacement, shall point to the referenced IfcProduct. If the relative placement is not used, the absolute placement is defined within the world coordinate system. Informal propositions for local placement: - If the LocalPlacement is specified, then all aggregated components should use this placement as their relative placement. Geometric Representations Currently, the use of 'SweptSolid', 'Clipping', 'Brep' and 'MappedRepresentation' representations are supported. In addition, the general representation types 'SurfaceModel' and 'BoundingBox' are allowed. The geometry use definitions for 'BoundingBox', 'SurfaceModel' and 'Brep' are explained at IfcBuildingElement. The geometry use definitions for 'SweptSolid' and 'Clipping' are identical to those explained in detail at IfcBeam. MappedRepresentation In addition to the standard and advanced geometric representation of IfcFlowDistributionElement that is defined using the SweptSolid or Clipping geometry, the MappedRepresentation shall be supported as it allows for reusing the geometry definition of the flow distribution element type at all occurrences of the same type. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier: 'Body' - RepresentationType: 'MappedRepresentation' The same constraints as those given for the standard SweptSolid and the advanced SweptSolid and Clipping geometric representations shall apply to the MappedRepresentation of the IfcRepresentationMap.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionflowelement.htm"
     },
     "IfcDistributionFlowElementType": {
-        "description": "The element type IfcDistributionFlowElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcDistributionFlowElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A distribution flow element type is used to define the common properties of a distribution flow element that may be applied to many occurrences of that type. Distribution flow element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDistributionFlowElementType are represented by instances of IfcDistributionFlowElement or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionflowelementtype.htm"
     },
     "IfcDistributionPort": {
         "attributes": {
             "FlowDirection": "Enumeration that identifies if this port is a Sink (inlet), a Source (outlet) or both a SinkAndSource."
         },
-        "description": "The product IfcDistributionPort defines the occurrence of a specialized port for use within the context of distribution elements. Its type is defined by IfcDistributionPortType or its subtypes.",
+        "description": "The product IfcDistributionPort defines the occurrence of a specialized port for use within the context of distribution elements. Its type is defined by IfcDistributionPortType or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionPortDuct: property set for duct distribution port occurrences - Pset_DistributionPortPipe: property set for pipe distribution port occurrences Use Definitions The images below will help present the concepts of how an IfcDistributionPort is used to connect occurrences together in a distribution system. These concepts will be exemplified using a duct segment connecting to a tee and distributing air out through two connecting duct segments, as shown below in Figure 1. For the duct segments in this example, the concepts of the type, occurrence and performance history entities would be modeled using the following instances and shown in Figure 2: - The type (and representation) is defined using IfcDuctSegmentType from the IfcHvacDomain schema - The occurrences (and placements) are defined using IfcFlowSegment from the IfcSharedBldgServicesDomain schema - The performance history characteristics for these occurrence are defined using IfcPerformanceHistory from the IfcControlExtension schema The fitting would be represented in a similar manner using instances of IfcDuctFittingType, IfcFlowFitting and IfcPerformanceHistory for the type, occurrence and performance history entities respectively. Figure 3 includes all the type and occurrence entities that are involved in the duct and fitting example, as well as how the property sets defining type are related. Also included is how a port is involved in the connectivity of these entities. If we look specifically at the point in the example where the duct segment connects to the inlet of the tee fitting, as shown in Figure 4, there is a port on the duct and a port on the tee which are used to logically relate the two together so that a connection is inferred. This connection may be physically realized with a specific fitting that is used to physically connect the duct segment and the tee fitting, such as a flange or coupling. It is important to note that the notion of a port is different from that of a connector. Figure 5 indicates how fluid flow properties and connection-specific information may be incorporated at the mass-flow boundary layers within this example.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionport.htm"
     },
     "IfcDocumentElectronicFormat": {
@@ -1463,14 +1463,14 @@
             "RelatingDocument": "The document that acts as the parent, referencing or original document in a relationship.",
             "RelationshipType": "Describes the type of relationship between documents. This could be sub-document, replacement etc. The interpretation has to be established in an application context."
         },
-        "description": "An IfcDocumentInformationRelationship is a relationship class that enables a document to have the ability to reference other documents.",
+        "description": "An IfcDocumentInformationRelationship is a relationship class that enables a document to have the ability to reference other documents. This class can be used to describe relationships in which one document may reference one or more other sub documents or where a document is used as a replacement for another document (but where both the original and the replacing document need to be retained).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcdocumentinformationrelationship.htm"
     },
     "IfcDocumentReference": {
         "attributes": {
             "ReferenceToDocument": "The document information that is being referenced."
         },
-        "description": "An IfcDocumentReference is a reference to the location of a document. The reference is given by a system interpretable Location attribute (e.g., an URL string) or by a human readable location, where the document can be found, and an optional inherited internal reference ItemReference, which refers to a system interpretable position within the document. The optional inherited Name attribute is meant to have meaning for human readers. Optional document metadata can also be captured through reference to IfcDocumentInformation.",
+        "description": "An IfcDocumentReference is a reference to the location of a document. The reference is given by a system interpretable Location attribute (e.g., an URL string) or by a human readable location, where the document can be found, and an optional inherited internal reference ItemReference, which refers to a system interpretable position within the document. The optional inherited Name attribute is meant to have meaning for human readers. Optional document metadata can also be captured through reference to IfcDocumentInformation. Provides a lightweight capability that enables a document to be identified solely by reference to a name by which it is commonly known. The reference can also be used to point to document information for more detail as required. For example, the IAI mission statement in a document \"Introduction to IAI\" can be referenced by IfcDocumentReference.Location = 'http://iai-international.org/intro.html', and IfcDocumentReference = 'Mission statement'. Additionally: IfcDocumentReference.ReferenceToDocument[1].Name = 'Introduction to IAI', and IfcDocumentReference.ReferenceToDocument[1].Description = 'Basic document to introduce the aims of IAI'.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcdocumentreference.htm"
     },
     "IfcDoor": {
@@ -1478,7 +1478,7 @@
             "OverallHeight": "Overall measure of the height, it reflects the Z Dimension of a bounding box, enclosing the ~~body of the~~ door opening. If omitted, the _OverallHeight_ should be taken from the geometric representation of the _IfcOpening_ in which the door is inserted.     >  NOTE  The body of the door might be taller then the door opening (e.g. in cases where the door lining includes a casing). In these cases the OverallHeight shall still be given as the door opening height, and not as the total height of the door lining.",
             "OverallWidth": "Overall measure of the width, it reflects the X Dimension of a bounding box, enclosing the ~~body of the~~ door opening. If omitted, the _OverallWidth_ should be taken from the geometric representation of the _IfcOpening_ in which the door is inserted.     >  NOTE  The body of the door might be wider then the door opening (e.g. in cases where the door lining includes a casing). In these cases the OverallWidth shall still be given as the door opening width, and not as the total width of the door lining."
         },
-        "description": "Definition from ISO 6707-1:1989: Construction for closing an opening, intended primarily for access with hinged, pivoted or sliding operation.",
+        "description": "Definition from ISO 6707-1:1989: Construction for closing an opening, intended primarily for access with hinged, pivoted or sliding operation. The door is a building element that is predominately used to provide controlled access for people and goods. It includes constructions with hinged, pivoted, sliding, and additionally revolving and folding operations. A door consists of a lining and one or several panels, properties concerning the lining and panel are defined by the IfcDoorLiningProperties and the IfcDoorPanelProperties. The door entity, IfcDoor, defines a particular occurrence of a door inserted in the spatial context of a project. A door can: - either be inserted as a filler in an opening, then the IfcDoor has an inverse attribute FillsVoids provided, - or be a \"free standing\" door, then the IfcDoor has no inverse attribute FillsVoids provided. The actual parameter of the door and/or its shape are defined by the IfcDoor as the occurrence definition (or project instance), or by the IfcDoorStyle as the specific definition (or project type). Parameters are given: - at the IfcDoor for occurrence specific parameters. The IfcDoor specifies: the door width and height the door opening direction (by the y-axis of the ObjectPlacement) - at the IfcDoorStyle, to which the IfcDoor is related by the inverse relationship IsDefinedBy pointing to IfcRelDefinesByType, for style parameters common to all occurrences of the same style. the operation type (single swing, double swing, revolving, etc.) the door hinge side (by using two different styles for right and left opening doors) the construction type the particular attributes for the lining by the IfcDoorLiningProperties the particular attributes for the panels by the IfcDoorPanelProperties The IfcDoor is normally inserted into an IfcOpeningElement (but does not need to - see above) using the IfcRelFillsElement relationship. It is also directly linked to the spatial structure of the project (and here normally to the IfcBuildingStorey, or to the IfcSpace) using the IfcRelContainedInSpatialStructure relationship. *Property Set Use Definition*: The property sets relating to the IfcDoor are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcDoor are part of this IFC release: - Pset_DoorCommon: common property set for all door occurrences - Pset_DoorWindowGlazingType: specific property set for the glazing properties of the door glazing, if available - Pset_DoorWindowShadingType: specific property set for the shading properties of the door glazing, if available *Geometry Use Definitions*: The geometric representation of IfcDoor is given by the IfcProductDefinitionShape, allowing multiple geometric representations. The IfcDoor, in case of an occurrence object, gets its parameter and shape from the IfcDoorStyle. If an IfcRepresentationMap (a block definition) is defined for the IfcDoorStyle, then the IfcDoor inserts it through the IfcMappedItem. Local Placement The local placement for IfcDoor is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point to the local placement of the same element (if given), in which the IfcDoor is used as a filling (normally an IfcOpeningElement), as provided by the IfcRelFillsElement relationship. - If the IfcDoor is not inserted into an IfcOpeningElement, then the PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representation The geometric representation of IfcDoor is defined using the following (potentially multiple) IfcShapeRepresentation's for its IfcProductDefinitionShape: - Profile: A 'GeometricCurveSet' consisting of a single closed curve defining the outer boundary of the door (lining). The door parametric representation uses this profile in order to apply the door lining and panel parameter. If not provided, the profile of the IfcOpeningElement is taken. - FootPrint: A 'GeometricCurveSet', or 'Annotation2D' representation defining the 2D shape of the door - Body: A 'SweptSolid', 'SurfaceModel', or 'Brep' representation defining the 3D shape of the door. In addition the parametric representation of a (limited) door shape is available by applying the parameters from IfcDoorStyle referencing IfcDoorLiningProperties and IfcDoorPanelProperties. The purpose of the parameter is described at those entities and below (door opening operation by door style). Profile - 'GeometricCurveSet' representation The door profile is represented by a three-dimensional closed curve within a particular shape representation. The profile is used to apply the parameter of the parametric door representation. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Profile' - RepresentationType : 'GeometricCurveSet', only a single closed curve shall be contained in the set of IfcShapeRepresentation.Items. A 'Profile' representation has to be provided if: - a parametric representation shall be applied to the door AND the door is 'free standing', or the opening into which the door is inserted is not extruded horizontally (i.e. where the opening profile does not match the door profile) FootPrint - 'GeometricCurveSet' or 'Annotation2D' representation The door foot print is represented by a set of two-dimensional curves (or in case of 'Annotation2D' additional hatching and text) within a particular shape representation. The foot print is used for the planview representation of the door. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'FootPrint' - RepresentationType : 'GeometricCurveSet', or 'Annotation2D' Body - 'SweptSolid', 'SurfaceModel', or 'Brep' representation The door body is either represented parameterically (see parametric representation) or by explicit 3D shape. The 3D shape is given by using extrusion geometry, or surface models, or Brep models within a particular shape representation. The body is used for the model view representation of the door. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'SweptSolid', 'SurfaceModel', or 'Brep' MappedRepresentation The 'FootPrint' and 'Body' geometric representation of IfcDoor can be shared among several identical doors using the 'MappedRepresentation'. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'FootPrint', 'Body' - RepresentationType : 'MappedRepresentation' The same constraints, as given for the 'FootPrint', 'Body' representation identifiers, shall apply to the MappedRepresentation of the IfcRepresentationMap. *Door opening operation by door style* The parameters that defines the shape of the IfcDoor, are given at the IfcDoorStyle and the property sets, which are included in the IfcDoorStyle. The IfcDoor only defines the local placement which determines the opening direction of the door. The overall size of the IfcDoor to be used to apply the lining or panel parameter provided by the IfcDoorStyle is determined by the IfcShapeRepresentation with the RepresentationIdentifier = 'Profile'. Only in case of an IfcDoor inserted into an IfcOpeningElement using the IfcRelFillsElement relationship, having a horizontal extrusion (along the y-axis of the IfcDoor), the overall size is determined by the extrusion profile of the IfcOpeningElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoor.htm"
     },
     "IfcDoorLiningProperties": {
@@ -1495,7 +1495,7 @@
             "TransomOffset": "Offset of the transom (if given) which divides the door leaf from a glazing (or window) above. The offset is given from the bottom of the door opening.",
             "TransomThickness": "Thickness (width in plane parallel to door leaf) of the transom (if given) which divides the door leaf from a glazing (or window) above."
         },
-        "description": "Definition of IAI: The door lining is the frame which enables the door leaf to be fixed in position. The door lining is used to hang the door leaf. The parameters of the door lining (IfcDoorLiningProperties) define the geometrically relevant parameter of the lining.",
+        "description": "Definition of IAI: The door lining is the frame which enables the door leaf to be fixed in position. The door lining is used to hang the door leaf. The parameters of the door lining (IfcDoorLiningProperties) define the geometrically relevant parameter of the lining. The IfcDoorLiningProperties are included in the list of properties (HasPropertySets) of the IfcDoorStyle. More information about the door lining can be included in the same list of the IfcDoorStyle using the IfcPropertySet for dynamic extensions. *Geometry Use Definitions* The IfcDoorLiningProperties does not hold its own geometric representation. However it defines parameters which can be used to create the shape of the door style (which is inserted by the IfcDoor into the spatial context of the project). Interpretation of parameter The parameters of the IfcDoorLiningProperties define a standard door lining, including (if given) a threshold and a transom. The outer boundary of the lining is determined by the occurrence parameter assigned to the IfcDoor, which inserts the IfcDoorStyle.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorliningproperties.htm"
     },
     "IfcDoorPanelProperties": {
@@ -1506,7 +1506,7 @@
             "PanelWidth": "Width of this panel, given as ratio relative to the total clear opening width of the door.",
             "ShapeAspectStyle": "Pointer to the shape aspect, if given. The shape aspect reflects the part of the door shape, which represents the door panel."
         },
-        "description": "A description of the door panel. A door panel is normally a door leaf that opens to allow people or goods to pass. The parameters of the door panel define the geometrically relevant parameter of the panel,",
+        "description": "A description of the door panel. A door panel is normally a door leaf that opens to allow people or goods to pass. The parameters of the door panel define the geometrically relevant parameter of the panel, The IfcDoorPanelProperties are included in the list of properties , given by attribute HasPropertySets of the IfcDoorStyle. More information about the door panel can be included in the same list of the IfcDoorStyle using the IfcPropertySet for dynamic extensions. *Geometry Use Definitions* The IfcDoorPanelProperties does not hold an own geometric representation. However it defines parameter, which can be used to create the shape of the door style (which is inserted by the IfcDoor into the spatial context of the project). Interpretation of parameters The parameters of the IfcDoorPanelProperties define a standard door panel, including (if given) a proportional width to define non-uniform double swing (or sliding, or folding) doors. The outer boundary of the panel is determined by the occurrence parameter assigned to the IfcDoor, which inserts the IfcDoorStyle. It has to take the lining parameter into account as well.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorpanelproperties.htm"
     },
     "IfcDoorStyle": {
@@ -1516,7 +1516,7 @@
             "ParameterTakesPrecedence": "The Boolean value reflects, whether the parameter given in the attached lining and panel properties exactly define the geometry (TRUE), or whether the attached style shape take precedence (FALSE). In the last case the parameter have only informative value.",
             "Sizeable": "The Boolean indicates, whether the attached _IfcMappedRepresentation_ (if given) can be sized (using scale factor of transformation), or not (FALSE). If not, the _IfcMappedRepresentation_ should be _IfcShapeRepresentation_ of the _IfcDoor_ (using _IfcMappedItem_ as the _Item_) with the scale factor = 1."
         },
-        "description": "Definition from IAI: The door style, IfcDoorStyle, defines a particular style of doors, which may be included into the spatial context of the building model through an (or multiple) instances of IfcDoor. A door style defines the overall parameter of the door style and refers to the particular parameter of the lining and one (or several) panels through the IfcDoorLiningProperties and the IfcDoorPanelProperties.",
+        "description": "Definition from IAI: The door style, IfcDoorStyle, defines a particular style of doors, which may be included into the spatial context of the building model through an (or multiple) instances of IfcDoor. A door style defines the overall parameter of the door style and refers to the particular parameter of the lining and one (or several) panels through the IfcDoorLiningProperties and the IfcDoorPanelProperties. The door entity, IfcDoor, defines a particular occurrence of a door inserted in the spatial context of a project. The actual parameter of the door and/or its shape is defined at the IfcDoorStyle, to which the IfcDoor is related by the inverse relationship IsDefinedBy pointing to IfcRelDefinedByType. The IfcDoorStyle also defines the particular attributes for the lining_, IfcDoorLiningProperties_, and panels, IfcDoorPanelProperties. *Geometry Use Definitions*: The IfcDoorStyle defines the baseline geometry, or the representation map, for all occurrences of the door style, given by the IfcDoor, pointing to this style. The representation of the door style may be given by the agreed set of minimal parameters, defined for the door lining and the door panel(s), or it may be given by a geometric representation used by the IfcRepresentationMap. The attribute ParameterTakesPrecedence decides, whether the set of parameters can be used to exactly represent the shape of the door style (TRUE), or whether the attached IfcRepresentationMap holds the exact representation (FALSE). Interpretation of parameter The IfcDoorStyleOperationTypeEnum defines the general layout of the door style. Depending on the enumerator, the appropriate instances of IfcDoorLiningProperties and IfcDoorPanelProperties are attached in the list of HasPropertySets. The _IfcDoorStyleOperationTypeEnum_mainly determines the hinge side (left hung, or right hung), the operation (swinging, sliding, folding, etc.) and the number of panels. See geometry use definitions at _IfcDoorStyleOperationTypeEnum_for the correct usage of opening symbols for different operation types.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorstyle.htm"
     },
     "IfcDraughtingCallout": {
@@ -1539,19 +1539,19 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdraughtingcalloutrelationship.htm"
     },
     "IfcDraughtingPreDefinedColour": {
-        "description": "The draughting pre defined colour is a pre defined colour for the purpose to identify a colour by name. Allowable names are:",
+        "description": "The draughting pre defined colour is a pre defined colour for the purpose to identify a colour by name. Allowable names are: - 'black', - 'red', - 'green', - 'blue', - 'yellow', - 'magenta', - 'cyan', - 'white', The following table states the RGB values associated with the names given by the IfcDraughtingPreDefinedColour.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcdraughtingpredefinedcolour.htm"
     },
     "IfcDraughtingPreDefinedCurveFont": {
-        "description": "The draughting predefined curve font type defines a selection of widely used curve fonts for draughting purposes by name.",
+        "description": "The draughting predefined curve font type defines a selection of widely used curve fonts for draughting purposes by name. Illustration from ISO 10303-46 TC2:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcdraughtingpredefinedcurvefont.htm"
     },
     "IfcDraughtingPreDefinedTextFont": {
-        "description": "The draughting pre defined text font is a pre defined text font for the purpose to identify a font by name. Allowable names are:",
+        "description": "The draughting pre defined text font is a pre defined text font for the purpose to identify a font by name. Allowable names are: - 'ISO 3098-1 font A', - 'ISO 3098-1 font B', The ISO 3098-1 font A is the text font as denoted as Letterng A in clause 3 of ISO 3098-1, the ISO 3098-1 font B is the text font as denoted as Letterng B in clause 3 of ISO 3098-1.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcdraughtingpredefinedtextfont.htm"
     },
     "IfcDuctFittingType": {
-        "description": "The element type IfcDuctFittingType defines a list of commonly shared property set definitions of a duct fitting and an optional set of product representations. It is used to define an duct fitting specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcDuctFittingType defines a list of commonly shared property set definitions of a duct fitting and an optional set of product representations. It is used to define an duct fitting specification (i.e. the specific product information, that is common to all occurrences of that product type). A Duct fitting type is used to define the common properties of a duct fitting that may be applied to many occurrences of that type. A duct fitting is a junction or transition in a flow distribution system (e.g., elbow, tee, etc.). Duct fitting types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDuctFittingType are represented by instances of IfcFlowFitting or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DuctFittingTypeCommon: common property set for all duct fitting types",
         "predefined_types": {
             "BEND": "A fitting with typically two ports used to change the direction of flow between connected elements.",
             "CONNECTOR": "Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two duct segments).",
@@ -1566,7 +1566,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcductfittingtype.htm"
     },
     "IfcDuctSegmentType": {
-        "description": "The element type IfcDuctSegmentType defines a list of commonly shared property set definitions of a duct segment and an optional set of product representations. It is used to define a duct segment specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcDuctSegmentType defines a list of commonly shared property set definitions of a duct segment and an optional set of product representations. It is used to define a duct segment specification (i.e. the specific product information, that is common to all occurrences of that product type). A Duct Segment type is used to define the common properties of a duct segment that may be applied to many occurrences of that type. A duct segment is used to typically join two sections of duct network. Duct segment types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDuctSegmentType are represented by instances of IfcFlowSegment or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DuctSegmentTypeCommon: common property set for all duct segment types",
         "predefined_types": {
             "FLEXIBLESEGMENT": "A flexible segment is a continuous non-linear segment of duct that can be deformed and change the direction of flow.",
             "NOTDEFINED": "Undefined segment.",
@@ -1576,7 +1576,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcductsegmenttype.htm"
     },
     "IfcDuctSilencerType": {
-        "description": "The element type IfcDuctSilencerType defines a list of commonly shared property set definitions of a duct silencer and an optional set of product representations. It is used to define a duct silencer specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcDuctSilencerType defines a list of commonly shared property set definitions of a duct silencer and an optional set of product representations. It is used to define a duct silencer specification (i.e. the specific product information, that is common to all occurrences of that product type). A duct silencer type is used to define the common properties of a duct silencer that may be applied to many occurrences of that type. A duct silencer is a device that is typically installed inside a duct distribution system for the purpose of reducing the noise levels from air movement, fan noise, etc. in the adjacent space or downstream of the duct silencer device. Duct silencer types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDuctSilencerType are represented by instances of IfcFlowTreatmentDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DuctSilencerTypeCommon: common property set for all duct silencer types",
         "predefined_types": {
             "FLATOVAL": "Flat-oval shaped duct silencer type.",
             "NOTDEFINED": "Undefined duct silencer type.",
@@ -1591,7 +1591,7 @@
             "EdgeEnd": "End point (vertex) of the edge. The same vertex can be used for both EdgeStart and EdgeEnd.",
             "EdgeStart": "Start point (vertex) of the edge."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: An edge is the topological construct corresponding to the connection of two vertices. More abstractly, it may stand for a logical relationship between two vertices. The domain of an edge, if present, is a finite, non-self-intersecting open curve in R^M^, that is, a connected 1-dimensional manifold. The bounds of an edge are two vertices, which need not be distinct. The edge is oriented by choosing its traversal direction to run from the first to the second vertex. If the two vertices are the same, the edge is a self loop. The domain of the edge does not include its bounds, and 0 \u2264 \u039e \u2264 \u221e. Associated with an edge may be a geometric curve to locate the edge in a coordinate space; this is represented by the edge curve (IfcEdgeCurve) subtype. The curve shall be finite and non-self-intersecting within the domain of the edge. An edge is a graph, so its multiplicity M and graph genus G^e^ may be determined by the graph traversal algorithm. Since M = E = 1, the Euler equation (1) reduces in the case to",
+        "description": "Definition from ISO/CD 10303-42:1992: An edge is the topological construct corresponding to the connection of two vertices. More abstractly, it may stand for a logical relationship between two vertices. The domain of an edge, if present, is a finite, non-self-intersecting open curve in R^M^, that is, a connected 1-dimensional manifold. The bounds of an edge are two vertices, which need not be distinct. The edge is oriented by choosing its traversal direction to run from the first to the second vertex. If the two vertices are the same, the edge is a self loop. The domain of the edge does not include its bounds, and 0 \u2264 \u039e \u2264 \u221e. Associated with an edge may be a geometric curve to locate the edge in a coordinate space; this is represented by the edge curve (IfcEdgeCurve) subtype. The curve shall be finite and non-self-intersecting within the domain of the edge. An edge is a graph, so its multiplicity M and graph genus G^e^ may be determined by the graph traversal algorithm. Since M = E = 1, the Euler equation (1) reduces in the case to where V = 1 or 2, and G^e^ = 1 or 0. Specifically, the topological edge defining data shall satisfy: Informal propositions: - The edge has dimensionality 1. - The extend of an edge shall be finite and nonzero",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcedge.htm"
     },
     "IfcEdgeCurve": {
@@ -1599,14 +1599,14 @@
             "EdgeGeometry": "The curve which defines the shape and spatial location of the edge. This curve may be unbounded and is implicitly trimmed by the vertices of the edge; this defines the edge domain. Multiple edges can reference the same curve.",
             "SameSense": "This logical flag indicates whether (TRUE), or not (FALSE) the senses of the edge and the curve defining the edge geometry are the same. The sense of an edge is from the edge start vertex to the edge end vertex; the sense of a curve is in the direction of increasing parameter."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: An edge curve is a special subtype of edge which has its geometry fully defined. The geometry is defined by associating the edge with a curve which may be unbounded. As the topological and geometric directions may be opposed, an indicator (same sense) is used to identify whether the edge and curve directions agree or are opposed. The Boolean value indicates whether the curve direction agrees with (TRUE) or is in the opposite direction (FALSE) to the edge direction. Any geometry associated with the vertices of the edge shall be consistent with the edge geometry.",
+        "description": "Definition from ISO/CD 10303-42:1992: An edge curve is a special subtype of edge which has its geometry fully defined. The geometry is defined by associating the edge with a curve which may be unbounded. As the topological and geometric directions may be opposed, an indicator (same sense) is used to identify whether the edge and curve directions agree or are opposed. The Boolean value indicates whether the curve direction agrees with (TRUE) or is in the opposite direction (FALSE) to the edge direction. Any geometry associated with the vertices of the edge shall be consistent with the edge geometry. Informal propositions: - The domain of the edge curve is formally defined to be the domain of its edge geometry as trimmed by the vertices. This domain does not include the vertices. - An edge curve has non-zero finite extent. - An edge curve is a manifold. - An edge curve is arcwise connected. - The edge start is not a part of the edge domain. - The edge end is not a part of the edge domain. - Vertex geometry shall be consistent with edge geometry.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcedgecurve.htm"
     },
     "IfcEdgeFeature": {
         "attributes": {
             "FeatureLength": "The length of the feature in orthogonal direction from the feature cross section."
         },
-        "description": "A feature describing the edge shape of an building element.",
+        "description": "A feature describing the edge shape of an building element. Geometry Use Definitions: The geometric representation of IfcEdgeFeature is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined in the supertype IfcFeatureElementSubtraction. Standard Geometric Representation The use of Standard Geometric Representations is defined in the supertype IfcFeatureElementSubtraction.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcedgefeature.htm"
     },
     "IfcEdgeLoop": {
@@ -1614,11 +1614,11 @@
             "EdgeList": "A list of oriented edge entities which are concatenated together to form this path.",
             "Ne": "The number of elements in the edge list. SIZEOF(EdgeList)"
         },
-        "description": "Definition from ISO/CD 10303-42:1992: An edge_loop is a loop with nonzero extent. It is a path in which the start and end vertices are the same. Its domain, if present, is a closed curve. An edge_loop may overlap itself.",
+        "description": "Definition from ISO/CD 10303-42:1992: An edge_loop is a loop with nonzero extent. It is a path in which the start and end vertices are the same. Its domain, if present, is a closed curve. An edge_loop may overlap itself. Informal propositions: - The genus of the IfcEdgeLoop shall be 1 or greater. - The Euler formula shall be satisfied: (number of vertices) + genus - (number of edges) = 1; - No edge may be referenced more than once by the same IfcEdgeLoop with the same sense. For this purpose, an edge which is not an oriented edge is considered to be referenced with the sense TRUE.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcedgeloop.htm"
     },
     "IfcElectricApplianceType": {
-        "description": "An IfcElectricApplianceType defines a particular type of common electrical appliance found in a typical AEC/FM facility. Electrical Appliances generally consist of electrical devices that are not a fixed part of the building but instead can be moved from one space to another and are powered with electricity.",
+        "description": "An IfcElectricApplianceType defines a particular type of common electrical appliance found in a typical AEC/FM facility. Electrical Appliances generally consist of electrical devices that are not a fixed part of the building but instead can be moved from one space to another and are powered with electricity. *Use Definitions* An IfcElectricApplianceType is a subtype of IfcFlowTerminalType that provides for various forms of electrical appliance. Usage of IfcElectricApplianceType defines the parameters for one or more occurrences of IfcFlowTerminal. *Property Set Use Definition*: The property sets relating to the IfcElectricApplianceType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcElectricApplianceType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "COMPUTER": "",
             "DIRECTWATERHEATER": "",
@@ -1654,11 +1654,11 @@
             "DistributionPointFunction": "Identifies the functions or purposes that a distribution point may fulfill from which that required may be selected.",
             "UserDefinedFunction": ""
         },
-        "description": "An IfcElectricDistributionPoint is a flow controller in which instances of electrical devices are brought together at a single place for a particular purpose",
+        "description": "An IfcElectricDistributionPoint is a flow controller in which instances of electrical devices are brought together at a single place for a particular purpose *Property Set Use Definition*: The property sets relating to the IfcElectricDistributionPoint_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an _IfcElectricDistributionPoint_are part of this IFC release: - Pset_ElectricDistributionPointCommon: common property set for all types of an electric distribution point panel, distribution board etc.), if available *Use Definitions* An IfcElectricDistributionPoint provides a housing for an aggregation of different types of instances of electrical distribution elements so that they can be viewed, operated or acted upon from a single place. Each item in the aggregation may have its own geometric representation and location by virtue of being a subtype of IfcProduct. IfcElectricDistributionPoint acts as the relating object in an IfcRelAggregates relationship, the electrical devices that are brought together being the related objects. *Geometry Use Definitions* The geometric representation of an occurrence of an IfcElectricDistributionPoint is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The local placement is defined in the supertype IfcProduct. It is defined by a subtype of IfcObjectPlacement which can define an absolute placement, relative placement, or grid reference, with each defining the local coordinate system referenced by all geometric representations. The PlacementRelTo relationship of IfcLocalPlacement, if given, shall point to the same IfcSpatialStructureElement which is used in the ContainedInStructure inverse attribute, or to a referenced spatial structure element at a higher level. If the relative placement is not used, the absolute placement is defined within the world coordinate system. Informal propositions for local placement: - If the LocalPlacement is specified, then all aggregated components should use this placement as their relative placement. Standard Geometric Representation Currently, the use of profiles to define the geometry for an occurrence of this class is not supported. The standard geometric representation is defined using explicit geometry. B-Rep Representation The faceted B-Rep capabilities (with or without voids) shall be supported for B-Rep representation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricdistributionpoint.htm"
     },
     "IfcElectricFlowStorageDeviceType": {
-        "description": "An IfcElectricFlowStorageDeviceType is a device in which electrical energy is stored and from which energy may be progressively released.",
+        "description": "An IfcElectricFlowStorageDeviceType is a device in which electrical energy is stored and from which energy may be progressively released. *Use Definitions* An IfcElectricFlowStorageDeviceType is a subtype of IfcFlowStorageDeviceType that provides for various devices that store electrical energy. Usage of IfcElectricFlowStorageDeviceType defines the parameters for one or more occurrences of IfcFlowStorageDevice. *Property Set Use Definition*: The property sets relating to the IfcElectricFlowStorageDeviceType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcElectricFlowStorageDeviceType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "BATTERY": "A device for storing energy in chemical form so that it can be released as electrical energy.",
             "CAPACITORBANK": "A device that stores electrical energy when an external power supply is present using the electrical property of capacitance.",
@@ -1671,7 +1671,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricflowstoragedevicetype.htm"
     },
     "IfcElectricGeneratorType": {
-        "description": "An IfcElectricGeneratorType defines a particular type of engine that is a machine for converting mechanical energy into electrical energy.",
+        "description": "An IfcElectricGeneratorType defines a particular type of engine that is a machine for converting mechanical energy into electrical energy. *Use Definitions,* An IfcElectricGeneratorType is a subtype of IfcEnergyConversionDeviceType that provides for all forms of electric engine. Usage of IfcElectricGeneratorType defines the parameters for one or more occurrences of IfcEnergyConversionDevice. No predefined types of electrical generator are specified at this stage. Use the IfcElectricalGeneratorType.Name and IfcElectricalGeneratorType.Description attributes to further qualify a generator. *Property Set Use Definition*: The property sets relating to the IfcElectricGeneratorType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcElectricGeneratorType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available - Pset_ElectricGeneratorTypeCommon: property set for properties that are common to all types of electrical generator, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "NOTDEFINED": "Undefined type.",
             "USERDEFINED": "User-defined type."
@@ -1679,7 +1679,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricgeneratortype.htm"
     },
     "IfcElectricHeaterType": {
-        "description": "An IfcElectricHeaterType is a device that emits electrical energy as heat.",
+        "description": "An IfcElectricHeaterType is a device that emits electrical energy as heat. *Use Definitions* An IfcElectricHeaterType is a subtype of IfcEnergyConversionDeviceType that provides for various devices that emit electrical energy as heat. Usage of IfcElectricHeaterType defines the parameters for one or more occurrences of IfcEnergyConversionDevice. Parameters are specified through property sets that are enumerated in the IfcElectricHeaterTypeEnum data type. *Property Set Use Definition*: The property sets relating to the IfcElectricHeaterType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcElectricHeaterType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available - Pset_ElectricHeaterTypeElectricalCableHeater: specific property set for the properties of an electrical cable heater emitting heat along its length, if available - Pset_ElectricHeaterTypeElectricalMatHeater: specific property set for the properties of an electrical mat heater emitting heat over its complete coverage area, if available - Pset_ElectricHeaterTypeElectricalPointHeater: specific property set for the properties of an electrical point heater emitting heat at the point of its location, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "ELECTRICCABLEHEATER": "",
             "ELECTRICMATHEATER": "",
@@ -1690,7 +1690,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricheatertype.htm"
     },
     "IfcElectricMotorType": {
-        "description": "Definition from BS6100 310 5201: An IfcElectricMotorType defines a particular type of engine that is a machine for converting electrical energy into mechanical energy.",
+        "description": "Definition from BS6100 310 5201: An IfcElectricMotorType defines a particular type of engine that is a machine for converting electrical energy into mechanical energy. *Use Definitions* An IfcElectricMotorType is a subtype of IfcEnergyConversionDeviceType that provides for all forms of electric motor. Usage of IfcElectricMotorType defines the parameters for one or more occurrences of IfcEnergyConversionDevice. *Property Set Use Definition*: The property sets relating to the IfcElectricMotorType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcElectricMotorType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available - Pset_ElectricMotorTypeCommon: property set for properties that are common to all types of electrical motor, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "DC": "A motor using either generated or rectified Direct Current (DC) power.",
             "INDUCTION": "An alternating current motor in which the primary winding on one member (usually the stator) is connected to the power source and a secondary winding or a squirrel-cage secondary winding on the other member (usually the rotor) carries the induced current. There is no physical electrical connection to the secondary winding, its current is induced.",
@@ -1703,7 +1703,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricmotortype.htm"
     },
     "IfcElectricTimeControlType": {
-        "description": "An IfcElectricTimeControlType is a device that applies control to the provision or flow of electrical energy over time.",
+        "description": "An IfcElectricTimeControlType is a device that applies control to the provision or flow of electrical energy over time. *Use Definitions* An IfcElectricTimeControlType is a subtype of IfcFlowControllerType. Usage of IfcElectricTimeControlType defines the parameters for one or more occurrences of IfcFlowController. *Property Set Use Definition*: The property sets relating to the IfcElectricTimeControlType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcElectricTimeControlType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "NOTDEFINED": "Undefined type.",
             "RELAY": "Electromagnetically operated contactor for making or breaking a control circuit.",
@@ -1728,7 +1728,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcelectricalbaseproperties.htm"
     },
     "IfcElectricalCircuit": {
-        "description": "An IfcElectricalCircuit defines a particular type of system that is for the purpose of distributing electrical power.",
+        "description": "An IfcElectricalCircuit defines a particular type of system that is for the purpose of distributing electrical power. *Use Definitions* Usage of IfcElectricalCircuit is as for the supertype IfcSystem *Property Set Use Definition*: The property sets relating to the IfcElectricalCircuit_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcElectricalCircuit are part of this IFC release: - Pset_ElectricalCircuit: common property set for the properties of an electrical circuit (as a subtype of IfcSystem), if available *Geometry Use Definitions* There is no geometric definition for a system or subtype of system. Geometry use is determined by the elements that are grouped within the system.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricalcircuit.htm"
     },
     "IfcElectricalElement": {
@@ -1751,14 +1751,14 @@
             "ReferencedInStructures": "Reference relationship to the spatial structure element, to which the element is additionally associated.",
             "Tag": "The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level."
         },
-        "description": "Generalization of all components that make up an AEC product. Those elements can be logically contained by a spatial structure element that constitutes a certain level within a project structure hierarchy (e.g., site, building, storey or space). This is done by using the IfcRelContainedInSpatialStructure relationship.",
+        "description": "Generalization of all components that make up an AEC product. Those elements can be logically contained by a spatial structure element that constitutes a certain level within a project structure hierarchy (e.g., site, building, storey or space). This is done by using the IfcRelContainedInSpatialStructure relationship. Elements are physically existent objects, although they might be void elements, such as holes. Elements either remain permanently in the AEC product, or only temporarily, as formwork does. Elements can be either assembled on site or pre-manufactured and built in on site. An element can have material and quantity information assigned through the IfcRelAssociatesMaterial and IfcRelDefinesByProperties relationship. In addition an element can be declared to be a specific occurrence of an element type (and thereby be defined by the element type properties) using the IfcRelDefinesByType relationship. An element can also be defined as an element assembly that is a group of semantically and topologically related elements that form a higher level part of the AEC product. Those element assemblies are defined by virtue of the IfcRelAggregates relationship. Elements that performs the same function may be grouped by an \"Element Group By Function\". It is realized by an instance of IfcGroup with the ObjectType = 'ElementGroupByFunction\". *Property Set Use Definition*: The property sets relating to the IfcElement are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcElement are part of this IFC release: - Pset_Draughting: common property set for elements introduced to handle the assignment of CAD related information (here layer name and object colour). IFC2x3 CHANGE The use of this property set is deprecated from IFC2x3 onwards, curve colours are handled by IfcCurveStyle, and layer assignment are handled by IfcPresentationLayerAssignment. - Pset_QuantityTakeOff: common property set for elements introduced to handle additional description of quantity take off. - Pset_ElementShading: common property set for elements that have shading properties to be used in energy calculations or simulations *Quantity Use Definition*: The quantities relating to the IfcElement are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. A detailed specification for individual quantities is introduced at the level of subtypes of IfcElement. *Geometry Use Definitions* The geometric representation of any IfcElement is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. A detailed specification for the shape representation is introduced at the level of subtypes of IfcElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelement.htm"
     },
     "IfcElementAssembly": {
         "attributes": {
             "AssemblyPlace": "A designation of where the assembly is intended to take place defined by an Enum."
         },
-        "description": "A container class that represents complex element assemblies aggregated from several elements, such as discrete elements, building elements, or other elements.",
+        "description": "A container class that represents complex element assemblies aggregated from several elements, such as discrete elements, building elements, or other elements. *Containment Use Definition* The IfcElementAssembly should have (and in most implementation scenarios it is mandatory) a relationship for its hierarchical containment in the spatial structure of the project. - The IfcElementAssembly is placed within the project spatial hierarchy using the objectified relationship IfcRelContainedInSpatialStructure, referring to it by its inverse attribute SELF\\IfcElement.ContainedInStructure. Subtypes of IfcSpatialStructureElement are valid spatial containers, with IfcBuildingStorey being the default container. The IfcElementAssembly shall represent an aggregate, i.e. it should have other elements, being subtypes of IfcElement, as contained (sub)parts. - The IfcElementAssembly is an aggregate i.e. being composed by other elements and acting as an assembly using the objectified relationship IfcRelAggregates, referring to it by its inverse attribute SELF\\IfcObjectDefinition.IsDecomposedBy. Components of an assembly are described by instances of subtypes of IfcElement. - In this case, the contained subtypes of IfcElement shall not be additionally contained in the project spatial hierarchy, i.e. the inverse attribute SELF\\IfcElement.ContainedInStructure of those IfcElement's shall be NIL. *Geometry Use Definitions* The geometric representation of IfcElementAssembly is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Local Placement The local placement for IfcElementAssembly is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. *Geometric Representations* The geometry of an IfcElementAssembly is generally formed from its components, in which case it does not need to have an explicit geometric representation. In some cases it may be useful to also expose a simple explicit representation as a bounding box representation of the complex composed shape independently. Informal proposition - The IfcElementAssembly shall have an aggregation relationship to the contained parts, i.e. the (INV) IsDecomposedBy relationship shall be utilized.",
         "predefined_types": {
             "ACCESSORY_ASSEMBLY": "Assembled accessories or components.",
             "ARCH": "A curved structure.",
@@ -1775,7 +1775,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelementassembly.htm"
     },
     "IfcElementComponent": {
-        "description": "An element component is a representation for minor items included in, added to or connecting to or between elements, which usually are not of interest from the overall building structure viewpoint. However, these small parts may have vital and load carrying functions within the construction. These items do not provide any actual space boundaries. Typical examples of _IfcElementComponent_s include different kinds of fasteners and various accessories.",
+        "description": "An element component is a representation for minor items included in, added to or connecting to or between elements, which usually are not of interest from the overall building structure viewpoint. However, these small parts may have vital and load carrying functions within the construction. These items do not provide any actual space boundaries. Typical examples of _IfcElementComponent_s include different kinds of fasteners and various accessories. Geometry Use Definitions: The geometric representation of IfcElementComponent is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The local placement for IfcElementComponent is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcElement or IfcElementAssembly, which is used in the Decomposes inverse attribute, i.e. the local placement is defined relative to the local placement of the element or element assembly in which the component is contained. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Surface Model Representation Any IfcElementComponent (if no further constraints are defined at the level of its subtypes) may be represented as a single or multiple surface models, based on either shell or face based models. It is ensured by assigning the value 'SurfaceModel' to the RepresentationType attribute of IfcShapeRepresentation. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. Brep Representation Any IfcElementComponent (if no further constraints are defined at the level of its subtypes) may be represented as a single or multiple Boundary Representation elements (which are restricted to faceted Brep with or without voids). The Brep representation allows for the representation of complex element shape. It is ensured by assigning the value 'Brep' to the RepresentationType attribute of IfcShapeRepresentation. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. Mapped Representation The mapped item, IfcMappedItem, should be used if appropriate as it allows for reusing the geometry definition of the equipment type at occurrences of the same equipement type. In this case the IfcShapeRepresentation.RepresentationType = 'MappedRepresentation' is used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcelementcomponent.htm"
     },
     "IfcElementComponentType": {
@@ -1787,14 +1787,14 @@
             "MethodOfMeasurement": "Name of the method of measurement used to calculate the element quantity. The method of measurement attribute has to be made recognizable by further agreements.",
             "Quantities": "The individual quantities for the element, can be a set of length, area, volume, weight or count based quantities."
         },
-        "description": "An IfcElementQuantity defines a set of derived measures of an element's physical property. Elements could be spatial structure elements (like buildings, storeys, or spaces) or building elements (like walls, slabs, finishes). The IfcElementQuantity gets assigned to the element by using the IfcRelDefinesByProperties relationship.",
+        "description": "An IfcElementQuantity defines a set of derived measures of an element's physical property. Elements could be spatial structure elements (like buildings, storeys, or spaces) or building elements (like walls, slabs, finishes). The IfcElementQuantity gets assigned to the element by using the IfcRelDefinesByProperties relationship. The optional MethodOfMeasurement attribute defines the code, e.g. from a standard method of measurement, which had been used to calculate the element quantity. The name attribute, given at the individual Quantities provides a recognizable semantic meaning of the element quantity. Both information is needed to establish a precise meaning for the measure value. An optional description may be assigned to each of the Quantities. All quantities assigned by a single instance of IfcElementQuantity are deemed to have been generated according to the same method of measurement. However several instances of IfcElementQuantity are assignable to an element, thus allowing for an element having quantities generated according to several methods of measurement. The IfcElementQuantity can have the following subtypes of IfcPhysicalQuantity within its SET of Quantities, which count for the basis measure types used: - count measure - weight measure - length measure - area measure - volume measure - time measure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelementquantity.htm"
     },
     "IfcElementType": {
         "attributes": {
             "ElementType": "The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute 'PredefinedType' is set to USERDEFINED."
         },
-        "description": "The IfcElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The IfcElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). An element type is used to define the common properties of a certain type or style of an element that may be applied to instances of that element type to assign a specific style. Element types (the instantiable subtypes) may be exchanged without being already assigned to occurrences.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelementtype.htm"
     },
     "IfcElementarySurface": {
@@ -1810,7 +1810,7 @@
             "SemiAxis1": "The first radius of the ellipse which shall be positive. Placement.Axes[1] gives the direction of the SemiAxis1.",
             "SemiAxis2": "The second radius of the ellipse which shall be positive."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: An ellipse (IfcEllipse) is a conic section defined by the lengths of the semi-major and semi-minor diameters and the position (center or mid point of the line joining the foci) and orientation of the curve. Interpretation of the data shall be as follows:",
+        "description": "Definition from ISO/CD 10303-42:1992: An ellipse (IfcEllipse) is a conic section defined by the lengths of the semi-major and semi-minor diameters and the position (center or mid point of the line joining the foci) and orientation of the curve. Interpretation of the data shall be as follows: Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcellipse.htm"
     },
     "IfcEllipseProfileDef": {
@@ -1818,15 +1818,15 @@
             "SemiAxis1": "The first radius of the ellipse. It is measured along the direction of Position.P[1].",
             "SemiAxis2": "The second radius of the ellipse. It is measured along the direction of Position.P[2]."
         },
-        "description": "Definition from IAI: The IfcEllipseProfileDef defines an ellipse as the profile definition used by the swept surface geometry or the swept area solid. It is given by its semi axis attributes and placed within the 2D position coordinate system, established by the Position attribute.",
+        "description": "Definition from IAI: The IfcEllipseProfileDef defines an ellipse as the profile definition used by the swept surface geometry or the swept area solid. It is given by its semi axis attributes and placed within the 2D position coordinate system, established by the Position attribute. Illustration: Table: Parameter for ellipse profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcellipseprofiledef.htm"
     },
     "IfcEnergyConversionDevice": {
-        "description": "The distribution flow element IfcEnergyConversionDevice defines the occurrence of a device used to perform energy conversion or heat transfer and typically participates in a flow distribution system. Its type is defined by IfcEnergyConversionDeviceType or its subtypes.",
+        "description": "The distribution flow element IfcEnergyConversionDevice defines the occurrence of a device used to perform energy conversion or heat transfer and typically participates in a flow distribution system. Its type is defined by IfcEnergyConversionDeviceType or its subtypes. IfcEnergyConversionDevice is a container entity that aggregates all components of the device it represents. The aggregation is handled via the IfcRelAggregates relationship. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences - Pset_EnergyConversionDeviceCoil: property set for coil energy conversion device occurrences - Pset_EnergyConversionDeviceSpaceHeaterPanel: property set for panel space heater energy conversion device occurrences - Pset_EnergyConversionDeviceSpaceHeaterSectional: property set for sectional space heater energy conversion device occurrences Geometry Use Definitions The geometric representation of IfcEnergyConversionDevice is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcDistributionFlowElement. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcDistributionFlowElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcenergyconversiondevice.htm"
     },
     "IfcEnergyConversionDeviceType": {
-        "description": "The element type IfcEnergyConversionType defines a list of commonly shared property set definitions of an energy conversion device and an optional set of product representations. It is used to define an energy conversion device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcEnergyConversionType defines a list of commonly shared property set definitions of an energy conversion device and an optional set of product representations. It is used to define an energy conversion device specification (i.e. the specific product information, that is common to all occurrences of that product type). A energy conversion type is used to define the common properties of a energy conversion device that may be applied to many occurrences of that type. An energy conversion device is a building systems device that converts energy from one form into another such as a boiler (i.e., combusting gas to heat water), chiller (i.e., using a refrigeration cycle to cool a liquid), or a cooling coil (i.e., using the phase-change characteristics of a refrigerant to cool air). Energy conversion types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcEnergyConversionType are represented by instances of IfcEnergyConversion or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcenergyconversiondevicetype.htm"
     },
     "IfcEnergyProperties": {
@@ -1834,7 +1834,7 @@
             "EnergySequence": "",
             "UserDefinedEnergySequence": "This attribute must be defined if the EnergySequence is USERDEFINED."
         },
-        "description": "Common definition to capture the properties of an energy source typically used within the context of building services.",
+        "description": "Common definition to capture the properties of an energy source typically used within the context of building services. IfcEnergyProperties is a statically defined property set and should be attached to the instance(s) of IfcDistributionFlowElement through the IfcRelDefinesByProperties relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcenergyproperties.htm"
     },
     "IfcEnvironmentalImpactValue": {
@@ -1843,19 +1843,19 @@
             "ImpactType": "Specification of the environmental impact type to be referenced.",
             "UserDefinedCategory": "A user defined value category into which the environmental impact value falls."
         },
-        "description": "An IfcEnvironmentalImpactValue is an amount or measure of an environmental impact or a value that affects an amount or measure of an environmental impact.",
+        "description": "An IfcEnvironmentalImpactValue is an amount or measure of an environmental impact or a value that affects an amount or measure of an environmental impact. The IfcEnvironmentalImpactValue contains the value of the environmental impact. For example this could represent the volume of carbon dioxide emission, amount of operational energy or mass of aluminum used in a product. Each instance of IfcEnvironmentalImpactValue may also have an ImpactType. There are many possible types of environmental impact value that may be identified. To allow for any type of environmental impact value, the IfcLabel datatype is assigned. The following defines some impact types that might be applied: Where a formal standard is not used, it is recommended that local agreements should be made to define allowable and understandable impact value types within a project or region.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcenvironmentalimpactvalue.htm"
     },
     "IfcEquipmentElement": {
-        "description": "Generalization of all equipment related objects, those objects are characterized as being pre-manufactured and being movable, and which provide some building service related or other servicing function. The term fixture is often used as a synonym or similar concept. The IfcEquipmentElement covers the fixture aspect as well.",
+        "description": "Generalization of all equipment related objects, those objects are characterized as being pre-manufactured and being movable, and which provide some building service related or other servicing function. The term fixture is often used as a synonym or similar concept. The IfcEquipmentElement covers the fixture aspect as well. Geometry Use Definitions: The geometric representation of IfcEquipmentElement is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Local Placement The local placement for IfcEquipmentElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement , which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. SurfaceModel Representation Any IfcEquipmentElement (so far no further constraints are defined at the level of its subtypes) may be represented as a single or multiple surface models, based on either shell or face based models. It is ensured by assigning the value 'SurfaceModel' to the RepresentationType attribute of IfcShapeRepresentation. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. Brep Representation Any IfcEquipmentElement (so far no further constraints are defined at the level of its subtypes) may be represented as a single or multiple Boundary Representation elements (which are restricted to faceted Brep with or without voids). The Brep representation allows for the representation of complex element shape. It is ensured by assigning the value 'Brep' to the RepresentationType attribute of IfcShapeRepresentation. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. MappedRepresentation The new mapped item, IfcMappedItem, should be used if appropriate as it allows for reusing the geometry definition of the equipment type at occurrences of the same equipment type. In this case the IfcShapeRepresentation.RepresentationType = MappedRepresentation is used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcequipmentelement.htm"
     },
     "IfcEquipmentStandard": {
-        "description": "An IfcEquipmentStandard is a standard for equipment allocation that can be assigned to persons within an organization.",
+        "description": "An IfcEquipmentStandard is a standard for equipment allocation that can be assigned to persons within an organization. An IfcEquipmentStandard is assigned a set of classification notations (through the IfcRelAssociatesClassification class within the IfcKernel schema) that determine the types of equipment that fulfill the requirements of the standard. In order to use the equipment standard class, a classification of equipment items must have been established. This does not mean that each individual equipment item needs to have a classification notation although this is considered to be desirable. Examples of equipment items that might fall within an equipment standard include number and type PC's and connections, task lighting, pictures etc. An equipment standard is assigned to one or several persons or organizations (like a work group or department) through the IfcRelAssignsToControl relationship via the Controls inverse attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcequipmentstandard.htm"
     },
     "IfcEvaporativeCoolerType": {
-        "description": "The element type IfcEvaporativeCoolerType defines a list of commonly shared property set definitions of an evaporative cooler and an optional set of product representations. It is used to define an evaporative cooler specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcEvaporativeCoolerType defines a list of commonly shared property set definitions of an evaporative cooler and an optional set of product representations. It is used to define an evaporative cooler specification (i.e. the specific product information, that is common to all occurrences of that product type). A evaporative cooler type is used to define the common properties of a evaporative cooler that may be applied to many occurrences of that type. An evaporative cooler is a device that cools air by saturating it with water vapor. Evaporative cooler types may be exchanged without being already assigned to occurrences. The occurrences of the IfcEvaporativeCoolerType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_EvaporativeCoolerTypeCommon: common property set for all evaporative cooler types",
         "predefined_types": {
             "DIRECTEVAPORATIVEAIRWASHER": "Direct evaporative air washer: Cools the air stream by evaporating water dircectly into the air stream using coolers with spray-type air washer consist of a chamber or casing containing spray nozzles, and tank for collecting spray water, and an eliminator section for removing entrained drops of water from the air.",
             "DIRECTEVAPORATIVEPACKAGEDROTARYAIRCOOLER": "Direct evaporative packaged rotary air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers that wet and wash the evaporative pad by rotating it through a water bath.",
@@ -1872,7 +1872,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcevaporativecoolertype.htm"
     },
     "IfcEvaporatorType": {
-        "description": "The element type IfcEvaporatorType defines a list of commonly shared property set definitions of an evaporator and an optional set of product representations. It is used to define an evaporator specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcEvaporatorType defines a list of commonly shared property set definitions of an evaporator and an optional set of product representations. It is used to define an evaporator specification (i.e. the specific product information, that is common to all occurrences of that product type). A evaporator type is used to define the common properties of an evaporator that may be applied to many occurrences of that type. An evaporator is a device in which a liquid refrigerent is vaporized and absorbs heat from the surrounding fluid. Evaporator types may be exchanged without being already assigned to occurrences. The occurrences of the IfcEvaporatorType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_EvaporatorTypeCommon: common property set for all evaporator types",
         "predefined_types": {
             "DIRECTEXPANSIONBRAZEDPLATE": "Direct-expansion evaporator where a refrigerant evaporates inside plates brazed or welded together to make up an assembly of separate channels.",
             "DIRECTEXPANSIONSHELLANDTUBE": "Direct-expansion evaporator where a refrigerant evaporates inside a series of baffles that channel the fluid throughout the shell side.",
@@ -1890,7 +1890,7 @@
             "ExtendedProperties": "The set of material properties defined by user for this material.",
             "Name": "The name given to the set of extended properties."
         },
-        "description": "A container class for user defined properties of associated material. This provides a mechanism to assign properties that have not been defined in IFC specification.",
+        "description": "A container class for user defined properties of associated material. This provides a mechanism to assign properties that have not been defined in IFC specification. purposes can be defined as:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcextendedmaterialproperties.htm"
     },
     "IfcExternalReference": {
@@ -1899,7 +1899,7 @@
             "Location": "Location, where the external source (classification, document or library). This can be either human readable or computer interpretable. For electronic location normally given as an URL location string, however other ways of accessing external references may be established in an application scenario.",
             "Name": "Optional name to further specify the reference. It can provide a human readable identifier (which does not necessarily need to have a counterpart in the internal structure of the document)."
         },
-        "description": "An IfcExternalReference is the identification of information that is not explicitly represented in the current model or in the project database (as an implementation of the current model). Such information may be contained in classifications, documents or libraries.",
+        "description": "An IfcExternalReference is the identification of information that is not explicitly represented in the current model or in the project database (as an implementation of the current model). Such information may be contained in classifications, documents or libraries. Only the Location (e.g. as an URL) is given to describe the place where the information can be found. Also an optional ItemReference as a key to allow more specific references (as to sections or tables) is provided. The ItemReference defines a system interpretable method to identify the relevant part of information at the data source (given by Location). In addition a human interpretable Name can be assigned to identify the information subject (e.g. classification code). IfcExternalReference is an abstract supertype of all external reference classes. See the use definitions given at the subtypes of IfcExternalReference.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcexternalreference.htm"
     },
     "IfcExternallyDefinedHatchStyle": {
@@ -1923,14 +1923,14 @@
             "Depth": "The distance the surface is to be swept.",
             "ExtrudedDirection": "The direction in which the surface is to be swept."
         },
-        "description": "The extruded area solid (IfcExtrudedAreaSolid) is defined by sweeping a bounded planar surface. The direction of the extrusion is given by the ExtrudedDirection attribute and the length of the extrusion is given by the Depth attribute. If the planar area has inner boundaries, i.e. holes defined, then those holes shall be swept into holes of the solid.",
+        "description": "The extruded area solid (IfcExtrudedAreaSolid) is defined by sweeping a bounded planar surface. The direction of the extrusion is given by the ExtrudedDirection attribute and the length of the extrusion is given by the Depth attribute. If the planar area has inner boundaries, i.e. holes defined, then those holes shall be swept into holes of the solid. The ExtrudedDirection is given within the position coordinate system as defined by IfcSweptAreaSolid.Position. Extrusions are not longer restricted to be perpendicular to the extruded surface of the profile. Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcextrudedareasolid.htm"
     },
     "IfcFace": {
         "attributes": {
             "Bounds": "Boundaries of the face."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A face is a topological entity of dimensionality 2 corresponding to the intuitive notion of a piece of surface bounded by loops. Its domain, if present, is an oriented, connected, finite 2-manifold in R^m^. A face domain shall not have handles but it may have holes, each hole bounded by a loop. The domain of the underlying geometry of the face, if present, does not contain its bounds, and 0 < \u039e < \u221e.",
+        "description": "Definition from ISO/CD 10303-42:1992: A face is a topological entity of dimensionality 2 corresponding to the intuitive notion of a piece of surface bounded by loops. Its domain, if present, is an oriented, connected, finite 2-manifold in R^m^. A face domain shall not have handles but it may have holes, each hole bounded by a loop. The domain of the underlying geometry of the face, if present, does not contain its bounds, and 0 < \u039e < \u221e. A face is represented by its bounding loops, which are defined as face bounds. A face has a topological normal n and the tangent to a loop is t. For a loop bounding a face with defined geometry, the cross product n x t points toward the interior of the face. That is, each loop runs counter-clockwise around the face when viewed from above, if we consider the normal n to point up. With each loop is associated a BOOLEAN flag to signify whether the loop direction is oriented with respect to the face normal (TRUE) or should be reversed (FALSE). A face shall have at least one bound, and the loops shall not intersect. One loop is optionally distinguished as the outer loop of the face. If so, it establishes a preferred way of embedding the face domain in the plane, in which the other bounding loops of the face are inside the outer bound. Because the face domain is arcwise connected, no inner loop will contain any other loop. This is true regardless of which embedding in the plane is chosen. The edges and vertices referenced by the loops of a face form a graph, of which the individual loops are the connected components. The Euler equation (1) for this graph becomes: Informal propositions: - No edge shall be referenced by the face more than twice. - Distinct face bounds of the face shall have no common vertices. - If geometry is present, distinct loops of the same face shall not intersect. - The face shall satisfy the Euler Equation: (number of vertices) - (number of edges) - (number of loops) + (sum of genus for loops) = 0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcface.htm"
     },
     "IfcFaceBasedSurfaceModel": {
@@ -1938,7 +1938,7 @@
             "Dim": "The space dimensionality of this class, it is always 3. 3",
             "FbsmFaces": "The set of connected face sets comprising the face based surface model."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A face based surface model is described by a set of connected face sets of dimensionality 2. The connected face sets shall not intersect except at edges and vertices, except that a face in one connected face set may overlap a face in another connected face set, provided the face boundaries are identical. There shall be at least one connected face set.",
+        "description": "Definition from ISO/CD 10303-42:1992: A face based surface model is described by a set of connected face sets of dimensionality 2. The connected face sets shall not intersect except at edges and vertices, except that a face in one connected face set may overlap a face in another connected face set, provided the face boundaries are identical. There shall be at least one connected face set. A connected face set may exist independently of a surface model. Informal propositions: - The connected face sets shall not overlap or intersect except at common faces, edges or vertices. - The fbsm faces have dimensionality 2.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcfacebasedsurfacemodel.htm"
     },
     "IfcFaceBound": {
@@ -1958,18 +1958,18 @@
             "FaceSurface": "The surface which defines the internal shape of the face. This surface may be unbounded. The domain of the face is defined by this surface and the bounding loops in the inherited attribute SELF\\FaceBounds.",
             "SameSense": "This flag indicates whether the sense of the surface normal agrees with (TRUE), or opposes (FALSE), the sense of the topological normal to the face."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A face surface (IfcFaceSurface) is a subtype of face in which the geometry is defined by an associated surface. The portion of the surface used by the face shall be embeddable in the plane as an open disk, possibly with holes. However, the union of the face with the edges and vertices of its bounding loops need not be embeddable in the plane. It may, for example, cover an entire sphere or torus. As both a face and a geometric surface have defined normal directions, a BOOLEAN flag (the orientation attribute) is used to indicate whether the surface normal agrees with (TRUE) or is opposed to (FALSE) the face normal direction. The geometry associated with any component of the loops of the face shall be consistent with the surface geometry, in the sense that the domains of all the vertex points and edge curves are contained in the face geometry surface. A surface may be referenced by more than one face surface.",
+        "description": "Definition from ISO/CD 10303-42:1992: A face surface (IfcFaceSurface) is a subtype of face in which the geometry is defined by an associated surface. The portion of the surface used by the face shall be embeddable in the plane as an open disk, possibly with holes. However, the union of the face with the edges and vertices of its bounding loops need not be embeddable in the plane. It may, for example, cover an entire sphere or torus. As both a face and a geometric surface have defined normal directions, a BOOLEAN flag (the orientation attribute) is used to indicate whether the surface normal agrees with (TRUE) or is opposed to (FALSE) the face normal direction. The geometry associated with any component of the loops of the face shall be consistent with the surface geometry, in the sense that the domains of all the vertex points and edge curves are contained in the face geometry surface. A surface may be referenced by more than one face surface. Informal propositions: - The domain of the face surface is formally defined to be the domain of its face geometry as trimmed by the loops, this domain does not include the bounding loops. - A face surface has non zero finite extent. - A face surface is a manifold. - A face surface is arcwise connected. - A face surface has surface genus 0. - The loops are not part of the face domain. - Loop geometry shall be consistent with face geometry. This implies that any edge - curves or vertex points used in defining the loops bounding the face surface shall lie on the face geometry. - The loops of the face shall not intersect.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcfacesurface.htm"
     },
     "IfcFacetedBrep": {
-        "description": "Definition from ISO/CD 10303-42:1992: A faceted brep is a simple form of boundary representation model in which all faces are planar and all edges are straight lines. Unlike the B-rep model, edges and vertices are not represented explicitly in the model but are implicitly available through the poly loop entity. A faceted B-rep has to meet the same topological constraints as the manifold solid Brep.",
+        "description": "Definition from ISO/CD 10303-42:1992: A faceted brep is a simple form of boundary representation model in which all faces are planar and all edges are straight lines. Unlike the B-rep model, edges and vertices are not represented explicitly in the model but are implicitly available through the poly loop entity. A faceted B-rep has to meet the same topological constraints as the manifold solid Brep. Informal proposition: - All the bounding loops of all the faces of all the shells in the IfcFacetedBrep shall be of type IfcPolyLoop.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcfacetedbrep.htm"
     },
     "IfcFacetedBrepWithVoids": {
         "attributes": {
             "Voids": "Set of closed shells defining voids within the solid."
         },
-        "description": "The IfcFacetedBrepWithVoids is a specialization of a faceted B-rep which contains one or more voids in its interior. The voids are represented as closed shells which are defined so that the shell normal point into the void.",
+        "description": "The IfcFacetedBrepWithVoids is a specialization of a faceted B-rep which contains one or more voids in its interior. The voids are represented as closed shells which are defined so that the shell normal point into the void. Informal propositions: - Each void shell shall be disjoint from the outer shell and from every other void shell - Each void shell shall be enclosed within the outer shell but not within any other void shell. In particular the outer shell is not in the set of void shells - Each shell in the IfcManifoldSolidBrep shall be referenced only once. - All the bounding loops of all the faces of all the shells in the IfcFacetedBrep shall be of type IfcPolyLoop.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcfacetedbrepwithvoids.htm"
     },
     "IfcFailureConnectionCondition": {
@@ -1985,7 +1985,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcfailureconnectioncondition.htm"
     },
     "IfcFanType": {
-        "description": "The element type IfcFanType defines a list of commonly shared property set definitions of a fan and an optional set of product representations. It is used to define a fan specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFanType defines a list of commonly shared property set definitions of a fan and an optional set of product representations. It is used to define a fan specification (i.e. the specific product information, that is common to all occurrences of that product type). A Fan type is used to define the common properties of a fan that may be applied to many occurrences of that type. A fan is a device which imparts mechanical work on a gas. A typical usage of a fan is to induce airflow in a building services air distribution system. Fan types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFanType are represented by instances of IfcFlowMovingDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_FanTypeCommon: common property set for all fan types Pset_FanTypeSmokeControl: property set for all fan types that are part of a smoke control system",
         "predefined_types": {
             "CENTRIFUGALAIRFOIL": "Air flows through the impeller radially using blades that are airfoil shaped.",
             "CENTRIFUGALBACKWARDINCLINEDCURVED": "Air flows through the impeller radially using blades that are backward curved.",
@@ -2000,36 +2000,36 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcfantype.htm"
     },
     "IfcFastener": {
-        "description": "Representations of fixing parts which are used as fasteners to connect or join elements with other elements.",
+        "description": "Representations of fixing parts which are used as fasteners to connect or join elements with other elements. General usage The exact type information of the IfcFastener is given in the ObjectType attribute inherited from IfcObject. Standard type designations are provided for guideline below. Note that mechanical fasteners are represented by instances of the subtype IfcMechanicalFastener. Geometry Use Definitions: The geometric representation of IfcFastener is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined in the supertype IfcElementComponent. Standard Geometric Representation The use of Standard Geometric Representations is defined in the supertype IfcElementComponent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcfastener.htm"
     },
     "IfcFastenerType": {
-        "description": "The element type (IfcFastenerType) defines a list of commonly shared property set definitions of a fastener and an optional set of product representations. It is used to define fasteners mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type).",
+        "description": "The element type (IfcFastenerType) defines a list of commonly shared property set definitions of a fastener and an optional set of product representations. It is used to define fasteners mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type). The occurrences of the IfcFastenerType are represented by instances of IfcFastener. General usage The exact type information of the IfcFastenerType is given in the ElementType attribute inherited from IfcElementType. Standard type designations are provided for guideline below. Note that mechanical fastener types are represented by instances of the subtype IfcMechanicalFastenerType.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcfastenertype.htm"
     },
     "IfcFeatureElement": {
-        "description": "Generalization of all existence dependent elements which modify the shape and appearance of the associated master element. The IfcFeatureElement offers the ability to handle shape modifiers as semantic objects within the IFC object model.",
+        "description": "Generalization of all existence dependent elements which modify the shape and appearance of the associated master element. The IfcFeatureElement offers the ability to handle shape modifiers as semantic objects within the IFC object model. In contrary to the aggregation, as used in IfcElementAssembly, that defines the aggregate as a container element, that has equally treated parts, the feature concept introduced by IfcFeatureElement defines the master element with subordinate parts as additions, or with voids or cut-outs as subtractions. *Containment Use Definition* As a subordinate part being fully dependent on the master element the IfcFeatureElement shall have no independent containment relationship to the spatial structure. - The SELF\\IfcElement.ContainedInStructure relationship shall be NIL. *Geometry Use Definition* The geometric representation of IfcFeatureElement is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Local Placement The local placement for IfcFeatureElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the master IfcElement (its relevant subtypes), which is associated to the IfcFeatureElement by the appropriate relationship object. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Shape Representation The geometry use definitions for the shape representation of the IfcFeatureElement is given at the level of its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfeatureelement.htm"
     },
     "IfcFeatureElementAddition": {
         "attributes": {
             "ProjectsElements": "Reference to the _IfcRelProjectsElement_ relationship that uses this _IfcFeatureElementAddition_ to create a volume addition at an element. The _IfcFeatureElementAddition_ can only be used to create a single addition at a single element using Boolean addition operation."
         },
-        "description": "A specialization of the general feature element, that represents an existence dependent element which modifies the shape and appearance of the associated master element. The IfcFeatureElementAddition offers the ability to handle shape modifiers as semantic objects within the IFC object model that add to the shape of the master element.",
+        "description": "A specialization of the general feature element, that represents an existence dependent element which modifies the shape and appearance of the associated master element. The IfcFeatureElementAddition offers the ability to handle shape modifiers as semantic objects within the IFC object model that add to the shape of the master element. The IfcFeatureElementAddition is associated to its master element by virtue of the objectified relationship IfcRelProjectsElement. This relationship implies a Boolean 'union' operation between the shape of the master element and the shape of the addition feature. *Containment use definition* The containment to the spatial structure is defined at the level of the supertype IfcFeatureElement *Geometry Use Definitions* The geometric representation of IfcFeatureElementAddition is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Local Placement The local placement for IfcFeatureElementAddition is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. The local placement is always defined in relation to the local placement of the element to which the feature element is added: - The PlacementRelTo relationship of IfcLocalPlacement shall point to the local placement of the same IfcElement, which is used in the HasAdditionFeature.RelatingElement inverse attribute. Shape Representation The geometry use definitions for the shape representation of the IfcFeatureElementAddition is given at the level of its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfeatureelementaddition.htm"
     },
     "IfcFeatureElementSubtraction": {
         "attributes": {
             "VoidsElements": "Reference to the Voids Relationship that uses this Opening Element to create a void within an Element. The Opening Element can only be used to create a single void within a single Element."
         },
-        "description": "A specialization of the general feature element, that represents an existence dependent elements which modifies the shape and appearance of the associated master element. The IfcFeatureElementSubtraction offers the ability to handle shape modifiers as semantic objects within the IFC object model that subtract from the shape of the master element.",
+        "description": "A specialization of the general feature element, that represents an existence dependent elements which modifies the shape and appearance of the associated master element. The IfcFeatureElementSubtraction offers the ability to handle shape modifiers as semantic objects within the IFC object model that subtract from the shape of the master element. *Containment use definition* The containment to the spatial structure is defined at the level of the supertype IfcFeatureElement *Geometry Use Definitions* The geometric representation of IfcFeatureElementSubtraction is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Local Placement The local placement for IfcFeatureElementSubtraction is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. The local placement is always defined in relation to the local placement of the building element from which the feature element is substracted: - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcElement, which is used in the VoidsElements.RelatingElement inverse attribute. Shape Representation The geometry use definitions for the shape representation of the IfcFeatureElementSubtraction is given at the level of its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfeatureelementsubtraction.htm"
     },
     "IfcFillAreaStyle": {
         "attributes": {
             "FillStyles": "The set of fill area styles to use in presenting visible curve segments, annotation fill areas or surfaces."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: The style for filling visible curve segments, annotation fill areas or surfaces with tiles or hatches.",
+        "description": "Definition from ISO/CD 10303-46:1992: The style for filling visible curve segments, annotation fill areas or surfaces with tiles or hatches. Definition from IAI: An IfcFillAreaStyle provides the style table for presentation information assigned to annotation fill areas or surfaces for hatching and tiling. The IfcFillAreaStyle defines hatches as model hatches, i.e. the distance between hatch lines, or the curve patterns of hatch lines are given in model space dimensions (that have to be scaled using the target plot scale). The IfcFillAreaStyle allows for the following combinations of defining the style of hatching and tiling: - Solid fill for areas and surfaces by only assigning IfcColour to the set of FillStyles. It then provides the background colour for the filled area or surface. - Vector based hatching for areas and surfaces based on two (potentially crossing) rows of hatch lines by assigning two instances of IfcFillAreaStyleHatching to the set of FillStyles. If an instance of IfcColour is assigned in addition to the set of FillStyles, it provides the background colour for the hatching. Measures given to a hatch or tile pattern are given in global drawing length units. The measure values for hatch or tile pattern apply to the model space with a target plot scale provided for the correct appearance in the default plot scale. For different scale and projection dependent fill area styles a different instance of IfcFillAreaStyle needs to be used by IfcPresentationStyleAssignment for different IfcGeometricRepresentationSubContext dependent representations. An IfcFillAreaStyle can be assigned to IfcFillArea via the IfcPresentationStyleAssignment through an intermediate IfcStyledItem or subtype IfcAnnotationFillAreaOccurrence.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcfillareastyle.htm"
     },
     "IfcFillAreaStyleHatching": {
@@ -2040,7 +2040,7 @@
             "PointOfReferenceHatchLine": "A Cartesian point which defines the offset of the reference hatch line from the origin of the (virtual) hatching coordinate system. The origin is used for mapping the fill area style hatching onto an annotation fill area or surface. The reference hatch line would then appear with this offset from the fill style target point.   If not given the reference hatch lines goes through the origin of the (virtual) hatching coordinate system.",
             "StartOfNextHatchLine": "A repetition factor that determines the distance between adjacent hatch lines."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: The fill area style hatching defines a styled pattern of curves for hatching an annotation fill area or a surface.",
+        "description": "Definition from ISO/CD 10303-46:1992: The fill area style hatching defines a styled pattern of curves for hatching an annotation fill area or a surface. Definition from IAI: The IfcFillAreaStyleHatching is used to define simple, vector-based hatching patterns, based on styled straight lines. The curve font, color and thickness is given by the HatchLineAppearance, the angle by the HatchLineAngle and the distance to the next hatch line by StartOfNextHatchLine, being either an offset distance or a vector. For better control of the hatching appearance, when using hatch lines with other fonts then continuous, the PatternStart allows to offset the start of the curve font pattern along the reference hatch line (if not given, the PatternStart is at zero distance from the virtual point of origin). If the reference hatch line does not go through the origin (of the virtual hatching coordinate system), it can be offset by using the PatternStart ~~PointOfReferenceHatchLine.~~ Illustration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcfillareastylehatching.htm"
     },
     "IfcFillAreaStyleTileSymbolWithStyle": {
@@ -2060,7 +2060,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcfillareastyletiles.htm"
     },
     "IfcFilterType": {
-        "description": "The element type IfcFilterType defines a list of commonly shared property set definitions of a filter and an optional set of product representations. It is used to define a filter specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFilterType defines a list of commonly shared property set definitions of a filter and an optional set of product representations. It is used to define a filter specification (i.e. the specific product information, that is common to all occurrences of that product type). A filter type is used to define the common properties of a filter that may be applied to many occurrences of that type. A filter is an apparatus used to remove particulate or gaseous matter from fluids and gases. Filter types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFilterType are represented by instances of IfcTreatmentDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_FilterTypeCommon: common property set for all filter types Pset_FilterTypeAirParticleFilter: property set for all air particle filter types",
         "predefined_types": {
             "AIRPARTICLEFILTER": "A filter used to remove particulates from air.",
             "NOTDEFINED": "Undefined filter type.",
@@ -2073,7 +2073,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcfiltertype.htm"
     },
     "IfcFireSuppressionTerminalType": {
-        "description": "The IfcFireSuppressionTerminalType defines a particular type of IfcFlowTerminal that has the purpose of delivering a fluid (gas or liquid) that will suppress a fire.",
+        "description": "The IfcFireSuppressionTerminalType defines a particular type of IfcFlowTerminal that has the purpose of delivering a fluid (gas or liquid) that will suppress a fire. *Use Definitions* An IfcFireSuppressionTerminalType provides for all forms of sprinkler, spreader and other form of terminal that is connected to a pipework system and intended to act in the role of suppressing a fire . An IfcFireSuppressionTerminalType may be included into the spatial context of the building model through an (or multiple) instances of IfcFlowTerminal. The parameters of the fire suppression terminal type are defined through the type driven property sets referred to by the predefined type attribute of IfcFireSuppressionTerminalType. *Property Set Use Definition*: The property sets relating to the IfcFireSuppressionTerminalType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcFireSuppressionTerminalType are part of this IFC release: - Pset_FireSuppressionTerminalTypeBreechingInlet: specific property set for the properties of a breeching inlet, if available - Pset_FireSuppressionTerminalTypeFireHydrant: specific property set for the properties of a fire hydrant, if available - Pset_FireSuppressionTerminalTypeSprinkler: specific property set for the properties of a sprinkler, if available - Pset_FireSuppressionTerminalTypeHoseReel: specific property set for the properties of a hose reel, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "BREECHINGINLET": "Symmetrical pipe fitting that unites two or more inlets into a single pipe. A breeching inlet may be used on either a wet or dry riser. Used by fire services personnel for fast connection of fire appliance hose reels. May also be used for foam.",
             "FIREHYDRANT": "Device, fitted to a pipe, through which a temporary supply of water may be provided.  May also be termed a stand pipe.",
@@ -2086,23 +2086,23 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcplumbingfireprotectiondomain/lexical/ifcfiresuppressionterminaltype.htm"
     },
     "IfcFlowController": {
-        "description": "The distribution flow element IfcFlowController defines the occurrence of elements of a distribution system that are used to regulate flow through a distribution system (e.g., damper, valve, switch, relay, etc.). Its type is defined by IfcFlowControllerType or its subtypes.",
+        "description": "The distribution flow element IfcFlowController defines the occurrence of elements of a distribution system that are used to regulate flow through a distribution system (e.g., damper, valve, switch, relay, etc.). Its type is defined by IfcFlowControllerType or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences - Pset_FlowControllerDamper: property set for damper flow controller occurrences - Pset_FlowControllerFlowMeter: property set for flowmeter flow controller occurrences Geometry Use Definitions The geometric representation of IfcFlowController is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcDistributionFlowElement. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcDistributionFlowElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowcontroller.htm"
     },
     "IfcFlowControllerType": {
-        "description": "The element type IfcFlowControllerType defines a list of commonly shared property set definitions of a flow controller and an optional set of product representations. It is used to define a flow controller specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowControllerType defines a list of commonly shared property set definitions of a flow controller and an optional set of product representations. It is used to define a flow controller specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow controller type is used to define the common properties of a flow controller that may be applied to many occurrences of that type. A flow controller is a device that regulates flow within a distribution system, such as a valve in a piping system, modulating damper in an air distribution system, or electrical switch in an electrical distribution system. Flow controller types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowControllerType are represented by instances of IfcFlowController or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowcontrollertype.htm"
     },
     "IfcFlowFitting": {
-        "description": "The distribution flow element IfcFlowFitting defines the occurrence of a junction or transition in a flow distribution system (e.g., elbow, tee, etc.). Its type is defined by IfcFlowFittingType or its subtypes.",
+        "description": "The distribution flow element IfcFlowFitting defines the occurrence of a junction or transition in a flow distribution system (e.g., elbow, tee, etc.). Its type is defined by IfcFlowFittingType or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences - Pset_FlowFittingDuctFitting: property set for duct fitting occurrences - Pset_FlowFittingPipeFitting: property set for pipe fitting occurrences Geometry Use Definitions The geometric representation of IfcFlowFitting is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcDistributionFlowElement. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcDistributionFlowElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowfitting.htm"
     },
     "IfcFlowFittingType": {
-        "description": "The element type IfcFlowFittingType defines a list of commonly shared property set definitions of a flow fitting and an optional set of product representations. It is used to define a flow fitting specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowFittingType defines a list of commonly shared property set definitions of a flow fitting and an optional set of product representations. It is used to define a flow fitting specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow fitting type is used to define the common properties of a flow fitting that may be applied to many occurrences of that type. A flow fitting is a device that is used to interconnect flow segments or other fittings within a distribution system, such as a tee in a ducted system that branches flow into two directions, a junction box in an electrical distribution system, etc. Flow fitting types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowFittingType are represented by instances of IfcFlowFitting or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowfittingtype.htm"
     },
     "IfcFlowInstrumentType": {
-        "description": "An IfcFlowInstrumentType defines a particular type of flow instrument that reads and displays the value of a particular property of a system at a point, or that displays the difference in the value of a property between two points.",
+        "description": "An IfcFlowInstrumentType defines a particular type of flow instrument that reads and displays the value of a particular property of a system at a point, or that displays the difference in the value of a property between two points. *Use Definitions* An IfcFlowInstrumentType provides for all forms of mechanical flow instrument (thermometers, pressure gauges etc.) and electrical flow instruments (ammeters, voltmeters etc.) Usage of IfcFlowInstrumentType defines the parameters for one or more occurrences of IfcDistributionControlElement. Parameters for mechanical flow instruments are specified through property sets that are enumerated in the IfcFlowInstrumentTypeEnum data type. Property sets for electrical flow instruments are not yet defined. *Property Set Use Definition*: The property sets relating to the IfcFlowInstrumentType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcFlowInstrumentType are part of this IFC release: - Pset_FlowInstrumentTypeThermometer: specific property set for the properties of a thermometer, if available - Pset_FlowInstrumentTypePressureGauge: specific property set for the properties of a pressure gauge, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "AMMETER": "A device that reads and displays the current flow in a circuit.",
             "FREQUENCYMETER": "A device that reads and displays the electrical frequency of an alternating current circuit.",
@@ -2118,7 +2118,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcflowinstrumenttype.htm"
     },
     "IfcFlowMeterType": {
-        "description": "The element type IfcFlowMeterType defines a list of commonly shared property set definitions of a flow meter and an optional set of product representations. It is used to define a flow meter specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowMeterType defines a list of commonly shared property set definitions of a flow meter and an optional set of product representations. It is used to define a flow meter specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow meter type is used to define the common properties of a flow meter that may be applied to many occurrences of that type. A flow meter is a device that is used to measure the flow rate in a system. flow meter types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowMeterType are represented by instances of IfcFlowController or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_FlowMeterTypeCommon: common property set for all flow meter types Pset_FlowMeterTypeEnergyMeter: property set for all flow meter types that are used to measure the flow of energy Pset_FlowMeterTypeGasMeter: property set for all flow meter types that are used to measure the flow of gas Pset_FlowMeterTypeOilMeter: property set for all flow meter types that are used to measure the flow of oil Pset_FlowMeterTypeWaterMeter: property set for all flow meter types that are used to measure the flow of water",
         "predefined_types": {
             "ELECTRICMETER": "",
             "ENERGYMETER": "An electric meter or energy meter is a device that measures the amount of electrical energy supplied to or produced by a residence, business or machine.",
@@ -2132,43 +2132,43 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcflowmetertype.htm"
     },
     "IfcFlowMovingDevice": {
-        "description": "The distribution flow element IfcFlowMovingDevice defines the occurrence of an apparatus used to distribute, circulate or perform conveyance of fluids, including liquids and gases, and typically participates in a flow distribution system (e.g., pump, fan). Its type is defined by IfcFlowMovingDeviceType or its subtypes.",
+        "description": "The distribution flow element IfcFlowMovingDevice defines the occurrence of an apparatus used to distribute, circulate or perform conveyance of fluids, including liquids and gases, and typically participates in a flow distribution system (e.g., pump, fan). Its type is defined by IfcFlowMovingDeviceType or its subtypes. IfcFlowMovingDevice is a container entity that aggregates all components of the device it represents. The aggregation is handled via the IfcRelAggregates relationship. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences - Pset_FlowMovingDeviceCompressor: property set for compressor occurrences - Pset_FlowMovingDeviceFan: property set for fan occurrences - Pset_FlowMovingDeviceFanCentrifugal: property set for centrifugal fan occurrences - Pset_FlowMovingDevicePump: property set for pump occurrences Geometry Use Definitions The geometric representation of IfcFlowMovingDevice is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcDistributionFlowElement. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcDistributionFlowElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowmovingdevice.htm"
     },
     "IfcFlowMovingDeviceType": {
-        "description": "The element type IfcFlowMovingDeviceType defines a list of commonly shared property set definitions of a flow moving device and an optional set of product representations. It is used to define a flow moving device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowMovingDeviceType defines a list of commonly shared property set definitions of a flow moving device and an optional set of product representations. It is used to define a flow moving device specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow moving type is used to define the common properties of a flow moving device that may be applied to many occurrences of that type. A flow moving device is a device that is used to produce a pressure differential in a distribution system, such as a pump, fan, compressor, etc. Flow moving types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowMovingDeviceType are represented by instances of IfcFlowMoving or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowmovingdevicetype.htm"
     },
     "IfcFlowSegment": {
-        "description": "The distribution flow element IfcFlowSegment defines the occurrence of a segment of a flow distribution system that is typically straight, contiguous and has two ports (e.g., a section of pipe or duct).",
+        "description": "The distribution flow element IfcFlowSegment defines the occurrence of a segment of a flow distribution system that is typically straight, contiguous and has two ports (e.g., a section of pipe or duct). The IfcFlowSegment defines a particular occurrence of a segment inserted in the spatial context of a project. The parameters defining the type of the segment and/or its shape are defined by the IfcFlowSegmentType, which is related by the inverse relationship IsDefinedBy pointing to IfcRelDefinesByType. The following parameters shall be given: - Segment length, taken from the Length attribute in the property set, provides the depth of the extrusion. - Segment profile dimensions are defined by the NominalDiameterOrWidth and NominalHeight attributes in the property set. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences - Pset_FlowSegmentDuctSegment: property set for duct segment occurrences - Pset_FlowSegmentPipeSegment: property set for pipe segment occurrences Geometry Use Definitions The geometric representation of IfcFlowSegment is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcDistributionFlowElement. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcDistributionFlowElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowsegment.htm"
     },
     "IfcFlowSegmentType": {
-        "description": "The element type IfcFlowSegmentType defines a list of commonly shared property set definitions of a flow segment and an optional set of product representations. It is used to define a flow segment specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowSegmentType defines a list of commonly shared property set definitions of a flow segment and an optional set of product representations. It is used to define a flow segment specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow segment type is used to define the common properties of a flow segment that may be applied to many occurrences of that type. A flow segment is a section of a distribution system, such as a duct, pipe, conduit, etc. that typically has only two ports. Flow segment types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowSegmentType are represented by instances of IfcFlowSegment or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowsegmenttype.htm"
     },
     "IfcFlowStorageDevice": {
-        "description": "The distribution flow element IfcFlowStorageDevice defines the occurrence of a device that participates in a distribution system and is used for temporary storage of a fluid such as a liquid or a gas (e.g., tank). Its type is defined by IfcFlowStorageDeviceType or its subtypes.",
+        "description": "The distribution flow element IfcFlowStorageDevice defines the occurrence of a device that participates in a distribution system and is used for temporary storage of a fluid such as a liquid or a gas (e.g., tank). Its type is defined by IfcFlowStorageDeviceType or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences - Pset_FlowStorageDeviceTank: property set for tank storage device occurrences Geometry Use Definitions The geometric representation of IfcFlowStorageDevice is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcDistributionFlowElement. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcDistributionFlowElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowstoragedevice.htm"
     },
     "IfcFlowStorageDeviceType": {
-        "description": "The element type IfcFlowStorageDeviceType defines a list of commonly shared property set definitions of a flow storage device and an optional set of product representations. It is used to define a flow storage device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowStorageDeviceType defines a list of commonly shared property set definitions of a flow storage device and an optional set of product representations. It is used to define a flow storage device specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow storage type is used to define the common properties of a flow storage device that may be applied to many occurrences of that type. A flow storage device is a device used for the temporary storage of a fluid such as a liquid or a gas (e.g., tank), the voltage potential induced by the induced electron flow (e.g., a battery), etc. Flow storage types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowStorageDeviceType are represented by instances of IfcFlowStorage or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowstoragedevicetype.htm"
     },
     "IfcFlowTerminal": {
-        "description": "The distribution flow element IfcFlowTerminal defines the occurrence of a permanently attached element that acts as a terminus or beginning of a distribution system (e.g., air outlet, drain, water closet, sink, etc.). A terminal is typically a point at which a system interfaces with an external environment. Its type is defined by IfcFlowTerminalType or its subtypes.",
+        "description": "The distribution flow element IfcFlowTerminal defines the occurrence of a permanently attached element that acts as a terminus or beginning of a distribution system (e.g., air outlet, drain, water closet, sink, etc.). A terminal is typically a point at which a system interfaces with an external environment. Its type is defined by IfcFlowTerminalType or its subtypes. An IfcFlowController can be either aggregated into the definition of the IfcFlowTerminal using the IfcRelAggregates relationship, or referenced using the IfcRelConnectsPorts objectified relationship. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences - Pset_FlowTerminalAirTerminal: property set for air terminal occurrences Geometry Use Definitions The geometric representation of IfcFlowTerminal is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcDistributionFlowElement. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_FlowTerminalAirTerminal: Occurrence-specific property set for individual air terminal occurrences. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcDistributionFlowElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowterminal.htm"
     },
     "IfcFlowTerminalType": {
-        "description": "The element type IfcFlowTerminalType defines a list of commonly shared property set definitions of a flow terminal and an optional set of product representations. It is used to define a flow terminal specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowTerminalType defines a list of commonly shared property set definitions of a flow terminal and an optional set of product representations. It is used to define a flow terminal specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow terminal type is used to define the common properties of a flow terminal that may be applied to many occurrences of that type. A flow terminal acts as a terminus or beginning element in a distribution system such as a ceiling register in a ducted air distribution system, a sink in a waste-water system, or a light fixture in an electrical lighting system. Flow terminal types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowTerminalType are represented by instances of IfcFlowTerminal or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowterminaltype.htm"
     },
     "IfcFlowTreatmentDevice": {
-        "description": "The distribution flow element IfcFlowTreatmentDevice defines the occurrence of a device typically used to remove unwanted matter from a fluid, either liquid or gas, and typically participates in a flow distribution system (e.g., air filter). Its type is defined by IfcFlowTreatmentDeviceType or its subtypes.",
+        "description": "The distribution flow element IfcFlowTreatmentDevice defines the occurrence of a device typically used to remove unwanted matter from a fluid, either liquid or gas, and typically participates in a flow distribution system (e.g., air filter). Its type is defined by IfcFlowTreatmentDeviceType or its subtypes. IfcFlowTreatmentDevice is a container entity that aggregates all components of the device it represents. The aggregation is handled via the IfcRelAggregates relationship. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences Geometry Use Definitions The geometric representation of IfcFlowTreatmentDevice is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcDistributionFlowElement. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcDistributionFlowElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowtreatmentdevice.htm"
     },
     "IfcFlowTreatmentDeviceType": {
-        "description": "The element type IfcFlowTreatmentDeviceType defines a list of commonly shared property set definitions of a flow treatment device and an optional set of product representations. It is used to define a flow treatment device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowTreatmentDeviceType defines a list of commonly shared property set definitions of a flow treatment device and an optional set of product representations. It is used to define a flow treatment device specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow treatment type is used to define the common properties of a flow treatment device that may be applied to many occurrences of that type. A flow treatment device is a device used to change the physical properties of the medium, such as an air, oil or water filter (used to remove particulates from the fluid), duct silencer (used to attenuate noise), etc. flow treatment types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowTreatmentDeviceType are represented by instances of IfcFlowTreatmentDevice or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowtreatmentdevicetype.htm"
     },
     "IfcFluidFlowProperties": {
@@ -2189,11 +2189,11 @@
             "WetBulbTemperatureSingleValue": "Wet bulb temperature of the fluid; only applicable if the fluid is air.",
             "WetBulbTemperatureTimeSeries": "Time series of fluid wet bulb temperature values. These values are only applicable if the fluid is air."
         },
-        "description": "Common definition to capture the basic flow properties of a fluid typically used within a flow distribution system.",
+        "description": "Common definition to capture the basic flow properties of a fluid typically used within a flow distribution system. In cases where an attribute has a SingleValue specified, the corresponding TimeSeries value shall be omitted. Contrarily, when a TimeSeries value is specified, the corresponding SingleValue shall be omitted. IfcFluidFlowProperties is a statically defined property set and should be attached to the instance(s) of the IfcDistributionPort through the IfcRelDefinesByProperties relationship. Where two ports are joined together via the IfcRelConnectsPorts relationship, instances of the IfcFluidFlowProperties can be shared.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcfluidflowproperties.htm"
     },
     "IfcFooting": {
-        "description": "A part of the foundation of a structure that spreads and transmits the load directly to the soil.",
+        "description": "A part of the foundation of a structure that spreads and transmits the load directly to the soil. *Property Set Use Definition*: The property sets relating to the IfcFooting are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcFooting are part of this IFC release: - Pset_ReinforcementBarCountOfIndependentFooting: property set for independent IfcFooting occurrences. - Pset_ReinforcementBarPitchOfContinuousFooting: property set for continuous IfcFooting occurrences. Geometry Use Definitions: The geometric representation of IfcFooting is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The local placement for IfcFooting is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Standard Geometric Representation Provided that it is possible the standard geometric representation of IfcFooting is defined using the swept solid representation. The RepresentationType attribute of IfcShapeRepresentation should have the value 'SweptSolid'. The following constraints apply to the standard representation: - Solid: IfcExtrudedAreaSolid shall be supported - Profile: All applicable profile types shall be supported - Extrusion: All extrusion directions shall be supported. If it is impossible to define the geometry using the swept solid representation the representations defined in its supertype IfcBuildingElement may be used.",
         "predefined_types": {
             "FOOTING_BEAM": "Footing elements that are in bending and are supported clear of the ground. They will normally span between piers, piles or pile caps. They are distinguished from beams in the building superstructure since they will normally require a lower grade of finish. They are distinguished from _STRIP_FOOTING_ since they are clear of the ground surface and hence require support to the lower face while the concrete is curing.",
             "NOTDEFINED": "The type of footing is not defined.",
@@ -2215,26 +2215,26 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcfuelproperties.htm"
     },
     "IfcFurnishingElement": {
-        "description": "Generalization of all furniture related objects. Furnishing objects are characterized as being",
+        "description": "Generalization of all furniture related objects. Furnishing objects are characterized as being - pre-manufactured and assembled on-site, or - manufactured on-site (built-in) Thus furnishing elements can either be movable, or not (as the built-ins). *Geometry Use Definitions*: The geometric representation of IfcFurnishingElement is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representation. Local Placement The local placement for IfcFurnishingElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement , which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representations Any IfcFurnishingElement can be represented by one or several geometric representations. This includes the general representation types 'BoundingBox', 'GeometricCurveSet', 'SurfaceModel', 'Brep', and 'MappedRepresentation' being defined here. Bounding Box Representation Any IfcFurnishingElement may be represented as a bounding box, which shows the maximum extend of the body within the coordinated system established by the IfcLocalPlacement. The bounding box representation is the simplest geometric representation available. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Box' - RepresentationType : 'BoundingBox' Foot Print Representation The foot print representation of IfcFurnishingElement is given by either a single or multiple 2D points and curves. The representation identifier and type of this geometric representation are: - IfcShapeRepresentation.RepresentationIdentifier = 'FootPrint' - IfcShapeRepresentation.RepresentationType = 'GeometricCurveSet' SurfaceModel Representation Any IfcFurnishingElement (so far no further constraints are defined at the level of its subtypes) may be represented as a single or multiple surface models, based on either shell or face based models. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. The representation identifier and type of this geometric representation are: - IfcShapeRepresentation.RepresentationIdentifier = 'Body' - IfcShapeRepresentation.RepresentationType = 'SurfaceModel' Brep Representation Any IfcFurnishingElement (so far no further constraints are defined at the level of its subtypes) may be represented as a single or multiple Boundary Representation elements (which are restricted to faceted Brep with or without voids). The Brep representation allows for the representation of complex element shape. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape. The representation identifier and type of this geometric representation are: - IfcShapeRepresentation.RepresentationIdentifier = 'Body' - IfcShapeRepresentation.RepresentationType = 'Brep' MappedRepresentation The IfcMappedItem should always be used in appropriate cases as it allows for reusing the geometry definition of the furnishing type for all occurrences of the same type. The representation identifier and type of this geometric representation are: - IfcShapeRepresentation.RepresentationIdentifier = 'FootPrint', or 'Body' (depending of the representation map) - IfcShapeRepresentation.RepresentationType = 'MappedRepresentation'",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfurnishingelement.htm"
     },
     "IfcFurnishingElementType": {
-        "description": "The IfcFurnishingElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The IfcFurnishingElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A furnishing element type is used to define the common properties of a certain type of a furnishing element that may be applied to many instances of that feature type to assign a specific style. Furnishing element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFurnishingElementType are represented by instances of IfcFurnishingElement (or its subtypes).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfurnishingelementtype.htm"
     },
     "IfcFurnitureStandard": {
-        "description": "An IfcFurnitureStandard is a standard for furniture allocation that can be assigned to persons within an organization.",
+        "description": "An IfcFurnitureStandard is a standard for furniture allocation that can be assigned to persons within an organization. A furniture standard is assigned a set of classification notations (through the IfcRelAssociatesClassification class within the IfcKernel schema) that determine the types of furniture that fulfill the requirements of the standard. In order to use the IfcFurnitureStandard class, a classification of furniture items must have been established. This does not mean that each individual furniture item needs to have a classification notation although this is considered to be desirable. A furniture standard is assigned to one or several persons or organizations (like a work group or department) through the IfcRelAssignsToControl relationship via the Controls inverse attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcfurniturestandard.htm"
     },
     "IfcFurnitureType": {
         "attributes": {
             "AssemblyPlace": "A designation of where the assembly is intended to take place defined by an Enum."
         },
-        "description": "An IfcFurnitureType defines a particular type of item of furniture such as a table, desk, chair, filing cabinet etc.",
+        "description": "An IfcFurnitureType defines a particular type of item of furniture such as a table, desk, chair, filing cabinet etc. Use Definitions An IfcFurnitureType provides for all forms of unit furniture. Refer to description for IfcSystemFurnitureElementType for descriptions of system elements that may be provided as part of a kit or 'flatpack' for local assembly. Occurrences of a type of furniture are specified through IfcFurnishingElement. *Property Set Use Definition*: The property sets relating to an IfcFurnitureType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcFurnitureType are part of this IFC release: - Pset_FurnitureTypeCommon: property set for the properties common to all types of furniture, if available - Pset_FurnitureTypeChair: specific property set for the properties of a chair, if available - Pset_FurnitureTypeDesk: specific property set for the properties of a desk, if available - Pset_FurnitureTypeFileCabinet: specific property set for the properties of a filing cabinet, if available - Pset_FurnitureTypeTable: specific property set for the properties of a table, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem. *Name Use Definitions* The name of the type of furniture is defined through the IfcFurnitureType.Name attribute (through inheritance from IfcRoot). The following items are examples of names that may be given to instances of IfcFurnitureType. It is concerned only with internal furniture. The list is drawn from the Uniclass classification system published by RIBA Enterprises Ltd and is reproduced by permission. A similar list could also be defined for external furniture. Note that the list does not contain any items that have an electrical or other services connection. Generally, these are dealt with under a relevant building services entity e.g. IfcElectricalApplianceType.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcfurnituretype.htm"
     },
     "IfcGasTerminalType": {
-        "description": "The element type IfcGasTerminalType defines a list of commonly shared property set definitions of a gas terminal and an optional set of product representations. It is used to define a gas terminal specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcGasTerminalType defines a list of commonly shared property set definitions of a gas terminal and an optional set of product representations. It is used to define a gas terminal specification (i.e. the specific product information, that is common to all occurrences of that product type). A gas terminal type is used to define the common properties of a gas terminal that may be applied to many occurrences of that type. A gas terminal is a device where gas is consumed or combusted, such as in a gas-fired hot water or steam boiler. Gas terminal types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcGasTerminalType are represented by instances of IfcFlowTerminal or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_GasTerminalTypeCommon: common property set for all gas terminal types Pset_GasTerminalTypeGasAppliance: property set for all gas appliance terminal types Pset_GasTerminalTypeGasBurner: property set for all gas burner terminal types",
         "predefined_types": {
             "GASAPPLIANCE": "",
             "GASBOOSTER": "",
@@ -2265,7 +2265,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcgeneralprofileproperties.htm"
     },
     "IfcGeometricCurveSet": {
-        "description": "Definition from ISO/CD 10303-42:1992: A geometric curve set is a collection of two or three dimensional points and curves.",
+        "description": "Definition from ISO/CD 10303-42:1992: A geometric curve set is a collection of two or three dimensional points and curves. The IfcGeometricCurveSet is used for the exchange of shape representations consisting of (2D or 3D) points and curves only.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcgeometriccurveset.htm"
     },
     "IfcGeometricRepresentationContext": {
@@ -2276,11 +2276,11 @@
             "TrueNorth": "Direction of the true north relative to the underlying coordinate system as established by the attribute _WorldCoordinateSystem_. It is given by a direction within the xy-plane of the underlying coordinate system. If not given, it defaults to the positive direction of the y-axis of the _WorldCoordinateSystem_.",
             "WorldCoordinateSystem": "Establishment of the engineering coordinate system (often referred to as the world coordinate system in CAD) for all representation contexts used by the project.  >   Note  it can be used to provide better numeric stability if the placement of the building(s) is far away from the origin. In most cases however it would be set to origin: (0.,0.,0.) and directions x(1.,0.,0.), y(0.,1.,0.), z(0.,0.,1.)."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A geometric representation context is a representation context in which the geometric representation items are geometrically founded. A geometric representation context is a distinct coordinate space, spatially unrelated to other coordinate spaces.",
+        "description": "Definition from ISO/CD 10303-42:1992: A geometric representation context is a representation context in which the geometric representation items are geometrically founded. A geometric representation context is a distinct coordinate space, spatially unrelated to other coordinate spaces. Definition from IAI: The IfcGeometricRepresentationContext defines the context that applies to several shape representations of products within a project. It defines the type of the context in which the shape representation is defined, and the numeric precision applicable to the geometric representation items defined in this context. In addition it can be used to offset the project coordinate system from a global point of origin, using the WorldCoordinateSystem attribute. The TrueNorth attribute can be given, if the y axis of the WorldCoordinateSystem does not point to the global northing. The use of one instance of IfcGeometricRepresentationContext to represent the model (3D) view is mandatory, the use of a second instance of IfcGeometricRepresentationContext to represent the plan (2D) view is optional (but needs to be given, if there are scale dependent plan views), the additional scale or view dependent contexts need to be handled by using the subtype IfcGeometricRepresentationSubContext pointing to the model view (or the plan view) as the ParentContext.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcgeometricrepresentationcontext.htm"
     },
     "IfcGeometricRepresentationItem": {
-        "description": "Definition from ISO/CD 10303-43:1992: An geometric representation item is a representation item that has the additional meaning of having geometric position or orientation or both. This meaning is present by virtue of:",
+        "description": "Definition from ISO/CD 10303-43:1992: An geometric representation item is a representation item that has the additional meaning of having geometric position or orientation or both. This meaning is present by virtue of: - being a Cartesian point or a direction - referencing directly a Cartesian point or direction - referencing indirectly a Cartesian point or direction An indirect reference to a Cartesian point or direction means that a given geometric item references the Cartesian point or direction through one or more intervening geometry or topology items. The derivation of the dimensionality of the IfcGeometricRepresentationItem is different to STEP, there is a specific derived attribute at each class that defines the dimensionality, whereas STEP does it for the representation_context and requires all geometric_representation_item's to have the same dimensionality therein. The definition of swept area solids as geometric representation items is different to STEP, it is based on a set of predefined profiles (or cross sections), i.e. a set of parameterized geometric primitives widely supported in the industry. Those profiles are used to create volumes through extrusion, revolution and cross section based sweep operations. This method was called attribute driven geometric representation and it was formerly known as implicit geometry in IFC.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcgeometricrepresentationitem.htm"
     },
     "IfcGeometricRepresentationSubContext": {
@@ -2294,7 +2294,7 @@
             "UserDefinedTargetView": "User defined target view, this attribute value shall be given, if the TargetView attribute is set to USERDEFINED.",
             "WorldCoordinateSystem": "ParentContext.WorldCoordinateSystem"
         },
-        "description": "Definition from IAI: The IfcGeometricRepresentationSubContext defines the context that applies to several shape representations of a product being a sub context, sharing the WorldCoordinateSystem, CoordinateSpaceDimension, Precision and TrueNorth attributes with the parent IfcGeometricRepresentationContext.",
+        "description": "Definition from IAI: The IfcGeometricRepresentationSubContext defines the context that applies to several shape representations of a product being a sub context, sharing the WorldCoordinateSystem, CoordinateSpaceDimension, Precision and TrueNorth attributes with the parent IfcGeometricRepresentationContext. The IfcGeometricRepresentationSubContext is used to define semantically distinguished representation types for different information content, dependent on the representation view and the target scale. It can be used to control the level of detail of the shape representation that is most applicable to this geometric representation context. addition the sub context is used to control the later appearance of the _IfcShapeRepresentation_within a plot view. Each IfcProduct can then have several instances of subtypes of IfcRepresentation, each being assigned to a different geometric representation context (IfcGeometricRepresentationContext or IfcGeometricRepresentationSubContext). The application can then choose the most appropriate representation for showing the geometric shape of the product, depending on the target view and scale.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcgeometricrepresentationsubcontext.htm"
     },
     "IfcGeometricSet": {
@@ -2302,7 +2302,7 @@
             "Dim": "The space dimensionality of this class, it is identical to the first element in the set. A where rule ensures that all elements have the same dimensionality. Elements[1].Dim",
             "Elements": "The geometric elements which make up the geometric set, these may be points, curves or surfaces; but are required to be of the same coordinate space dimensionality."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: This entity is intended for the transfer of models when a topological structure is not available.",
+        "description": "Definition from ISO/CD 10303-42:1992: This entity is intended for the transfer of models when a topological structure is not available. The IfcGeometricSet is used for the exchange of shape representations consisting of (2D or 3D) points, curves, and/or surfaces, which do not have a topological structure (such as connected face sets or shells) and are not solid models (such as swept solids, CSG or Brep)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcgeometricset.htm"
     },
     "IfcGrid": {
@@ -2312,7 +2312,7 @@
             "VAxes": "List of grid axes defining the second row of grid lines.",
             "WAxes": "List of grid axes defining the third row of grid lines. It may be given in the case of a triangular grid."
         },
-        "description": "IfcGrid ia a planar design grid defined in 3D space used as an aid in locating structural and design elements. The position of the grid (ObjectPlacement) is defined by a 3D coordinate system (and thereby the design grid can be used in plan, section or in any position relative to the world coordinate system). The position can be relative to the object placement of other products or grids. The XY plane of the 3D coordinate system is used to place the grid axes, which are 2D curves (e.g., line, circle, trimmed curve, polyline, or composite curve).",
+        "description": "IfcGrid ia a planar design grid defined in 3D space used as an aid in locating structural and design elements. The position of the grid (ObjectPlacement) is defined by a 3D coordinate system (and thereby the design grid can be used in plan, section or in any position relative to the world coordinate system). The position can be relative to the object placement of other products or grids. The XY plane of the 3D coordinate system is used to place the grid axes, which are 2D curves (e.g., line, circle, trimmed curve, polyline, or composite curve). The inherited attributes Name and Description can be used to define a descriptive name of the grid and to indicate the grid's purpose. A grid is defined by (normally) two, or (in case of a triangular grid) three lists of grid axes. The following table shows some examples. The grid axes, defined within the design grid, are those elements to which project objects will be placed relatively using the IfcGridPlacement. Informal Proposition - Grid axes, which are referenced in different lists of axes (UAxes, VAxes, WAxes) shall not be parallel. - Grid axes should be defined such as there are no two grid axes which intersect twice. *Geometry Use Definitions* The geometric representation of IfcGrid is given by the IfcProductDefinitionShape, allowing geometric representations. Included are: Local Placement The local placement for IfcGrid is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representations Currently, the use of a 2D 'FootPrint' representation of type 'GeometricCurveSet' is supported. GeometricCurveSet representation The 2D geometric representation of IfcGrid is defined using the 'GeometricCurveSet' geometry. The following attribute values should be inserted - IfcShapeRepresentation.RepresentationIdentifier = 'FootPrint'. - IfcShapeRepresentation.RepresentationType = 'GeometricCurveSet' . The following constraints apply to the 2D representation: - The IfcGeometricCurveSet shall be an (and the only) Item of the IfcShapeRepresentation. It should contain an IfcGeometricCurveSet containing subtypes of IfcCurve, each representing a grid axis. Applicable subtypes of IfcCurve are: IfcPolyline, IfcCircle, IfcTrimmedCurve (based on BaseCurve referencing IfcLine or IfcCircle). - Each subtype of IfcCurve may have a curve style assigned, using IfcAnnotationCurveOccurrence referencing IfcCurveStyle. - Optionally the grid axis labels may be added as IfcTextLiteral, and they may have text styles assigned, using IfcAnnotationTextOccurrence referencing IfcTextStyle. Illustrations",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcgrid.htm"
     },
     "IfcGridAxis": {
@@ -2325,7 +2325,7 @@
             "PartOfW": "If provided, the _IfcGridAxis_ is part of the _WAxes_ of _IfcGrid_.",
             "SameSense": "Defines whether the original sense of curve is used or whether it is reversed in the context of the grid axis."
         },
-        "description": "An individual axis, the IfcGridAxis, is defined in the context of a design grid. The axis definition is based on a curve of dimensionality 2. The grid axis is positioned within the XY plane of the position coordinate system defined by the IfcDesignGrid.",
+        "description": "An individual axis, the IfcGridAxis, is defined in the context of a design grid. The axis definition is based on a curve of dimensionality 2. The grid axis is positioned within the XY plane of the position coordinate system defined by the IfcDesignGrid. *Geometry Use Definitions*: The standard geometric representation of IfcGridAxis is defined using a 2D curve entity. Grid axes are normally defined by an offset to another axis. The IfcOffsetCurve2D supports this concept. Each grid axis has a sense given by the parameterization of the curve. The attribute SameSense is an indicator of whether or not the sense of the grid axis agrees with, or opposes, that of the underlying curve. Illustration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcgridaxis.htm"
     },
     "IfcGridPlacement": {
@@ -2333,14 +2333,14 @@
             "PlacementLocation": "A constraint on one or both ends of the path for an ExtrudedSolid.",
             "PlacementRefDirection": "Reference to a second grid axis intersection, which defines the orientation of the grid placement."
         },
-        "description": "The IfcGridPlacement provides a specialization of IfcObjectPlacement in which the placement and axis direction of the object coordinate system is defined by a reference to the design grid as defined in IfcGrid.",
+        "description": "The IfcGridPlacement provides a specialization of IfcObjectPlacement in which the placement and axis direction of the object coordinate system is defined by a reference to the design grid as defined in IfcGrid. The location of the object coordinate system is given by the attribute PlacementLocation. The axis direction (of x-axis) of the object coordinate system is given: - by the tangent of the first grid axis (PlacementLocation.IntersectingAxes[1]) at the virtual intersection (maybe using the offset curve, if PlacementLocation.OffsetDistances is given) in case that the PlacementRefDirection is not given, - by the tangent between the virtual grid intersection of PlacementLocation and the virtual grid intersection of PlacementRefDirection in case that the PlacementRefDirection is given. The direction of the y-axis of the _IfcGridPlacement_is the orthogonal complement to the x-axis. The plane defined by the x and y axis shall be co-planar to the xy plane of the local placement of the IfcGrid. The direction of the z-axis is the orientation of the cross product of the x-axis and the y-axis, i.e. the z-axis of the IfcGridPlacement shall be co-linear to the z-axis of the local placement of the IfcGrid. *Geometry use definitions*: The following example shows the usage of placement location and direction for an IfcGridPlacement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcgridplacement.htm"
     },
     "IfcGroup": {
         "attributes": {
             "IsGroupedBy": "Contains the relationship that assigns the group members to the group object."
         },
-        "description": "The IfcGroup is an generalization of any arbitrary group. A group is a logical collection of objects. It does not have its own position, nor can it hold its own shape representation. Therefore a group is an aggregation under some non-geometrical / topological grouping aspects.",
+        "description": "The IfcGroup is an generalization of any arbitrary group. A group is a logical collection of objects. It does not have its own position, nor can it hold its own shape representation. Therefore a group is an aggregation under some non-geometrical / topological grouping aspects. A group can hold any collection of objects (being products, processes, controls, resources, actors or other groups). Thus groups can be nested. An object can be part of zero, one, or many groups. Grouping relationships are not required to be hierarchical. The group collection is handled by an instance of IfcRelAssignsToGroup, which assigns all group members to the IfcGroup.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcgroup.htm"
     },
     "IfcHalfSpaceSolid": {
@@ -2349,11 +2349,11 @@
             "BaseSurface": "Surface defining side of half space.",
             "Dim": "The space dimensionality of this class, it is always 3 3"
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A half space solid is defined by the half space which is the regular subset of the domain which lies on one side of an unbounded surface. The side of the surface which is in the half space is determined by the surface normal and the agreement flag. If the agreement flag is TRUE, then the subset is the one the normal points away from. If the agreement flag is FALSE, then the subset is the one the normal points into. For a valid half space solid the surface shall divide the domain into exactly two subsets. Also, within the domain the surface shall be manifold and all surface normals shall point into the same subset.",
+        "description": "Definition from ISO/CD 10303-42:1992: A half space solid is defined by the half space which is the regular subset of the domain which lies on one side of an unbounded surface. The side of the surface which is in the half space is determined by the surface normal and the agreement flag. If the agreement flag is TRUE, then the subset is the one the normal points away from. If the agreement flag is FALSE, then the subset is the one the normal points into. For a valid half space solid the surface shall divide the domain into exactly two subsets. Also, within the domain the surface shall be manifold and all surface normals shall point into the same subset. Informal propositions: - The base surface shall divide the domain into exactly two subsets. If the half space solid is of subtype boxed half space (IfcBoxedHalfSpace), the domain in question is that of the attribute enclosure. In all other cases the domain is all of space and the base surface shall be unbounded. - The base surface shall be an unbounded surface (subtype of IfcElementarySurface). Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifchalfspacesolid.htm"
     },
     "IfcHeatExchangerType": {
-        "description": "The element type IfcHeatExchangerType defines a list of commonly shared property set definitions of a heat exchanger and an optional set of product representations. It is used to define a heat exchanger specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcHeatExchangerType defines a list of commonly shared property set definitions of a heat exchanger and an optional set of product representations. It is used to define a heat exchanger specification (i.e. the specific product information, that is common to all occurrences of that product type). A heat exchanger type is used to define the common properties of a heat exchanger that may be applied to many occurrences of that type. A heat exchanger is a device used to provide heat transfer between non-mixing media such as plate and shell and tube heat exchangers. The occurrences of the IfcHeatExchangerType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_HeatExchangerTypeCommon: common property set for all heat exchanger types Pset_HeatExchangerTypePlate: property set for all plate heat exchanger types",
         "predefined_types": {
             "NOTDEFINED": "Undefined heat exchanger type.",
             "PLATE": "Plate heat exchanger.",
@@ -2363,7 +2363,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcheatexchangertype.htm"
     },
     "IfcHumidifierType": {
-        "description": "The element type IfcHumidifierType defines a list of commonly shared property set definitions of a humidifier and an optional set of product representations. It is used to define a humidifier specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcHumidifierType defines a list of commonly shared property set definitions of a humidifier and an optional set of product representations. It is used to define a humidifier specification (i.e. the specific product information, that is common to all occurrences of that product type). A Humidifier type is used to define the common properties of a humidifier that may be applied to many occurrences of that type. A humidifier is a device that adds moisture into the air. Humidifier types may be exchanged without being already assigned to occurrences. The occurrences of the IfcHumidifierType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_HumidifierTypeCommon: common property set for all humidifier types",
         "predefined_types": {
             "ADIABATICAIRWASHER": "Water vapor is added into the airstream through adiabatic evaporation using an air washing element.",
             "ADIABATICATOMIZING": "Water vapor is added into the airstream through adiabatic evaporation using an atomizing element.",
@@ -2402,14 +2402,14 @@
             "OverallWidth": "Total extent of the width, defined parallel to the x axis of the position coordinate system.",
             "WebThickness": "Thickness of the web of the I-shape. The web is centred on the x-axis and the y-axis of the position coordinate system."
         },
-        "description": "Definition from IAI: The IfcIShapeProfileDef defines a section profile that provides the defining parameters of a symmetrical 'I' section to be used by the swept surface geometry or the swept area solid. The I-shape profile has values for its overall depth, width and its web and flange thickness. Additionally a fillet radius may be given. It represents a I-section that is symmetrical about its major and minor axes; and that has both top and bottom flanges being equal and centred on the web.",
+        "description": "Definition from IAI: The IfcIShapeProfileDef defines a section profile that provides the defining parameters of a symmetrical 'I' section to be used by the swept surface geometry or the swept area solid. The I-shape profile has values for its overall depth, width and its web and flange thickness. Additionally a fillet radius may be given. It represents a I-section that is symmetrical about its major and minor axes; and that has both top and bottom flanges being equal and centred on the web. Illustration: Table: Parameter of the I-shape profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcishapeprofiledef.htm"
     },
     "IfcImageTexture": {
         "attributes": {
             "UrlReference": ""
         },
-        "description": "Definition from IAI: An IfcImageTexture provides a 2-dimensional distribution of the lighting parameters of a surface onto which it is mapped.",
+        "description": "Definition from IAI: An IfcImageTexture provides a 2-dimensional distribution of the lighting parameters of a surface onto which it is mapped. The following additional definitions from ISO/IEC FCD 19775:200x, the Extensible 3D (X3D) specification, apply: - The ImageTexture node defines a texture map by specifying an image file and general parameters for mapping to geometry. Texture maps are defined in a 2D coordinate system (s, t) that ranges from [0.0, 1.0] in both directions. The bottom edge of the image corresponds to the S-axis of the texture map, and left edge of the image corresponds to the T-axis of the texture map. The lower-left pixel of the image corresponds to s=0, t=0, and the top-right pixel of the image corresponds to s=1, t=1. - The texture is read from the URL specified by the url [reference attribute]. When the url field contains no values ([]), texturing is disabled. Browsers shall support the JPEG and PNG image file formats. Support for the GIF format is also recommended (including transparency). The following general recommendations for image file format support from ISO/IEC FCD 19775:200x, the Extensible 3D (X3D) specification, also apply: Texture nodes that require support for the PNG image format shall interpret the PNG pixel formats in the following way: - Greyscale pixels without alpha or simple transparency are treated as intensity textures. - Greyscale pixels with alpha or simple transparency are treated as intensity plus alpha textures. - RGB pixels without alpha channel or simple transparency are treated as full RGB textures. - RGB pixels with alpha channel or simple transparency are treated as full RGB plus alpha textures. If the image specifies colours as indexed-colour (i.e., palettes or colourmaps), the following semantics should be used (note that `greyscale' refers to a palette entry with equal red, green, and blue values): - If all the colours in the palette are greyscale and there is no transparency chunk, it is treated as an intensity texture. - If all the colours in the palette are greyscale and there is a transparency chunk, it is treated as an intensity plus opacity texture. - If any colour in the palette is not grey and there is no transparency chunk, it is treated as a full RGB texture. - If any colour in the palette is not grey and there is a transparency chunk, it is treated as a full RGB plus alpha texture. Texture nodes that require support for JPEG files shall interpret JPEG files as follows: - Greyscale files (number of components equals 1) are treated as intensity textures. - YCbCr files are treated as full RGB textures. - No other JPEG file types are required. It is recommended that other JPEG files are treated as a full RGB textures. Texture nodes that recommend support for GIF files shall follow the applicable semantics described above for the PNG format.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcimagetexture.htm"
     },
     "IfcInventory": {
@@ -2421,7 +2421,7 @@
             "OriginalValue": "An estimate of the original cost value of the inventory.",
             "ResponsiblePersons": "Persons who are responsible for the inventory."
         },
-        "description": "An IfcInventory is a list of items within an enterprise.",
+        "description": "An IfcInventory is a list of items within an enterprise. Various types of inventory can be included. These are identified by the range of values within the inventory type enumeration which currently includes space, asset, furniture. User defined inventories can also be defined for lists of particular types of element such as may be required in operating and maintenance instrucions. Such inventories should be constrained to contain a list of elements of a restricted type. There are a number of actors that can be associated with an inventory, each actor having a role. Principal actors are identified as attributes of the class. Additional actors can be specified through the relationship class IfcRelAssignsToActor in which case roles should be defined through the IfcActorRole class which must be asserted for each defined role. There are a number of costs that can be associated with an inventory, each cost having a role. Principal costs are identified as attributes of the class. Additional costs can be specified through the relationship class IfcRelAssociatesCost in which case roles must be asserted.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcinventory.htm"
     },
     "IfcIrregularTimeSeries": {
@@ -2440,7 +2440,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifcirregulartimeseriesvalue.htm"
     },
     "IfcJunctionBoxType": {
-        "description": "An IfcJunctionBoxType defines a particular type of junction box which is a housing inside which cables from electrical components are connected electrically.",
+        "description": "An IfcJunctionBoxType defines a particular type of junction box which is a housing inside which cables from electrical components are connected electrically. *Use Definitions* An IfcJunctionBoxType is a subtype of IfcFlowFittingType and provides for all forms of junction boxes. Usage of IfcJunctionBoxType defines the parameters for one or more occurrences of IfcFlowFitting. *Property Set Use Definition*: There are no property sets currently defined for IfcJunctionBoxType. *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "NOTDEFINED": "Undefined type.",
             "USERDEFINED": "User-defined type."
@@ -2458,18 +2458,18 @@
             "Thickness": "Constant wall thickness of profile, see illustration above (= ts).",
             "Width": "Leg length, see illustration above (= b). If not given, the value of the Depth attribute is applied to Width."
         },
-        "description": "Definition from IAI: The IfcLShapeProfileDef defines a section profile that provides the defining parameters of an L-shaped section (equilateral L profiles are also covered by this entity) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The shorter leg has the same direction as the positive x-axis, the longer or equal leg the same as the positive y-axis. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
+        "description": "Definition from IAI: The IfcLShapeProfileDef defines a section profile that provides the defining parameters of an L-shaped section (equilateral L profiles are also covered by this entity) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The shorter leg has the same direction as the positive x-axis, the longer or equal leg the same as the positive y-axis. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box. The centre of gravity, if given, is located in x direction along the negative x axis, the offset value is given by the offset parameter CentreOfGravityInX, and in y-direction along the negative y axis, the offset value is given by the offset parameter CentreOfGravityInY. Illustration: Table: Parameters of equal-sided and non-equal sided L-shaped section definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifclshapeprofiledef.htm"
     },
     "IfcLaborResource": {
         "attributes": {
             "SkillSet": "The skill set required for this type of labor."
         },
-        "description": "An IfcLaborResource is used in construction with particular skills or crafts required to perform certain types of construction or management related work.",
+        "description": "An IfcLaborResource is used in construction with particular skills or crafts required to perform certain types of construction or management related work. Labor resources do not identify individual persons (i.e. IfcActors) for cost estimating purpose.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifclaborresource.htm"
     },
     "IfcLampType": {
-        "description": "An IfcLampType is a type of device that is designed to emit light.",
+        "description": "An IfcLampType is a type of device that is designed to emit light. *Use Definitions* An IfcLampType provides for all forms of lamp and its usage defines the parameters for one or more occurrences of IfcFlowTerminal. Instances of IfcFlowTerminal that are defined as types of IfcLampType are connected via instances of IfcDistributionPort to an instance of IfcFlowTerminal that is defined as a type of IfcLightFixtureType. Rendering using lighting data is achieved using light source entities within the presentation capabilities of IFC. *Property Set Use Definition*: The property sets relating to the IfcLampType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcLampType are part of this IFC release: - Pset_LampTypeCommon: property set for properties that are common to all types of lamp installed within a light fixture, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "COMPACTFLUORESCENT": "A fluorescent lamp having a compact form factor produced by shaping the tube.",
             "FLUORESCENT": "A typically tubular discharge lamp in which most of the light is emitted by one or several layers of phosphors excited by ultraviolet radiation from the discharge.",
@@ -2506,11 +2506,11 @@
             "MainPlaneAngle": "The main plane angle (A, B or C angles, according to the light distribution curve chosen).",
             "SecondaryPlaneAngle": "The list of secondary plane angles (the \u03b1, \u03b2 or \u03b3 angles) according to the light distribution curve chosen.  > NOTE: The _SecondaryPlaneAngle_ and _LuminousIntensity_ lists are corresponding lists."
         },
-        "description": "The IfcLightDistributionData defines the luminous intensity of a light source given at a particular main plane angle. It is based on some standardized light distribution curves, the MainPlaneAngle is either the",
+        "description": "The IfcLightDistributionData defines the luminous intensity of a light source given at a particular main plane angle. It is based on some standardized light distribution curves, the MainPlaneAngle is either the - A angle; if the IfcLightDistributionCurveEnum is set to TYPE_A - B angle; if the IfcLightDistributionCurveEnum is set to TYPE_B - C angle; if the IfcLightDistributionCurveEnum is set to TYPE_C For each MainPlaneAngle (considered as being the row of a table) a list of _SecondaryPlaneAngle'_s are given (considered to be the columns of a table). They are either the: - \u03b1 angle; if the IfcLightDistributionCurveEnum is set to TYPE_A - \u03b2 angle; if the IfcLightDistributionCurveEnum is set to TYPE_B - \u03b3 angle; if the IfcLightDistributionCurveEnum is set to TYPE_C For each pair of MainPlaneAngle and SecondaryPlaneAngle the LuminousIntensity is provides (the unit is given by the IfcUnitAssignment referring to the LuminousIntensityDistributionUnit, normally cd/klm).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightdistributiondata.htm"
     },
     "IfcLightFixtureType": {
-        "description": "An IfcLightFixtureType is a container type that is designed for the purpose of housing one or more lamps and the devices that control, restrict or vary their emission.",
+        "description": "An IfcLightFixtureType is a container type that is designed for the purpose of housing one or more lamps and the devices that control, restrict or vary their emission. *Use Definitions* An IfcLightFixtureType provides for all forms of light fixture and its usage defines the parameters for one or more occurrences of IfcFlowTerminal. Instances of IfcFlowTerminal that are defined as types of IfcLightFixtureType have one or more instances of IfcFlowTerminal that are defined as types of IfcLampType connected using instances of IfcDistributionPort. Rendering using lighting data is achieved using light source entities within the presentation capabilities of IFC. *Property Set Use Definition*: The property sets relating to the IfcLightFixtureType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcLightFixtureType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available - Pset_LightFixtureTypeCommon: property set for properties that are common to all types of light fixture, if available - Pset_LightFixtureTypeThermal: specific property set for the thermal properties of a light fixture, if available - Pset_LightFixtureTypeExitSign: specific property set for the properties of an exit sign, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "DIRECTIONSOURCE": "A light fixture that is considered to have a length or surface area from which it emits light in a direction. A light fixture containing one or more fluorescent lamps is an example of a direction source.",
             "NOTDEFINED": "Undefined type.",
@@ -2545,7 +2545,7 @@
         "attributes": {
             "Orientation": "Definition from ISO/CD 10303-46:1992: This direction is the direction of the light source. Definition from VRML97 - ISO/IEC 14772-1:1997: The direction field specifies the direction vector of the illumination emanating from the light source in the local coordinate system. Light is emitted along parallel rays from an infinite distance away."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: The light source directional is a subtype of light source. This entity has a light source direction. With a conceptual origin at infinity, all the rays of the light are parallel to this direction. This kind of light source lights a surface based on the surface's orientation, but not position.",
+        "description": "Definition from ISO/CD 10303-46:1992: The light source directional is a subtype of light source. This entity has a light source direction. With a conceptual origin at infinity, all the rays of the light are parallel to this direction. This kind of light source lights a surface based on the surface's orientation, but not position. Definition from ISO/IEC 14772-1:1997: The directional light node defines a directional light source that illuminates along rays parallel to a given 3-dimensional vector. Directional light nodes do not attenuate with distance. Directional light nodes are specified in the local coordinate system and are affected by ancestor transformations.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsourcedirectional.htm"
     },
     "IfcLightSourceGoniometric": {
@@ -2557,7 +2557,7 @@
             "LuminousFlux": "Luminous flux is a photometric measure of radiant flux, i.e. the volume of light emitted from a light source. Luminous flux is measured either for the interior as a whole or for a part of the interior (partial luminous flux for a solid angle). All other photometric parameters are derivatives of luminous flux. Luminous flux is measured in lumens (lm). The luminous flux is given as a nominal value for each lamp.",
             "Position": "The position of the light source. It is used to orientate the light distribution curves."
         },
-        "description": "The IfcLightSourceGoniometric defines a light source for which exact lighting data is available. It specifies the type of a light emitter, defines the position and orientation of a light distribution curve and the data concerning lamp and photometric information.",
+        "description": "The IfcLightSourceGoniometric defines a light source for which exact lighting data is available. It specifies the type of a light emitter, defines the position and orientation of a light distribution curve and the data concerning lamp and photometric information. Illustration: Example of a light emitter having two light sources (of type IfcLightSourceGoniometric).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsourcegoniometric.htm"
     },
     "IfcLightSourcePositional": {
@@ -2568,7 +2568,7 @@
             "QuadricAttenuation": "Definition from the IAI: This real indicates the value of the attenuation in the lighting equation that proportional to the square value of the distance from the light source.",
             "Radius": "The maximum distance from the light source for a surface still to be illuminated. Definition from VRML97 - ISO/IEC 14772-1:1997: A Point light node illuminates geometry within radius of its location."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: The light source positional entity is a subtype of light source. This entity has a light source position and attenuation coefficients. A positional light source affects a surface based on the surface's orientation and position.",
+        "description": "Definition from ISO/CD 10303-46:1992: The light source positional entity is a subtype of light source. This entity has a light source position and attenuation coefficients. A positional light source affects a surface based on the surface's orientation and position. Definition from ISO/IEC 14772-1:1997: The Point light node specifies a point light source at a 3D location in the local coordinate system. A point light source emits light equally in all directions; that is, it is omnidirectional. Point light nodes are specified in the local coordinate system and are affected by ancestor transformations. Point light node's illumination falls off with distance as specified by three attenuation coefficients. The attenuation factor is where r is the distance from the light to the surface being illuminated. The default is no attenuation. An attenuation value of (0, 0, 0) is identical to (1, 0, 0). Attenuation values shall be greater than or equal to zero.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsourcepositional.htm"
     },
     "IfcLightSourceSpot": {
@@ -2578,7 +2578,7 @@
             "Orientation": "Definition from ISO/CD 10303-46:1992: This is the direction of the axis of the cone of the light source specified in the coordinate space of the representation being projected.. Definition from VRML97 - ISO/IEC 14772-1:1997: The direction field specifies the direction vector of the light's central axis defined in the local coordinate system.",
             "SpreadAngle": "Definition from ISO/CD 10303-46:1992: This planar angle measure is the angle between the line that starts at the position of the spot light source and is in the direction of the spot light source and any line on the boundary of the cone of influence. Definition from VRML97 - ISO/IEC 14772-1:1997: The cutOffAngle (name of spread angle in VRML) field specifies the outer bound of the solid angle. The light source does not emit light outside of this solid angle."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: The light source spot entity is a subtype of light source. Spot light source entities have a light source colour, position, direction, attenuation coefficients, concentration exponent, and spread angle. If a point lies outside the cone of influence of a light source of this type as determined by the light source position, direction and spread angle its colour is not affected by that light source.",
+        "description": "Definition from ISO/CD 10303-46:1992: The light source spot entity is a subtype of light source. Spot light source entities have a light source colour, position, direction, attenuation coefficients, concentration exponent, and spread angle. If a point lies outside the cone of influence of a light source of this type as determined by the light source position, direction and spread angle its colour is not affected by that light source. Definition from ISO/IEC 14772-1:1997: The Spot light node defines a light source that emits light from a specific point along a specific direction vector and constrained within a solid angle. Spot lights may illuminate geometry nodes that respond to light sources and intersect the solid angle defined by the Spot light. Spot light nodes are specified in the local coordinate system and are affected by ancestors' transformations. Figure (from VRML97): Definition of spot light",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsourcespot.htm"
     },
     "IfcLine": {
@@ -2586,11 +2586,11 @@
             "Dir": "The direction of the line, the magnitude and units of Dir affect the parameterization of the line.",
             "Pnt": "The location of the line."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A line is an unbounded curve with constant tangent direction. A line is defined by a point and a direction. The positive direction of the line is in the direction of the Dir vector. The line is parameterized as follows:",
+        "description": "Definition from ISO/CD 10303-42:1992: A line is an unbounded curve with constant tangent direction. A line is defined by a point and a direction. The positive direction of the line is in the direction of the Dir vector. The line is parameterized as follows: and the parametric range is -\u00a5 < u < \u00a5",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcline.htm"
     },
     "IfcLinearDimension": {
-        "description": "The linear dimension is a draughting callout that presents the length (or distance) between two points along a linear curve. It consists of a dimension curve and optionally one or two projection curves.",
+        "description": "The linear dimension is a draughting callout that presents the length (or distance) between two points along a linear curve. It consists of a dimension curve and optionally one or two projection curves. Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifclineardimension.htm"
     },
     "IfcLocalPlacement": {
@@ -2598,7 +2598,7 @@
             "PlacementRelTo": "Reference to Object that provides the relative placement by its local coordinate system. If it is omitted, then the local placement is given to the WCS, established by the geometric representation context.",
             "RelativePlacement": "Geometric placement that defines the transformation from the related coordinate system into the relating. The placement can be either 2D or 3D, depending on the dimension count of the coordinate system."
         },
-        "description": "Definition from IFC: The IfcLocalPlacement defines the relative placement of a product in relation to the placement of another product or the absolute placement of a product within the geometric representation context of the project.",
+        "description": "Definition from IFC: The IfcLocalPlacement defines the relative placement of a product in relation to the placement of another product or the absolute placement of a product within the geometric representation context of the project. The IfcLocalPlacement allows that an IfcProduct can be placed by this IfcLocalPlacement (through the attribute_ObjectPlacement_) within the local coordinate system of the object placement of another IfcProduct, which is referenced by the PlacementRelTo. Rules to prevent cyclic relative placements have to be introduced on the application level. If the PlacementRelTo is not given, then the IfcProduct is placed absolutely within the world coordinate system. *Geometry use definitions*: The following conventions shall apply as default relative positions if the relative placement is used. The conventions are given for all five direct subtypes of IfcProduct, the IfcSpatialStructureElement, IfcElement, IfcAnnotation, IfcGrid, IfcPort. More detailed placement information is given at the level of subtypes of those five types mentioned. - For the subtypes of IfcSpatialStructureElement the following conventions apply IfcSite shall be placed absolutely within the world coordinate system established by the geometric representation context of the IfcProject IfcBuilding shall be placed relative to the local placement of IfcSite IfcBuildingStorey shall be placed relative to the local placement of IfcBuilding - For IfcGrid and IfcAnnotation the convention applies that it shall be placed relative to the local placement of its container (IfcSite, IfcBuilding, IfcBuildingStorey) it should be the same container element that is referenced by the IfcRelContainedInSpatialStructure containment relationship, - For IfcPort the convention applies that it shall be placed relative to the local placement of the element it belongs to (IfcElement) it should be the same element that is referenced by the IfcRelConnectsPortToElement connection relationship, - For IfcElement the convention applies that it shall be placed relative: to the local placement of its container (IfcSite, IfcBuilding, IfcBuildingStorey) it should be the same container element that is referenced by the IfcRelContainedInSpatialStructure containment relationship, to the local placement of the IfcElement to which it is tied by an element composition relationship for features that are located relative to the main component (such as openings), as expressed by IfcRelVoidsElement and_IfcRelProjectsElement_, for elements that fill an opening (such as doors or windows), as expressed by_IfcRelFillsElement_, for coverings that cover the element, as expressed by_IfcRelCoversBldgElements,_ for sub components that are aggregated to the main component, as expressed by IIfcRelAggregates and IfcRelNests) If the PlacementRelTo relationship is not given, then it defaults to an absolute placement within the world coordinate system established by the referenced geometric representation context within the project.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifclocalplacement.htm"
     },
     "IfcLocalTime": {
@@ -2613,14 +2613,14 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifclocaltime.htm"
     },
     "IfcLoop": {
-        "description": "Definition from ISO/CD 10303-42:1992: A loop is a topological entity constructed from a single vertex, or by stringing together connected (oriented) edges, or linear segments beginning and ending at the same vertex. It is typically used to bound a face lying on a surface. A loop has dimensionality of 0 or 1. The domain of a 0-dimensional loop is a single point. The domain of a 1-dimensional loop is a connected, oriented curve, but need not to be manifold. As the loop is a circle, the location of its beginning/ending point is arbitrary. The domain of the loop includes its bounds, an 0 \u2264 \u039e < \u221e.",
+        "description": "Definition from ISO/CD 10303-42:1992: A loop is a topological entity constructed from a single vertex, or by stringing together connected (oriented) edges, or linear segments beginning and ending at the same vertex. It is typically used to bound a face lying on a surface. A loop has dimensionality of 0 or 1. The domain of a 0-dimensional loop is a single point. The domain of a 1-dimensional loop is a connected, oriented curve, but need not to be manifold. As the loop is a circle, the location of its beginning/ending point is arbitrary. The domain of the loop includes its bounds, an 0 \u2264 \u039e < \u221e. A loop is represented by a single vertex, or by an ordered collection of oriented edges, or by an ordered collection of points. A loop is a graph, so M and the graph genus G^l^ may be determined by the graph traversal algorithm. Since M= 1, the Euler equation (1) reduces in this case to where V and E~l~ are the number of unique vertices and oriented edges in the loop and G^l^ is the genus of the loop. Informal propositions: - A loop has a finite extent. - A loop describes a closed (topological) curve with coincident start and end vertices.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcloop.htm"
     },
     "IfcManifoldSolidBrep": {
         "attributes": {
             "Outer": "A closed shell defining the exterior boundary of the solid. The shell normal shall point away from the interior of the solid."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A manifold solid B-rep is a finite, arcwise connected volume bounded by one or more surfaces, each of which is a connected, oriented, finite, closed 2-manifold. There is no restriction on the genus of the volume, nor on the number of voids within the volume.",
+        "description": "Definition from ISO/CD 10303-42:1992: A manifold solid B-rep is a finite, arcwise connected volume bounded by one or more surfaces, each of which is a connected, oriented, finite, closed 2-manifold. There is no restriction on the genus of the volume, nor on the number of voids within the volume. The Boundary Representation (B-rep) of a manifold solid utilizes a graph of edges and vertices embedded in a connected, oriented, finite, closed two manifold surface. The embedded graph divides the surface into arcwise connected areas known as faces. The edges and vertices, therefore, form the boundaries of the face and the domain of a face does not include its boundaries. The embedded graph may be disconnected and may be a pseudo graph. The graph is labeled; that is, each entity in the graph has a unique identity. The geometric surface definition used to specify the geometry of a face shall be 2-manifold embeddable in the plane within the domain of the face. In other words, it shall be connected, oriented, finite, non-self-intersecting, and of surface genus 0. Faces do not intersect except along their boundaries. Each edge along the boundary of a face is shared by at most one other face in the assemblage. The assemblage of edges in the B-rep do not intersect except at their boundaries (i.e., vertices). The geometry curve definition used to specify the geometry of an edge shall be arcwise connected and shall not self intersect or overlap within the domain of the edge. The geometry of an edge shall be consistent with the geometry of the faces of which it forms a partial bound. The geometry used to define a vertex shall be consistent with the geometry of the faces and edges of which it forms a partial bound. A B-rep is represented by one or more closed shells which shall be disjoint. One shell, the outer, shall completely enclose all the other shells and no other shell may enclose a shell. The facility to define a B-rep with one or more internal voids is provided by a subtype. The following version of the Euler formula shall be satisfied, where V, E, F, L~l~ and S are the numbers of unique vertices, edges, faces, loop uses and shells in the model and G^s^ is the sum of the genus of the shells. Informal proposition: - The dimensionality of a manifold solid brep shall be 3. - The extent of the manifold solid brep shall be finite and non-zero. - All elements of the manifold solid brep shall have defined associated geometry. - The shell normals shall agree with the B-rep normal and point away from the solid represented by the B-rep. - Each face shall be referenced only once by the shells of the manifold solid brep. - The Euler equation shall be satisfied for the boundary representation, where the genus term \"shell term\" us the sum of the genus values for the shells of the brep.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcmanifoldsolidbrep.htm"
     },
     "IfcMappedItem": {
@@ -2628,7 +2628,7 @@
             "MappingSource": "A representation map that is the source of the mapped item. It can be seen as a block (or cell or marco) definition.",
             "MappingTarget": "A representation item that is the target onto which the mapping source is mapped. It is constraint to be a Cartesian transformation operator."
         },
-        "description": "Definition from ISO/CD 10303-43:1992: A mapped item is the use of an existing representation (the mapping source - mapped representation) as a representation item in a second representation.",
+        "description": "Definition from ISO/CD 10303-43:1992: A mapped item is the use of an existing representation (the mapping source - mapped representation) as a representation item in a second representation. Definition from IAI: The IfcMappedItem is the inserted instance of a source definition (to be compared with a block / shared cell / macro definition). The instance is inserted by applying a Cartesian transformation operator as the MappingTarget. Informal Propositions - A mapped item shall not be self-defining by participating in the definition of the representation being mapped. - The dimensionality of the mapping source and the mapping target has to be the same, if the mapping source is a geometric representation item.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcmappeditem.htm"
     },
     "IfcMaterial": {
@@ -2652,7 +2652,7 @@
         "attributes": {
             "RepresentedMaterial": "Reference to the material to which the representation applies."
         },
-        "description": "The IfcMaterialDefinitionRepresentation defines presentation information relating to IfcMaterial. It allows for multiple presentations of the same material for different geometric representation contexts.  ",
+        "description": "The IfcMaterialDefinitionRepresentation defines presentation information relating to IfcMaterial. It allows for multiple presentations of the same material for different geometric representation contexts.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcmaterialdefinitionrepresentation.htm"
     },
     "IfcMaterialLayer": {
@@ -2662,7 +2662,7 @@
             "Material": "Optional reference to the material from which the layer is constructed. Note, that if this value is not given, it does not denote a layer with no material (an air gap), it only means that the material is not specified at that point.",
             "ToMaterialLayerSet": "Reference to the material layer set, in which the material layer is included."
         },
-        "description": "A single and identifiable part of an element which is constructed of a number of layers (one or more).  Each IfcMaterialLayer is located relative to the referencing IfcMaterialLayerSet.",
+        "description": "A single and identifiable part of an element which is constructed of a number of layers (one or more). Each IfcMaterialLayer is located relative to the referencing IfcMaterialLayerSet.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmateriallayer.htm"
     },
     "IfcMaterialLayerSet": {
@@ -2671,7 +2671,7 @@
             "MaterialLayers": "Identification of the layers from which the material layer set is composed.",
             "TotalThickness": "Total thickness of the material layer set is derived from the function IfcMlsTotalThickness. IfcMlsTotalThickness(SELF)"
         },
-        "description": "Definition from IAI: A designation by which materials of an element constructed of a number of material layers is known and through which the relative positioning of individual layers can be expressed.",
+        "description": "Definition from IAI: A designation by which materials of an element constructed of a number of material layers is known and through which the relative positioning of individual layers can be expressed. *Geometry use* Each IfcMaterialLayerSet implicitly defines a reference line (MlsBase), to which the start of the first IfcMaterialLayer is aligned. The total thickness of a layer set is calculated from the individual layer thicknesses, the first layer starting from the reference line and following layers being placed on top of the previous (no gaps or overlaps).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmateriallayerset.htm"
     },
     "IfcMaterialLayerSetUsage": {
@@ -2681,7 +2681,7 @@
             "LayerSetDirection": "Orientation of the layer set relative to element reference geometry. The meaning of the value of this attribute shall be specified in the geometry use section for each element. For extruded shape representation, direction can be given along the extrusion path (e.g. for slabs) or perpendicular to it (e.g. for walls). > NOTE  the LayerSetDirection for IfcWallStandardCase shall be AXIS2 (i.e. the y-axis) and for standard IfcSlab it shall be AXIS3 (i.e. the z-axis).",
             "OffsetFromReferenceLine": "Offset of the material layer set base line (MlsBase) from reference geometry (line or plane). The offset can be positive or negative, unless restricted for a particular building element type in its use definition or by implementer agreement. The reference geometry for each relevant subtype of _IfcElement_ is defined in use definition for the element. Examples are given in the use definition of _IfcMaterialLayerSetUsage_."
         },
-        "description": "Definition from IAI: Determines the usage of IfcMaterialLayerSet in terms of its location and orientation relative to the associated element geometry. The location of material layer set shall be compatible with the building element geometry (i.e. material layers shall fit inside the element geometry). The rules to ensure the compatibility depend on the type of the building element.",
+        "description": "Definition from IAI: Determines the usage of IfcMaterialLayerSet in terms of its location and orientation relative to the associated element geometry. The location of material layer set shall be compatible with the building element geometry (i.e. material layers shall fit inside the element geometry). The rules to ensure the compatibility depend on the type of the building element. The IfcMaterialLayerSetUsage is always assigned to an individual occurrence object only (i.e. to relevant subtypes of IfcElement). The IfcMaterialLayerSet, referenced by ForLayerSet can however be shared among several occurrence objects. If the element type is available (i.e. the relevant subtype of IfcElementType, then the IfcMaterialLayerSet can be assigned to the type object. The assignment between a subtype of IfcElement and the IfcMaterialLayerSetUsage_is handled by _IfcRelAssociatesMaterial. Use Definition The IfcMaterialLayerSetUsage is primarily intended to be associated with planar building elements having a constant thickness. With further agreements on the interpretation of LayerSetDirection, the usage can be extended also to other cases, e.g. to curved building elements, provided that the material layer thicknesses are constant. Generally, an element may be layered in any of its primary directions, denoted by its x, y or z axis. The geometry use definitions at each specific types of building element will determine the applicable LayerSetDirection. Fig 1: shows an example of the use of IfcMaterialLayerSetUsage aligned to the axis of a wall. Fig 2: shows an example of the use of IfcMaterialLayerSetUsage aligned to a slab. Fig 3: shows an example of the use of IfcMaterialLayerSetUsage aligned to a roof slab with non-perpendicular extrusion.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmateriallayersetusage.htm"
     },
     "IfcMaterialList": {
@@ -2703,7 +2703,7 @@
             "UnitComponent": "The unit in which the physical quantity is expressed.",
             "ValueComponent": "The value of the physical quantity when expressed in the specified units."
         },
-        "description": "Definition from ISO/CD 10303-41:1992: A measure with unit is the specification of a physical quantity as defined in ISO 31 (clause 2).",
+        "description": "Definition from ISO/CD 10303-41:1992: A measure with unit is the specification of a physical quantity as defined in ISO 31 (clause 2). IfcMeasureWithUnit has two usages: 1. For representing measure value together with its unit on the entity type attribute level; thus overriding the IFC model global unit assignments. 2. For conversion based unit to give the conversion rate and its base.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmeasurewithunit.htm"
     },
     "IfcMechanicalConcreteMaterialProperties": {
@@ -2715,7 +2715,7 @@
             "WaterImpermeability": "Description of the water impermeability denoting the water repelling properties.",
             "Workability": "Description of the workability of the fresh concrete defined according to local standards."
         },
-        "description": "",
+        "description": "Mechanical material properties for concrete.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcmechanicalconcretematerialproperties.htm"
     },
     "IfcMechanicalFastener": {
@@ -2723,11 +2723,11 @@
             "NominalDiameter": "The nominal diameter describing the cross-section size of the fastener.",
             "NominalLength": "The nominal length describing the longitudinal dimensions of the fastener."
         },
-        "description": "Fasteners connecting building elements mechanically.",
+        "description": "Fasteners connecting building elements mechanically. General usage The exact type information of the IfcMechanicalFastener is given in the ObjectType attribute inherited from IfcObject. Standard type designations are provided for guideline below. Geometry Use Definitions: The geometric representation of IfcMechanicalFastener is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined in the supertype IfcElementComponent. Standard Geometric Representation The use of Standard Geometric Representations is defined in the supertype IfcElementComponent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcmechanicalfastener.htm"
     },
     "IfcMechanicalFastenerType": {
-        "description": "The element type (IfcMechanicalFastenerType) defines a list of commonly shared property set definitions of a fastener and an optional set of product representations. It is used to define mechanical fasteners mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type).",
+        "description": "The element type (IfcMechanicalFastenerType) defines a list of commonly shared property set definitions of a fastener and an optional set of product representations. It is used to define mechanical fasteners mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type). The occurrences of the IfcMechanicalFastenerType are represented by instances of IfcMechanicalFastener. General usage The exact type information of the IfcMechanicalFastenerType is given in the ElementType attribute inherited from IfcElementType. Standard type designations are provided for guideline below.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcmechanicalfastenertype.htm"
     },
     "IfcMechanicalMaterialProperties": {
@@ -2751,7 +2751,7 @@
             "UltimateStress": "A measure of the ultimate stress of the material.",
             "YieldStress": "A measure of the yield stress (or characteristic 0.2 percent proof stress) of the material."
         },
-        "description": "This is a collection of mechanical properties related to steel (or other metallic and isotropic) materials.",
+        "description": "This is a collection of mechanical properties related to steel (or other metallic and isotropic) materials. NOTE: In certain dimensioning calculations a secant modulus is used instead of the Young\u00b4s modulus. Essentially, this is the same measure, but with a slightly different physical meaning. In such cases, i. e. when a secant modulus is needed, the value of the inherited attribute YoungModulus should be applied. Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcmechanicalsteelmaterialproperties.htm"
     },
     "IfcMember": {
@@ -2759,7 +2759,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcmember.htm"
     },
     "IfcMemberType": {
-        "description": "The element type (IfcMemberType) defines a list of commonly shared property set definitions of a structural member and an optional set of product representations. It is used to define a structural member specification (i.e. the specific product information that is common to all occurrences of that product type).",
+        "description": "The element type (IfcMemberType) defines a list of commonly shared property set definitions of a structural member and an optional set of product representations. It is used to define a structural member specification (i.e. the specific product information that is common to all occurrences of that product type). A structural member type is used to define the common properties of a certain type of a structural member that may be applied to many instances of that type to assign a specific style. Structural member types may be exchanged without being already assigned to occurrences. The occurrences of the IfcMemberType are represented by instances of IfcMember. Use definition for steel members When using the IfcMemberType as the underlying type for steel members within steel construction aware applications the following additional conventions apply: Material association:**** The IfcMemberType is associated with exactly one instance IfcMaterial by the IfcRelAssociatesMaterial relationship. This material association assigns a common material to all occurrences (IfcBeam, IfcColumn or IfcBuildingElementProxy) of the IfcMemberType. If an individual occurrence has its own material assignment (see IfcMember), then this overrides the material assignment given at the IfcMemberType. Geometric representation:**** The IfcMemberType type has (at least) one representation map assigned through the RepresentationMaps relation. The representation map has a full geometric representation given by: - IfcExtrudedAreaSolid for straight beams, - IfcRevolvedAreaSolid for curved beams based on circular arcs, or - IfcSurfaceCurveSweptAreaSolid for all other curved beams. The attribute ProfileName of the extruded IfcProfile instance may contain a standardized name according to local standards. However, a geometric representation of the profile is necessary as specified below. An importing application is allowed to check for the existence of the profile name: in case of identifying it as a standardized name, the corresponding profile geometry and possibly other cross sectional properties can be read from a library. Otherwise the explicit IFC geometry and possible non geometric IfcProfileProperties have to be used. Only 'SweptSolid' representation should be used to represent steel members. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'SweptSolid' The following additional constraints apply to the 'SweptSolid' representation: - Solid: IfcExtrudedAreaSolid shall be supported. - Profile: IfcArbitraryClosedProfileDef, IfcArbitraryOpenProfileDef, IfcArbitraryProfileDefWithVoids, IfcCircleProfileDef, IfcCompositeProfileDef, IfcIShapeProfileDef, IfcRectangleProfileDef, IfcRoundedRectangleProfileDef, IfcCShapeProfileDef, IfcCircleHollowProfileDef, IfcCraneRailAShapeProfileDef, IfcCraneRailFShapeProfileDef, IfcLShapeProfileDef, IfcRectangleHollowProfileDef, IfcTShapeProfileDef, IfcUShapeProfileDef, IfcZShapeProfileDef and IfcAsymmetricIShapeProfileDef. - Extrusion: The extrusion axis shall be perpendicular to the swept profile, i.e. pointing into the direction of the z-axis of the position of the IfcExtrudedAreaSolid. In addition to the full 'SweptSolid' representation a simple representation for the axis of gravity can be used., i.e. as a second IfcRepresentationMap. It represents the neutral axis of stress which is not necessarily in the profiles center of gravity. In this case the following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Axis' - RepresentationType : 'GeometricCurveSet' Position number:**** The position number is specified in the attribute IfcTypeProduct.Tag. Non geometric profile properties:**** Non geometric profile properties (for instance mechanical properties) are specified through IfcProfileProperties (and its specific subtypes). These properties are attached to IfcMemberType by the relationship IfcRelAssociatesProfileProperties. If an individual occurrence has its own profile property assignment (see IfcMember), then this overrides the profile property assignment given at the IfcMemberType. Quantity related properties:**** Quantity related properties, which do not relate to the profile, are specified through IfcElementQuantity (and its specific subtypes). These properties are attached to the IfcMemberType by the relationship IfcRelDefinesByProperties. If an individual occurrence has its own element quantity assignment (see IfcMember), then this overrides the quantity assignment given at the IfcMemberType. The following quantities are foreseen, but will be subjected to the local standard of measurement used:",
         "predefined_types": {
             "BRACE": "A linear element (usually sloped) often used for bracing of a girder or truss.",
             "CHORD": "Upper or lower longitudinal member of a truss, used horizontally or sloped.",
@@ -2784,7 +2784,7 @@
             "DataValue": "Value with data type defined by the DataType enumeration.",
             "ValueSource": "Reference source for data values."
         },
-        "description": "An IfcMetric is used to capture quantitative resultant metrics that can be applied to objectives.",
+        "description": "An IfcMetric is used to capture quantitative resultant metrics that can be applied to objectives. IfcMetric is a subtype of IfcConstraint and may be associated with any subtype of IfcObject through the IfcRelAssociatesConstraint relationship in the IfcControlExtension schema. The aim of IfcMetric is to capture the quantitative aspects of a constraint.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcmetric.htm"
     },
     "IfcMonetaryUnit": {
@@ -2795,7 +2795,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmonetaryunit.htm"
     },
     "IfcMotorConnectionType": {
-        "description": "An IfcMotorConnectionType provides the means for connecting a motor as the driving device to the driven device.",
+        "description": "An IfcMotorConnectionType provides the means for connecting a motor as the driving device to the driven device. *Use Definitions* An IfcMotorConnectionType is a subtype of IfcEnergyConversionDeviceType that provides for various forms of connection mechanism. Usage of IfcMotorConnectionType defines the parameters for one or more occurrences of IfcEnergyConversionDevice. Parameters are specified through property sets that are enumerated in the IfcMotorConnectionTypeEnum data type. *Property Set Use Definition*: There are no property sets currently defined for IfcMotorConnectionType. *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "BELTDRIVE": "An indirect connection made through the medium of a shaped, flexible continuous loop.",
             "COUPLING": "An indirect connection made through the medium of the viscosity of a fluid.",
@@ -2811,7 +2811,7 @@
             "MoveTo": "The place to which actors and their associated equipment are moving.",
             "PunchList": "A list of points concerning a move that require attention."
         },
-        "description": "An IfcMove is an activity that moves people, groups within an organization or complete organizations together with their associated furniture and equipment from one place to another. The objects to be moved, normally people, equipment, and furniture, are assigned by the IfcRelAssignsToProcess relationship.",
+        "description": "An IfcMove is an activity that moves people, groups within an organization or complete organizations together with their associated furniture and equipment from one place to another. The objects to be moved, normally people, equipment, and furniture, are assigned by the IfcRelAssignsToProcess relationship. Actors, equipment and furniture are moved from one IfcSpatialStructureElement to another. The IfcSpatialStructureElement to be moved from and that to be moved to are assigned to the IfcMove class using the IfcRelAssignsToProcess relationship. The actors (as IfcActor), equipment and furnitures to be moved are assigned to the IfcMove using the IfcRelAssignsToProcess relationship Each IfcMove must have a name. This requirement is enforced by a rule. The inherited attribute OperatesOn refers to the IfcRelAssignsToProcess relationship, keeping the reference to IfcActor, IfcEquipmentElement_and_IfcFurnishingElement. The QuantityInProcess attribute at the relationship object can be used to specify a quantity of the objects to be moved. Constraints may be applied to a move through instances of the IfcConstraint class (or its subtypes) that are associated through the IfcRelAssociatesConstraint relationship class Moves can be nested, i.e. a move object can contain other (more detailed) move objects. This is handled by the IfcRelNests relationship pointing (with RelatingObject) to the containing move and (with RelatedObjects) to the contained (sub)moves. Moves are assigned to a move schedule (represented as IfcWorkSchedule with Purpose attribute 'Move') by using the IfcRelAssignsTask relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcmove.htm"
     },
     "IfcNamedUnit": {
@@ -2827,7 +2827,7 @@
             "IsDefinedBy": "Set of relationships to type or property (statically or dynamically defined) information that further define the object. In case of type information, the associated _IfcTypeObject_ contains the specific information (or type, or style), that is common to all instances of _IfcObject_ referring to the same type.",
             "ObjectType": "The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute _PredefinedType_ is set to USERDEFINED."
         },
-        "description": "An IfcObject is the generalization of any semantically treated thing or process. Objects are things as they appear - i.e. occurrences.",
+        "description": "An IfcObject is the generalization of any semantically treated thing or process. Objects are things as they appear - i.e. occurrences. Objects can be named, using the inherited Name attribute, which should be a user recognizable label for the object occurrence. Further explanations to the object can be given using the inherited Description attribute. The ObjectType attribute is used: - to store the user defined value for all subtypes of IfcObject, where a PredefinedType attribute is given, and its value is set to USERDEFINED. - to provide a type information (could be seen as a very lightweight classifier) of the subtype of IfcObject, if no PredefinedType attribute is given. This is often the case, if no comprehensive list of predefined types is available. Objects are independent pieces of information that might contain or reference other pieces of information. There are four essential kind of relationships in which objects can be involved: - Assignment of other objects - an assignment relationship that refers to other types of objects. See supertype IfcObjectDefinition for more information. - Association to external resources - an association relationship that refers to external sources of information. See supertype IfcObjectDefinition for more information. - Aggregation of other objects - an aggregation relationship that establishes a whole/part relation. See supertype IfcObjectDefinition for more information. - Refinement by type and properties - a refinement relationship (IfcRelDefines) that uses a type definition or (partial) property set definition to define the properties of the object instance. It is a specific - occurrence relationship with implied dependencies (as the occurrence properties depend on the specific properties).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcobject.htm"
     },
     "IfcObjectDefinition": {
@@ -2837,7 +2837,7 @@
             "HasAssociations": "Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.",
             "IsDecomposedBy": "Reference to the decomposition relationship, that allows this object to be the composition of other objects. An object can be decomposed by several other objects."
         },
-        "description": "Definition from IAI: An IfcObjectDefinition is the generalization of any semantically treated thing or process, either being a type or an occurrences. Object defintions can be named, using the inherited Name attribute, which should be a user recognizable label for the object occurrence. Further explanations to the object can be given using the inherited Description attribute. ",
+        "description": "Definition from IAI: An IfcObjectDefinition is the generalization of any semantically treated thing or process, either being a type or an occurrences. Object defintions can be named, using the inherited Name attribute, which should be a user recognizable label for the object occurrence. Further explanations to the object can be given using the inherited Description attribute. Objects are independent pieces of information that might contain or reference other pieces of information. There are three essential kinds of relationships in which object definitions (by their instantiable subtypes) can be involved: - Assignment of other objects - an assignment relationship (IfcRelAssigns) that refers to other types of objects and creates a bi-directional association. The semantic of the assignment is established at the level of the subtypes of the general IfcRelAssigns relationship. There is no dependency implied a priori by the assignment. - Association to external resources - an association relationship (IfcRelAssociates) that refers to external sources of information (most notably a classification or document) and creates a uni-directional association. There is no dependency implied by the association. - Aggregation of other objects - an aggregation relationship (IfcRelDecomposes) that establishes a whole/part relation and creates a bi-directional relation. There is an implied dependency established.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcobjectdefinition.htm"
     },
     "IfcObjectPlacement": {
@@ -2845,7 +2845,7 @@
             "PlacesObject": "The _IfcObjectPlacement_ shall be used to provide a placement and an object coordinate system for a single instance of _IfcProduct_.",
             "ReferencedByPlacements": "Placements that are given relative to this placement of an object."
         },
-        "description": "Abstract supertype for the special types defining the object coordinate system. The IfcObjectPlacement has to be provided for each product that has a shape representation.",
+        "description": "Abstract supertype for the special types defining the object coordinate system. The IfcObjectPlacement has to be provided for each product that has a shape representation. The object placement can be given: - absolute, i.e. by an axis2 placement, relative to the world coordinate system, - relative, i.e. by an axis2 placement, relative to the object placement of another product, - by grid reference, i.e. by the virtual intersection and reference direction given by two axes of a design grid. In any case the object placement has to unambiguously define the object coordinate system as either two-dimensional axis placement (IfcAxis2Placement2D) or three-dimensional axis placement (IfcAxis2Placement3D). The axis placement may have to be calculated. Informal proposition - No two or more elements (subtypes of IfcProduct) shall share the same instance of IfcObjectPlacement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcobjectplacement.htm"
     },
     "IfcObjective": {
@@ -2855,11 +2855,11 @@
             "ResultValues": "A list of any resultant values used for comparison purposes.",
             "UserDefinedQualifier": "A user defined value that qualifies the type of objective constraint when ObjectiveQualifier attribute of type _IfcObjectiveEnum_ has value USERDEFINED."
         },
-        "description": "An IfcObjective captures qualitative information for an objective-based constraint.",
+        "description": "An IfcObjective captures qualitative information for an objective-based constraint. IfcObjective is a subtype of IfcConstraint and may be associated with any subtype of IfcObject through the IfcRelAssociatesConstraint relationship in the IfcControlExtension schema. The aim of IfcObjective is to specify the purpose for which the constraint is applied and to capture the values of the constraint. These may be both the benchmark values that are intended to indicate the constraint extent and the resulting values in use that enable performance comparisons to be applied.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcobjective.htm"
     },
     "IfcOccupant": {
-        "description": "An_IfcOccupant_ is a type of actor that defines the form of occupancy of a property.",
+        "description": "An_IfcOccupant_ is a type of actor that defines the form of occupancy of a property. The principal purpose of IfcOccupant is to determine the nature of occupancy of a property for a particular actor. All characteristics relating to the actor (name, organization details etc.) are inherited from the IfcActor class. The property to be occupied is defined by IfcSpatialStructureElement and the assignment of the occupant to the property is via the IfcRelOccupiesSpaces relationship class. Particular details of the agreement relating to the occupancy of a property are dealt with in the Pset_PropertyAgreement that is defined for the instance of IfcSpatialStructureElement. This means that an occupant may be related to a site, building, building storey or space or to any composition of site, building, building storey or space through the IfcSpatialStructureElement.ElementComposition. For instance, if the property concerned is several office spaces on a building storey, it might be appropriate to reference IfcBuildingStorey.ElementComposition=PARTIAL. Occupants of a property may be considered to be the parties to an agreement. The roles that the occupant may play in respect to an agreement are defined in the IfcOccupantTypeEnum. If the role is not specified by the predefined contents of this enumeration, the value USERDEFINED may be set and the IfcOccupant.UserDefinedOccupant attribute asserted.",
         "predefined_types": {
             "ASSIGNEE": "Actor receiving the assignment of a property agreement from an assignor.",
             "ASSIGNOR": "Actor assigning a property agreement to an assignor.",
@@ -2879,7 +2879,7 @@
             "Distance": "The distance of the offset curve from the basis curve. distance may be positive, negative or zero. A positive value of distance defines an offset in the direction which is normal to the curve in the sense of an anti-clockwise rotation through 90 degrees from the tangent vector T at the given point. (This is in the direction of orthogonal complement(T).)",
             "SelfIntersect": "An indication of whether the offset curve self-intersects; this is for information only."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: An offset curve 2d (IfcOffsetCurve2d) is a curve at a constant distance from a basis curve in two-dimensional space. This entity defines a simple plane-offset curve by offsetting by distance along the normal to basis curve in the plane of basis curve. The underlying curve shall have a well-defined tangent direction at every point. In the case of a composite curve, the transition code between each segment shall be cont same gradient or cont same gradient same curvature.",
+        "description": "Definition from ISO/CD 10303-42:1992: An offset curve 2d (IfcOffsetCurve2d) is a curve at a constant distance from a basis curve in two-dimensional space. This entity defines a simple plane-offset curve by offsetting by distance along the normal to basis curve in the plane of basis curve. The underlying curve shall have a well-defined tangent direction at every point. In the case of a composite curve, the transition code between each segment shall be cont same gradient or cont same gradient same curvature. The offset curve 2d takes its parameterization from the basis curve. The offset curve 2d is parameterized as where T is the unit tangent vector to the basis curve C(u) at parameter value u, and d is distance. The underlying curve shall be two-dimensional.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcoffsetcurve2d.htm"
     },
     "IfcOffsetCurve3D": {
@@ -2889,7 +2889,7 @@
             "RefDirection": "The direction used to define the direction of the offset curve 3d from the basis curve.",
             "SelfIntersect": "An indication of whether the offset curve self-intersects, this is for information only."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: An offset curve 3d is a curve at a constant distance from a basis curve in three-dimensional space. The underlying curve shall have a well-defined tangent direction at every point. In the case of a composite curve the transition code between each segment shall be cont same gradient or cont same gradient same curvature. The offset curve at any point (parameter) on the basis curve is in the direction V x T where V is the fixed reference direction and T is the unit tangent to the basis curve. For the offset direction to be well defined, T shall not at any point of the curve be in the same, or opposite, direction as V.",
+        "description": "Definition from ISO/CD 10303-42:1992: An offset curve 3d is a curve at a constant distance from a basis curve in three-dimensional space. The underlying curve shall have a well-defined tangent direction at every point. In the case of a composite curve the transition code between each segment shall be cont same gradient or cont same gradient same curvature. The offset curve at any point (parameter) on the basis curve is in the direction V x T where V is the fixed reference direction and T is the unit tangent to the basis curve. For the offset direction to be well defined, T shall not at any point of the curve be in the same, or opposite, direction as V. The offset curve 3d takes its parameterization from the basis curve. The offset curve 3d is parameterized as where T is the unit tangent vector to the basis curve C(u) at parameter value u, and d is distance. The underlying curve shall be three-dimensional. Informal propositions: - At no point on the curve shall ref direction be parallel, or opposite to, the direction of the tangent vector.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcoffsetcurve3d.htm"
     },
     "IfcOneDirectionRepeatFactor": {
@@ -2900,14 +2900,14 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifconedirectionrepeatfactor.htm"
     },
     "IfcOpenShell": {
-        "description": "Definition from ISO/CD 10303-42:1992: An open shell is a shell of the dimensionality 2. Its domain, if present, is a finite, connected, oriented, 2-manifold with boundary, but is not a closed surface. It can be thought of as a closed shell with one or more holes punched in it. The domain of an open shell satisfies 0 < \u039e < 1. An open shell is functionally more general than a face because its domain can have handles.",
+        "description": "Definition from ISO/CD 10303-42:1992: An open shell is a shell of the dimensionality 2. Its domain, if present, is a finite, connected, oriented, 2-manifold with boundary, but is not a closed surface. It can be thought of as a closed shell with one or more holes punched in it. The domain of an open shell satisfies 0 < \u039e < 1. An open shell is functionally more general than a face because its domain can have handles. The shell is defined by a collection of faces, which may be oriented faces. The sense of each face, after taking account of the orientation, shall agree with the shell normal as defined below. The orientation can be supplied directly as a BOOLEAN attribute of an oriented face, or be defaulted to TRUE if the shell member is a face without the orientation attribute. The following combinatorial restrictions on open shells and geometrical restrictions on their domains are designed, together with the informal propositions, to ensure that any domain associated with an open shell is an orientable manifold. - Each face reference shall be unique. - An open shell shall have at least one face. - A given face may exist in more than one open shell. The boundary of an open shell consists of the edges that are referenced only once by the face - bounds (loops) of its faces, together with all of their vertices. The domain of an open shell, if present, contains all edges and vertices of its faces. In the current IFC Release only poly loops (IfcPolyLoop) are defined for bounds of face bound (IfcFaceBound.Bound). This will allow for faceted B-rep only. For further specification, including the Euler formulas to be satisfied, please refer to ISO 10303-42:1994. Informal propositions: - Every edge shall be referenced exactly twice by the face bounds of the face. - Each oriented edge shall be unique. - No edge shall be referenced by more than two faces. - Distinct faces of the shell do not intersect, but may share edges or vertices. - Distinct edges do not intersect but may share vertices. - Each face reference shall be unique. - The loops of the shell shall not be a mixture of poly loop and other loop types. Note: this is given, since only poly loop is defined as face bound definition. - The closed shell shall be an oriented arcwise connected 2-manifold. - The Euler equation shall be satisfied. Note: Please refer to ISO/IS 10303-42:1994, p.148 for the equation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcopenshell.htm"
     },
     "IfcOpeningElement": {
         "attributes": {
             "HasFillings": "Reference to the Filling Relationship that is used to assign Elements as Fillings for this Opening Element. The Opening Element can be filled with zero-to-many Elements."
         },
-        "description": "The opening element stands for opening, recess or chase, all reflecting voids. It represents a void within any element that has physical manifestation. Openings must be handled by all sectors and disciplines in AEC/FM industry, therefore the interoperability for opening elements is provided at this high level.",
+        "description": "The opening element stands for opening, recess or chase, all reflecting voids. It represents a void within any element that has physical manifestation. Openings must be handled by all sectors and disciplines in AEC/FM industry, therefore the interoperability for opening elements is provided at this high level. There are two different types of opening elements: - an opening, where the thickness of the opening is greater or equal to the thickness of the element; - a recess or niche, where the thickness of the recess is smaller than the thickness of the element. The inherited attribute ObjectType should be used to capture the differences, - the attribute is set to 'Opening' for an opening or - the attribute is set to 'Recess' for a recess or niche. - If the value for ObjectType is omitted, opening is assumed. An IfcOpeningElement has to be inserted into a building element (all subtypes of IfcBuildingElement) by using the IfcRelVoidsElement relationship. ~~It is also directly linked to the spatial structure of the project (and here normally to the IfcBuildingStorey) by using the IfcRelContainedInSpatialStructure relationship~~. It should not be linked directly to the spatial structure of the project, i.e. the inverse relationship ContainedInStructure shall be NIL. It is assigned to the spatial structure through the elements it penetrates. *Property Set Use Definition*: The property sets relating to the IfcOpeningElement are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcOpeningElement are part of this IFC release: - Pset_OpeningElementCommon: common property set for all opening occurrences *Quantity Use Definition*: The quantities relating to the IfcOpeningElement are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. The following quantities are foreseen, but will be subjected to the local standard of measurement: *Geometry Use Definitions* The geometric representation of IfcOpeningElement is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. Local Placement The local placement for IfcOpeningElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement should point to the local placement of the same element, which is voided by the opening, i.e. referred to by VoidsElement.RelatingBuildingElement. Geometric Representation Currently, the use of 'SweptSolid', 'Brep', and 'MappedRepresentation' representation is supported. Swept Solid Representation with Horizontal Extrusion The 'SweptSolid' geometric representation of IfcOpeningElement, using horizontal extrusion direction (for walls), is defined using the swept area solid geometry. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'SweptSolid' The following additional constraints apply to the swept solid representation: - Solid: IfcExtrudedAreaSolid is required, the set of IfcShapeRepresentation.Items may include a single, or multiple, instances of IfcExtrudedAreaSolid. - Profile: IfcRectangleProfileDef, IfcCircleProfileDef and IfcArbitraryClosedProfileDef shall be supported. - Extrusion: The profile shall be extruded horizontally (i.e. perpendicular to the extrusion direction of the voided element), e.g. for wall openings, or vertically (i.e. in the extrusion direction of the voided element), e.g., for floor openings. If multiple instances of IfcExtrudedAreaSolid are used, the extrusion direction should be equal. Special agreement for defining openings in round building elements, e.g., in round walls. The opening width, in case of a rectangular opening equal with the IfcRectangleProfileDef.XDim, is defined as the straight line distance between two parallel jambs. If the jambs are defined radial (to the center of the arc used to define the round wall) then the opening width is defined to be the outer arc length. EXAMPLE for openings EXAMPLE for recesses Swept Solid Representation with Vertical Extrusion The 'SweptSolid' geometric representation of IfcOpeningElement, using vertical extrusion direction (for walls), is defined using the swept area solid geometry, however the extrusion direction may be vertical, i.e. in case of a wall opening, the extrusion would be in the direction of the wall height. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'SweptSolid' The following additional constraints apply to the swept solid representation: - Solid: IfcExtrudedAreaSolid is required, the set of IfcShapeRepresentation.Items may include a single, or multiple, instances of IfcExtrudedAreaSolid. - Profile: IfcRectangleProfileDef, IfcCircleProfileDef and IfcArbitraryClosedProfileDef shall be supported. - Extrusion: The profile shall be extruded vertically, i.e. for wall openings along the extrusion direction of the voided element. If multiple instances of IfcExtrudedAreaSolid are used, the extrusion direction should be equal. Vertical extrusions shall be used when an opening or recess has a non rectangular foot print geometry that does not change along the height of the opening or recess. Brep Representation The general b-rep geometric representation of IfcOpeningElement is defined using the Brep geometry. The Brep representation allows for the representation of complex element shape. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'Brep'",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcopeningelement.htm"
     },
     "IfcOpticalMaterialProperties": {
@@ -2929,7 +2929,7 @@
         "attributes": {
             "ActionID": "A unique identifier assigned to an action on issue."
         },
-        "description": "An IfcOrderAction is the point at which requests for work are received and processed within an organization.",
+        "description": "An IfcOrderAction is the point at which requests for work are received and processed within an organization. The IfcOrderAction represents tasks that might be carried out by a Helpdesk acting the role of interface for the organization between the facility user and the functional requirement of fulfilling their needs. The actual task represented by the IfcOrderAction class is turning a request into an order and initiating the action that will enable the order to be completed. IfcRelAssignsToControl is used to relate one or more instances of IfcOrderAction to an IfcProjectOrder or one of its subtypes including maintenance work order.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcorderaction.htm"
     },
     "IfcOrganization": {
@@ -2967,7 +2967,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcorientededge.htm"
     },
     "IfcOutletType": {
-        "description": "An IfcOutletType defines a particular type of outlet which is a device installed at a point to receive an inserted plug.",
+        "description": "An IfcOutletType defines a particular type of outlet which is a device installed at a point to receive an inserted plug. *Use Definitions* An IfcOutletType provides for all forms of outlet. Usage of IfcOutletType defines the parameters for one or more occurrences of IfcFlowTerminal. Parameters are specified through property sets that are enumerated in the IfcOutletTypeEnum data type. *Property Set Use Definition*: The property sets relating to the IfcProtectiveDeviceType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcProtectiveDeviceType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available - Pset_OutletTypeCommon: property set for properties that are common to all types of cabled outlet, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "AUDIOVISUALOUTLET": "An outlet used for an audio or visual device.",
             "COMMUNICATIONSOUTLET": "An outlet used for connecting communications equipment.",
@@ -2988,21 +2988,21 @@
             "OwningUser": "Direct reference to the end user who currently \"owns\" this object. Note that IFC includes the concept of ownership transfer from one user to another and therefore distinguishes between the Owning User and Creating User.",
             "State": "Enumeration that defines the current access state of the object."
         },
-        "description": "IfcOwnerHistory defines all history and identification related information. In order to provide fast access it is directly attached to all independent objects, relationships and properties.",
+        "description": "IfcOwnerHistory defines all history and identification related information. In order to provide fast access it is directly attached to all independent objects, relationships and properties. IfcOwnerHistory is used to identify the creating and owning application and user for the associated object, as well as capture the last modifying application and user.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifcownerhistory.htm"
     },
     "IfcParameterizedProfileDef": {
         "attributes": {
             "Position": "Position coordinate system of the parameterized profile definition."
         },
-        "description": "The parameterized profile definition defines a 2D position coordinate system to which the parameters of the different profiles relate to. All profiles are defined centric to the origin of the position coordinate system, or more specific, the origin [0.,0.] shall be in the center of the bounding box ~~gravity~~ of the profile.",
+        "description": "The parameterized profile definition defines a 2D position coordinate system to which the parameters of the different profiles relate to. All profiles are defined centric to the origin of the position coordinate system, or more specific, the origin [0.,0.] shall be in the center of the bounding box ~~gravity~~ of the profile. The Position attribute of the IfcParameterizedProfileDef is used to position the profile within the XY plane of the underlying coordinate system of the swept surface geometry, the swept area solid or the sectioned spine. It can be used to position the profile at any cardinal point that becomes the origin [0.,0.,0.] of the extruded or rotated surface or solid.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcparameterizedprofiledef.htm"
     },
     "IfcPath": {
         "attributes": {
             "EdgeList": "The list of oriented edges which are concatenated together to form this path."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A path is a topological entity consisting of an ordered collection of oriented edges, such that the edge start vertex of each edge coincides with the edge end of its predecessor. The path is ordered from the edge start of the first oriented edge to the edge end of the last edge. The BOOLEAN value sense in the oriented edge indicates whether the edge direction agrees with the direction of the path (TRUE) or is the opposite direction (FALSE).",
+        "description": "Definition from ISO/CD 10303-42:1992: A path is a topological entity consisting of an ordered collection of oriented edges, such that the edge start vertex of each edge coincides with the edge end of its predecessor. The path is ordered from the edge start of the first oriented edge to the edge end of the last edge. The BOOLEAN value sense in the oriented edge indicates whether the edge direction agrees with the direction of the path (TRUE) or is the opposite direction (FALSE). An individual edge can only be referenced once by an individual path. An edge can be referenced by multiple paths. An edge can exist independently of a path. Informal proposition: - A path has dimensionality 1. - A path is arcwise connected. - The edges of the path do not intersect except at common vertices. - A path has a finite, non-zero extent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcpath.htm"
     },
     "IfcPerformanceHistory": {
@@ -3020,14 +3020,14 @@
             "PanelPosition": "Position of this permeable covering panel within the overall window or door type.",
             "ShapeAspectStyle": "Optional link to a shape aspect definition, which points to the part of the geometric representation of the window style, which is used to represent the permeable covering."
         },
-        "description": "Definition from BS 6100: A permeable covering is a permeable cover for an opening which allows airflow .",
+        "description": "Definition from BS 6100: A permeable covering is a permeable cover for an opening which allows airflow . A description of a panel within a door or window (as fillers for opening) which allows for air flow. It is given by its properties (IfcPermeableCoveringProperties). A permeable covering is a casement, i.e. a component, fixed or opening, consisting essentially of a frame and the infilling. The infilling is normally a grill, a louver or a screen. The way of operation is defined in the operation type. The IfcPermeableCoveringProperties are included in the list of properties (HasPropertySets) of the IfcWindowStyle or the IfcDoorStyle. More information about the permeable covering can be included in the same list of the window or door style using the IfcPropertySet for dynamic extensions. This particularly applies for additional properties for the various operation types *Geometry Use Definitions* The IfcPermeableCoveringProperties does not hold an own geometric representation. However it defines parameter, which can be used to create the shape of the IfcWindowStyle (which is inserted by the IfcWindow into the spatial context of the project), or of the IfcDoorStyle (which is inserted by the IfcDoor). Interpretation of parameter The parameters at the IfcPermeableCoveringProperties define a standard permeable covering. The outer boundary of the panel is determined by the occurrence parameter assigned to the IfcWindow or IfcDoor. It has to take the lining parameter into account as well. The position of the permeable covering within the overall window or door is determined by the PanelPosition attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcarchitecturedomain/lexical/ifcpermeablecoveringproperties.htm"
     },
     "IfcPermit": {
         "attributes": {
             "PermitID": "A unique identifier assigned to a permit."
         },
-        "description": "An IfcPermit is a document that allows permission to carry out actions in places and on artifacts where security or other access restrictions apply.",
+        "description": "An IfcPermit is a document that allows permission to carry out actions in places and on artifacts where security or other access restrictions apply. *Use Definitions* The permit will identify the restrictions that apply and when access may be gained to carry out the actions. IfcRelAssignsToControl is used to identify related spaces, assets etc. upon which actions are permitted to take place. *Property Set Use Definition*: The property sets relating to an IfcPermit are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcPermit are part of this IFC release: - Pset_Permit: property set for the properties of a permit to do work or carry out an action, if available",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcpermit.htm"
     },
     "IfcPerson": {
@@ -3061,7 +3061,7 @@
             "Quality": "Additional indication of a quality of the quantities that are grouped under this physical complex quantity.",
             "Usage": "Additional indication of a usage type of the quantities that are grouped under this physical complex quantity."
         },
-        "description": "The complex physical quantity, IfcPhysicalComplexQuantity, is an entity that holds a set of single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity), that all apply to a given component or aspect of the element.",
+        "description": "The complex physical quantity, IfcPhysicalComplexQuantity, is an entity that holds a set of single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity), that all apply to a given component or aspect of the element. A section \"Quantity Use Definition\" at individual entities as subtypes of IfcBuildingElement gives guidance to the usage of the Name and Discrimination attribute to characterize the complex quantities.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcphysicalcomplexquantity.htm"
     },
     "IfcPhysicalQuantity": {
@@ -3070,21 +3070,21 @@
             "Name": "Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements.",
             "PartOfComplex": "Reference to a physical complex quantity in which the physical quantity may be contained."
         },
-        "description": "The physical quantity, IfcPhysicalQuantity, is an abstract entity that holds a complex or simple quantity measure together with a semantic definition of the usage for the single or several measure value.",
+        "description": "The physical quantity, IfcPhysicalQuantity, is an abstract entity that holds a complex or simple quantity measure together with a semantic definition of the usage for the single or several measure value. The Name attribute defines the actual usage or kind of measure. The interpretation of the name label has to be established within the actual exchange context. In addition an informative text may be associated to each quantity by the Description attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcphysicalquantity.htm"
     },
     "IfcPhysicalSimpleQuantity": {
         "attributes": {
             "Unit": "Optional assignment of a unit. If no unit is given, then the global unit assignment, as established at the IfcProject, applies to the quantity measures."
         },
-        "description": "The physical quantity, IfcPhysicalSimpleQuantity, is an entity that holds a single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity) together with a semantic definition of the usage for the measure value.",
+        "description": "The physical quantity, IfcPhysicalSimpleQuantity, is an entity that holds a single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity) together with a semantic definition of the usage for the measure value. A section \"Quantity Use Definition\" at individual entities as subtypes of IfcBuildingElement gives guidance to the usage of the Name attribute to characterize the individual quantities. If the Unit attribute is given, the value attribute (introduced at the level of subtypes of IfcPhysicalSimpleQuantity) are given as quantities of this unit, otherwise the global unit definitions (given by IfcUnitAssignment) are used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcphysicalsimplequantity.htm"
     },
     "IfcPile": {
         "attributes": {
             "ConstructionType": "General designator for how the pile is constructed."
         },
-        "description": "A slender timber, concrete, or steel structural element, driven, jetted, or otherwise embedded on end in the ground for the purpose of supporting a load.",
+        "description": "A slender timber, concrete, or steel structural element, driven, jetted, or otherwise embedded on end in the ground for the purpose of supporting a load. Geometry Use Definitions: The geometric representation of IfcPile is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Included are: Local Placement The local placement for IfcPile is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Standard Geometric Representation using Swept Solid Representation The standard geometric representation of IfcPile is defined using the swept solid representation. The RepresentationType attribute of IfcShapeRepresentation should have the value 'SweptSolid'. The following constraints apply to the standard representation: - Solid: IfcExtrudedAreaSolid shall be supported - Profile: IfcRectangleProfileDef and IfcCircleProfileDef shall be supported - Extrusion: The profile shall be extruded vertically, i.e., in the direction of the z-axis of the co-ordinate system of the referred spatial structure element. It might be further constraint to be in the direction of the global z-axis in implementers agreements. The extrusion axis shall be perpendicular to the swept profile, i.e. pointing into the direction of the z-axis of the Position of the IfcExtrudedAreaSolid. Advanced Geometric Representation using CSG Representation The advanced geometric representation of IfcPile is defined using the Swept Solid or CSG representation. The RepresentationType attribute of IfcShapeRepresentation should have the value 'SweptSolid' or 'CSG'. The following additional constraints apply to the advanced representation: - Solid: see standard geometric representation, - Profile: IfcRectangleProfileDef, IfcCircleProfileDef, IfcIShapeProfileDef and IfcArbitraryProfileDef shall be supported. - Extrusion: All extrusion directions shall be supported - Boolean result: The IfcBooleanClippingResult shall be supported, allowing for Boolean differences between the swept solid (here IfcExtrudedAreaSolid) and one or several IfcHalfSpaceSolid.",
         "predefined_types": {
             "COHESION": "A cohesion pile.",
             "FRICTION": "A friction pile.",
@@ -3095,7 +3095,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcpile.htm"
     },
     "IfcPipeFittingType": {
-        "description": "The element type IfcPipeFittingType defines a list of commonly shared property set definitions of a pipe fitting and an optional set of product representations. It is used to define a pipe fitting specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcPipeFittingType defines a list of commonly shared property set definitions of a pipe fitting and an optional set of product representations. It is used to define a pipe fitting specification (i.e. the specific product information, that is common to all occurrences of that product type). A pipe fitting type is used to define the common properties of a Pipe fitting that may be applied to many occurrences of that type. A pipe fitting is a junction or transition in a flow distribution system (e.g., elbow, tee, etc.). Pipe fitting types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcPipeFittingType are represented by instances of IfcFlowFitting or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_PipeFittingTypeCommon: common property set for all pipe fitting types",
         "predefined_types": {
             "BEND": "A fitting with typically two ports used to change the direction of flow between connected elements.",
             "CONNECTOR": "Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two pipe segments).",
@@ -3110,7 +3110,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcpipefittingtype.htm"
     },
     "IfcPipeSegmentType": {
-        "description": "The element type IfcPipeSegmentType defines a list of commonly shared property set definitions of a pipe segment and an optional set of product representations. It is used to define a pipe segment specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcPipeSegmentType defines a list of commonly shared property set definitions of a pipe segment and an optional set of product representations. It is used to define a pipe segment specification (i.e. the specific product information, that is common to all occurrences of that product type). A pipe segment type is used to define the common properties of a pipe segment that may be applied to many occurrences of that type. A pipe segment is used to typically join two sections of a piping network. Pipe segment types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcPipeSegmentType are represented by instances of IfcFlowSegment or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_PipeSegmentTypeCommon: common property set for all pipe segment types Pset_PipeSegmentTypeGutter: property set for all gutter segment types",
         "predefined_types": {
             "FLEXIBLESEGMENT": "A flexible segment is a continuous non-linear segment of pipe that can be deformed and change the direction of flow.",
             "GUTTER": "A gutter segment is a continuous open-channel segment of pipe.",
@@ -3128,7 +3128,7 @@
             "Pixel": "Flat list of hexadecimal values, each describing one pixel by 1, 2, 3, or 4 components.",
             "Width": "The number of pixels in width (S) direction."
         },
-        "description": "Definition from IAI: An IfcPixelTexture provides a 2D image-based texture map as an explicit array of pixel values (image field). In contrary to the IfcImageTexture the IfcPixelTexture holds a 2 dimensional list of pixel color (and opacity) directly, instead of referencing to an URL.",
+        "description": "Definition from IAI: An IfcPixelTexture provides a 2D image-based texture map as an explicit array of pixel values (image field). In contrary to the IfcImageTexture the IfcPixelTexture holds a 2 dimensional list of pixel color (and opacity) directly, instead of referencing to an URL. The following additional definitions from ISO/IEC FCD 19775:200x, the Extensible 3D (X3D) specification, apply: The following general recommendations for explicit image array format support from ISO/IEC FCD 19775:200x, the Extensible 3D (X3D) specification, also apply: Note that alpha equals (1.0 -transparency), if alpha and transparency each range from 0.0 to 1.0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcpixeltexture.htm"
     },
     "IfcPlacement": {
@@ -3136,7 +3136,7 @@
             "Dim": "The space dimensionality of this class, derived from the dimensionality of the location. Location.Dim",
             "Location": "The geometric position of a reference point, such as the center of a circle, of the item to be located."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A placement entity defines the local environment for the definition of a geometry item. It locates the item to be defined and, in the case of the axis placement subtypes, gives its orientation.",
+        "description": "Definition from ISO/CD 10303-42:1992: A placement entity defines the local environment for the definition of a geometry item. It locates the item to be defined and, in the case of the axis placement subtypes, gives its orientation. Additional definition from ISO/WD SC4/WG12/N071 Part42.2 geometry_schema: A placement locates a geometric item with respect to the coordinate system of its geometric context. The IfcPlacement is an abstract supertype not to be directly instantiated, whereas the STEP P42 entity placement can be instantiated to define a placement without orientation. The derived attribute Dim has been added, see also note at IfcGeometricRepresentationItem.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcplacement.htm"
     },
     "IfcPlanarBox": {
@@ -3155,7 +3155,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcplanarextent.htm"
     },
     "IfcPlane": {
-        "description": "Definition from ISO/CD 10303-42:1992: A plane is an unbounded surface with a constant normal. A plane is defined by a point on the plane and the normal direction to the plane. The data is to be interpreted as follows:",
+        "description": "Definition from ISO/CD 10303-42:1992: A plane is an unbounded surface with a constant normal. A plane is defined by a point on the plane and the normal direction to the plane. The data is to be interpreted as follows: In the above parameterization the length unit for the unit vectors x and y is derived from the context of the plane.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcplane.htm"
     },
     "IfcPlate": {
@@ -3163,7 +3163,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcplate.htm"
     },
     "IfcPlateType": {
-        "description": "The element type IfcPlateType defines a list of commonly shared property set definitions of a thin planar element and an optional set of product representations (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcPlateType defines a list of commonly shared property set definitions of a thin planar element and an optional set of product representations (i.e. the specific product information, that is common to all occurrences of that product type). A plate type is used to define the common properties of a certain type of a plate that may be applied to many instances of that type to assign a specific style. Plate types may be exchanged without being already assigned to occurrences. It is used to define a planar, or plate-like parts to be located by one or several instances of IfcPlate. The occurrences of the IfcPlateType are represented by instances of IfcPlate. Use definition for steel members When using the IfcPlateType as underlying type for steel members in steel construction applications the following additional conventions apply: Material association: The IfcPlateType is associated with exactly one instance of IfcMaterial by the IfcRelAssociatesMaterial relationship. This material association assigns a common material to all occurrences (IfcPlate) of the IfcPlateType. If an individual occurrence has an own material assignment (see IfcPlate), then that assignment overrides the material assignment given at the IfcPlateType. Geometric representation: The plate type must have a full geometric representation, normally given by IfcExtrudedAreaSolid. Possibly standardized profile names for the plate have no meaning. The IfcPlateType has (at least) one representation map assigned through the RepresentationMaps relation. The representation map has a full geometric representation given by: - Solid: Only IfcExtrudedAreaSolid shall be supported. - Profile: Only _IfcArbitraryClosedProfileDef_shall be supported. The profile represents the contour of the plate. - Extrusion: The extrusion axis shall be perpendicular to the swept profile, i.e. pointing into the direction of the z-axis of the position of the IfcExtrudedAreaSolid. Since the profile instance represents the contour of the plate, the extrusion direction corresponds to the plate thickness. Position number: The position number is specified in the attribute IfcTypeProduct.Tag. Non geometric profile properties: Non geometric profile properties (for instance mechanical properties) are specified through IfcProfileProperties (and its specific subtypes that are related to the cross section). These properties are attached to IfcPlateType by the relationship IfcRelAssociatesProfileProperties. If an individual occurrence has an own profile property assignment (see IfcPlate), then this assignment overrides the profile property assignment given in IfcPlateType. Quantity related properties: Quantity related properties,which do not relate to the profile, are specified through IfcElementQuantity (and its specific subtypes). These properties are attached to the IfcPlateType by the relationship IfcRelDefinesByProperties. If an individual occurrence has an own element quantity assignment (see IfcPlate), then this assignment overrides the quantity assignment given in IfcPlateType. The following quantities are foreseen, but will be subjected to the local standard of measurement used:",
         "predefined_types": {
             "CURTAIN_PANEL": "A planar element within a curtain wall, often consisting of a frame with fixed glazing.",
             "NOTDEFINED": "Undefined linear element.",
@@ -3182,7 +3182,7 @@
             "Dim": "The space dimensionality of this class, determined by the space dimensionality of the basis curve. BasisCurve.Dim",
             "PointParameter": "The parameter value of the point location."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A point on curve is a point which lies on a curve. The point is determined by evaluating the curve at a specific parameter value. The coordinate space dimensionality of the point is that of the basis curve.",
+        "description": "Definition from ISO/CD 10303-42:1992: A point on curve is a point which lies on a curve. The point is determined by evaluating the curve at a specific parameter value. The coordinate space dimensionality of the point is that of the basis curve. Informal Propositions: - The value of the point parameter shall not be outside the parametric range of the curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcpointoncurve.htm"
     },
     "IfcPointOnSurface": {
@@ -3192,14 +3192,14 @@
             "PointParameterU": "The first parameter value of the point location.",
             "PointParameterV": "The second parameter value of the point location."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A point on surface is a point which lies on a parametric surface. The point is determined by evaluating the surface at a particular pair of parameter values.",
+        "description": "Definition from ISO/CD 10303-42:1992: A point on surface is a point which lies on a parametric surface. The point is determined by evaluating the surface at a particular pair of parameter values. Informal Propositions: - The parametric values specified for u and v shall not be outside the parametric range of the basis surface.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcpointonsurface.htm"
     },
     "IfcPolyLoop": {
         "attributes": {
             "Polygon": "List of points defining the loop. There are no repeated points in the list."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A poly loop is a loop with straight edges bounding a planar region in space. A poly loop is a loop of genus 1 where the loop is represented by an ordered coplanar collection of points forming the vertices of the loop. The loop is composed of straight line segments joining a point in the collection to the succeeding point in the collection. The closing segment is from the last to the first point in the collection. ",
+        "description": "Definition from ISO/CD 10303-42:1992: A poly loop is a loop with straight edges bounding a planar region in space. A poly loop is a loop of genus 1 where the loop is represented by an ordered coplanar collection of points forming the vertices of the loop. The loop is composed of straight line segments joining a point in the collection to the succeeding point in the collection. The closing segment is from the last to the first point in the collection. The direction of the loop is in the direction of the line segments. A poly loop shall conform to the following topological constraints: The IfcPolyLoop is always closed and the last segment is from the last IfcCartesianPoint in the list of Polygon's to the first IfcCartesianPoint. Therefore the first point shall not be repeated at the end of the list, neither by referencing the same instance, nor by using an additional instance of_IfcCartesianPoint_ having the coordinates as the first point. Informal propositions: - All the points in the polygon defining the poly loop shall be coplanar. - The first and the last Polygon shall be different by value.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcpolyloop.htm"
     },
     "IfcPolygonalBoundedHalfSpace": {
@@ -3207,7 +3207,7 @@
             "PolygonalBoundary": "Two-dimensional ~~polyline~~ bounded curve, defined in the xy plane of the position coordinate system.",
             "Position": "Definition of the position coordinate system for the bounding polyline ~~and the base surface~~."
         },
-        "description": "The polygonal bounded half space is a special subtype of a half space solid, where the material of the half space used in Boolean expressions is bounded by a polygonal boundary. The base surface of the half space is positioned by its normal relativeto the object coordinate system (as defined at the supertype IfcHalfSpaceSolid), and its polygonal (with or without arc segments) boundary is defined in the XY plane of the position coordinate system established by the Position attribute, the subtraction body is extruded perpendicular to the XY plane of the position coordinate system, i.e. into the direction of the positive Z axis defined by the Position attribute.",
+        "description": "The polygonal bounded half space is a special subtype of a half space solid, where the material of the half space used in Boolean expressions is bounded by a polygonal boundary. The base surface of the half space is positioned by its normal relativeto the object coordinate system (as defined at the supertype IfcHalfSpaceSolid), and its polygonal (with or without arc segments) boundary is defined in the XY plane of the position coordinate system established by the Position attribute, the subtraction body is extruded perpendicular to the XY plane of the position coordinate system, i.e. into the direction of the positive Z axis defined by the Position attribute. The boundary is defined by a 2 dimensional polyline (or 2 dimensional composite curve, consisting of straight segments and circular arc segments) within the XY plane of the position coordinate system. The side of the surface which is in the half space is determined by the surface normal and the agreement flag. If the agreement flag is TRUE, then the subset is the one the normal points away from. If the agreement flag is FALSE, then the subset is the one the normal points into. Informal propositions: - The IfcPolyline or the IfcCompositeCurve providing the PolygonalBoundary shall be closed. - If the PolygonalBoundary is given by an IfcCompositeCurve, it shall only have IfcCompositeCurveSegment's of type IfcPolyline, or IfcTrimmedCurve (having a BasisCurve of type IfcLine, or IfcCircle) Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcpolygonalboundedhalfspace.htm"
     },
     "IfcPolyline": {
@@ -3223,7 +3223,7 @@
             "ConnectedTo": "Reference to the port connection relationship. The relationship then refers to the other port to which this port is connected.",
             "ContainedIn": "Reference to the element to port connection relationship. The relationship then refers to the element in which this port is contained."
         },
-        "description": "An IfcPort provides the means for an element to connect to other elements.",
+        "description": "An IfcPort provides the means for an element to connect to other elements. An IfcPort is associated with an IfcElement, it belongs to, through the objectified relationship IfcRelConnectsPortToElement. Exactly two ports, belonging to two different elements, are connected with each other through the objectified relationship IfcRelConnectsPorts. An instance of IfcElement may have one or more points at which it connects to other instances of IfcElement. An instance of IfcPort is located at a point where a connection can occur. The location of the port is determined in the context of the local coordinate system of the element to which it belongs. *Containment Use Definitions* As a subordinate part being fully dependent on the master element the IfcPort shall have no independent containment relationship to the spatial structure. *Geometry Use Definition* The geometric representation of IfcPort is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Local Placement The local placement for IfcPort is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point to the local placement of the master IfcElement (its relevant subtypes), which is associated to the IfcPort by the relationship object IfcRelConnectsPortToElement. Shape Representation The geometry use definitions for the shape representation of the IfcPort is given at the level of its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcport.htm"
     },
     "IfcPostalAddress": {
@@ -3248,7 +3248,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcpredefinedcurvefont.htm"
     },
     "IfcPreDefinedDimensionSymbol": {
-        "description": "The pre defined dimension symbol is a pre defined symbol for the purpose to identify a dimension symbol by name. Allowable names are:",
+        "description": "The pre defined dimension symbol is a pre defined symbol for the purpose to identify a dimension symbol by name. Allowable names are: - 'arc length', - 'conical taper', - 'counterbore', - 'countersink', - 'depth', - 'diameter', - 'plus minus', - 'slope', - 'spherical diameter', - 'spherical radius', - 'square' Illustration from ISO 10303-202, page 203:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcpredefineddimensionsymbol.htm"
     },
     "IfcPreDefinedItem": {
@@ -3259,7 +3259,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcpredefineditem.htm"
     },
     "IfcPreDefinedPointMarkerSymbol": {
-        "description": "The pre defined point marker symbol is a pre defined symbol for the purpose to identify a point marker by name. Allowable names are:",
+        "description": "The pre defined point marker symbol is a pre defined symbol for the purpose to identify a point marker by name. Allowable names are: - 'asterisk', - 'circle', - 'dot', - 'plus', - 'square', - 'triangle', - 'x', Illustration from ISO 10303-202, page 210:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcpredefinedpointmarkersymbol.htm"
     },
     "IfcPreDefinedSymbol": {
@@ -3267,11 +3267,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcpredefinedsymbol.htm"
     },
     "IfcPreDefinedTerminatorSymbol": {
-        "description": "The pre defined terminator symbol is a pre defined symbol for the purpose to identify a terminator by name. Allowable names are:",
+        "description": "The pre defined terminator symbol is a pre defined symbol for the purpose to identify a terminator by name. Allowable names are: - 'blanked arrow', - 'blanked box', - 'blanked dot', - 'dimension origin', - 'filled arrow', - 'filled box', - 'filled dot', - 'integral symbol', - 'open arrow', - 'slash', - 'unfilled arrow' Illustration from ISO 10303-202, page 212:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcpredefinedterminatorsymbol.htm"
     },
     "IfcPreDefinedTextFont": {
-        "description": "The pre defined text font determines those qualified names which can be used for fonts that are in scope of the current data exchange specification (in contrary to externally defined text fonts). There are two choices:",
+        "description": "The pre defined text font determines those qualified names which can be used for fonts that are in scope of the current data exchange specification (in contrary to externally defined text fonts). There are two choices: - _IfcDraughtingPreDefinedTextFont_for definitions from ISO/IS 10303-46:1994 for (old) vector based and monospace text. - _IfcTextStyleFontModel_for definitions from Cascading Style Sheets, level 1, W3C Recommendation 17 Dec 1996, revised 11 Jan 1999, CSS1, for all true type text. The use of the CSS1 definitions is the preferred way to represent text fonts.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcpredefinedtextfont.htm"
     },
     "IfcPresentationLayerAssignment": {
@@ -3281,7 +3281,7 @@
             "Identifier": "An (internal) identifier assigned to the layer.",
             "Name": "Name of the layer."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: The presentation layer assignment entity assigns an identifying name and optionally a description to a set of presentation and representation items.",
+        "description": "Definition from ISO/CD 10303-46:1992: The presentation layer assignment entity assigns an identifying name and optionally a description to a set of presentation and representation items. The presentation layer assignment provides the layer name (and optionally a description) for a collection of (styled or unstyled) representation items. Visibility and access control and layer style assignment (colour, line style, line width) is handled by the subtype IfcPresentationLayerAssignmentWithStyle.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifcpresentationlayerassignment.htm"
     },
     "IfcPresentationLayerWithStyle": {
@@ -3291,14 +3291,14 @@
             "LayerOn": "A logical setting, TRUE indicates that the layer is set to 'On', FALSE that the layer is set to 'Off', UNKNOWN that such information is not available.",
             "LayerStyles": "Assignment of presentation styles to the layer to provide a default style for representation items. >  NOTE  In most cases the assignment of styles to a layer is restricted to an IfcCurveStyle representing the layer curve colour, layer curve thickness, and layer curve type."
         },
-        "description": "An IfcPresentationLayerAssignmentWithStyle extends the presentation layer assignment with capabilities to define visibility control, access control and common style information.",
+        "description": "An IfcPresentationLayerAssignmentWithStyle extends the presentation layer assignment with capabilities to define visibility control, access control and common style information. The visibility control allows to define a layer to be either 'on' or 'off', and/or 'frozen' or 'not frozen'. The access control allows to block graphical entities from manipulations by setting a layer to be either 'blocked' or 'not blocked'. Common style information can be given to the layer.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifcpresentationlayerwithstyle.htm"
     },
     "IfcPresentationStyle": {
         "attributes": {
             "Name": "Name of the presentation style."
         },
-        "description": "Definition from IAI: An abstract generalization of style table for presentation information assigned to geometric representation items. It includes styles for curves, areas, surfaces, text and symbols. Style information may include colour, hatching, rendering, text fonts, etc.",
+        "description": "Definition from IAI: An abstract generalization of style table for presentation information assigned to geometric representation items. It includes styles for curves, areas, surfaces, text and symbols. Style information may include colour, hatching, rendering, text fonts, etc. Each subtype of IfcPresentationStyle can be assigned to IfcGeometricRepresentationItem's via the IfcPresentationStyleAssignment through an intermediate IfcStyledItem or one of its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcpresentationstyle.htm"
     },
     "IfcPresentationStyleAssignment": {
@@ -3314,7 +3314,7 @@
             "ProcedureType": "Predefined procedure types from which that required may be set.",
             "UserDefinedProcedureType": "A user defined procedure type."
         },
-        "description": "An IfcProcedure is an identifiable step to be taken within a process that is considered to occur over zero or a non-measurable period of time.",
+        "description": "An IfcProcedure is an identifiable step to be taken within a process that is considered to occur over zero or a non-measurable period of time. Use Definitions An instance of IfcProcedure may nest other instances of IfcProcedure using IfcRelNests. Instances of IfcProcedure, since they are subtypes of IfcProcess, may also participate in sequence relationships using IfcRelSequences. IfcProcedure is used to capture information about stepped processes such as calibration, start/stop procedures for equipment items etc. Note that a particular type of IfcProcedure is a caution, warning or other form of advisory note. Typically, it is anticipated that such a procedure would be assigned to the specific IfcProcess for which it gives advice using IfcRelAssignsToProcess. Note that both nesting and sequencing can be supported concurrently. For example, B, C and D may be procedures nested in procedure A. Sequence relationships can also be established such that B precedes C and C precedes D.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcprocedure.htm"
     },
     "IfcProcess": {
@@ -3332,7 +3332,7 @@
             "ReferencedBy": "Reference to the IfcRelAssignsToProduct relationship, by which other subtypes of IfcObject can be related to the product.",
             "Representation": "Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement."
         },
-        "description": "Any object, or any aid to define, organize and annotate an object, that relates to a geometric or spatial context. Subtypes of IfcProduct usually hold a shape representation and a local placement within the project structure.",
+        "description": "Any object, or any aid to define, organize and annotate an object, that relates to a geometric or spatial context. Subtypes of IfcProduct usually hold a shape representation and a local placement within the project structure. This includes manufactured, supplied or created objects (referred to as elements) for incorporation into an AEC/FM project. This also includes objects that are created indirectly by other products, as spaces are defined by bounding elements. Products can be designated for permanent use or temporary use, an example for the latter is formwork. Products are defined by their properties and representations. In addition to physical products (covered by the subtype IfcElement) and spatial items (covered by the subtype IfcSpatialStructureElement) the IfcProduct also includes non-physical items, that relate to a geometric or spatial contexts, such as grid, port, annotation, structural actions, etc. Use Definition Any instance of IfcProduct defines a particular occurrence of a product, the common type information, that relates to many similar (or identical) occurrences of IfcProduct, is handled by the IfcTypeProduct (and its subtypes), assigned to one or many occurrences of IfcProduct by using the objectified relationship IfcRelDefinesByType. The IfcTypeProduct may provide, in addition to common properties, also a common geometric representation for all occurrences. An IfcProduct occurs at a specific location in space if it has a geometric representation assigned. It can be placed relatively to other products, but ultimately relative to the world coordinate system defined for this project. The inherited ObjectType attribute can be used to designate a particular type of the product instance. If subtypes of IfcProduct have a PredefinedType defined, the ObjectType is used to provide the user defined, particular type of the product instance, if the PredefinedType is set to USERDEFINED.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcproduct.htm"
     },
     "IfcProductDefinitionShape": {
@@ -3340,7 +3340,7 @@
             "HasShapeAspects": "Reference to the shape aspect that represents part of the shape or its feature distinctively.",
             "ShapeOfProduct": "The _IfcProductDefinitionShape_ shall be used to provide a representation for a single instance of _IfcProduct_."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A product definition shape identifies a product\u2019s shape as the conceptual idea of the form of a product.",
+        "description": "Definition from ISO/CD 10303-42:1992: A product definition shape identifies a product\u2019s shape as the conceptual idea of the form of a product. Definition from IAI: The IfcProductDefinitionShape defines all shape relevant information about an IfcProduct. It allows for multiple geometric shape representations of the same product.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcproductdefinitionshape.htm"
     },
     "IfcProductRepresentation": {
@@ -3367,7 +3367,7 @@
             "ProfileName": "Name of the profile type according to some standard profile table.",
             "ProfileType": "Defines the type of geometry into which this profile definition shall be resolved, either a curve or a surface area. In case of curve the profile should be referenced by a swept surface, in case of area the profile should be referenced by a swept area solid."
         },
-        "description": "Definition from IAI: The IfcProfileDef is the supertype of all definitions of standard and arbitrary profiles within IFC. It is used to define a standard set of commonly used profiles by their parameters or by their explicit curve geometry. Those profile definitions are used within the geometry and geometric model resource to create either swept surfaces, swept area solids, or sectioned spines.",
+        "description": "Definition from IAI: The IfcProfileDef is the supertype of all definitions of standard and arbitrary profiles within IFC. It is used to define a standard set of commonly used profiles by their parameters or by their explicit curve geometry. Those profile definitions are used within the geometry and geometric model resource to create either swept surfaces, swept area solids, or sectioned spines. The purpose of the profile definition within the swept surfaces or swept area solids is to define a uniform cross section being swept: - along a line (extrusion) using IfcSurfaceOfLinearExtrusion or IfcExtrudedAreaSolid - along a circular arc (revolution) using IfcSurfaceOfRevolution or IfcRevolvedAreaSolid - along a directrix lying on a reference surface using IfcSurfaceCurveSweptAreaSolid The purpose fo the profile definition within the sectioned spine is to define a varying cross sections at several positions along a spine curve. The subtype IfcDerivedProfileDef is particularly suited to provide the consecutive profiles to be based on transformations of the start profile and thus maintaining the identity of vertices and edges. - Parameterized profiles are 2D primitives, which are used within the industry to describe cross sections by a description of its parameters. - Arbitrary profiles are cross sections defined by an outer boundary as bounded curve, which may also include holes, defined by inner boundaries. - Derived profiles, based on a transformation of a parent profile, are also part of the profile definitions available. - In addition composite profiles can be defined, which include two or more profile definitions to define the resulting profile. An IfcProfileDef is treated as bounded area if it is used within swept area solids. In this case, the inside of the profile is part of the profile. The attribute ProfileType is set to AREA. An IfcProfileDef is treated as a curve if it is used within swept surfaces. In this case, the inside of the profile (if the curve is closed) is not part of the profile. The attribute ProfileType is set to CURVE. The optional attribute ProfileName can be used to designate a standard profile type as e.g. given in profile tables for steel profiles. Illustration: Table: Use of parameterized profiles within the swept area solid Use cases: Results of the different usage of the ProfileType attribute are demonstrated here. The ProfileType defines whether the inside (the bounded area) is part of the profile definition (Area) or not (Curve). Table: Resulting area or curve depending on ProfileType",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcprofiledef.htm"
     },
     "IfcProfileProperties": {
@@ -3375,7 +3375,7 @@
             "ProfileDefinition": "Optional reference to an instance of IfcProfileDef, which contains a further geometrical definition.",
             "ProfileName": "Standardized profile name as published in a profile table. All profile properties are applicable to this standardized profile name."
         },
-        "description": "This is a collection of properties applicable to all linear structural members having a profile definition.",
+        "description": "This is a collection of properties applicable to all linear structural members having a profile definition. The entity IfcProfileProperties contains additionally an optional reference to an instance of IfcProfileDef_which contains a further geometrical definition of this profile. The connection between instances of _IfcProfileProperties and IfcStructuralMembers is defined by using an instance of IfcRelAssociatesProfileProperties.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcprofileproperties.htm"
     },
     "IfcProject": {
@@ -3385,7 +3385,7 @@
             "RepresentationContexts": "Context of the representations used within the project. When the project includes shape representations for its components, one or several geometric representation contexts need to be included that define e.g. the world coordinate system, the coordinate space dimensions, and/or the precision factor.",
             "UnitsInContext": "Units globally assigned to measure types used within the context of this project."
         },
-        "description": "The undertaking of some design, engineering, construction, or maintenance activities leading towards a product. The project establishes the context for information to be exchanged or shared, and it may represent a construction project but does not have to.",
+        "description": "The undertaking of some design, engineering, construction, or maintenance activities leading towards a product. The project establishes the context for information to be exchanged or shared, and it may represent a construction project but does not have to. The representation context, in the case of a geometric representation context, which is referenced from the IfcProject, includes: - the default units used - the world coordinate system - the coordinate space dimension - the precision used within the geometric representations, and - optionally the indication of the true north relative to the world coordinate system *Property Set Use Definition*: The property sets relating to the IfcProject are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcProject are part of this IFC release: - Pset_ProjectCommon: common property set for the single project occurrence. *Spatial Structure Use Definition* The IfcProject is used to reference the root of the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). The spatial structure elements are linked together, and to the IfcProject, by using the objectified relationship IfcRelAggregates. The IfcProject references them by its inverse relationship: - IfcProject.Decomposes -- referencing (IfcSite || IfcBuilding) by IfcRelAggregates.RelatingObject. The IfcSite or IfcBuilding referenced shall be the root of the spatial structure. - IfcProject.IsDecomposedBy -- it shall be NIL, i.e. the IfcProject shall not be decomposed into any parts. Informal propositions: 1. There shall only be one project within the exchange context. This is enforced by the global rule IfcSingleProjectInstance.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcproject.htm"
     },
     "IfcProjectOrder": {
@@ -3393,7 +3393,7 @@
             "ID": "A unique identification assigned to a project order that enables its differentiation from other project orders.",
             "Status": "The current status of a project order.Examples of status values that might be used for a project order status include: - PLANNED - REQUESTED - APPROVED - ISSUED - STARTED - DELAYED - DONE"
         },
-        "description": "An IfcProjectOrder sets common properties for project orders issued in a construction or facilities management project.",
+        "description": "An IfcProjectOrder sets common properties for project orders issued in a construction or facilities management project. *Use Definitions* Actor attributes such as the organization to which the order is sent, issuing organization, person responsible atc. are handled by assigning instances of IfcActor through IfcRelAssignsToProjectOrder. The IfcActorRole must be asserted with the value of the role set when used in this context. A work plan (acting as a service) may be assigned to a project order (acting as a client) to describe how the project order should be fulfilled. This is handled by assigning instances of IfcWorkPlan through IfcRelAssignsToProjectOrder. The reverse of this situation may be true whereby the work plan (acting as a client) may have project orders (acting as a service). This is handled by assigning instances of IfcProjectOrder to an IfcWorkPlan through IfcRelAssignsToControl. Approvals including signoff, authorization etc. are handled using the the IfcRelAssociatesApproval relationship class. A cost schedule may be assigned to a project order are handled through the IfcRelAssignsToProjectOrder relationship. *Property Set Use Definition*: The property sets relating to an IfcProjectOrder are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcProjectOrder are part of this IFC release: - Pset_ProjectOrderChangeOrder: specific property set for the properties of a change order, if available - Pset_ProjectOrderMaintenanceWorkOrder: specific property set for the properties of a maintenance work order, if available - Pset_ProjectOrderMoveOrder: specific property set for the properties of a move order, if available - Pset_ProjectOrderPurchaseOrder: specific property set for the properties of a purchase order, if available - Pset_ProjectOrderWorkOrder: specific property set for the properties of a general work order, if available",
         "predefined_types": {
             "CHANGEORDER": "An instruction to make a change to a product or work being undertaken and a description of the work that is to be performed.",
             "MAINTENANCEWORKORDER": "An instruction to carry out maintenance work and a description of the work that is to be performed.",
@@ -3409,7 +3409,7 @@
         "attributes": {
             "Records": "Records in the sequence of occurrence the incident of a project order and the objects that are related to that project order. For instance, a maintenance incident will connect a work order with the objects (elements or assets) that are subject to the provisions of the work order"
         },
-        "description": "An IfcProjectOrderRecord records information in sequence about the incidence of each order that is connected with one or a set of objects.",
+        "description": "An IfcProjectOrderRecord records information in sequence about the incidence of each order that is connected with one or a set of objects. Use Definitions Each IfcProjectOrderRecord is constrained to record a particular type of incident as indicated by the value of the enumeration IfcProjectOrderRecordTypeEnum.",
         "predefined_types": {
             "CHANGE": "",
             "MAINTENANCE": "",
@@ -3426,7 +3426,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcprojectioncurve.htm"
     },
     "IfcProjectionElement": {
-        "description": "The IfcProjectionElement is a specialization of the general feature element to represent projections applied to building elements. It represents a solid attached to any element that has physical manifestation. Projections must be handled by all sectors and disciplines in AEC/FM industry, therefore the interoperability for opening elements is provided at this high level.",
+        "description": "The IfcProjectionElement is a specialization of the general feature element to represent projections applied to building elements. It represents a solid attached to any element that has physical manifestation. Projections must be handled by all sectors and disciplines in AEC/FM industry, therefore the interoperability for opening elements is provided at this high level. An IfcProjectionElement has to be linked to a building element (all subtypes of IfcBuildingElement) by using the IfcRelProjectsElement relationship. Its existence depends on the existence of the master element. ~~It is also directly linked to the spatial structure of the project (and here normally to the IfcBuildingStorey) by using the IfcRelContainedInSpatialStructure relationship~~. It should not be linked directly to the spatial structure of the project, i.e. the inverse relationship ContainedInStructure shall be NIL. It is assigned to the spatial structure through the element it projects. *Quantity Use Definition*: The quantities relating to the IfcProjectionElement are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. The following quantities are foreseen, but will be subjected to the local standard of measurement: *Geometry Use Definition* The geometric representation of IfcProjectionElement is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. Local Placement The local placement for IfcOpeningRecess is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement should point to the local placement of the same element, to which the projection adds, i.e. referred to by ProjectsElement.RelatingBuildingElement. Swept Solid Representation The geometric representation of IfcProjectionElement is defined using the swept area solid geometry. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'SweptSolid' The following additional constraints apply to the swept solid representation: - Solid: IfcExtrudedAreaSolid is required. - Profile: IfcRectangleProfileDef, IfcCircleProfileDef and IfcArbitraryClosedProfileDef shall be supported. - Extrusion: The profile shall be extruded horizontally (i.e. perpendicular to the extrusion direction of the modified element), e.g. for wall projections, or vertically (i.e. in the extrusion direction of the projected element), e.g., for floor projections. EXAMPLE Brep Representation The general b-rep geometric representation of IfcProjectionElement is defined using the Brep geometry. The Brep representation allows for the representation of complex element shape. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'Brep'",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcprojectionelement.htm"
     },
     "IfcProperty": {
@@ -3446,7 +3446,7 @@
             "Unit": "Unit for the upper and lower bound values, if not given, the default value for the measure type (given by the TYPE of the upper and lower bound values) is used as defined by the global unit assignment at IfcProject.",
             "UpperBoundValue": "Upper bound value for the interval defining the property value. If the value is not given, it indicates an open bound (all values to be greater than or equal to LowerBoundValue)."
         },
-        "description": "A property with a bounded value (IfcPropertyBoundedValue) defines a property object which has a maximum of two (numeric or descriptive) values assigned, the first value specifying the upper bound and the second value specifying the lower bound. It defines a property - value bound (min-max) combination for which the property name, the upper bound value with measure type, the lower bound value with measure type (and optional the unit) is given.",
+        "description": "A property with a bounded value (IfcPropertyBoundedValue) defines a property object which has a maximum of two (numeric or descriptive) values assigned, the first value specifying the upper bound and the second value specifying the lower bound. It defines a property - value bound (min-max) combination for which the property name, the upper bound value with measure type, the lower bound value with measure type (and optional the unit) is given. The unit is handled by the Unit attribute: - If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, then the unit assigned by the Unit attribute overrides the globally assigned unit. The IfcPropertyBoundedValue allows for the specification of an interval for the value component of the property description. If either the LowerBoundValue or the UpperBoundValue is not given, then it indicates an open bound (either a minimum value or a maximum value). The interval is by definition inclusive, i.e. the value given for the LowerBoundValue or the UpperBoundValue is included in the interval. Examples of a property with bounded value are: Informal proposition: - If the measure type for the upper and lover bound value is a numeric measure, then the following shall be true: UpperBoundValue > LowerBoundValue.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertyboundedvalue.htm"
     },
     "IfcPropertyConstraintRelationship": {
@@ -3456,14 +3456,14 @@
             "RelatedProperties": "The properties to which a constraint is to be related.",
             "RelatingConstraint": "The constraint that is to be related."
         },
-        "description": "An IfcPropertyConstraintRelationship is a relationship class that enables a constraint to be related to one or more properties.",
+        "description": "An IfcPropertyConstraintRelationship is a relationship class that enables a constraint to be related to one or more properties. An IfcPropertyConstraintRelationship allows for the specification of a constraint to be applied to many properties. The constraints applied therefore enable a property to carry values identifying requirements as well as those identifying the fulfilment of those requirements. The example below shows how a constraint may be applied to a property within a property set. For simplicity, only the mandatory attributes are shown as asserted. It shows how a property 'ThingWeight' which has a nominal value of 19.5 kg has two constraints that are logically aggregated by an AND connection. One of the constraints has a benchmark of 'GREATERTHANOREQUALTO' whilst the second has a benchmark of 'LESSTHANOREQUALTO'. This means that the constraint must lie between these two bounding values. The relating constraint is instantiated as an objective named as 'Weight Constraint' and qualified as a SPECIFICATION constraint. The two related constraints are both specified as metrics since they can have specific values.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcpropertyconstraintrelationship.htm"
     },
     "IfcPropertyDefinition": {
         "attributes": {
             "HasAssociations": "Reference to the relationship IfcRelAssociates and thus to those externally defined concepts, like classifications, documents, or library information, which are associated to the property definition."
         },
-        "description": "The IfcPropertyDefinition defines the generalization of all characteristics (i.e. a grouping of individual properties), that may be assigned to objects. Currently, subtypes of IfcPropertyDefinition include property set definitions, and property sets..",
+        "description": "The IfcPropertyDefinition defines the generalization of all characteristics (i.e. a grouping of individual properties), that may be assigned to objects. Currently, subtypes of IfcPropertyDefinition include property set definitions, and property sets.. Property definitions define information that is shared among multiple instances of objects. The assignment of the shared information to objects is handled by the IfcRelDefines relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcpropertydefinition.htm"
     },
     "IfcPropertyDependencyRelationship": {
@@ -3474,7 +3474,7 @@
             "Expression": "Expression that further describes the nature of the dependency relation.",
             "Name": "Name of the relationship that provides additional meaning to the nature of the dependency."
         },
-        "description": "An IfcPropertyDependencyRelationship describes an identified dependency between the value of one property and that of another.",
+        "description": "An IfcPropertyDependencyRelationship describes an identified dependency between the value of one property and that of another. While the IfcPropertyDependencyRelationship may be used to describe the dependency, and it may do so in terms of the expression of how the dependency operates, it is not possible through the current IFC model for the value of the related property to be actually derived from the value of the relating property. The determination of value according to the dependency is required to be performed by an application that can then use the Expression attribute to flag the form of the dependency.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertydependencyrelationship.htm"
     },
     "IfcPropertyEnumeratedValue": {
@@ -3482,7 +3482,7 @@
             "EnumerationReference": "Enumeration from which a enumeration value has been selected. The referenced enumeration also establishes the unit of the enumeration value.",
             "EnumerationValues": "Enumeration values, which shall be listed in the referenced IfcPropertyEnumeration, if such a reference is provided."
         },
-        "description": "A property with an enumerated value (IfcPropertyEnumeratedValue) defines a property object which has a value assigned which is chosen from an enumeration. It defines a property - value combination for which the property name, the value with measure type (and optional the unit) are given.",
+        "description": "A property with an enumerated value (IfcPropertyEnumeratedValue) defines a property object which has a value assigned which is chosen from an enumeration. It defines a property - value combination for which the property name, the value with measure type (and optional the unit) are given. The unit is handled by the Unit attribute of the IfcPropertyEnumeration: - If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, then the unit assigned by the unit attribute overrides the globally assigned unit. More precisely: The IfcPropertyEnumeratedValue defines a property, which value is selected from a defined list of enumerators. The enumerators are stored in a dynamic enumeration of values including the type information from IfcValue (see IfcPropertyEnumeration). This enables applications to use an enumeration value as a property within a property set (IfcPropertySet) including the allowed list of values. Examples of a property with enumerated value with are: The IfcPropertyEnumeratedValue refers to an IfcPropertyEnumeration, e.g. for the above:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertyenumeratedvalue.htm"
     },
     "IfcPropertyEnumeration": {
@@ -3491,7 +3491,7 @@
             "Name": "Name of this enumeration.",
             "Unit": "Unit for the enumerator values, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject."
         },
-        "description": "A collection of simple or measure values that define a prescribed set of alternatives from which 'enumeration values' are selected. This enables inclusion of enumeration values in property sets. IfcPropertyEnumeration provides a name for the enumeration as well as a list of unique (numeric or descriptive) values (that may have a measure type assigned). The entity defines the list of potential enumerators to be exchanged together (or separately) with properties of type IfcPropertyEnumeratedValue that selects their actual property values from this enumeration.",
+        "description": "A collection of simple or measure values that define a prescribed set of alternatives from which 'enumeration values' are selected. This enables inclusion of enumeration values in property sets. IfcPropertyEnumeration provides a name for the enumeration as well as a list of unique (numeric or descriptive) values (that may have a measure type assigned). The entity defines the list of potential enumerators to be exchanged together (or separately) with properties of type IfcPropertyEnumeratedValue that selects their actual property values from this enumeration. The unit is handled by the Unit attribute: - If the Unit attribute is not given, than the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, the unit assigned by the unit attribute overrides the globally assigned unit.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertyenumeration.htm"
     },
     "IfcPropertyListValue": {
@@ -3499,7 +3499,7 @@
             "ListValues": "List of values.",
             "Unit": "Unit for the list values, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject."
         },
-        "description": "An IfcPropertyListValue defines a property that has several (numeric or descriptive) values assigned, these values are given by an ordered list.",
+        "description": "An IfcPropertyListValue defines a property that has several (numeric or descriptive) values assigned, these values are given by an ordered list. An IfcPropertyListValue is a list of values. The order in which values appear is significant. Each value in the list is unique i.e. no duplicate values are allowed. All list members should be of the same type. The unit applicable to all values is handled by the Unit attribute: - If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, then the unit assigned by the Unit attribute overrides the globally assigned unit. Example of a property with list value is:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertylistvalue.htm"
     },
     "IfcPropertyReferenceValue": {
@@ -3514,7 +3514,7 @@
         "attributes": {
             "HasProperties": "Contained set of properties. For property sets defined as part of the IFC Object model, the property objects within a property set are defined as part of the standard. If a property is not contained within the set of predefined properties, its value has not been set at this time."
         },
-        "description": "The IfcPropertySet defines all dynamically extensible properties. The property set is a container class that holds properties within a property tree. These properties are interpreted according to their name attribute.",
+        "description": "The IfcPropertySet defines all dynamically extensible properties. The property set is a container class that holds properties within a property tree. These properties are interpreted according to their name attribute. Property sets, defining a particular type of object, can be assigned an object type (IfcTypeObject). Property sets are assigned to objects (IfcObject) through an objectified relationship (IfcRelDefinedByProperties). If the same set of properties applies to more than one object, it should be assigned by a single instance of IfcRelDefinedByProperties to a set of related objects. Those property sets are referred to as shared property sets. Use Definition Instances of IfcPropertySet are used to assign named sets of individual properties (complex or single properties). Each individual property has a significant name string. Some property sets have predefined instructions on assigning those significant name, these are listed under \"property sets\" main menu item within this specification. The naming convention \"Pset_Xxx\" applies to those property sets and shall be used as the value to the Name attribute. In addition any user defined property set can be captured, those property sets shall have a Name value not including the \"Pset_\" prefix.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcpropertyset.htm"
     },
     "IfcPropertySetDefinition": {
@@ -3522,7 +3522,7 @@
             "DefinesType": "The property style to which the property set might belong.",
             "PropertyDefinitionOf": "Reference to the relation to one or many objects that are characterized by the property definition. The reference may be omitted, if the property definition is used to define a style library and no instances, to which the particular style of property set is associated, exist yet."
         },
-        "description": "An IfcPropertySetDefinition is a generalization of property sets, that are either:",
+        "description": "An IfcPropertySetDefinition is a generalization of property sets, that are either: The subtypes of the IfcPropertySetDefinition are either the dynamically extendable IfcPropertySet, or all other statically defined subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcpropertysetdefinition.htm"
     },
     "IfcPropertySingleValue": {
@@ -3530,7 +3530,7 @@
             "NominalValue": "Value and measure type of this property.  >  NOTE  By virtue of the defined data type, that is selected from the SELECT IfcValue, the appropriate unit can be found within the IfcUnitAssignment, defined for the project if no value for the unit attribute is given.",
             "Unit": "Unit for the nominal value, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject."
         },
-        "description": "A property with a single value (IfcPropertySingleValue) defines a property object which has a single (numeric or descriptive) value assigned. It defines a property - single value combination for which the property name, the value with measure type (and optionally the unit) is given.",
+        "description": "A property with a single value (IfcPropertySingleValue) defines a property object which has a single (numeric or descriptive) value assigned. It defines a property - single value combination for which the property name, the value with measure type (and optionally the unit) is given. The unit is handled by the Unit attribute: - If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, then the unit assigned by the Unit attribute overrides the globally assigned unit. Examples of a property with single value are:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertysinglevalue.htm"
     },
     "IfcPropertyTableValue": {
@@ -3541,11 +3541,11 @@
             "DefiningValues": "List of defining values, which determine the defined values.",
             "Expression": "Expression for the derivation of defined values from the defining values, the expression is given for information only, i.e. no automatic processing can be expected from the expression."
         },
-        "description": "A property with a range value (IfcPropertyTableValue) defines a property object which has two lists of (numeric or descriptive) values assigned, the values specifying a table with two columns. The defining values provide the first column and establish the scope for the defined values (the second column). Interpolations are out of scope of the IfcPropertyTableValue. An optional Expression attribute may give the equation used for deriving the range value, which is for information purposes only.",
+        "description": "A property with a range value (IfcPropertyTableValue) defines a property object which has two lists of (numeric or descriptive) values assigned, the values specifying a table with two columns. The defining values provide the first column and establish the scope for the defined values (the second column). Interpolations are out of scope of the IfcPropertyTableValue. An optional Expression attribute may give the equation used for deriving the range value, which is for information purposes only. The IfcPropertyTableValue defines a defining/defined property value combination for which the property name, the table with defining and defined values with measure type (and optional the units for defining and defined values)are given. The units are handled by the DefiningUnit and DefinedUnit attributes: - If the DefiningUnit or DefinedUnit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the DefiningUnit or DefinedUnit attribute is given, then the unit assigned by the unit attribute overrides the globally assigned unit. The IfcPropertyTableValue allows for the specification of a table of defining/defined value pairs of the property description. Examples of a property with range value are: Informal propositions: - The list of DerivedValues and the list of DefiningValues are corresponding lists.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertytablevalue.htm"
     },
     "IfcProtectiveDeviceType": {
-        "description": "An IfcProtectiveDeviceType is a device that breaks an electrical circuit when a stated electric current that passes through it is exceeded.",
+        "description": "An IfcProtectiveDeviceType is a device that breaks an electrical circuit when a stated electric current that passes through it is exceeded. *Use Definitions* An IfcProtectiveDeviceType is a subtype of IfcFlowControllerType that provides for various devices that ensure the safety of an electrical circuit. Usage of IfcProtectiveDeviceType defines the parameters for one or more occurrences of IfcFlowController. Parameters are specified through property sets that are enumerated in the IfcIfcProtectiveDeviceTypeEnum data type. *Property Set Use Definition*: The property sets relating to the IfcProtectiveDeviceType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcProtectiveDeviceType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available - Pset_ProtectiveDeviceTypeCommon: property set for properties that are common to all types of protective device, if available - Pset_ProtectiveDeviceTypeCircuitBreaker: specific property set for the properties of a circuit breaker , if available - Pset_ProtectiveDeviceTypeEarthFailureDevice: specific property set for the properties of an earth failure device, if available - Pset_ProtectiveDeviceTypeFuseDisconnector: specific property set for the properties of a fuse disconnector, if available - Pset_ProtectiveDeviceTypeResidualCurrentCircuitBreaker: specific property set for the properties of a residual current circuit breaker, if available - Pset_ProtectiveDeviceTypeResidualCurrentSwitch: specific property set for the properties of a residual current switch, if available - Pset_ProtectiveDeviceTypeVaristor: specific property set for the properties of a varistor, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "CIRCUITBREAKER": "A mechanical switching device capable of making, carrying, and breaking currents under normal circuit conditions and also making, carrying for a specified time and breaking, current under specified abnormal circuit conditions such as those of short circuit.",
             "EARTHFAILUREDEVICE": "",
@@ -3563,11 +3563,11 @@
             "ProxyType": "High level (and only) semantic meaning attached to the IfcProxy, defining the basic construct type behind the Proxy, e.g. Product or Process.",
             "Tag": "The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level."
         },
-        "description": "The IfcProxy is intended to be a kind of a container for wrapping objects which are defined by associated properties, which may or may not have a geometric representation and placement in space. A proxy may have a semantic meaning, defined by the Name attribute, and property definitions, attached through the property assignment relationship, which definition may be outside of the definitions given by the current release of IFC.",
+        "description": "The IfcProxy is intended to be a kind of a container for wrapping objects which are defined by associated properties, which may or may not have a geometric representation and placement in space. A proxy may have a semantic meaning, defined by the Name attribute, and property definitions, attached through the property assignment relationship, which definition may be outside of the definitions given by the current release of IFC. The ProxyType may give an indication to which high level semantic breakdown of object the semantic definition of the proxy relates to. the Tag attribute may be used to assign a human or system interpretable identifier (such as a serial number or bar code).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcproxy.htm"
     },
     "IfcPumpType": {
-        "description": "The element type IfcPumpType defines a list of commonly shared property set definitions of a pump and an optional set of product representations. It is used to define a pump specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcPumpType defines a list of commonly shared property set definitions of a pump and an optional set of product representations. It is used to define a pump specification (i.e. the specific product information, that is common to all occurrences of that product type). A pump type is used to define the common properties of a pump that may be applied to many occurrences of that type. A pump is a device which imparts mechanical work on a liquid. A typical use of a pump is to circulate chilled water or heating hot water in a building services distribution system. Pump types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcPumpType are represented by instances of IfcFlowMovingDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_PumpTypeCommon: common property set for all pump types",
         "predefined_types": {
             "CIRCULATOR": "A Circulator pump is a generic low-pressure, low-capacity pump. It may have a wet rotor and may be driven by a flexible-coupled motor.",
             "ENDSUCTION": "An End Suction pump, when mounted horizontally, has a single horizontal inlet on the impeller suction side and a vertical discharge. It may have a direct or close-coupled motor.",
@@ -3622,11 +3622,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcquantityweight.htm"
     },
     "IfcRadiusDimension": {
-        "description": "The radial dimension is a draughting callout that presents the radial length of a conic element. It consists of a dimension curve and may have projection curves (but is often defined without projection curves).",
+        "description": "The radial dimension is a draughting callout that presents the radial length of a conic element. It consists of a dimension curve and may have projection curves (but is often defined without projection curves). Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcradiusdimension.htm"
     },
     "IfcRailing": {
-        "description": "Definition of IAI: The railing is a frame assembly adjacent to human circulation spaces and at some space boundaries where it is used in lieu of walls or to complement walls. Designed to aid humans, either as an optional physical support, or to prevent injury by falling. A list of references to accessory/mounting hardware for this railing might be given by including these assessories (IfcDiscreteAssessory) through the objectified relationship IfcRelAggregates.",
+        "description": "Definition of IAI: The railing is a frame assembly adjacent to human circulation spaces and at some space boundaries where it is used in lieu of walls or to complement walls. Designed to aid humans, either as an optional physical support, or to prevent injury by falling. A list of references to accessory/mounting hardware for this railing might be given by including these assessories (IfcDiscreteAssessory) through the objectified relationship IfcRelAggregates. *Property Set Use Definition*: The property sets relating to the IfcRailing are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcRailing are part of this IFC release: - Pset_RailingCommon: common property set for all railing occurrences *Geometry Use Definitions* The geometric representation of IfcRailing is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local placement The local placement for IfcRailing is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level - If the IfcRailing, however, is used by an IfcStair or IfcRamp, and this container class defines its own local placement, then the PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the aggregate. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representation Currently the use of 'BoundingBox', 'SurfaceModel', 'Brep' and 'MappedRepresentation' representations of IfcRailing are supported. The conventions to use these representations are given at the level of the supertype, IfcBuildingElement.",
         "predefined_types": {
             "BALUSTRADE": "Similar to the definitions of a guardrail except the location is at the edge of a floor, rather then a stair or ramp. Examples are balustrates at roof-tops or balconies.",
             "GUARDRAIL": "A type of railing designed to guard human occupants from falling off a stair, ramp or landing where there is a vertical drop at the edge of such floors/landings.",
@@ -3637,7 +3637,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrailing.htm"
     },
     "IfcRailingType": {
-        "description": "The element type (IfcRailingType) defines a list of commonly shared property set definitions of a railing element and an optional set of product representations. It is used to define a railing specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type (IfcRailingType) defines a list of commonly shared property set definitions of a railing element and an optional set of product representations. It is used to define a railing specification (i.e. the specific product information, that is common to all occurrences of that product type). A railing type is used to define the common properties of a certain type of railing that may be applied to many instances of that type to assign a specific style. Railing types may be exchanged without being already assigned to occurrences. The occurrences of the IfcRailingType are represented by instances of IfcRailing.",
         "predefined_types": {
             "BALUSTRADE": "Similar to the definitions of a guardrail except the location is at the edge of a floor, rather then a stair or ramp. Examples are balustrates at roof-tops or balconies.",
             "GUARDRAIL": "A type of railing designed to guard human occupants from falling off a stair, ramp or landing where there is a vertical drop at the edge of such floors/landings.",
@@ -3651,15 +3651,15 @@
         "attributes": {
             "ShapeType": "Predefined shape types for a ramp that are specified in an Enum."
         },
-        "description": "Definition from ISO 6707-1:1989: Inclined way or floor joining two surfaces at different levels.",
+        "description": "Definition from ISO 6707-1:1989: Inclined way or floor joining two surfaces at different levels. Definition of IAI: An vertical passageway which provides a human circulation link between one floor level and another floor level at a different elevation. It may include a landing as an intermediate floor slab. A ramp normally does not include steps (stepped ramps are out of scope for this IFC Release). The ramp is a container entity that aggregates all components of the ramp, it represents. The aggregation is handled via the IfcRelAggregates relationship, relating an IfcRamp with the related flights (IfcRampFlight) and landings (IfcSlab with type 'Landing'). *Property Set Use Definition*: The property sets relating to the IfcRamp are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcRamp are part of this IFC release: - Pset_RampCommon: common property set for all ramp occurrences *Geometry Use Definitions*: The geometric representation of IfcRamp is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Independent geometric representations should only be used when the IfcRamp is not defined as an aggregate. If defined as an aggregate, the geometric representation is the sum of the representation of the components within the aggregate. Local placement The local placement for IfcRamp is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. If the LocalPlacement is given for the IfcRamp, then all components, which are aggregated to the ramp should use this placement as their relative placement. Geometric Representations If the IfcRamp has components (referenced by SELF\\IfcProduct.IsDecomposedBy) then no independent geometric representation shall be defined for the IfcRamp. The IfcRamp is then geometrically represented by the geometric representation of its components. The components are accessed via SELF\\IfcProduct.IsDecomposedBy[1].RelatedObjects. If the IfcRamp has no components defined (empty set of SELF\\IfcProduct.IsDecomposedBy) then the IfcRamp may be represented by an IfcShapeRepresentation with the RepresentationType = 'Brep'. Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcramp.htm"
     },
     "IfcRampFlight": {
-        "description": "Inclined slab segment, normally providing a human circulation link between two landings, floors or slabs at different elevations.",
+        "description": "Inclined slab segment, normally providing a human circulation link between two landings, floors or slabs at different elevations. An IfcRampFlight is normally aggregated by a ramp (IfcRamp) through the IfcRelAggregates relationship, the ramp flight is then included in the set of IfcRelAggregates.RelatedObjects. A ramp flight normally connects the floor slab of zero to two different storeys (or partial storeys) within a building. The connection relationship between the IfcRampFlight and the IfcSlab is expressed using the IfcRelConnectsElements relationship. *Property Set Use Definition*: The property sets relating to the IfcRampFlight are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcRampFlight are part of this IFC release: - Pset_RampFlightCommon: common property set for all ramp flight occurrences *Geometry Use Definitions*: The geometric representation of IfcRampFlight is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local placement The local placement for IfcRampFlight is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level. - If the IfcRampFlight, however, is used by an IfcRamp, and this container class defines its own local placement, then the PlacementRelTo relationship of IfcLocalPlacement shall point to the local placement of the aggregate. Standard Geometric Representation The standard geometric representation of IfcRampFlight is defined using the swept area geometry. The following constraints apply to the standard representation: - Solid: IfcExtrudedAreaSolid is required, - Profile: IfcRectangleProfileDef shall be supported. - Extrusion: The profile shall be extruded in any direction relative to the XY plane of the position coordinate system of the IfcExtrudedAreaSolid. Therefore non-perpendicular sweep operation has to be supported. It might be further constrained to be in the direction of the global z-axis in implementers agreements.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrampflight.htm"
     },
     "IfcRampFlightType": {
-        "description": "The element type (IfcRampFlightType) defines a list of commonly shared property set definitions of a ramp flight and an optional set of product representations. It is used to define an ramp flight specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type (IfcRampFlightType) defines a list of commonly shared property set definitions of a ramp flight and an optional set of product representations. It is used to define an ramp flight specification (i.e. the specific product information, that is common to all occurrences of that product type). A ramp flight type is used to define the common properties of a certain type of a ramp flight that may be applied to many instances of that type to assign a specific style. Ramp flight types may be exchanged without being already assigned to occurrences. The occurrences of the IfcRampFlightType are represented by instances of IfcRampFlight.",
         "predefined_types": {
             "NOTDEFINED": "Undefined ramp flight.",
             "SPIRAL": "A ramp flight with a circular or elliptic walking line.",
@@ -3673,7 +3673,7 @@
             "Weights": "The array of weights associated with the control points. This is derived from the weights data. IfcListToArray(WeightsData,0,SELF\\IfcBSplineCurve.UpperIndexOnControlPoints)",
             "WeightsData": "The supplied values of the weights."
         },
-        "description": "A rational Bezier curve is a B-spline curve described in terms of control points and basic functions. It describes weights in addition to the control points defined at the supertype IfcBSplineCurve.",
+        "description": "A rational Bezier curve is a B-spline curve described in terms of control points and basic functions. It describes weights in addition to the control points defined at the supertype IfcBSplineCurve. All weights shall be positive and the curve is given by: where",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcrationalbeziercurve.htm"
     },
     "IfcRectangleHollowProfileDef": {
@@ -3682,7 +3682,7 @@
             "OuterFilletRadius": "Radius of the circular arcs, by which all four corners of the outer contour of rectangle are equally rounded. If not given, zero (= no rounding arcs) applies.",
             "WallThickness": "Thickness of the material."
         },
-        "description": "Definition from IAI: The IfcRectangleHollowProfileDef defines a section profile that provides the defining parameters of a rectangular (or square) hollow section to be used by the swept surface geometry or the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. A square hollow section can be defined by equal values for h and b. The centre of the position coordinate system is in the profiles centre of the bounding box (for symmetric profiles identical with the centre of gravity). Normally, the longer sides are parallel to the y-axis, the shorter sides parallel to the x-axis.",
+        "description": "Definition from IAI: The IfcRectangleHollowProfileDef defines a section profile that provides the defining parameters of a rectangular (or square) hollow section to be used by the swept surface geometry or the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. A square hollow section can be defined by equal values for h and b. The centre of the position coordinate system is in the profiles centre of the bounding box (for symmetric profiles identical with the centre of gravity). Normally, the longer sides are parallel to the y-axis, the shorter sides parallel to the x-axis. Illustration: Figure: Parameters of rectangular or square hollow profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcrectanglehollowprofiledef.htm"
     },
     "IfcRectangleProfileDef": {
@@ -3690,7 +3690,7 @@
             "XDim": "The extent of the rectangle in the direction of the x-axis.",
             "YDim": "The extent of the rectangle in the direction of the y-axis."
         },
-        "description": "Definition from IAI: The IfcRectangleProfileDef defines a rectangle as the profile definition used by the swept surface geometry or the swept area solid. It is given by its X extent and its Y extent, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system.",
+        "description": "Definition from IAI: The IfcRectangleProfileDef defines a rectangle as the profile definition used by the swept surface geometry or the swept area solid. It is given by its X extent and its Y extent, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system. Illustration: Table: Parameter of rectangle profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcrectangleprofiledef.htm"
     },
     "IfcRectangularPyramid": {
@@ -3699,7 +3699,7 @@
             "XLength": "The length of the base measured along the placement X axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[1]_.",
             "YLength": "The length of the base measured along the placement Y axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[2]_."
         },
-        "description": "Definition from ISO 10303-42:ed.2, 2000: A rectangular pyramid is a solid pyramid with a rectangular base. The apex of the pyramid is directly above the centre point of the base. The rectangular pyramid is specified by its position, which provides a placement coordinate system, its length, depth and height.",
+        "description": "Definition from ISO 10303-42:ed.2, 2000: A rectangular pyramid is a solid pyramid with a rectangular base. The apex of the pyramid is directly above the centre point of the base. The rectangular pyramid is specified by its position, which provides a placement coordinate system, its length, depth and height. The inherited Position attribute defines the IfcAxis2Placement3D and provides the location and orientation of the pyramid: - SELF\\IfcCsgPrimitive3D.Position: The position defines a placement coordinate system for the pyramid. - SELF\\IfcCsgPrimitive3D.Position.Location: The pyramid has one corner of its base at the location and the edges of the base are aligned with the first two placement axes in the positive sense.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcrectangularpyramid.htm"
     },
     "IfcRectangularTrimmedSurface": {
@@ -3713,7 +3713,7 @@
             "V2": "Second v parametric value.",
             "Vsense": "Flag to indicate whether the direction of the second parameter of the trimmed surface agrees with or opposes the sense of v in the basis surface."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: The trimmed surface is a simple bounded surface in which the boundaries are the constant parametric lines u~1~ = u1, u~2~ = u2, v~1~ = v1 and v~2~ = v2. All these values shall be within the parametric range of the referenced surface. Cyclic properties of the parameter range are assumed.",
+        "description": "Definition from ISO/CD 10303-42:1992: The trimmed surface is a simple bounded surface in which the boundaries are the constant parametric lines u~1~ = u1, u~2~ = u2, v~1~ = v1 and v~2~ = v2. All these values shall be within the parametric range of the referenced surface. Cyclic properties of the parameter range are assumed. The rectangular trimmed surface inherits its parameterization directly from the basis surface and has parameter ranges from 0 to |u~2~ - u~1~| and 0 to |v~2~-v~1~|. Informal propositions: - The domain of the trimmed surface shall be within the domain of the surface being trimmed.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcrectangulartrimmedsurface.htm"
     },
     "IfcReferencesValueDocument": {
@@ -3723,7 +3723,7 @@
             "ReferencedDocument": "A document such as a price list or quotation from which costs are obtained.",
             "ReferencingValues": "Costs obtained from a single document such as a price list or quotation."
         },
-        "description": "An IfcReferencesValueDocument is a means of referencing many instances of IfcAppliedValue to a single document where the document is a price list, quotation, list of environmental impact values or other source of information.",
+        "description": "An IfcReferencesValueDocument is a means of referencing many instances of IfcAppliedValue to a single document where the document is a price list, quotation, list of environmental impact values or other source of information. Use Definitions The purpose of this class is to be able to identify a reference source from which applied values are obtained. Since many objects may be obtain such values from the same referenced document, use of a relationship class allows the document to be identified once only when information is exchanged or shared rather than many times.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcreferencesvaluedocument.htm"
     },
     "IfcRegularTimeSeries": {
@@ -3743,7 +3743,7 @@
             "SteelGrade": "The nominal steel grade defined according to local standards.",
             "TotalCrossSectionArea": "The total effective cross-section area of the reinforcement of a specific steel grade."
         },
-        "description": "An IfcReinforcementProperties defines the set of properties for a specific combination of reinforcement bar steel grade, bar type and effective depth.",
+        "description": "An IfcReinforcementProperties defines the set of properties for a specific combination of reinforcement bar steel grade, bar type and effective depth. General usage: The total cross section area for the specific steel grade is always provided. Additionally also general reinforcing bar configurations as a count of bars may be provided as defined in attribute BarCount. In this case the nominal bar diameter should be identical for all given bars as defined in attribute NominalBarDiameter.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcreinforcementbarproperties.htm"
     },
     "IfcReinforcementDefinitionProperties": {
@@ -3751,7 +3751,7 @@
             "DefinitionType": "Descriptive type name applied to reinforcement definition properties.",
             "ReinforcementSectionDefinitions": "The list of section reinforcement properties attached to the reinforcement definition properties."
         },
-        "description": "An IfcReinforcementDefinitionProperties defines the cross section properties of reinforcement included in reinforced concrete building elements. The property set definition may be used both in conjunction with insitu and precast structures.",
+        "description": "An IfcReinforcementDefinitionProperties defines the cross section properties of reinforcement included in reinforced concrete building elements. The property set definition may be used both in conjunction with insitu and precast structures. General usage: This subtype of IfcPropertySetDefinition is used to define the reinforcement properties in early design stages, such as in requirement definition or scheme design. In later design stages explicit instances of subtypes of IfcReinforcingElement are used. The intended usage may be indicated using the DefinitionType attribute value as a designator: recommended values are 'Reinforcement area requirement' or 'Reinforcement configuration requirement'. Other values may be used according to local standards. Only one property set definition of this kind is used for each concrete building element in each intended usage indicated by the DefinitionType attribute value. This set then defines a list of cross section properties in a discrete number of longitudinal sections as instances of IfcSectionReinforcementProperties (one for each structural reinforcement bar role), which in turn have a section cross section property defined as a profile and a number of reinforcement properties, one for each steel grade / bar type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcreinforcementdefinitionproperties.htm"
     },
     "IfcReinforcingBar": {
@@ -3762,14 +3762,14 @@
             "CrossSectionArea": "The effective cross-section area of the reinforcing bar.",
             "NominalDiameter": "The nominal diameter defining the cross-section size of the reinforcing bar."
         },
-        "description": "A steel bar, usually with manufactured deformations in the surface, used in concrete and masonry construction to provide additional strength.",
+        "description": "A steel bar, usually with manufactured deformations in the surface, used in concrete and masonry construction to provide additional strength. *Property Set Use Definition*: The property sets relating to the IfcReinforcingBar are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcReinforcingBar are part of this IFC release: - Pset_ReinforcingBarBendingsBECCommon: common property set for all IfcReinforcingBar occurrences for bending information according to the Finnish BEC-standard. - Pset_ReinforcingBarBendingsBS8666Common: common property set for all IfcReinforcingBar occurrences for bending information according to the BS8666 standard. - Pset_ReinforcingBarBendingsDIN135610Common: common property set for all IfcReinforcingBar occurrences for bending information according to the DIN 1356-10 standard. - Pset_ReinforcingBarBendingsISOCD3766Common: common property set for all IfcReinforcingBar occurrences for bending information according to the ISO CD 3766 standard. Geometry Use Definitions: The geometric representation of IfcReinforcingBar is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcBuildingElementComponent. Standard Geometric Representation using Swept Solid Representation The standard geometric representation of IfcReinforcingBar is defined using the swept solid representation. The RepresentationType attribute of IfcShapeRepresentation should have the value 'SweptSolid'. The solid is formed from a cross section approximated as a circular disk swept along any arbitrary curve. Given this, the following constraints apply to the standard representation: - Solid: IfcSweptDiskSolid introduced in IFC Release 2x2 shall be supported. - Profile: The circular disk cross section approximation is defined by the Radius attribute of IfcSweptDiskSolid. - Extrusion: The extrusion along any arbitrary curve is defined by the Directrix attribute of IfcSweptDiskSolid. Simplified Geometric Representation Simplified geometric representations may be used based on local agreements.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcreinforcingbar.htm"
     },
     "IfcReinforcingElement": {
         "attributes": {
             "SteelGrade": "The nominal steel grade defined according to local standards."
         },
-        "description": "Bars, wires, strands, and other slender members embedded in concrete in such a manner that the reinforcement and the concrete act together in resisting forces.",
+        "description": "Bars, wires, strands, and other slender members embedded in concrete in such a manner that the reinforcement and the concrete act together in resisting forces. Geometry Use Definitions: The geometric representation of IfcReinforcingElement is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcBuildingElementComponent. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcBuildingElementComponent. Further constraints on the geometric representation may be defined in subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcreinforcingelement.htm"
     },
     "IfcReinforcingMesh": {
@@ -3783,11 +3783,11 @@
             "TransverseBarNominalDiameter": "The nominal diameter denoting the cross-section size of the transverse bars.",
             "TransverseBarSpacing": "The spacing between the transverse bars. Note: an even distribution of bars is presumed; other cases are handled by Psets."
         },
-        "description": "A series of longitudinal and transverse wires or bars of various gauges, arranged at right angles to each other and welded at all points of intersection; usually used for concrete slab reinforcement. Also known as welded wire fabric.",
+        "description": "A series of longitudinal and transverse wires or bars of various gauges, arranged at right angles to each other and welded at all points of intersection; usually used for concrete slab reinforcement. Also known as welded wire fabric. *Property Set Use Definition*: The property sets relating to the IfcReinforcingMesh are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcReinforcingMesh are part of this IFC release: - Pset_ReinforcingBarBendingsBECCommon: common property set for all IfcReinforcingMesh occurrences for bending information according to the Finnish BEC-standard. Geometry Use Definitions: The geometric representation of IfcReinforcinMesh is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined in the supertype IfcBuildingElementComponent. Standard Geometric Representation The use of Standard Geometric Representations is defined in the supertype IfcBuildingElementComponent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcreinforcingmesh.htm"
     },
     "IfcRelAggregates": {
-        "description": "The aggregation relationship IfcRelAggregates is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The aggregation relationship can be applied to all subtypes of object.",
+        "description": "The aggregation relationship IfcRelAggregates is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The aggregation relationship can be applied to all subtypes of object. Some further specializations of decomposition may imply additional constraints and meanings, such as the requirement of aggregates to represent physical containment. In cases of physical containment the representation (within the same representation context) of the whole can be taken from the sum of the representations of the parts. Decompositions imply a dependency, i.e. the definition of the whole depends on the definition of the parts and the parts depend on the existence of the whole. The behavior that is implied from the dependency has to be established inside the applications.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelaggregates.htm"
     },
     "IfcRelAssigns": {
@@ -3795,14 +3795,14 @@
             "RelatedObjects": "Related objects, which are assigned to a single object. The type of the single (or relating) object is defined in the subtypes of IfcRelAssigns.",
             "RelatedObjectsType": "Particular type of the assignment relationship. It can constrain the applicable object types, used within the role of RelatedObjects."
         },
-        "description": "The assignment relationship, IfcRelAssigns, is a generalization of \"link\" relationships among instances of IfcObject and its various 1^st^ level subtypes. A link denotes the specific association through which one object (the client) applies the services of other objects (the suppliers), or through which one object may navigate to other objects.",
+        "description": "The assignment relationship, IfcRelAssigns, is a generalization of \"link\" relationships among instances of IfcObject and its various 1^st^ level subtypes. A link denotes the specific association through which one object (the client) applies the services of other objects (the suppliers), or through which one object may navigate to other objects. The client is denoted as the relating object and is established at the level of the specific, instantiable subtypes of IfcRelAssigns. The suppliers are denoted as the related objects and they are established by the RelatedObjects attribute. The assignment relationship establishs a bi-directional relationship among the participating objects and does not imply any dependency. The subtypes of IfcRelAssigns establishes the particular semantic meaning of the assignment relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassigns.htm"
     },
     "IfcRelAssignsTasks": {
         "attributes": {
             "TimeForTask": "Contained object for the time related information for the work schedule element."
         },
-        "description": "An IfcRelAssignsTasks is a relationship class that assigns an IfcTask to an IfcWorkControl. The assignment is further qualified by attaching an IfcScheduleTimeControl to the assignment to give the time constraints of the work task, when assigned to a work plan or schedule.",
+        "description": "An IfcRelAssignsTasks is a relationship class that assigns an IfcTask to an IfcWorkControl. The assignment is further qualified by attaching an IfcScheduleTimeControl to the assignment to give the time constraints of the work task, when assigned to a work plan or schedule. Use Definitions The inherited attributes have the following meaning: - SELF\\IfcRelAssigns.RelatedObjects - is the reference to the related IfcTask, which is assigned to the work control. The task gets the time information from the reference to the IfcScheduleTimeControl. - SELF\\IfcRelAssignsToControl.RelatingControl - is the reference to the relating IfcWorkControl (either a work plan or a work schedule) which gets a task assigned. Each task in a work schedule may have a set of associated time criteria that define information about when the task should be completed. This time information is separated from the the actual work task into the IfcScheduleTimeControl class. Where the work schedule requires that the task and the time control are brought together, this is achieved through the use of the IfcRelAssignsTask class.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcrelassignstasks.htm"
     },
     "IfcRelAssignsToActor": {
@@ -3810,7 +3810,7 @@
             "ActingRole": "Role of the actor played within the context of the assignment to the object(s).",
             "RelatingActor": "Reference to the information about the actor. It comprises the information about the person or organization and its addresses."
         },
-        "description": "This objectified relationship (IfcRelAssignsToActor) handles the assignment of objects (subtypes of IfcObject) to an actor (subtypes of IfcActor).",
+        "description": "This objectified relationship (IfcRelAssignsToActor) handles the assignment of objects (subtypes of IfcObject) to an actor (subtypes of IfcActor). The IfcRelAssignsToActor objectified relationship defines a relationship between an IfcActor and one or many objects. An particular role of the actor played in that relationship can be associated. If specified, it takes priority over the role that may be directly assigned to the person or organization. Reference to the objects (or single object) on which the actor acts upon in a certain role (if given) is specified in the inherited RelatedObjects attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstoactor.htm"
     },
     "IfcRelAssignsToControl": {
@@ -3824,7 +3824,7 @@
         "attributes": {
             "RelatingGroup": "Reference to group that finally contains all assigned group members."
         },
-        "description": "This objectified relationship (IfcRelAssignsToGroup) handles the assignment of objects (subtypes of IfcObject) to a group (subtypes of IfcGroup).",
+        "description": "This objectified relationship (IfcRelAssignsToGroup) handles the assignment of objects (subtypes of IfcObject) to a group (subtypes of IfcGroup). The relationship handles the assignment of group members to the group object. It allows for grouping arbitrary objects within a group, including other groups. The grouping relationship can be applied in a recursive manner. The resulting group is of type IfcGroup. The Purpose attribute defined at the supertype IfcReleationship, may assign a descriptor, that defines the purpose of the group. The inherited attribute RelatedObjects gives the references to the objects, which are the elements within the group. The RelatingGroup is the group, that comprises all elements. Informal proposition: - The group assignment relationship shall be a-cyclic, i.e. a group should not participate in its own grouping relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstogroup.htm"
     },
     "IfcRelAssignsToProcess": {
@@ -3832,18 +3832,18 @@
             "QuantityInProcess": "Quantity of the object specific for the operation by this process.",
             "RelatingProcess": "Reference to the process to which the objects are assigned to."
         },
-        "description": "This objectified relationship (IfcRelAssignsToProcess) handles the assignment of an object as an item the process operates on. Process is related to the product that it operate on (normally as input or output) through this relationship. Processes can operate on things other than products, and can operate in ways other than input and output.",
+        "description": "This objectified relationship (IfcRelAssignsToProcess) handles the assignment of an object as an item the process operates on. Process is related to the product that it operate on (normally as input or output) through this relationship. Processes can operate on things other than products, and can operate in ways other than input and output. The inherited attribute RelatedObjects gives the references to the objects, which the process operates on. The RelatingProcess is the process, that operates on the object. The operation types are captured in the inherited attribute Name.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstoprocess.htm"
     },
     "IfcRelAssignsToProduct": {
         "attributes": {
             "RelatingProduct": "Reference to the Product to which the objects are assigned to."
         },
-        "description": "This objectified relationship IfcRelAssignsToProduct handles the assignment of objects (subtypes of IfcObject) to a product (subtypes of IfcProduct).",
+        "description": "This objectified relationship IfcRelAssignsToProduct handles the assignment of objects (subtypes of IfcObject) to a product (subtypes of IfcProduct). The Name attribute should be used to classify the usage of the IfcRelAssignsToProduct objectified relationship. The following Name values are proposed: - 'Reference' : Assignment of a product (via RelatingProduct) to a spatial structure (via RelatedObjects) to which it is referenced (in contrary to being contained - which is handled by IfcRelContainedInSpatialStructure). - 'Context' : Assignment of a context specific representation, such as of structural members to a different context representation (with potentially different decomposition breakdown) such as of building elements for a specific context specific representation. - 'View' : Assignment of a product (via RelatingProduct) that is decomposed according to a discipline view, to another product (via RelatedObjects) that is decomposed according to a different discipline view. An example is the assignment of the architectural slab to a different decomposition of the pre manufactured sections of a slab (under a precast concrete discipline view).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstoproduct.htm"
     },
     "IfcRelAssignsToProjectOrder": {
-        "description": "An IfcRelAssignsToProjectOrder is a relationship class that captures the incidence of a project order for a set of objects and whose occurrences can be recorded within a project record in sequence as a series of events.",
+        "description": "An IfcRelAssignsToProjectOrder is a relationship class that captures the incidence of a project order for a set of objects and whose occurrences can be recorded within a project record in sequence as a series of events. IfcRelAssignsToProjectOrder is a subtype of IfcRelAssignsToControl. It acts so as to assign items to a project order. The instance of IfcProjectOrder acts as the relating control (which is inherited from IfcRelAssignsToControl). Specific objects may be assigned to the project order via the inherited IfcRelAssignsToControl.RelatedObjects attribute. Examples are a cost schedule (IfcCostSchedule), a work plan (IfcWorkPlan), actors concerned with the project order (IfcActor) etc. It may also be relevant to assign physical components to the order to identify that this is the originating order for such objects. This can be particularly relevant in the operating phase of the facility lifecycle where the Facilities Manager may wish to obtain details about the original purchase of components. It is more efficient to achieve this through assigning the objects to the project order through IfcRelAssignsToProjectOrder rather than assigning the project order to each object through multiple instances of IfcRelAssignsToProduct.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcrelassignstoprojectorder.htm"
     },
     "IfcRelAssignsToResource": {
@@ -3857,14 +3857,14 @@
         "attributes": {
             "RelatedObjects": "Objects or Types, to which the external references or information is associated."
         },
-        "description": "The association relationship (IfcRelAssociates) refer to external sources of information (most notably a classification, library or document). There is no dependency implied by the association.",
+        "description": "The association relationship (IfcRelAssociates) refer to external sources of information (most notably a classification, library or document). There is no dependency implied by the association. Association relationships can the established to objects (occurrences) or to types (both object types, IfcTypeObject, or partial types, IfcPropertySetDefinition). The association relationship establishs a uni-directional association. The subtypes of IfcRelAssociates establishes the particular semantic meaning of the association relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassociates.htm"
     },
     "IfcRelAssociatesAppliedValue": {
         "attributes": {
             "RelatingAppliedValue": ""
         },
-        "description": "An IfcRelAssociatesAppliedValue is a subtype of IfcRelAssociates that enables the association of an instance of IfcAppliedValue with one or more instances of IfcObject.",
+        "description": "An IfcRelAssociatesAppliedValue is a subtype of IfcRelAssociates that enables the association of an instance of IfcAppliedValue with one or more instances of IfcObject. Because IfcRelAssociatesAppliedValue is a subtype of IfcRelAssociates, this means that a single instance of IfcCostValue or IfcEnvironmentalImpactValue can be related to many objects of whatever type (product, process, resource etc.) Note that IfcRelAssociatesAppliedValue, when used for costing purposes, should be used only for relating specific cost values to objects and not for relating cost schedule items to cost schedule (for which purpose IfcRelSchedulesCostItems should be used).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcrelassociatesappliedvalue.htm"
     },
     "IfcRelAssociatesApproval": {
@@ -3878,7 +3878,7 @@
         "attributes": {
             "RelatingClassification": "Classification applied to the objects."
         },
-        "description": "This objectified relationship (IfcRelAssociatesClassification) handles the assignment of a classification object (items of the select IfcClassificationSelect) to objects (subtypes of IfcObject).",
+        "description": "This objectified relationship (IfcRelAssociatesClassification) handles the assignment of a classification object (items of the select IfcClassificationSelect) to objects (subtypes of IfcObject). The relationship is used to assign a classification notation or a classification reference to objects. A single notation can be applied to multiple objects. Depending on the type of the RelatingClassification, either a reference to a fully described classification system can be made, or just a reference using the classification code. The inherited attribute RelatedObjects define the objects to which the classification is applied. The attribute RelatingClassification is the reference to a classification, applied to the object(s).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassociatesclassification.htm"
     },
     "IfcRelAssociatesConstraint": {
@@ -3893,21 +3893,21 @@
         "attributes": {
             "RelatingDocument": "Document information or reference which is applied to the objects."
         },
-        "description": "This objectified relationship (IfcRelAssociatesDocument) handles the assignment of a document information (items of the select IfcDocumentSelect) to objects (subtypes of IfcObject).",
+        "description": "This objectified relationship (IfcRelAssociatesDocument) handles the assignment of a document information (items of the select IfcDocumentSelect) to objects (subtypes of IfcObject). The relationship is used to assign a document reference or a more detailed document information to objects. A single document reference can be applied to multiple objects. The inherited attribute RelatedObjects define the objects to which the document association is applied. The attribute RelatingDocument is the reference to a document reference, applied to the object(s).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassociatesdocument.htm"
     },
     "IfcRelAssociatesLibrary": {
         "attributes": {
             "RelatingLibrary": "Reference to a library, from which the definition of the property set is taken."
         },
-        "description": "This objectified relationship (IfcRelAssociatesLibrary) handles the assignment of a library item (items of the select IfcLibrarySelect) to objects (subtypes of IfcObject).",
+        "description": "This objectified relationship (IfcRelAssociatesLibrary) handles the assignment of a library item (items of the select IfcLibrarySelect) to objects (subtypes of IfcObject). The relationship is used to assign a library reference or a more detailed link to a library information to objects, property sets or types. A single library reference can be applied to multiple items. The inherited attribute RelatedObjects define the items to which the library association is applied. The attribute RelatingLibrary is the reference to a library reference, applied to the item(s).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassociateslibrary.htm"
     },
     "IfcRelAssociatesMaterial": {
         "attributes": {
             "RelatingMaterial": "Material definition (either a single material, a list of materials, or a set of material layers) assigned to the elements."
         },
-        "description": "Objectified relationship between a material definition and elements or element types to which this material definition applies. The material definition can be:",
+        "description": "Objectified relationship between a material definition and elements or element types to which this material definition applies. The material definition can be: - A single material - A material list, e.g. for composite elements - A material layer set, for layered elements with an indication of the layering direction and individual layer thicknesses - A material layer set usage, i.e. a material layer set with positioning information along the reference axis or surface of the element. The IfcRelAssociatesMaterial relationship is a special type of the IfcRelAssociates relationship. It can be applied to subtypes of IfcElement and subtypes of IfcElementType. - The IfcElement has an inverse relation to its material definition by the HasAssociations attribute, inherited from IfcObject. - The IfcElementType has an inverse relation to its material definition by the HasAssociations attribute, inherited from IfcPropertyDefinition. If both, the element occurrence (by an instance of IfcElement) and the element type (by an instance of IfcElementType, connected through IfcRelDefinesByType) have an associated material, then the material associated to the element occurrence overrides the material associated to the element type. Informal proposition - An IfcMaterialLayerSetUsage shall not be associated with a subtype of IfcElementType, it should only be associated with individual occurrences",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelassociatesmaterial.htm"
     },
     "IfcRelAssociatesProfileProperties": {
@@ -3916,7 +3916,7 @@
             "ProfileSectionLocation": "Reference to a shape aspect with a single member of the ShapeRepresentations list. This member holds the location at which the profile properties apply.",
             "RelatingProfileProperties": "Profile property definition assigned to the instances."
         },
-        "description": "Definition from IAI: The IfcRelAssociatesProfileProperties is an objectified relationship between non geometric profile properties (subtypes of IfcProfileProperties) and elements to which these properties apply, e.g. building elements and building element types as used within the structural engineering domain for steel, timber or concrete structures.",
+        "description": "Definition from IAI: The IfcRelAssociatesProfileProperties is an objectified relationship between non geometric profile properties (subtypes of IfcProfileProperties) and elements to which these properties apply, e.g. building elements and building element types as used within the structural engineering domain for steel, timber or concrete structures. If the ProfileSectionLocation attribute is given, it points to a shape aspect of the geometric or topological representation of the structural member. This allows the assignment of several profile properties (by many instances of IfcRelAssociatesProfileProperties) to accommodate varying profiles and members with different profile sections. If the ProfileOrientation attribute is given, it provides an orientation of the profile. - For IfcStructuralCurveMember it is a rotation about the longitudinal axis of the underlying curve, the x axis is determined by a line from the start vertex to the end vertex. If the longitudinal axis is not parallel to the structural z axis of the structural coordinate system of the analysis model, i.e. the curve member is a beam (or non-vertical member), the ProfileOrientation defaults to [0.,0.,1.] (if the z axis is not orthogonal to the x axis, an adjustment is made to maintain orthogonality, see function IfcBuildAxes for an algorithm). The \u03b2 angle is then measured from the structural z axis to determine the location of the structural z axis of the profile. If the longitudinal axis is parallel to the structural z axis of the structural coordinate system of the analysis model, i.e. the curve member is a column, the ProfileOrientation defaults to [1.,0.,0.]. The \u03b2 angle is then measured from the structural x axis to determine the location of the structural z axis of the profile. - If the ProfileOrientation attribute is given as an IfcDirection, it would default to: For 'beams' as [0., sin\u03b2, cos\u03b2 ] For 'columns' as [cos\u03b2, -sin\u03b2, 0.]",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcrelassociatesprofileproperties.htm"
     },
     "IfcRelConnects": {
@@ -3929,7 +3929,7 @@
             "RelatedElement": "Reference to an Element that is connected by the objectified relationship.",
             "RelatingElement": "Reference to an Element that is connected by the objectified relationship."
         },
-        "description": "The IfcRelConnectsElements objectified relationship provides the generalization of the connectivity between elements. It is a 1 to 1 relationship. The concept of two elements being physically or logically connected is described independently from the connecting elements. The connectivity may be related to the shape representation of the connected entities by providing a connection geometry.",
+        "description": "The IfcRelConnectsElements objectified relationship provides the generalization of the connectivity between elements. It is a 1 to 1 relationship. The concept of two elements being physically or logically connected is described independently from the connecting elements. The connectivity may be related to the shape representation of the connected entities by providing a connection geometry. - In this case the geometrical constraints of the connection are provided by the optional relationship to the IfcConnectionGeometry. The connection geometry is provided as a point, curve or surface within the local placement coordinate systems of the connecting elements. - If the connection geometry is omitted then the connection is provided as a logical connection. Under this circumstance, the connection point, curve or surface has to be recalculated by the receiving application.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelconnectselements.htm"
     },
     "IfcRelConnectsPathElements": {
@@ -3939,7 +3939,7 @@
             "RelatingConnectionType": "Indication of the connection type in relation to the path of the RelatingObject.",
             "RelatingPriorities": "Priorities for connection. It refers to the layers of the RelatingObject."
         },
-        "description": "The IfcRelConnectsPathElements relationship provides the connectivity information between two elements, which have a path information. Currently it is applied to IfcWall and IfcWallStandardCase.",
+        "description": "The IfcRelConnectsPathElements relationship provides the connectivity information between two elements, which have a path information. Currently it is applied to IfcWall and IfcWallStandardCase. The objectified relationship provides all additional information required to describe the connection between two path based elements that might have single or multiple layers of material. The connection type specifies where at the path based element a connection is given (at the start, in the middle or at the end). Illustration: The following figure shows the application of IfcRelConnectsPathElements with the ConnectionGeometry of type IfcConnectionCurveGeometry.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrelconnectspathelements.htm"
     },
     "IfcRelConnectsPortToElement": {
@@ -3947,7 +3947,7 @@
             "RelatedElement": "Reference to an Element that is connected by the objectified relationship.",
             "RelatingPort": "Reference to an Port that is connected by the objectified relationship."
         },
-        "description": "An IfcRelConnectsPortToElement defines the relationship that is made between a port and the IfcElement in which it is contained. It is a 1 to 1 relationship.",
+        "description": "An IfcRelConnectsPortToElement defines the relationship that is made between a port and the IfcElement in which it is contained. It is a 1 to 1 relationship. Ports contained in different elements are connected to each other using the IfcRelConnectsPorts relationship. Using both relationships, a topological system can be defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelconnectsporttoelement.htm"
     },
     "IfcRelConnectsPorts": {
@@ -3956,7 +3956,7 @@
             "RelatedPort": "Reference to the second port that is connected by the objectified relationship.",
             "RelatingPort": "Reference to the first port that is connected by the objectified relationship."
         },
-        "description": "An IfcRelConnectsPorts defines the relationship that is made between two ports at their point of connection. It may include the connection geometry between two ports.",
+        "description": "An IfcRelConnectsPorts defines the relationship that is made between two ports at their point of connection. It may include the connection geometry between two ports. IfcRelConnectsPorts is required for defining how instances of IfcPort connect together. Each of the port is being logically attached to the IfcElement by using the IfcRelConnectsPortToElement relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelconnectsports.htm"
     },
     "IfcRelConnectsStructuralActivity": {
@@ -3972,7 +3972,7 @@
             "RelatedStructuralMember": "The structural member that is associated with the element of which it represents the analytical idealization.",
             "RelatingElement": "The physical element, representing a design or detailing part, that is connected to the structural member as its (partial) analytical  idealization."
         },
-        "description": "The one-to-one relationship assigns a structural member (as instance of IfcStructuralMember or its subclasses) to a physical element  (as instance of IfcElement or its subclasses) to keep the association between the design or detailing element and the structural analysis element. ",
+        "description": "The one-to-one relationship assigns a structural member (as instance of IfcStructuralMember or its subclasses) to a physical element (as instance of IfcElement or its subclasses) to keep the association between the design or detailing element and the structural analysis element. Both, the IfcElement and the IfcStructuralMember, may involve any number (zero, one, or many) associations between physical and analytical element. Multiple instances of IfcRelConnectsStructuralElement can therefore be used to reflect the many-to-many nature of the association between physical and analytical elements.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcrelconnectsstructuralelement.htm"
     },
     "IfcRelConnectsStructuralMember": {
@@ -3984,14 +3984,14 @@
             "RelatingStructuralMember": "Reference to an instance of IfcStructuralMember (or its subclasses) which is connected to the specified structural connection.",
             "SupportedLength": "Defines the 'supported length' of this structural connection. See Fig. for more detail."
         },
-        "description": "The entity IfcRelConnectsStructuralMember defines all needed properties describing the connection between structural members and structural connections (nodes or supports).",
+        "description": "The entity IfcRelConnectsStructuralMember defines all needed properties describing the connection between structural members and structural connections (nodes or supports). Use Definition Point Connection Instances of the entity IfcRelConnectsStructuralMember shall be used to describe a connection between an instance of IfcStructuralPointConnection and either an instance of IfcStructuralCurveMember or IfcStructuralSurfaceMember. The RelatedStructuralConnection for point connections has to be of type = 'IfcStructuralPointConnection'. Curve Connection Instances of the entity IfcRelConnectsStructuralMember shall be used to describe a connection between an instance of IfcStructuralCurveConnection and an instance of either IfcStructuralCurveMember or IfcStructuralSurfaceMember. The RelatedStructuralConnection for curve connections has to be of type = 'IfcStructuralCurveConnection'. Surface Connection Instances of the entity IfcRelConnectsStructuralMember shall be used to describe a connection between an instance of IfcStructuralSurfaceConnection and an instance of IfcStructuralSurfaceMember (or an instance of a volumetric member, if defined in future extensions). The RelatedStructuralConnection for curve connections has to be of type = 'IfcStructuralSurfaceConnection'. Coordinate System for Applied Conditions All values defined by AppliedCondition or AdditionalConditions are given within the coordinate system provided by ConditionCoordinateSystem, which is defined in relation to the local coordinate system of the structural member. If the ConditionCoordinateSystem is not defined, the local placement of the structural member is used instead. Supported Length Optionally a supported length can be given, which gives the length (or width) of the physical connection along a curve connection.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcrelconnectsstructuralmember.htm"
     },
     "IfcRelConnectsWithEccentricity": {
         "attributes": {
             "ConnectionConstraint": "The connection constraint explicitly states the eccentricity between a structural element and a structural connection, either given by two point (used to calculate the eccentricity), or by explicit x, y, and z offsets."
         },
-        "description": "The entity IfcRelConnectsWithEccentricity adds the definition of eccentricity to the connection between a structural member and a structural connection (representing either a node or support). ",
+        "description": "The entity IfcRelConnectsWithEccentricity adds the definition of eccentricity to the connection between a structural member and a structural connection (representing either a node or support). Use Definition Point Connection Instances of the entity IfcRelConnectsWithEccentricity_shall be used to describe a connection with eccentricity between an instance of _IfcStructuralPointConnection and an instance of IfcStructuralCurveMember or IfcStructuralSurfaceMember. The RelatedStructuralConnection for point connections therefore has to be of type'IfcStructuralPointConnection'. The eccentricity is defined by a connection constraint being of type 'IfcConnectionPointGeometry', or by its subtype 'IfcConnectionPointEccentricity'. It refers to the IfcVertexPoint, used by the IfcStructuralCurveMember, or IfcStructuralSurfaceMember, that is used in this connection, and optionally to the IfcVertexPoint, used by the IfcStructuralPointConnection. In addition the eccentricity can be given by x, y, and z distance values.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcrelconnectswitheccentricity.htm"
     },
     "IfcRelConnectsWithRealizingElements": {
@@ -3999,7 +3999,7 @@
             "ConnectionType": "The type of the connection given for informal purposes, it may include labels, like 'joint', 'rigid joint', 'flexible joint', etc.",
             "RealizingElements": "Defines the elements that realize a connection relationship."
         },
-        "description": "IfcRelConnectsWithRealizingElements defines a generic relationship that is made between two elements that require the realization of that relationship by means of further realizing elements.",
+        "description": "IfcRelConnectsWithRealizingElements defines a generic relationship that is made between two elements that require the realization of that relationship by means of further realizing elements. An IfcRelConnectsWithRealizingElements is a specialization of IfcRelConnectsElement where the connecting operation has the additional attribute of (one or many) realizing elements that may be used to realize or further qualify the relationship. It is defined as a ternary relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelconnectswithrealizingelements.htm"
     },
     "IfcRelContainedInSpatialStructure": {
@@ -4007,7 +4007,7 @@
             "RelatedElements": "Set of ~~elements~~ products, which are contained within this level of the spatial structure hierarchy.",
             "RelatingStructure": "Spatial structure element, within which the element is contained. Any element can only be contained within one element of the project spatial structure."
         },
-        "description": "This objectified relationship, IfcRelContainedInSpatialStructure, is used to assign elements to a certain level of the spatial project structure. Any element can only be assigned once to a certain level of the spatial structure. The question, which level is relevant for which type of element, can only be answered within the context of a particular project and might vary within the various regions.",
+        "description": "This objectified relationship, IfcRelContainedInSpatialStructure, is used to assign elements to a certain level of the spatial project structure. Any element can only be assigned once to a certain level of the spatial structure. The question, which level is relevant for which type of element, can only be answered within the context of a particular project and might vary within the various regions. The containment relationship of an element within a spatial structure has to be a hierarchical relationship, an element can only be contained within a single spatial structure element. The reference relationship between an element and the spatial structure may not be hierarchical, i.e. an element can reference many spatial structure elements. Predefined spatial structure elements to which elements can be assigned are - site as IfcSite - building as IfcBuilding - storey as IfcBuildingStorey - space as IfcSpace Occurrences of the same element type can be assigned to different spatial structure elements depending on the context of the occurrence. *Containment Use Definition*:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelcontainedinspatialstructure.htm"
     },
     "IfcRelCoversBldgElements": {
@@ -4015,7 +4015,7 @@
             "RelatedCoverings": "Relationship to the set of coverings at this element.",
             "RelatingBuildingElement": "Relationship to the element that is covered."
         },
-        "description": "The IfcRelCoversBldgElements is an objectified relationship between an element and one to many coverings, which cover the building element.",
+        "description": "The IfcRelCoversBldgElements is an objectified relationship between an element and one to many coverings, which cover the building element. Coverings may be defined primarily as coverings of elements, like an isolation covers a pipe, or as coverings of spaces, as a cladding is often referred to as a space finish. - IfcRelCoversBldgElements, this relationship, expresses the primary relation to the element, - IfcRelCoversSpaces expresses the primary relation to the space.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelcoversbldgelements.htm"
     },
     "IfcRelCoversSpaces": {
@@ -4023,7 +4023,7 @@
             "RelatedCoverings": "Relationship to the set of coverings covering this space.",
             "RelatedSpace": "Relationship to the space object that is covered."
         },
-        "description": "The objectified relationship, IfcRelCoversSpace, relates a space object to one or many coverings, which faces (or is assigned to) the space.",
+        "description": "The objectified relationship, IfcRelCoversSpace, relates a space object to one or many coverings, which faces (or is assigned to) the space. The IFC specification provides two relationships: - IfcRelCoversBldgElements to assign coverings to elements, and - IfcRelCoversSpaces to assign coverings to spaces Which relationship should be applied has to be determined by the context of the project or application .",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelcoversspaces.htm"
     },
     "IfcRelDecomposes": {
@@ -4031,28 +4031,28 @@
             "RelatedObjects": "The objects being nested or aggregated.",
             "RelatingObject": "The object that represents the nest or aggregation."
         },
-        "description": "The decomposition relationship, IfcRelDecomposes, defines the general concept of elements being composed or decomposed. The decomposition relationship denotes a whole/part hierarchy with the ability to navigate from the whole (the composition) to the parts and vice versa.",
+        "description": "The decomposition relationship, IfcRelDecomposes, defines the general concept of elements being composed or decomposed. The decomposition relationship denotes a whole/part hierarchy with the ability to navigate from the whole (the composition) to the parts and vice versa. Decompositions may be constraint by requiring both, the whole and its parts, to be of the same type - thus establishing a nesting relationship. Or they may require some form of physical containment, thus establishing special types of aggregation relationships. Decompositions imply a dependency, i.e. the definition of the whole depends on the definition of the parts and the parts depend on the existence of the whole. The decomposition relationship can be applied in a recursive manner, i.e. a decomposed element can be part in another decomposition. Cyclic references have to be prevented at application level.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreldecomposes.htm"
     },
     "IfcRelDefines": {
         "attributes": {
             "RelatedObjects": "Reference to the objects (or single object) to which the property definition applies."
         },
-        "description": "A definition relationship (IfcRelDefines) that uses a type definition or property set definition (seens as partial type information) to define the properties of the object instance. It is a specific - occurrence relationship with implied dependencies (as the occurrence properties depend on the specific properties).",
+        "description": "A definition relationship (IfcRelDefines) that uses a type definition or property set definition (seens as partial type information) to define the properties of the object instance. It is a specific - occurrence relationship with implied dependencies (as the occurrence properties depend on the specific properties). The IfcRelDefines relationship establishes the link between one type (specific) information and several objects (occurrences). Those occurrences then share the same type (or partial type) information.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreldefines.htm"
     },
     "IfcRelDefinesByProperties": {
         "attributes": {
             "RelatingPropertyDefinition": "Reference to the property set definition for that object or set of objects."
         },
-        "description": "This objectified relationship (IfcRelDefinesByProperties) defines the relationships between property set definitions and objects. Properties are aggregated in property sets, property sets can be grouped to define an object type.",
+        "description": "This objectified relationship (IfcRelDefinesByProperties) defines the relationships between property set definitions and objects. Properties are aggregated in property sets, property sets can be grouped to define an object type. The IfcRelDefinesByProperties is a 1-to-N relationship, as it allows for the assignment of one property set to a single or to many objects. Those objects then share the same property definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreldefinesbyproperties.htm"
     },
     "IfcRelDefinesByType": {
         "attributes": {
             "RelatingType": "Reference to the type (or style) information for that object or set of objects."
         },
-        "description": "This objectified relationship (IfcRelDefinesByType) defines the relationships between an object type and objects.",
+        "description": "This objectified relationship (IfcRelDefinesByType) defines the relationships between an object type and objects. The IfcRelDefinesByType is a 1-to-N relationship, as it allows for the assignment of one type information to a single or to many objects. Those objects then share the same object type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreldefinesbytype.htm"
     },
     "IfcRelFillsElement": {
@@ -4079,11 +4079,11 @@
             "RelatedSpaceProgram": "Related space program for the interaction requirement.",
             "RelatingSpaceProgram": "Relating space program for the interaction requirement."
         },
-        "description": "The interaction requirement (IfcRelInteractionRequirements) is provided as a relationship that defines the requirements for the interaction (adjacency) of two spaces in the architectural program.",
+        "description": "The interaction requirement (IfcRelInteractionRequirements) is provided as a relationship that defines the requirements for the interaction (adjacency) of two spaces in the architectural program. In addition the relationship can define the interaction between two parties, such as persons, departments, organizations, that are associated to the space programs (interaction relations between workstations, workstation groups, floor blocks, or spaces, are defined through their associated space programs). The interaction requirement is encoded as an normalised ratio measure between 0 and 1.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcarchitecturedomain/lexical/ifcrelinteractionrequirements.htm"
     },
     "IfcRelNests": {
-        "description": "The nesting relationship IfcRelNests is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The nesting relationship can be applied to all subtypes of object, however it requires both the whole and the part to be of the same object type.",
+        "description": "The nesting relationship IfcRelNests is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The nesting relationship can be applied to all subtypes of object, however it requires both the whole and the part to be of the same object type. Decompositions imply a dependency, i.e. the definition of the whole depends on the definition of the parts and the parts depend on the existence of the whole. The behavior that is implied from the dependency has to be established inside the applications.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelnests.htm"
     },
     "IfcRelOccupiesSpaces": {
@@ -4094,7 +4094,7 @@
         "attributes": {
             "OverridingProperties": "A property set, which contains those properties, that have a different value for the subset of objects."
         },
-        "description": "The objectified relationship (IfcRelOverridesProperties) defines the relationships between objects and a standard property set. It also defines a set of properties, which values override the standard values given within the standard property set.",
+        "description": "The objectified relationship (IfcRelOverridesProperties) defines the relationships between objects and a standard property set. It also defines a set of properties, which values override the standard values given within the standard property set. The inherited attributes should be interpreted as follows: - SELF\\IfcRelDefinedByProperties.RelatingPropertyDefinition: Property set, which defines the standard set of properties assigned to all objects, that have the same set of properties, - SELF\\IfcRelDefines.RelatedObjects: An object occurrence, to which the same set of properties is applied. The object is characterized that certain property values, given by the standard set of properties, have a different value than those defined for all objects of the same style, - OverridingProperties: A set of properties, that have a different value for the subset of objects. The set of the individual overriding properties have to correspond with a standard property set and its containing properties, as given by the RelatingPropertyDefinition attribute. The correspondence is established by the Name attribute. It is provided as specialization of IfcRelDefinedByProperties relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreloverridesproperties.htm"
     },
     "IfcRelProjectsElement": {
@@ -4102,7 +4102,7 @@
             "RelatedFeatureElement": "Reference to the _IfcFeatureElementAddition_ that defines an addition to the volume of the element, by using a Boolean addition operation. An example is a projection at the associated element.",
             "RelatingElement": "Element at which a projection is created by the associated _IfcProjectionElement_."
         },
-        "description": "The IfcRelProjectsElement is an objectified relationship between an element and one projection element that creates a modifier to the shape of the element. This relationship implies a Boolean operation of addition for the geometric bodies of the building element and the projection element.",
+        "description": "The IfcRelProjectsElement is an objectified relationship between an element and one projection element that creates a modifier to the shape of the element. This relationship implies a Boolean operation of addition for the geometric bodies of the building element and the projection element. The relationship is defined to be a 1:1 relationship, if a building element has more than one projection, several relationship objects have to be used, each pointing to a different projection element.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelprojectselement.htm"
     },
     "IfcRelReferencedInSpatialStructure": {
@@ -4110,11 +4110,11 @@
             "RelatedElements": "Set of products, which are referenced within this level of the spatial structure hierarchy. > NOTE  Referenced elements are contained elsewhere within the spatial structure, they are referenced additionally by this spatial structure element, e.g., because they span several stories.",
             "RelatingStructure": "Spatial structure element, within which the element is referenced. Any element can be contained within zero, one or many elements of the project spatial structure."
         },
-        "description": "This objectified relationship, IfcRelReferencedInSpatialStructure, is used to assign elements in addition to those levels of the project spatial structure, in which they are referenced, but not primarily contained.",
+        "description": "This objectified relationship, IfcRelReferencedInSpatialStructure, is used to assign elements in addition to those levels of the project spatial structure, in which they are referenced, but not primarily contained. Any element can be referenced to zero, one or several levels of the spatial structure. Whereas the IfcRelContainsInSpatialStructure relationship is required to be hierarchical (an element can only be contained in exactly one spatial structure element), the IfcRelReferencedInSpatialStructure is not restricted to be hierarchical. Predefined spatial structure elements to which elements can be assigned are - site as IfcSite - building as IfcBuilding - storey as IfcBuildingStorey - space as IfcSpace The same element can be assigned to different spatial structure elements depending on the context. *Use Definition*",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelreferencedinspatialstructure.htm"
     },
     "IfcRelSchedulesCostItems": {
-        "description": "An IfcRelSchedulesCostItems is a subtype of IfcRelAssignsToControl that enables one or many instances of IfcCostItem to be assigned to an instance of IfcCostSchedule.",
+        "description": "An IfcRelSchedulesCostItems is a subtype of IfcRelAssignsToControl that enables one or many instances of IfcCostItem to be assigned to an instance of IfcCostSchedule. IfcRelSchedulesCostItems is used specifically for assigning instances of IfcCostItem to an IfcCostSchedule and incorporates WHERE rules that rigidly enforce this usage.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcrelschedulescostitems.htm"
     },
     "IfcRelSequence": {
@@ -4124,7 +4124,7 @@
             "SequenceType": "The way in which the time lag applies to the sequence.",
             "TimeLag": "Time Duration of the sequence, it is the time lag between the predecessor and the successor as specified by the SequenceType."
         },
-        "description": "This objectified relationship handles the concatenation of processes over time. The sequence is defined as relationship between two processes. The related object is the successor of the relating object, being the predecessor. A time lag is assigned to a sequence, and the sequence type defines the way in which the time lag applies to the sequence.",
+        "description": "This objectified relationship handles the concatenation of processes over time. The sequence is defined as relationship between two processes. The related object is the successor of the relating object, being the predecessor. A time lag is assigned to a sequence, and the sequence type defines the way in which the time lag applies to the sequence. IfcRelSequence is defined as an one-to-one relationship, therefore it assigns one predecessor to one successor. However, each IfcProcess can have multiple predecessors and successors, as the sequence relationship is truly an N-to-M relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelsequence.htm"
     },
     "IfcRelServicesBuildings": {
@@ -4132,7 +4132,7 @@
             "RelatedBuildings": "Spatial structure elements (including site, building, storeys) that are serviced by the system.",
             "RelatingSystem": "System that services the Buildings."
         },
-        "description": "An objectified relationship that defines the relationship between a system and the sites, buildings, storeys or spaces, it serves. Examples of systems are:",
+        "description": "An objectified relationship that defines the relationship between a system and the sites, buildings, storeys or spaces, it serves. Examples of systems are: - building service systems (heating, cooling, waste water system) represented by instances of IfcSystem - idealized structural analysis systems represented by instances of IfcStructuralAnalysisSystem",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelservicesbuildings.htm"
     },
     "IfcRelSpaceBoundary": {
@@ -4143,7 +4143,7 @@
             "RelatedBuildingElement": "Reference to ~~Building~~ Element, that defines the Space Boundaries.",
             "RelatingSpace": "Reference to one spaces that is delimited by this boundary."
         },
-        "description": "The space boundary (IfcRelSpaceBoundary) defines the physical or virtual delimiter of a space as its relationship to the surrounding elements.",
+        "description": "The space boundary (IfcRelSpaceBoundary) defines the physical or virtual delimiter of a space as its relationship to the surrounding elements. - In the case of physical space boundary, the placement and shape of the boundary may be given, and the building element, providing the boundary, is referenced, - In the case of virtual space boundary, the placement and shape of the boundary may be given, but no building element is referenced. The exact definition of how space boundaries are broken down depends on the view, more detailed conventions on how space boundaries are decomposed can only be given at the domain or application type level. The IfcRelSpaceBoundary is defined as an objectified relationship that handles the element to space relationship by objectifying the relationship between an element and the space it bounds. It is given as a one-to-one relationship, but allows each building element to define many such relationship and each space to be defined by many such relationships. *Use Definitions* If the IfcRelSpaceBoundary is used to express a virtual boundary, the attribute PhysicalOrVirtualBoundary has to be set to VIRTUAL. If this virtual boundary is between two spaces, and the correct location is of interest, the attribute RelatedBuildingElement shall point to an instance of IfcVirtualElement, and the attribute ConnectionGeometry is required to be inserted. If the IfcRelSpaceBoundary is used to express a physical boundary between two spaces, the attribute PhysicalOrVirtualBoundary has to be set to PHYSICAL. The attribute RelatedBuildingElement has to be given and points to the element providing the space boundary. The attribute ConnectionGeometry may be inserted, in this case it describes the physical space boundary geometrically, or it may be omitted, in that case it describes a physical space boundary logically. *Geometry Use Definitions*: The IfcRelSpaceBoundary may have geometry attached. If geometry is not attached, the relationship between space and building element is handled only on a logical level. If geometry is attached, it is given within the local coordinate systems of the space and (if given in addition) of the building element. The connection geometry, when given, can be given as a curve (for 2D representations of space boundaries) or as a surface (for 3D representations of space boundaries). The geometric representation (through the ConnectionGeometry attribute) is defined using either 2D curve geometry or extruded surfaces for space boundaries which bounds prismatic spaces. The following constraints apply to the 2D curve representation: - Curve: IfcPolyline, IfcTrimmedCurve or IfcCompositeCurve The following constraints apply to the surface representation: - Surface: IfcSurfaceOfLinearExtrusion - Profile: IfcArbitraryOpenProfileDef - Extrusion: The extrusion direction shall be vertically, i.e., along the positive Z Axis of the co-ordinate system of the containing spatial structure element.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelspaceboundary.htm"
     },
     "IfcRelVoidsElement": {
@@ -4155,7 +4155,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelvoidselement.htm"
     },
     "IfcRelationship": {
-        "description": "The abstract generalization of all objectified relationships in IFC. Objectified relationships are the preferred way to handle relationships among objects. This allows to keep relationship specific properties directly at the relationship and opens the possibility to later handle relationship specific behavior.",
+        "description": "The abstract generalization of all objectified relationships in IFC. Objectified relationships are the preferred way to handle relationships among objects. This allows to keep relationship specific properties directly at the relationship and opens the possibility to later handle relationship specific behavior. There are two different types of relationships, 1-to-1 relationships and 1-to-many relationship. used within the subtypes of IfcRelationship. The following convention applies to all subtypes: - The two sides of the objectified relationship are named - Relating+<name of relating object> and - Related+<name of related object> - In case of the 1-to-many relationship, the related side of the relationship shall be an aggregate SET 1:N",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelationship.htm"
     },
     "IfcRelaxation": {
@@ -4176,7 +4176,7 @@
             "RepresentationMap": "Use of the representation within an _IfcRepresentationMap_. If used, this _IfcRepresentation_ may be assigned to many representations as one of its _Items_ using an _IfcMappedItem_. Using _IfcRepresentationMap_ is the way to share one representation (often of type _IfcShapeRepresentation_) by many products.",
             "RepresentationType": "The description of the type of a representation context. The representation type defines the type of geometry or topology used for representing the product representation. More information is given at the subtypes _IfcShapeRepresentation_ and _IfcTopologyRepresentation_.   The supported values for context type are to be specified by implementers agreements."
         },
-        "description": "Definition from ISO/CD 10303-43:1992: A representation is one or more representation items that are related in a specified representation context as the representation of some concept.",
+        "description": "Definition from ISO/CD 10303-43:1992: A representation is one or more representation items that are related in a specified representation context as the representation of some concept. The IfcRepresentation defines the general concept of representing product properties.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcrepresentation.htm"
     },
     "IfcRepresentationContext": {
@@ -4185,7 +4185,7 @@
             "ContextType": "The description of the type of a representation context. The supported values for context type are to be specified by implementers agreements.",
             "RepresentationsInContext": "All shape representations that are defined in the same representation context."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A representation context is a context in which a set of representation items are related.",
+        "description": "Definition from ISO/CD 10303-42:1992: A representation context is a context in which a set of representation items are related. The IfcRepresentationContext defines the context to which the IfcRepresentation of a product is related.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcrepresentationcontext.htm"
     },
     "IfcRepresentationItem": {
@@ -4193,7 +4193,7 @@
             "LayerAssignments": "Assignment of the representation item to a single or multiple layer(s). The _LayerAssignments_ can override a _LayerAssignments_ of the _IfcRepresentation_ it is used  within the list of _Items_. > NOTE  Implementation agreements can restrict the maximum number of layer assignments to 1.",
             "StyledByItem": "Reference to the _IfcStyledItem_ that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve."
         },
-        "description": "Definition from ISO/CD 10303-43:1992: A representation item is an element of product data that participates in one or more representations or contributes to the definition of another representation item. A representation item contributes to the definition of another representation item when it is referenced by that representation item.",
+        "description": "Definition from ISO/CD 10303-43:1992: A representation item is an element of product data that participates in one or more representations or contributes to the definition of another representation item. A representation item contributes to the definition of another representation item when it is referenced by that representation item. Definition from IAI The IfcRepresentationItem is used within (and only within - directly or indirectly through other IfcRepresentationItem's or IfcShapeAspect's) an IfcRepresentation to represent an IfcProductRepresentation. Most commonly these IfcRepresentationItem's are geometric or topological representation items, that can (but not need to) have presentation style infomation assigned.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcrepresentationitem.htm"
     },
     "IfcRepresentationMap": {
@@ -4202,14 +4202,14 @@
             "MappedRepresentation": "A representation that is mapped to at least one mapped item.",
             "MappingOrigin": "An axis2 placement that defines the position about which the mapped representation is mapped."
         },
-        "description": "Definition from ISO/CD 10303-43:1992: A representation map is the identification of a representation and a representation item in that representation for the purpose of mapping. The representation item defines the origin of the mapping. The representation map is used as the source of a mapping by a mapped item.",
+        "description": "Definition from ISO/CD 10303-43:1992: A representation map is the identification of a representation and a representation item in that representation for the purpose of mapping. The representation item defines the origin of the mapping. The representation map is used as the source of a mapping by a mapped item. An IfcRepresentationMap defines the base definition (also referred to as block, cell or macro) within the mapping origin, defined as the placement coordinate system. The representation map is restricted to Cartesian mapping.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcrepresentationmap.htm"
     },
     "IfcResource": {
         "attributes": {
             "ResourceOf": "Reference to the IfcRelAssignsToResource relationship and thus pointing to those objects, which are used as resources."
         },
-        "description": "The IfcResource contains the information needed to represent the costs, schedule, and other impacts from the use of a thing in a process. It is not intended to use IfcResource to model the general properties of the things themselves, while an optional linkage from IfcResource to the things to be used can be specified (i.e. the relationship from subtypes of IfcResource to IfcProduct through the IfcRelAssignsToResource relationship).",
+        "description": "The IfcResource contains the information needed to represent the costs, schedule, and other impacts from the use of a thing in a process. It is not intended to use IfcResource to model the general properties of the things themselves, while an optional linkage from IfcResource to the things to be used can be specified (i.e. the relationship from subtypes of IfcResource to IfcProduct through the IfcRelAssignsToResource relationship). There are two basic intended use of IfcResource. First, if the attributes of the thing are not needed for the purpose of the use of IfcResource, or the types of things are not explicitly modeled in IFC yet, then the linkage between the resource and the thing doesn\u2019t have to be instantiated in the system. That is, the attributes of IfcResource (or its subtypes) alone are sufficient to represent the use of the thing as a resource for the purpose of the project. Second, if the attributes of the thing are needed for the use of IfcResource objects, and they are modeled explicitly as objects (e.g. classes or properties), then the IfcResource instances can be linked to the instances of the type of the things being referenced. Things that might be used as resources and that are already modeled in the IFC include physical products, people and organizations, and materials. The relationship object IfcRelAssignsToResource is provided for this approach. The inherited attribute ObjectType is used as a textual code that identifies the resource type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcresource.htm"
     },
     "IfcRevolvedAreaSolid": {
@@ -4218,7 +4218,7 @@
             "Axis": "Axis about which revolution will take place.",
             "AxisLine": "The line of the axis of revolution. IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(Axis.Location,    IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(Axis.Z,1.0))"
         },
-        "description": "A revolved area solid (IfcRevolvedAreaSolid) is a solid created by revolving a planar bounded surface about an axis. Both, the axis and planar bounded surface shall be in the same plane and the axis shall not intersect the interior of the swept area. If the swept area has inner boundaries, i.e. holes defined, then those holes shall be swept into holes of the solid. The direction of revolution is clockwise when viewed along the axis in the positive direction.",
+        "description": "A revolved area solid (IfcRevolvedAreaSolid) is a solid created by revolving a planar bounded surface about an axis. Both, the axis and planar bounded surface shall be in the same plane and the axis shall not intersect the interior of the swept area. If the swept area has inner boundaries, i.e. holes defined, then those holes shall be swept into holes of the solid. The direction of revolution is clockwise when viewed along the axis in the positive direction. Informal propositions: - The AxisLine shall lie in the plane of the SweptArea (as defined at supertype IfcSweptAreaSolid). - The AxisLine shall not intersect the interior of the SweptArea (as defined at supertype IfcSweptAreaSolid). - The Angle shall be between 0\u00b0 and 360\u00b0, or 0 and 2p (depending on the unit type for IfcPlaneAngleMeasure). Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcrevolvedareasolid.htm"
     },
     "IfcRibPlateProfileProperties": {
@@ -4237,7 +4237,7 @@
             "BottomRadius": "",
             "Height": ""
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A right circular cone is a CSG primitive in the form of a cone. It is defined by an axis, a point on the axis, (...) and a distance giving the location along the axis from the point to the base of the cone. In addition, a radius is given (...).",
+        "description": "Definition from ISO/CD 10303-42:1992: A right circular cone is a CSG primitive in the form of a cone. It is defined by an axis, a point on the axis, (...) and a distance giving the location along the axis from the point to the base of the cone. In addition, a radius is given (...). In contrary to the ISO/CD 10303-42 definition, the IfcRightCircularCone may not be truncated. It provides: - SELF\\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcCsgPrimitive3D.Position.Location: The center of the circular area being the bottom face of the cylinder. - SELF\\IfcCsgPrimitive3D.Position.Position[3]:_The z-axis of the inherited placement coordinate system provides the center axis of the _IfcRightCircularCone, and the apex is at the Height value applied to the positive direction of the z-axis. The BottomRadius defines the circular base at the xy-plane of the placement coordinate system. _",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcrightcircularcone.htm"
     },
     "IfcRightCircularCylinder": {
@@ -4245,14 +4245,14 @@
             "Height": "",
             "Radius": ""
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A right circular cylinder is a CSG primitive in the form of a solid cylinder of finite height. It is defined by an axis point at the centre of one planar circular face, an axis, a height, and a radius. The faces are perpendicular to the axis and are circular discs with the specified radius. The height is the distance from the first circular face centre in the positive direction of the axis to the second circular face centre.",
+        "description": "Definition from ISO/CD 10303-42:1992: A right circular cylinder is a CSG primitive in the form of a solid cylinder of finite height. It is defined by an axis point at the centre of one planar circular face, an axis, a height, and a radius. The faces are perpendicular to the axis and are circular discs with the specified radius. The height is the distance from the first circular face centre in the positive direction of the axis to the second circular face centre. The inherited Position attribute defines the IfcAxis2Placement3D and provides: - SELF\\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcCsgPrimitive3D.Position.Location: The center of the circular area being the bottom face of the cylinder. - _SELF\\IfcCsgPrimitive3D.Position.Position[3]:_The z axis provides the center axis and the height is measured from the origin along the positive direction of the z axis.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcrightcircularcylinder.htm"
     },
     "IfcRoof": {
         "attributes": {
             "ShapeType": "Predefined shape types for a roof that are specified in an enumeration."
         },
-        "description": "Definition from ISO 6707-1:1989: Construction enclosing the building from above.",
+        "description": "Definition from ISO 6707-1:1989: Construction enclosing the building from above. The IfcRoof is a description of the total roof. It acts as a container entity, that aggregates all components of the roof, it represents. The aggregation is handled via the IfcRelAggregates relationship, relating a roof (IfcRoof) with the related roof entities, like slabs (IfcSlab), rafters and purlins (IfcBeam), or other (included) roofs, such as dormers (IfcRoof). *Property Set Use Definition*: The property sets relating to the IfcRoof are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcRoof are part of this IFC release: - Pset_RoofCommon: common property set for all roof occurrences *Quantity Use Definition*: The quantities relating to the IfcRoof are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. It is accessible by the inverse IsDefinedBy relationship. The following quantities are foreseen, but will be subjected to the local standard of measurement: *Geometry Use Definitions*: The geometric representation of IfcRoof is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Independent geometric representations should only be used when the IfcRoof is not defined as an aggregate. If defined as an aggregate, the geometric representation is the sum of the representation of the components within the aggregate. Local Position The local placement for IfcRoof is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level.. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. If the LocalPlacement is given for the IfcRoof, then all components, which are aggregated to the roof should use this placement as their relative placement. Geometric Representation If the IfcRoof has components (referenced by_SELF\\IfcObject.IsDecomposedBy_) then no independent geometric representation shall defined for the IfcRoof. The IfcRoof is then geometrically represented by the geometric representation of its components. The components are accessed via SELF\\IfcObject.IsDecomposedBy[1].RelatedObjects. If the IfcRoof has no components defined (empty set of SELF\\IfcObject.IsDecomposedBy) then the IfcRoof may be represented by an IfcShapeRepresentation with the RepresentationType = 'Brep'. Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcroof.htm"
     },
     "IfcRoot": {
@@ -4262,21 +4262,21 @@
             "Name": "Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.",
             "OwnerHistory": "Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE: only the last modification in stored."
         },
-        "description": "Definition from IAI: The IfcRoot is the most abstract and root class for all IFC entity definitions that roots in the kernel or in subsequent layers of the IFC object model. It is therefore the common supertype all all IFC entities, beside those defined in an IFC resource schema. All entities that are subtypes of IfcRoot can be used independently, whereas resource schema entities, that are not subtypes of IfcRoot, are not supposed to be independent entities.",
+        "description": "Definition from IAI: The IfcRoot is the most abstract and root class for all IFC entity definitions that roots in the kernel or in subsequent layers of the IFC object model. It is therefore the common supertype all all IFC entities, beside those defined in an IFC resource schema. All entities that are subtypes of IfcRoot can be used independently, whereas resource schema entities, that are not subtypes of IfcRoot, are not supposed to be independent entities. The IfcRoot assigns the globally unique ID, and the ownership and history information to the entity. In addition it may provide for a name and a description about the concepts.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcroot.htm"
     },
     "IfcRoundedEdgeFeature": {
         "attributes": {
             "Radius": "The radius of the feature cross section."
         },
-        "description": "An edge feature with a rounded cross section shape.",
+        "description": "An edge feature with a rounded cross section shape. Geometry Use Definitions: The geometric representation of IfcRoundedEdgeFeature is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined in the supertype IfcFeatureElementSubtraction. Standard Geometric Representation The use of Standard Geometric Representations is defined in the supertype IfcFeatureElementSubtraction.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcroundededgefeature.htm"
     },
     "IfcRoundedRectangleProfileDef": {
         "attributes": {
             "RoundingRadius": "Radius of the circular arcs, by which all four corners of the rectangle are equally rounded. If not given, zero (= no rounding arcs) applies."
         },
-        "description": "Definition from IAI: The IfcRoundedRectangleProfileDef defines a rectangle with equally rounded corners as the profile definition used by the swept surface geometry or the swept area solid. It is given by the X extent, the Y extent, and the radius for the rounded corners, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, i.e. in the center of the bounding box.",
+        "description": "Definition from IAI: The IfcRoundedRectangleProfileDef defines a rectangle with equally rounded corners as the profile definition used by the swept surface geometry or the swept area solid. It is given by the X extent, the Y extent, and the radius for the rounded corners, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, i.e. in the center of the bounding box. Illustration: Table: Parameter of rounded rectangle profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcroundedrectangleprofiledef.htm"
     },
     "IfcSIUnit": {
@@ -4285,11 +4285,11 @@
             "Name": "The word, or group of words, by which the SI unit is referred to.",
             "Prefix": "The SI Prefix for defining decimal multiples and submultiples of the unit."
         },
-        "description": "Definition from ISO/CD 10303-41:1992: An SI unit is the fixed quantity used as a standard in terms of which items are measured as defined by ISO 1000 (clause 2).",
+        "description": "Definition from ISO/CD 10303-41:1992: An SI unit is the fixed quantity used as a standard in terms of which items are measured as defined by ISO 1000 (clause 2). IfcSIUnit covers both standard base SI units, like meter and second, and derived SI units, like Pascal, square meter and cubic meter.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsiunit.htm"
     },
     "IfcSanitaryTerminalType": {
-        "description": "IfcSanitaryTerminalType defines a particular type of IfcFlowTerminal that is a fixed appliance or terminal usually supplied with water and used for drinking, cleaning or foul water disposal or that is an item of equipment directly used with such an appliance or terminal.",
+        "description": "IfcSanitaryTerminalType defines a particular type of IfcFlowTerminal that is a fixed appliance or terminal usually supplied with water and used for drinking, cleaning or foul water disposal or that is an item of equipment directly used with such an appliance or terminal. Refer also to definition in BS6100 100 3406. *Use Definitions* The IfcSanitaryTerminalType defines a particular type of sanitary terminal, which may be included into the spatial context of the building model through an (or multiple) instances of IfcFlowTerminal. The parameters of the sanitary terminal type are defined through the type driven property sets referred to by the predefined type attribute of IfcSanitaryTerminalType. *Property Set Use Definition*: The property sets relating to the IfcSanitaryTerminalType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcSanitaryTerminalType are part of this IFC release: - Pset_SanitaryTerminalTypeBath: specific property set for the properties of a bath , if available - Pset_SanitaryTerminalTypeBidet: specific property set for the properties of a bidet , if available - Pset_SanitaryTerminalTypeCistern: specific property set for the properties of a cistern (associated with a WC, urinal or range of such devices), if available - Pset_SanitaryTerminalTypeSanitaryFountain: specific property set for the properties of a sanitary fountain, typically for drinking water, if available - Pset_SanitaryTerminalTypeShower: specific property set for the properties of a shower, if available - Pset_SanitaryTerminalTypeSink: specific property set for the properties of a sink , if available - Pset_SanitaryTerminalTypeToiletPan: specific property set for the properties of a toilet pan, if available - Pset_SanitaryTerminalTypeUrinal: specific property set for the properties of a urinal, if available - Pset_SanitaryTerminalTypeWCSeat: specific property set for the properties of a WC seat, if available - Pset_SanitaryTerminalTypeWashHandBasin: specific property set for the properties of a wash hand basin, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "BATH": "Sanitary appliance for immersion of the human body or parts of it.",
             "BIDET": "Waste water appliance for washing the excretory organs while sitting astride the bowl.",
@@ -4328,7 +4328,7 @@
             "StatusTime": "The date or time at which the status of the tasks within the schedule is analyzed.",
             "TotalFloat": "The difference between the duration available to carry out a task and the scheduled duration of the task.  NOTE: Total Float time may be calculated as being the difference between the scheduled duration of a task and the available duration from earliest start to latest finish. Float time may be either positive, zero or negative. Where it is zero or negative, the task becomes critical."
         },
-        "description": "The IfcScheduleTimeControl captures the time-related information about a process including the different types (i.e. actual, or scheduled) of starting and ending times, duration, float times, etc.",
+        "description": "The IfcScheduleTimeControl captures the time-related information about a process including the different types (i.e. actual, or scheduled) of starting and ending times, duration, float times, etc. Use Definitions Scheduled and actual durations of a task and all float times should be derived within an application from relevant start and finish times that are also attributes of this class. Note that they are not directly derived within the IFC specification at this stage due to the differences in data type between time measures date/time selections. The critical nature of an IfcScheduleTimeControl may also be derived within an application by comparing relevant start and finish date/time selections but is not derived within the IFC specification at this stage.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcscheduletimecontrol.htm"
     },
     "IfcSectionProperties": {
@@ -4337,7 +4337,7 @@
             "SectionType": "An indicator whether a specific piece of a cross section is uniform or tapered in longitudinal direction.",
             "StartProfile": "The cross section profile at the start point of the longitudinal section."
         },
-        "description": "An IfcSectionProperties defines the cross section properties for a single longitudinal piece of a cross section.",
+        "description": "An IfcSectionProperties defines the cross section properties for a single longitudinal piece of a cross section. General usage: The section piece may be either uniform or tapered. In the latter case an end profile should also be provided. The start and end profiles are assumed to be of the same profile type. Generally only rectangular or circular cross section profiles are assumed to be used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcsectionproperties.htm"
     },
     "IfcSectionReinforcementProperties": {
@@ -4349,7 +4349,7 @@
             "SectionDefinition": "Definition of the cross section profile and longitudinal section type.",
             "TransversePosition": "The position for the section reinforcement properties in transverse direction."
         },
-        "description": "An IfcSectionReinforcementProperties defines the cross section properties of reinforcement for a single longitudinal piece of a cross section with a specific reinforcement usage type.",
+        "description": "An IfcSectionReinforcementProperties defines the cross section properties of reinforcement for a single longitudinal piece of a cross section with a specific reinforcement usage type. General usage: Several sets of cross section reinforcement properties represented by instances of IfcReinforcementProperties may be attached to the section reinforcement properties, one for each combination of steel grade and reinforcement bar type and size.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcsectionreinforcementproperties.htm"
     },
     "IfcSectionedSpine": {
@@ -4359,11 +4359,11 @@
             "Dim": "The dimensionality of the spine curve is always 3. 3",
             "SpineCurve": "A single composite curve, that defines the spine curve. Each of the composite curve segments correspond to the part between two cross-sections."
         },
-        "description": "Definition from ISO/DIS 10303-42-ed2:1999: A sectioned spine is a representation of the shape of a three dimensional object composed of a spine curve and a number of planar cross sections. The shape is defined between the first element of cross sections and the last element of this set.",
+        "description": "Definition from ISO/DIS 10303-42-ed2:1999: A sectioned spine is a representation of the shape of a three dimensional object composed of a spine curve and a number of planar cross sections. The shape is defined between the first element of cross sections and the last element of this set. A sectioned spine (IfcSectionedSpine) is a representation of the shape of a three dimensional object composed by a number of planar cross sections, and a spine curve. The shape is defined between the first element of cross sections and the last element of the cross sections. A sectioned spine may be used to represent a surface or a solid but the interpolation of the shape between the cross sections is not defined. For the representation of a solid all cross sections are areas. For representation of a surface all cross sections are curves. The cross sections are defined as profiles, whereas the consecutive profiles may be derived by a transformation of the start profile or the previous consecutive profile. The spine curve shall be of type IfcCompositeCurve, each of its segments (IfcCompositeCurveSegment) shall correspond to the part between exactly two consecutive cross-sections. Informal propositions - non of the cross sections, after being placed by the cross section positions, shall intersect - non of the cross sections, after being placed by the cross section positions, shall lie in the same plane - the local origin of each cross section position shall lie at the beginning or end of a composite curve segment.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsectionedspine.htm"
     },
     "IfcSensorType": {
-        "description": "An IfcSensorType defines a particular type of sensor which is used for detection in a control system such as a building automation control system.",
+        "description": "An IfcSensorType defines a particular type of sensor which is used for detection in a control system such as a building automation control system. *Use Definitions* An IfcSensorType provides for all forms of sensor. Usage of IfcSensorType defines the parameters for one or more occurrences of IfcDistributionControlElement. Parameters are specified through property sets that are enumerated in the IfcSensorTypeEnum data type. *Property Set Use Definition*: The property sets relating to the IfcSensorType defined by the IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcSensorType are part of this IFC release: - Pset_SensorTypeCO2Sensor: specific property set for the properties of a CO2 sensor, if available - Pset_SensorTypeFireSensor: specific property set for the properties of a fire sensor, if available - Pset_SensorTypeGasSensor: specific property set for the properties of a gas sensor, if available - Pset_SensorTypeHeatSensor: specific property set for the properties of a heat sensor, if available - Pset_SensorTypeHumiditySensor: specific property set for the properties of a humidity sensor, if available - Pset_SensorTypeLightSensor: specific property set for the properties of a light sensor, if available - Pset_SensorTypeMovementSensor: specific property set for the properties of a movement sensor, if available - Pset_SensorTypePressureSensor: specific property set for the properties of a pressure sensor, if available - Pset_SensorTypeSmokeSensor: specific property set for the properties of a smoke sensor, if available - Pset_SensorTypeSoundSensor: specific property set for the properties of a sound sensor, if available - Pset_SensorTypeTemperatureSensor: specific property set for the properties of a temperature sensor, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "CO2SENSOR": "",
             "FIRESENSOR": "A device that senses or detects fire",
@@ -4388,7 +4388,7 @@
             "ServiceLifeDuration": "The length or duration of a service life.",
             "ServiceLifeType": "Predefined service life types from which that required may be set."
         },
-        "description": "An IfcServiceLife is the period of time that an artefact (typically a product or asset) will last.",
+        "description": "An IfcServiceLife is the period of time that an artefact (typically a product or asset) will last. IfcServiceLife is related to one or more products through the IfcRelAssignsToProduct relationship class. An IfcServiceLife may also be assigned to an asset through use of the IfcRelAssignsToGroup relationship class Note that the IfcServiceLife.ServiceLifeDuration attribute replaces the previous IfcAsset.ExpectedLife attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcservicelife.htm"
     },
     "IfcServiceLifeFactor": {
@@ -4397,7 +4397,7 @@
             "MostUsedValue": "Most used of the three values assigned to the service life factor.",
             "UpperValue": "Upper of the three values assigned to the service life factor."
         },
-        "description": "An IfcServiceLifeFactor captures the various factors that impact upon the expected service life of an artefact.",
+        "description": "An IfcServiceLifeFactor captures the various factors that impact upon the expected service life of an artefact. Note that each instance of IfcServiceLifeFactor may have a name that describes the form of impact that the factor has on the service life. Because there is a significant list of such potential impacts, they are not explicitly collected together into an enumeration. In order to name an instance of IfcServiceLifeFactor, the inherited Name attribute should be used. Within the IFC specification, any number of service life factors may be allowed to impact upon the service life of an artefact. In many cases, it is probable that the ISO standard that specifies good practice for service life consideration will be applied. Within the ISO standard, there are seven defined (named) service life factors that may be applied to an IfcServiceLife. These are captured in the IfcServiceLifeFactorEnum (together with a user defined capability). Each factor can have three values that define an upper, lower and most used (or median) value. One or more instances of IfcServiceLifeFactor can be related to an IfcServiceLife through the IfcRelDefinesByProperties relationship class.",
         "predefined_types": {
             "A_QUALITYOFCOMPONENTS": "",
             "B_DESIGNLEVEL": "",
@@ -4419,18 +4419,18 @@
             "ProductDefinitional": "An indication that the shape aspect is on the physical boundary of the product definition shape. If the value of this attribute is TRUE, it shall be asserted that the shape aspect being identified is on such a boundary. If the value is FALSE, it shall be asserted that the shape aspect being identified is not on such a boundary. If the value is UNKNOWN, it shall be asserted that it is not known whether or not the shape aspect being identified is on such a boundary.  --- EXAMPLE: Would be FALSE for a center line, identified as shape aspect; would be TRUE for a cantilever. ---",
             "ShapeRepresentations": "List of ~~shape~~ representations. Each member defines a valid representation of a particular type within a particular representation context as being an aspect (or part) of a product definition."
         },
-        "description": "Definition from ISO/CD 10303-41:1992: The shape aspect is an identifiable element of the shape of a product.",
+        "description": "Definition from ISO/CD 10303-41:1992: The shape aspect is an identifiable element of the shape of a product. Definition from IAI: The IfcShapeAspect allows for grouping of shape representation items that represent aspects (or components) of the shape of a product. Thereby shape representations of components of the product shape represent a distinctive part to a product that can be explicitly addressed.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcshapeaspect.htm"
     },
     "IfcShapeModel": {
         "attributes": {
             "OfShapeAspect": "Reference to the shape aspect, for which it is the shape representation."
         },
-        "description": "The IfcShapeModel represents the concept of a particular geometric and/or topological representation of a product's shape or a product component's shape within a representation context. This representation context has to be a geometric representation context (with the exception of topology representations without associated geometry). The two subtypes are IfcShapeRepresentation to cover the geometric models (or sets) that represent a shape, and IfcTopologyRepresentation to cover the conectivity of a product or product component. The topology may or may not have geometry associated.",
+        "description": "The IfcShapeModel represents the concept of a particular geometric and/or topological representation of a product's shape or a product component's shape within a representation context. This representation context has to be a geometric representation context (with the exception of topology representations without associated geometry). The two subtypes are IfcShapeRepresentation to cover the geometric models (or sets) that represent a shape, and IfcTopologyRepresentation to cover the conectivity of a product or product component. The topology may or may not have geometry associated. The IfcShapeModel can be a shape representation (geometric and/or topologogical) of a product (via IfcProductDefinitionShape), or a shape representation (geometric and/or topologogical) of a component of a product shape (via IfcShapeAspect).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcshapemodel.htm"
     },
     "IfcShapeRepresentation": {
-        "description": "Definition from ISO/CD 10303-42:1992: The shape representation is a specific kind of representation that represents a shape.",
+        "description": "Definition from ISO/CD 10303-42:1992: The shape representation is a specific kind of representation that represents a shape. Definition from IAI: The IfcShapeRepresentation represents the concept of a particular geometric representation of a product or a product component within a specific geometric representation context. The inherited attribute RepresentationType is used to define the geometric model used for the shape representation, the inherited attribute RepresentationIdentifier is used to denote the part of the representation captured by the IfcShapeRepresentation (e.g. Axis, Body, etc.). Several representation types for shape representation are included as predefined types: Table 1: string values for the inherited attribute 'RepresentationType'.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcshaperepresentation.htm"
     },
     "IfcShellBasedSurfaceModel": {
@@ -4438,7 +4438,7 @@
             "Dim": "The space dimensionality of this class, it is always 3. 3",
             "SbsmBoundary": ""
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A shell based surface model is described by a set of open or closed shells of dimensionality 2. The shells shall not intersect except at edges and vertices. In particular, distinct faces may not intersect. A complete face of one shell may be shared with another shell. Coincident portions of shells shall both reference the same faces, edges and vertices defining the coincident region. There shall be at least one shell.",
+        "description": "Definition from ISO/CD 10303-42:1992: A shell based surface model is described by a set of open or closed shells of dimensionality 2. The shells shall not intersect except at edges and vertices. In particular, distinct faces may not intersect. A complete face of one shell may be shared with another shell. Coincident portions of shells shall both reference the same faces, edges and vertices defining the coincident region. There shall be at least one shell. A shell may exist independently of a surface model. Informal propositions - The dimensionality of the shell based surface model is 2. - The shells shall not overlap or intersect except at common faces, edges or vertices.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcshellbasedsurfacemodel.htm"
     },
     "IfcSimpleProperty": {
@@ -4453,7 +4453,7 @@
             "RefLongitude": "World Longitude at reference point (most likely defined in legal description). Defined as integer values for degrees, minutes, seconds, and, optionally, millionths of seconds with respect to the world geodetic system WGS84. > Longitudes are measured relative to the geodetic zero meridian, nominally the same as the Greenwich prime meridian: longitudes west of the zero meridian have positive values - from 0 till +180, longitudes east of the zero meridian have negative values - from 0 till -180.",
             "SiteAddress": "Address given to the site for postal purposes."
         },
-        "description": "Definition from ISO 6707-1:1989: Area where construction works are undertaken.",
+        "description": "Definition from ISO 6707-1:1989: Area where construction works are undertaken. A defined area of land, possibly covered with water, on which the project construction is to be completed. A site may be used to erect building(s) or other AEC products. A site (IfcSite) may include a definition of the single geographic reference point for this site (global position using Longitude, Latitude and Elevation) for the project. This definition may specify an exact global position of the origin of the local placement of the IfcSite in geospatial terms or it may specify an approximate position intended for informational purposes only. The geometrical placement of the site, defined by the IfcLocalPlacement, shall be always relative to the spatial structure element, in which this site is included, or absolute, i.e. to the world coordinate system, as established by the geometric representation context of the project. The world coordinate system, established at the IfcProject.RepresentationContexts, may include a definition of the true north within the XY plane of the world coordinate system, if provided, it can be obtained at IfcGeometricRepresentationContext.TrueNorth. A project may span over several connected or disconnected sites. Therefore site complex provides for a collection of sites included in a project. A site can also be decomposed in parts, where each part defines a site section. This is defined by the composition type attribute of the supertype IfcSpatialStructureElements which is interpreted as follow: - COMPLEX = site complex - ELEMENT = site - PARTIAL = site section *Property Set Use Definition* The property sets relating to the IfcSite are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcSite are part of this IFC release: - Pset_SiteCommon: common property set for all types of site *Quantity Use Definition* The quantities relating to the IfcSite are defined by the IfcElementQuantity and attached by the IfcRelAssignsProperties. The following quantities are foreseen, but will be subjected to the local standard of measurement: *Spatial Structure Use Definition* The IfcSite is used to build the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). The spatial structure elements are linked together by using the objectified relationship IfcRelAggregates. The IfcSite references them by its inverse relationships: - IfcSite.Decomposes -- referencing (IfcProject || IfcSite) by IfcRelAggregates.RelatingObject, If it refers to another instance of IfcSite, the referenced IfcSite needs to have a different and higher CompositionType, i.e. COMPLEX (if the other IfcSite has ELEMENT), or ELEMENT (if the other IfcSite has PARTIAL). - IfcSite.IsDecomposedBy -- referencing (IfcSite || IfcBuilding || IfcSpace) by IfcRelAggregates.RelatedObjects. If it refers to another instance of IfcSite, the referenced IfcSite needs to have a different and lower CompositionType, i.e. ELEMENT (if the other IfcSite has COMPLEX), or PARTIAL (if the other IfcSite has ELEMENT). If there are building elements and/or other elements directly related to the IfcSite (like a fence, or a shear wall), they are associated with the IfcSite by using the objectified relationship IfcRelContainedInSpatialStructure. The IfcIfcSite references them by its inverse relationship: * IfcSite.ContainsElements -- referencing any subtype of IfcProduct (with the exception of other spatial structure element) by IfcRelContainedInSpatialStructure.RelatedElements. *Geometry Use Definitions* The geometric representation of IfcSite is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. Local placement The local placement for IfcSite is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point to the IfcSpatialStructureElement of type \"IfcSite\", if relative placement is used (e.g. to position a site relative a a site complex, or a site section to a site). - If the relative placement is not used, the absolute placement is defined within the world coordinate system. If there is only one site object, then this is the default situation. Foot Print Representation The foot print representation of IfcSite is given by either a single 2D curve (such as IfcPolyline or IfcCompositeCurve), or by a list of 2D curves (in case of inner boundaries). The representation identifier and type of this geometric representation of IfcSite is: - IfcShapeRepresentation.RepresentationIdentifier = 'FootPrint' - IfcShapeRepresentation.RepresentationType = 'GeometricCurveSet' Survey Points Representation The survey point representation of IfcSite is defined using a set of survey points and optionally breaklines. The breaklines are restricted to only connect points given in the set of survey points. Breaklines, if given, are used to constrain the triangulation. The representation identifier and type of this geometric representation of IfcSite is: - IfcShapeRepresentation.RepresentationIdentifier = 'SurveyPoints' - IfcShapeRepresentation.RepresentationType = 'GeometricSet' Facetation Representation The facetation representation of IfcSite is defined using a surface model, based on the IfcFaceBasedSurfaceModel or on the IfcShellBasedSurfaceModel. Normally the surface model is the result after triangulation of the site survey points. The representation identifier and type of this representation of IfcSite is: - IfcShapeRepresentation.RepresentationIdentifier = 'Facetation' - IfcShapeRepresentation.RepresentationType = 'SurfaceModel' Body Representation The body (or solid model) representation of IfcSite is defined using a faceted boundary representation based on the IfcFacetedBrep or on the IfcFacetedBrepWithVoids. The representation identifier and type of this representation of IfcSite is: - IfcShapeRepresentation.RepresentationIdentifier = 'Body' - IfcShapeRepresentation.RepresentationType = 'Brep'",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcsite.htm"
     },
     "IfcSlab": {
@@ -4469,7 +4469,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcslab.htm"
     },
     "IfcSlabType": {
-        "description": "The element type (IfcSlabType) defines a list of commonly shared property set definitions of a slab and an optional set of product representations. It is used to define a slab specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type (IfcSlabType) defines a list of commonly shared property set definitions of a slab and an optional set of product representations. It is used to define a slab specification (i.e. the specific product information, that is common to all occurrences of that product type). An IfcSlabType is used to define the common properties of a specific slab that may be applied to many instances of that type to assign a specific style. A slab type can be used for a floor slab, a roof slab, a stair landing or a ramp flight. Building element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The IfcSlabType can have common material (using the inverse relationship HasAssociations) or property set information (using HasPropertySets) assigned. If present, it does apply equally to all occurrences of the IfcSlabType. Property set information may be overridden at the occurrence. The occurrences of the IfcSlabType are represented by instances of IfcSlab. ~~or IfcRampFlight~~ Informal proposition: - The material assignment, if provided using the IfcRelAssociatesMaterial relationship, shall not reference the IfcMaterialLayerSetUsage.",
         "predefined_types": {
             "BASESLAB": "The slab is used to represent a floor slab against the ground (and thereby being a part of the foundation). Another name is mat foundation.",
             "FLOOR": "The slab is used to represent a floor slab.",
@@ -4502,7 +4502,7 @@
             "SoundScale": "Reference sound scale",
             "SoundValues": "Sound values at a specific frequency. There may be cases where less than eight values are specified."
         },
-        "description": "Common definition to capture the properties of sound typically used within the context of building services and flow distribution systems. Sound properties are sound power or pressure levels across eight octave bands specifying the amount of sound generation or sound attenuation.",
+        "description": "Common definition to capture the properties of sound typically used within the context of building services and flow distribution systems. Sound properties are sound power or pressure levels across eight octave bands specifying the amount of sound generation or sound attenuation. IfcSoundProperties is a statically defined property set and should be attached to the instance(s) of IfcDistributionFlowElement through the IfcRelDefinesByProperties relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcsoundproperties.htm"
     },
     "IfcSoundValue": {
@@ -4525,7 +4525,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcspace.htm"
     },
     "IfcSpaceHeaterType": {
-        "description": "The element type IfcSpaceHeaterType defines a list of commonly shared property set definitions of a space heater and an optional set of product representations. It is used to define a space heater specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcSpaceHeaterType defines a list of commonly shared property set definitions of a space heater and an optional set of product representations. It is used to define a space heater specification (i.e. the specific product information, that is common to all occurrences of that product type). A space heater type is used to define the common properties of a space heater device that may be applied to many occurrences of that type. Space heaters utilize a combination of radiation and/or natural convection using a heating source such as steam or hot water. Examples of space heaters include radiators, convectors, baseboard and finned-tube heaters, etc. Space heater types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcSpaceHeaterType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_SpaceHeaterTypeCommon: common property set for all space heater types Pset_SpaceHeaterTypeHydronic: property set for all hydronic space heater types",
         "predefined_types": {
             "BASEBOARDHEATER": "",
             "CONVECTOR": "A heat-distributing unit that operates with gravity-circulated air.",
@@ -4549,7 +4549,7 @@
             "SpaceProgramIdentifier": "Identifier for this space program. It often refers to a number (or code) assigned to the space program. Example: R-001.",
             "StandardRequiredArea": "The floor area programmed for this space (according to client requirements)."
         },
-        "description": "Architectural program for a space in the building or facility being designed; essentially the requirements definition for such a building space.",
+        "description": "Architectural program for a space in the building or facility being designed; essentially the requirements definition for such a building space. The assignment of a person or an organization to a space program, e.g., as the anticipated occupants of the space, is handled through using the objectified relationship IfcRelAssignsToActor referring to IfcActor. Space programs can be nested, i.e. an IfcSpaceProgram can specify a program group up to any desired level. This is handled through using the objectified relationship IfcRelNests. *Property Set Use Definition*: The property sets relating to the IfcSpaceProgram are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcSpaceProgram are part of this IFC release: - Pset_SpaceProgramCommon: common property set for all types of the space program *General Use Definition* The IfcSpaceProgram entity is used to define: - the architectural program for a space in the building or facility being designed; - the standard for space allocation that can be assigned to persons within an organization. As the architectural program, the IfcSpaceProgram class sets down the requirements definition for a space in the building or facility being designed. Used in this way, it defines the client requirements for the space before the building in designed. Space programs can change over the life cycle of a building, after the building is occupied. Changes to space programs take place in the facilities management/operations phase of the building life cycle. As a space standard for facilities management (FM), the IfcSpaceProgram class defines the requirements for usage of a space according to the roles of persons that will occupy the space. This could take into account role driven elements such as whether the space should be a single person office, corner space, glazing on two sides etc. In order to use the class as an space standard within FM, a classification of spaces must have been established. This does not mean that each individual space needs to have a classification although for locating persons having an assigned space standard, this would be desirable.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcarchitecturedomain/lexical/ifcspaceprogram.htm"
     },
     "IfcSpaceThermalLoadProperties": {
@@ -4565,11 +4565,11 @@
             "UserDefinedPropertySource": "This attribute must be defined if the PropertySource is USERDEFINED.",
             "UserDefinedThermalLoadSource": "This attribute must be defined if the ThermalLoadSource is USERDEFINED."
         },
-        "description": "The space thermal load IfcSpaceThermalLoadProperties defines all thermal losses and gains occurring within a space or zone. Those losses or gains can either be requirements (desired values) or criteria (actual values). The thermal load source attribute defines an enumeration of possible sources of the thermal load. The maximum, minimum, time series and applicable value ratio values are all interpreted according to the source. The maximum and minimum values should not be used if time series values are provided.",
+        "description": "The space thermal load IfcSpaceThermalLoadProperties defines all thermal losses and gains occurring within a space or zone. Those losses or gains can either be requirements (desired values) or criteria (actual values). The thermal load source attribute defines an enumeration of possible sources of the thermal load. The maximum, minimum, time series and applicable value ratio values are all interpreted according to the source. The maximum and minimum values should not be used if time series values are provided. The IfcSpaceThermalLoadProperties is a statically defined property set and should be attached to the instance(s) of IfcSpace through the IfcRelDefinesByProperties relationship. If there are several different thermal loads occurring within a space, multiple instances of IfcSpaceThermalLoadProperties should be assigned.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcspacethermalloadproperties.htm"
     },
     "IfcSpaceType": {
-        "description": "The IfcSpaceType defines a list of commonly shared property set definitions of a space and an optional set of product representations. It is used to define an space specification (i.e. the specific space information, that is common to all occurrences of that space type).",
+        "description": "The IfcSpaceType defines a list of commonly shared property set definitions of a space and an optional set of product representations. It is used to define an space specification (i.e. the specific space information, that is common to all occurrences of that space type). A space type is used to define the common properties of a certain type of space that may be applied to many instances of that type to assign a specific style. Space types may be exchanged without being already assigned to occurrences. The occurrences of IfcSpaceType are represented by instances of IfcSpace.",
         "predefined_types": {
             "NOTDEFINED": "",
             "USERDEFINED": ""
@@ -4584,22 +4584,22 @@
             "ReferencesElements": "Set of spatial reference relationships, that holds those elements, which are referenced, but not contained, within this element of the project spatial structure. >  NOTE  The spatial reference relationship, established by IfcRelReferencedInSpatialStructure, is not required to be an hierarchical relationship, i.e. each element can be assigned to 0, 1 or many spatial structure elements. EXAMPLE  A curtain wall maybe contained in the ground floor, but maybe referenced in all floors, it reaches.",
             "ServicedBySystems": "Set of relationships to Systems, that provides a certain service to the Building. The relationship is handled by the objectified relationship IfcRelServicesBuildings."
         },
-        "description": "A spatial structure element (IfcSpatialStructureElement) is the generalization of all spatial elements that might be used to define a spatial structure. That spatial structure is often used to provide a project structure to organize a building project.",
+        "description": "A spatial structure element (IfcSpatialStructureElement) is the generalization of all spatial elements that might be used to define a spatial structure. That spatial structure is often used to provide a project structure to organize a building project. A spatial project structure might define as many levels of decomposition as necessary for the building project. Elements within the spatial project structure are: - site as IfcSite - building as IfcBuilding - storey as IfcBuildingStorey - space as IfcSpace or aggregations or parts thereof. The composition type declares an element to be either an element itself, or an aggregation (complex) or a decomposition (part). The interpretation of these types is given at each subtype of IfcSpatialStructureElement. The IfcRelAggregates is defined as an 1-to-many relationship and used to establish the relationship between exactly two levels within the spatial project structure. Finally the highest level of the spatial structure is assigned to IfcProject using the IfcRelAggregates. Informal proposition: - The spatial project structure, established by the IfcRelAggregates, shall be acyclic. - A site should not be (directly or indirectly) associated to a building, storey or space. - A building should not be (directly or indirectly) associated to a storey or space. - A storey should not be (directly or indirectly) associated to a space. *Spatial Structure Use Definition*",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcspatialstructureelement.htm"
     },
     "IfcSpatialStructureElementType": {
-        "description": "The element type (IfcSpatialStructureElementType) defines a list of commonly shared property set definitions of a spatial structure element and an optional set of product representations. It is used to define an element specification (i.e. the specific element information, that is common to all occurrences of that element type).",
+        "description": "The element type (IfcSpatialStructureElementType) defines a list of commonly shared property set definitions of a spatial structure element and an optional set of product representations. It is used to define an element specification (i.e. the specific element information, that is common to all occurrences of that element type). A spatial structure element type is used to define the common properties of a certain type of a spatial structure element that may be applied to many instances of that type to assign a specific style. Spatial structure element types (i.e. the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of subtypes of the abstract IfcSpatialStructureElementType are represented by instances of subtypes of IfcSpatialStructureElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcspatialstructureelementtype.htm"
     },
     "IfcSphere": {
         "attributes": {
             "Radius": ""
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A sphere is a CSG primitive with a spherical shape defined by a centre and a radius.",
+        "description": "Definition from ISO/CD 10303-42:1992: A sphere is a CSG primitive with a spherical shape defined by a centre and a radius. The inherited Position attribute defines the IfcAxis2Placement3D and provides: - SELF\\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcCsgPrimitive3D.Position.Location: The center of the sphere.. - _SELF\\IfcCsgPrimitive3D.Position.Position[3]:_The z axis points at its positve direction towards the north pole, and by its negative directions towards the south pole.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsphere.htm"
     },
     "IfcStackTerminalType": {
-        "description": "The IfcStackTerminalType defines a particular type of IfcFlowTerminal placed at the top of a ventilating stack (to prevent ingress by birds, rainwater etc.) or rainwater pipe (to act as a collector or hopper for discharge from guttering).",
+        "description": "The IfcStackTerminalType defines a particular type of IfcFlowTerminal placed at the top of a ventilating stack (to prevent ingress by birds, rainwater etc.) or rainwater pipe (to act as a collector or hopper for discharge from guttering). *Use Definitions* An IfcStackTerminalType identifies a particular type of IfcFlowTerminal that is placed at the top of a vertical pipe in a waste/drainage/rainwater system to fulfill a particular purpose. The purpose is by default in the context of the stack subsystem in which the terminal participates. The particular type of the stack terminal is defined by the set value of the stack terminal type enumeration. An IfcStackTerminalType may be included into the spatial context of the building model through an (or multiple) instances of IfcFlowTerminal. *Property Set Use Definition*: Note that there are no predefined property sets assigned to this type at present. *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "BIRDCAGE": "Guard cage, typically wire mesh, at the top of the stack preventing access by birds.",
             "COWL": "A cowling placed at the top of a stack to eliminate downdraft.",
@@ -4613,7 +4613,7 @@
         "attributes": {
             "ShapeType": "Predefined shape types for a stair that are specified in an Enum."
         },
-        "description": "Definition from ISO 6707-1:1989: Construction comprising a succession of horizontal stages (steps or landings) that make it possible to pass on foot to other levels.",
+        "description": "Definition from ISO 6707-1:1989: Construction comprising a succession of horizontal stages (steps or landings) that make it possible to pass on foot to other levels. A vertical passageway allowing occupants to walk (step) from one floor level to another floor level at a different elevation. It may include a landing as an intermediate floor slab. The stair is a container entity that aggregates all components of the stair, it represents. The aggregation is handled via the IfcRelAggregates relationship, relating an IfcStair with the related flights (IfcStairFlight) and landings (IfcSlab with type 'Landing'). *Property Set Use Definition*: The property sets relating to the IfcStair are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcStair are part of this IFC release: - Pset_StairCommon: common property set for all stair occurrences *Geometry Use Definitions*: The geometric representation of IfcStair is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Independent geometric representations should only be used when the IfcStair is not defined as an aggregate. If defined as an aggregate, the geometric representation is the sum of the representation of the components within the aggregate. Local placement The local placement for IfcStair is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. If the LocalPlacement is given for the IfcStair, then all components, which are aggregated to the stair should use this placement as their relative placement. Geometric Representation If the IfcStair has components (referenced by SELF\\IfcObject.IsDecomposedBy) then no independent geometric representation shall defined for the IfcStair. The IfcStair is then geometrically represented by the geometric representation of its components. The components are accessed via SELF\\IfcObject.IsDecomposedBy[1].RelatedObjects. If the IfcStair has no components defined (empty set of SELF\\IfcObject.IsDecomposedBy) then the IfcStair may be represented by an IfcShapeRepresentation with the RepresentationType = 'Brep'. Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcstair.htm"
     },
     "IfcStairFlight": {
@@ -4623,11 +4623,11 @@
             "RiserHeight": "Vertical distance from tread to tread. The riser height is supposed to be equal for all stairs in a stair flight.",
             "TreadLength": "Horizontal distance from the front to the back of the tread. The tread length is supposed to be equal for all steps of the stair flight."
         },
-        "description": "Assembly of building components in a single \"run\" of stair steps (not interrupted by a landing). The stair steps and any stringers are included in this object. A winder is regarded as part of a stair flight.",
+        "description": "Assembly of building components in a single \"run\" of stair steps (not interrupted by a landing). The stair steps and any stringers are included in this object. A winder is regarded as part of a stair flight. An IfcStairFlight is normally aggregated by a stair (IfcStair) through the IfcRelAggregates relationship, the stair flight is then included in the set of IfcRelAggregates.RelatedObjects. An IfcStairFlight normally connects the floor slab of zero to two different storeys (or partial storeys) within a building. The connection relationship between the IfcStairFlight and the IfcSlab is expressed using the IfcRelConnectsElements relationship. *Property Set Use Definition*: The property sets relating to the IfcStairFlight are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcStairFlight are part of this IFC release: - Pset_StairFlightCommon: common property set for all stair flight occurrences *Geometry Use Definitions*: The geometric representation of IfcStairFlight is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local placement The local placement for IfcStairFlight is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level. - If the IfcStairFlight, however, is used by an IfcStair, and this container class defines its own local placement, then the PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the aggregate. Standard Geometric Representation The standard geometric representation of IfcStair is defined using the following multiple shape representations for its definition: - WalkingLine: A two-dimensional open curve (IfcBoundedCurve) defining the walking line for the stair flight. - Boundary: A two-dimensional closed curve (IfcBoundedCurve) defining the boundary of the stair flight. - Body: A Brep representation (subtypes of IfcManifoldSolidBrep) defining the 3D shape of the stair flight First Representation: WalkingLine The walking line is represented by a two-dimensional open curve within a particular shape representation. The curve is directed (direction has to be interpreted as specified at the subtypes of IfcCurve). Second Representation: Boundary The flight boundary is represented by a two-dimensional closed curve within a particular shape representation. Third Representation: Body The three dimensional shape of the flight is represented by a Brep representation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcstairflight.htm"
     },
     "IfcStairFlightType": {
-        "description": "The element type (IfcStairFlightType) defines a list of commonly shared property set definitions of a stair flight and an optional set of product representations. It is used to define an stair flight specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type (IfcStairFlightType) defines a list of commonly shared property set definitions of a stair flight and an optional set of product representations. It is used to define an stair flight specification (i.e. the specific product information, that is common to all occurrences of that product type). A stair flight type is used to define the common properties of a certain type of a stair flight that may be applied to many instances of that type to assign a specific style. Stair flight types may be exchanged without being already assigned to occurrences. The occurrences of the IfcStairFlightType are represented by instances of IfcStairFlight.",
         "predefined_types": {
             "CURVED": "A stair flight with a curved walking line.",
             "FREEFORM": "A stair flight with a free form walking line (and outer boundaries).",
@@ -4644,7 +4644,7 @@
             "CausedBy": "Optional reference to an instance of IfcStructuralReaction representing a result of another structural analysis model which creates this action upon the considered structural analysis model.",
             "DestabilizingLoad": "Indicates if this action may cause a stability problem. If it is 'FALSE', no further investigations regarding stability problems are necessary."
         },
-        "description": "A structural action is a structural activity that acts upon a structural item or building element.",
+        "description": "A structural action is a structural activity that acts upon a structural item or building element. Example: The following figure illustrates the rationale for the use of the attribute 'CausedBy' for the representation of the dependencies between actions and action results. The given simplified structure contains two mechanical models that are analyzed independently, but do influence each other.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralaction.htm"
     },
     "IfcStructuralActivity": {
@@ -4653,7 +4653,7 @@
             "AssignedToStructuralItem": "References to the IfcRelConnectsStructuralActivity relationship by which activities can be associated to structural representations.",
             "GlobalOrLocal": "Indicates if the load values are defined by using the local  coordinate system or the global project coordinate system."
         },
-        "description": "The abstract entity IfcStructuralActivity combines the definition of actions (such as forces, displacement, etc) and reactions (supports and deformations) which are specified by using the basic load definitions from the_IfcStructuralLoadResource_. It also uses the inherited capabilities for the definition of a location and a local coordinate system.",
+        "description": "The abstract entity IfcStructuralActivity combines the definition of actions (such as forces, displacement, etc) and reactions (supports and deformations) which are specified by using the basic load definitions from the_IfcStructuralLoadResource_. It also uses the inherited capabilities for the definition of a location and a local coordinate system. The differentiation between actions and reactions is realized by instantiating objects either from subclasses of IfcStructuralAction or IfcStructuralReaction respectively. They inherit commonly needed attributes from the abstract superclass IfcStructuralActivity. Possible dependencies between actions and reactions must be explicitly captured. The use of the location and local coordinate system, given by ObjectPlacement, is optional as it is not always needed or useful. In addition the IfcStructuralActivity defines the relation needed to associate actions and/or reactions to the IfcStructuralItem to which it applies.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralactivity.htm"
     },
     "IfcStructuralAnalysisModel": {
@@ -4662,7 +4662,7 @@
             "LoadedBy": "References to all load groups to be analyzed.",
             "OrientationOf2DPlane": "If the selected model type (PredefinedType) describes a 2D system the orientation is needed to define the upright direction to the focused plane (z-axes). This is needed because all data for the structural analysis model (structural members, structural activities) are defined by using 3-D space. The orientation is given in relation to the coordinate system of the project. By 3D systems this value is not asserted."
         },
-        "description": "The IfcStructuralAnalysisModel is used to assemble all information needed to represent a structural analysis model. It encompasses certain general properties (such as analysis type), references to all contained structural members, structural supports or connecting members, the connection properties, as well as loads and the respective load results.",
+        "description": "The IfcStructuralAnalysisModel is used to assemble all information needed to represent a structural analysis model. It encompasses certain general properties (such as analysis type), references to all contained structural members, structural supports or connecting members, the connection properties, as well as loads and the respective load results. Important functionalities for the description of an analysis model are derived from existing IFC entities: - From IfcSystem it inherits the ability to couple the analysis model via IfcRelServicesBuildings to one or more IfcBuildings as necessary. - From IfcGroup it inherits the inverse attribute IsGroupedBy, pointing to the relationship class IfcRelAssignsToGroup. This allows to group structural members (instances of IfcStructuralMember), and supports (instances of IfcStructuralConnection) which belong to a specific analysis model. NOTE: Loads (as instances of IfcStructuralAction) are not included through IsGroupedBy. Loads are assigned through the LoadedBy attribute relationship, using load groups as a grouping mechanism. Only top-level load groups should be referenced via LoadedBy. NOTE: Results (as instances of IfcStructuralReaction) are not included through IsGroupedBy. Results are assigned through the HasResults attribute relationship, using result groups as a grouping mechanism. - From IfcObject it inherits the inverse attribute IsDecomposedBy pointing to the relationship class IfcRelNests. It provides the hierarchy between the separate (partial) analysis models.",
         "predefined_types": {
             "IN_PLANE_LOADING_2D": "",
             "LOADING_3D": "",
@@ -4692,7 +4692,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralcurveconnection.htm"
     },
     "IfcStructuralCurveMember": {
-        "description": "Definition from IAI: Instances of the entity IfcStructuralCurveMember shall be used to describe linear structural elements. Profile and material properties are defined by using objectified relationships:",
+        "description": "Definition from IAI: Instances of the entity IfcStructuralCurveMember shall be used to describe linear structural elements. Profile and material properties are defined by using objectified relationships: - The material properties are defined by IfcMechanicalMaterialProperties (and subtypes), they are connected through IfcMaterial and IfcRelAssociatesMaterial and are accessible via the inherited inverse relationship HasAssociations. - The profile properties are defined by IfcMechanicalProfileProperties (and subtypes), they are connected through IfcRelAssociatesProfileProperties and are accessible via the inherited inverse relationship HasAssociations. *Use Definition* *Topology Use Definition* Instances of IfcStructuralCurveMember shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". Placement The placement for IfcStructuralCurveMember is determined at its supertype IfcProduct. It is defined by the optional IfcObjectPlacement, referenced by ObjectPlacement at IfcProduct, which establishes, if given, the object coordinate system that is referenced by all topological representations of that product. - If the ObjectPlacement attribute is omitted, then all topological representations are given directly in world coordinates. This is the preferred representation. - If the ObjectPlacement attribute is provided, then it establishes an object coordinate system for all topological representations which are given object coordinates. If the PlacementRelTo relationship of IfcLocalPlacement is omitted, the object coordinate system is established within the world coordinate system. If the PlacementRelTo relationship of IfcLocalPlacement is given, it shall point to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. Topology Representation Instances of IfcStructuralCurveMember shall have a topology representation given by an edge with an optional additional geometric representation of the included curve. It can be provided by either - IfcEdge - IfcOrientedEdge - IfcEdgeCurve which should be the single item of IfcTopologyRepresentation.Items. The IfcEdge might be referenced by two or many IfcSubedge, representing sections of the IfcStructuralCurveMember with changing properties. See subtype IfcStructuralCurveMemberVarying for the use definition.",
         "predefined_types": {
             "CABLE": "",
             "COMPRESSION_MEMBER": "",
@@ -4705,21 +4705,21 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralcurvemember.htm"
     },
     "IfcStructuralCurveMemberVarying": {
-        "description": "Definition from IAI: Instances of the entity IfcStructuralCurveMemberVarying shall be used to describe linear structural elements with varying profile properties.",
+        "description": "Definition from IAI: Instances of the entity IfcStructuralCurveMemberVarying shall be used to describe linear structural elements with varying profile properties. The varying profile properties are assigned through the IfcRelAssociatesProfileProperties with an additional link to the IfcShapeAspect, which relates the profile properties to the different vertices of the structural curve member. *Use Definition* *Topology Use Definition* Instances of IfcStructuralCurveMemberVarying shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". The guidelines on using the location and topological representation capabilities are identical with the supertype IfcStructuralCurveMember. The additional requirement is that if the varying profile not only has different (morphing) profiles at the start and end edge, then the IfcTopologyRepresentation.Item[1]_shall be an _IfcEdge (or IfcEdgeCurve, IfcOrientedEdge) that is referenced by the Parent attribute of at least two IfcSubedge's. *Shape Aspect Use Definition* The attribute HasAssociations references a set of IfcRelAssociatesProfileProperties, each referring to an IfcShapeAspect, that has a list of ShapeRepresentations. Each individual IfcShapeRepresentation within that list shall have a single (or two) item(s) within its list of Items. The type of the item shall be: - IfcVertexPoint It references either a start or an end vertex (or both) to which the profile properties apply.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralcurvemembervarying.htm"
     },
     "IfcStructuralItem": {
         "attributes": {
             "AssignedStructuralActivity": "Inverse relationship to all structural activities (i.e. to actions or reactions) which are assigned to this structural member."
         },
-        "description": "**Definition",
+        "description": "**Definition from IAI:** The abstract entity_IfcStructuralItem_ covers structural members and structural connections. It defines the relation needed to associate structural actions to structural members and connections. ****Topology Use Definition**** Instances of IfcStructuralItem shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". **Local Placement** All IfcStructuralItem_s which are grouped within a common _IfcStructuralAnalysisModel should have equal object placements. Placement within the world coordinate system of the project is the easiest way to ensure this, especially if structural items belong to more than one analysis model. All geometric entities within the topological representation (such as IfcVertexPoint, IfcEdgeCurve, or IfcFaceSurface) are founded in the object coordinate system established by ObjectPlacement. in Release IFC2x Edition 2.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralitem.htm"
     },
     "IfcStructuralLinearAction": {
         "attributes": {
             "ProjectedOrTrue": "Defines if the load values are given by using the length of the member on which they act (true length) or by using the projected length resulting from the loaded member and the global project coordinate system. It is only considered if the global project coordinate system is used, and if the action is of type IfcStructuralLinearAction or IfcStructuralPlanarAction."
         },
-        "description": "Instances of the entity IfcStructuralLinearAction are used to define constant linear actions. Structural loads applicable to linear actions are IfcStructuralLoadLinearForce and IfcStructuralLoadTemperature.",
+        "description": "Instances of the entity IfcStructuralLinearAction are used to define constant linear actions. Structural loads applicable to linear actions are IfcStructuralLoadLinearForce and IfcStructuralLoadTemperature. The structural load, defining the linear action is given by the attribute AppliedLoad at the supertype IfcStructuralActivity. The coordinate system, in which the AppliedLoad is defined is given by the attribute ObjectPlacement at the supertype IfcProduct. *Topology Use Definition* Special case: If applied to building elements, placement and representation of the structural action are often implied by those of the building elements and are therefore optional for the actions. Standard case: If applied to structural items, instances of IfcStructuralLinearAction shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". Placement The placement for IfcStructuralLinearAction is determined at its supertype IfcProduct. It is defined by the optional IfcObjectPlacement, referenced by ObjectPlacement at IfcProduct, which establishes, if given, the object coordinate system that is referenced by the applied load. - If the ObjectPlacement attribute is omitted, then all topological representations are given directly in world coordinates. - If the ObjectPlacement attribute is provided, then it establishes an object coordinate system for all topological representations which are given object coordinates. If the PlacementRelTo relationship of IfcLocalPlacement is omitted, the object coordinate system is established within the world coordinate system. If the PlacementRelTo relationship of IfcLocalPlacement is given, it shall point to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. Topology Representation Instances of IfcStructuralLinearAction shall have a topology representation given by an edge with an optional additional geometric representation of the included curve. It can be provided by either - IfcEdge - IfcOrientedEdge - IfcEdgeCurve which should be the single item of IfcTopologyRepresentation.Items. If the topological item is not of type IfcEdgeCurve, a line connection is assumed between the two vertices of the edge.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructurallinearaction.htm"
     },
     "IfcStructuralLinearActionVarying": {
@@ -4728,14 +4728,14 @@
             "VaryingAppliedLoadLocation": "A shape aspect, containing a list of shape representations, each defining either one Cartesian point or one point on curve (by parameter values) which are needed to provide the positions of the VaryingAppliedLoads. The values contained in the list of IfcShapeAspect.ShapeRepresentations correspond to the values at the same position in the list VaryingAppliedLoads.",
             "VaryingAppliedLoads": "Derived list of all varying applied loads by pushing the inherited AppliedLoad value to the beginning of the list of SubsequentAppliedLoads. IfcAddToBeginOfList(SELF\\IfcStructuralActivity.AppliedLoad, SubsequentAppliedLoads)"
         },
-        "description": "Instances of the entity IfcStructuralLinearActionVarying are used to define varying linear actions. IfcStructuralLinearActionVarying inherits the needed attributes and applicable structural load types from its superclass IfcStructuralLinearAction.",
+        "description": "Instances of the entity IfcStructuralLinearActionVarying are used to define varying linear actions. IfcStructuralLinearActionVarying inherits the needed attributes and applicable structural load types from its superclass IfcStructuralLinearAction. *Topology Use Definition* Instances of IfcStructuralLinearActionVarying shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". The definition of the topological representation is given at the supertype IfcStructuralLinearAction. One additional constraint applies: - The topology representation has to be given by an IfcEdgeCurve to provide a parameterized geometric representation of the curve between both vertices. This parameterization is needed for the location of the varying loads. *Shape Aspect Use Definition* The attribute VaryingAppliedLoadLocation reference a shape aspect, that has a list of ShapeRepresentations. Each individual IfcShapeRepresentation within that list shall have a single item within its list of Items. The type of the item shall be either: - IfcCartesianPoint, or - IfcPointOnCurve Each list member within the list of ShapeRepresentations corresponds to the list member (at same position) of the list VaryingAppliedLoads, and provides the position of the applied load. At least two applied load values shall be given, the distribution of the applied linear loads across the surface of the planar action is constructed by linear interpolation. The following examples shows a definition of a varying applied loads by four points on curve. Example:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructurallinearactionvarying.htm"
     },
     "IfcStructuralLoad": {
         "attributes": {
             "Name": "Optionally defines a name for this load."
         },
-        "description": "The abstract entity IfcStructuralLoad is the supertype of all loads which can be defined (actions or reactions, as well as dynamic or static).",
+        "description": "The abstract entity IfcStructuralLoad is the supertype of all loads which can be defined (actions or reactions, as well as dynamic or static). Subtypes of this entity are an important part of the definition of actions and reactions. They are used to specify the load values. The location and the used coordinate system are defined by instances of IfcStructuralActivity which reference an instance of IfcStructuralLoad for the definition of the load values. This offers the possibility to use instances of IfcStructuralLoad by several instances of IfcStructuralActivity.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralload.htm"
     },
     "IfcStructuralLoadGroup": {
@@ -4747,7 +4747,7 @@
             "Purpose": "Description of the purpose of this instance. Among else, possible values of the Purpose of load combinations are 'SLS', 'ULS', 'ALS' to indicate serviceability, ultimate, or accidental limit state.",
             "SourceOfResultGroup": "Results which were computed using this load group."
         },
-        "description": "The entity IfcStructuralLoadGroup is used to structure the physical impacts. By using the grouping features inherited from IfcGroup, instances of IfcStructuralAction (or its subclasses) and of IfcStructuralLoadGroup can be used to define load groups, load cases and load combinations. An optional coefficient can be provided to represent safety factors known from several codes of practice. (see also IfcLoadGroupTypeEnum)",
+        "description": "The entity IfcStructuralLoadGroup is used to structure the physical impacts. By using the grouping features inherited from IfcGroup, instances of IfcStructuralAction (or its subclasses) and of IfcStructuralLoadGroup can be used to define load groups, load cases and load combinations. An optional coefficient can be provided to represent safety factors known from several codes of practice. (see also IfcLoadGroupTypeEnum) Use Definition The following example illustrates the use of this entity class for the different load group types. Common to all these types is the application of the same grouping mechanism (via IfcGroup) for the specification of the needed groups that may optionally contain an additional load factor (attribute Coefficient). The calculation of internal forces and the provision of safety coefficients is dependent on the building codes used; therefore only a generic representation of load groups is provided by this entity class.",
         "predefined_types": {
             "LOAD_CASE": "Groups LOAD_GROUPs and instances of subtypes of _IfcStructuralAction_.\n      It should be used as a container for loads with the same origin.",
             "LOAD_COMBINATION": "An intermediate level between LOAD_CASE and LOAD_COMBINATION.  This level is obsolete and deprecated.  Before the introduction of _IfcRelAssignsToGroupByFactor_, the purpose of this level was to provide a factor with which one or more LOAD_CASEs occur in a LOAD_COMBINATION.",
@@ -4767,7 +4767,7 @@
             "LinearMomentY": "Linear moment about the y-axis.",
             "LinearMomentZ": "Linear moment about the z-axis."
         },
-        "description": "An instance of the entity IfcStructuralLoadLinearForce shall be used to define actions on curves.",
+        "description": "An instance of the entity IfcStructuralLoadLinearForce shall be used to define actions on curves. All values are given within the chosen coordinate system of the 'activity element' (subtypes of IfcStructuralActivity), either the local coordinate system of the activity element or the global project coordinate system which is referenced by the activity element as its geometric representation context. The units of the force and moment values are given within the global unit assignment (IfcUnitAssignment).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadlinearforce.htm"
     },
     "IfcStructuralLoadPlanarForce": {
@@ -4776,7 +4776,7 @@
             "PlanarForceY": "Planar force value in y-direction.",
             "PlanarForceZ": "Planar force value in z-direction."
         },
-        "description": "An instance of the entity IfcStructuralLoadPlanarForce shall be used to define actions on faces.",
+        "description": "An instance of the entity IfcStructuralLoadPlanarForce shall be used to define actions on faces. All values are given within the chosen coordinate system of the 'activity element' (subtypes of IfcStructuralActivity), either the local coordinate system of the activity element or the global project coordinate system which is referenced by the activity element as its geometric representation context. The units of the force values are given within the global unit assignment (IfcUnitAssignment).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadplanarforce.htm"
     },
     "IfcStructuralLoadSingleDisplacement": {
@@ -4788,14 +4788,14 @@
             "RotationalDisplacementRY": "Rotation about the y-axis.",
             "RotationalDisplacementRZ": "Rotation about the z-axis."
         },
-        "description": "Instances of the entity IfcStructuralLoadSingleDisplacement shall be used to define the displacements of an action operating on a single point.",
+        "description": "Instances of the entity IfcStructuralLoadSingleDisplacement shall be used to define the displacements of an action operating on a single point. All values are given within the chosen coordinate system of the 'activity element' (subtypes of IfcStructuralActivity), either the local coordinate system of the activity element or the global project coordinate system which is referenced by the activity element as its geometric representation context. The units of the displacement and rotation values are given within the global unit assignment (IfcUnitAssignment).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadsingledisplacement.htm"
     },
     "IfcStructuralLoadSingleDisplacementDistortion": {
         "attributes": {
             "Distortion": "The distortion curvature given to the displacement load."
         },
-        "description": "Instances of the entity IfcStructuralLoadSingleForceWarping, as a subtype of IfcStructuralLoadSingleForce, shall be used to define an action operation on a single point. In addition to forces and moments defined by its supertype a warping moment can be defined.",
+        "description": "Instances of the entity IfcStructuralLoadSingleForceWarping, as a subtype of IfcStructuralLoadSingleForce, shall be used to define an action operation on a single point. In addition to forces and moments defined by its supertype a warping moment can be defined. All values are given within the chosen coordinate system of the 'activity element' (subtypes of IfcStructuralActivity), either the local coordinate system of the activity element or the global project coordinate system which is referenced by the activity element as its geometric representation context. The units of the displacement and rotation values are given within the global unit assignment (IfcUnitAssignment).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadsingledisplacementdistortion.htm"
     },
     "IfcStructuralLoadSingleForce": {
@@ -4807,14 +4807,14 @@
             "MomentY": "Moment about the y-axis.",
             "MomentZ": "Moment about the z-axis."
         },
-        "description": "Instances of the entity IfcStructuralLoadSingleForce shall be used to define the forces and moments of an action operating on a single point.",
+        "description": "Instances of the entity IfcStructuralLoadSingleForce shall be used to define the forces and moments of an action operating on a single point. All values are given within the chosen coordinate system of the 'activity element' (subtypes of IfcStructuralActivity), either the local coordinate system of the activity element or the global project coordinate system which is referenced by the activity element as its geometric representation context. The units of the force and moment values are given within the global unit assignment (IfcUnitAssignment).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadsingleforce.htm"
     },
     "IfcStructuralLoadSingleForceWarping": {
         "attributes": {
             "WarpingMoment": "The warping moment at the point load."
         },
-        "description": "Instances of the entity IfcStructuralLoadSingleForceWarping, as a subtype of IfcStructuralLoadSingleForce, shall be used to define an action operation on a single point. In addition to forces and moments defined by its supertype a warping moment can be defined.",
+        "description": "Instances of the entity IfcStructuralLoadSingleForceWarping, as a subtype of IfcStructuralLoadSingleForce, shall be used to define an action operation on a single point. In addition to forces and moments defined by its supertype a warping moment can be defined. All values are given within the chosen coordinate system of the 'activity element' (subtypes of IfcStructuralActivity), either the local coordinate system of the activity element or the global project coordinate system which is referenced by the activity element as its geometric representation context. The units of the force and moment values are given within the global unit assignment (IfcUnitAssignment).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadsingleforcewarping.htm"
     },
     "IfcStructuralLoadStatic": {
@@ -4827,7 +4827,7 @@
             "DeltaT_Y": "Temperature change which is applied to the outer fiber of the positive Y-direction. A positive value describes an increase in temperature.",
             "DeltaT_Z": "Temperature change which is applied to the outer fiber of the positive Z-direction. A positive value describes an increase in temperature."
         },
-        "description": "An instance of the entity IfcStructuralLoadTemperature shall be used to define actions which are caused by a temperature change. The change of temperature is given with a constant value which is applied to the complete section and values for the outer fibre of the positive Y and Z directions.",
+        "description": "An instance of the entity IfcStructuralLoadTemperature shall be used to define actions which are caused by a temperature change. The change of temperature is given with a constant value which is applied to the complete section and values for the outer fibre of the positive Y and Z directions. All values are given within the chosen coordinate system of the 'activity element' (subtypes of IfcStructuralActivity), either the local coordinate system of the activity element or the global project coordinate system which is referenced by the activity element as its geometric representation context. The unit of the temperature values are given within the global unit assignment (IfcUnitAssignment).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadtemperature.htm"
     },
     "IfcStructuralMember": {
@@ -4835,14 +4835,14 @@
             "ConnectedBy": "Inverse relationship to all structural connections (i.e. to supports or connecting elements) which are defined for this structural member.",
             "ReferencesElement": "Inverse link to the relationship object, that connects a physical element to this structural member (the element of which this structural member is the analytical idealization)."
         },
-        "description": "Definition from IAI: The abstract entity IfcStructuralMember is the superclass of all structural elements representing the structural behavior of building elements. A further differentiation is made for structural curve members and structural face members (see IfcStructuralCurveMember and IfcStructuralFaceMember). Structural members can have ",
+        "description": "Definition from IAI: The abstract entity IfcStructuralMember is the superclass of all structural elements representing the structural behavior of building elements. A further differentiation is made for structural curve members and structural face members (see IfcStructuralCurveMember and IfcStructuralFaceMember). Structural members can have - a material definition, using IfcStructuralMember o-- IfcRelAssociatesMaterial --o IfcMaterial - a profile definition, using IfcStructuralMember o-- IRelAssociatesProfileProperties --o IfcProfileProperties - a parent analysis model, using IfcStructuralMember o-- IfcRelAssignsToGroup --o IfcStructuralAnalysisModel *Use Definition*",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralmember.htm"
     },
     "IfcStructuralPlanarAction": {
         "attributes": {
             "ProjectedOrTrue": "Defines if the load values are given by using the length of the member on which they act (true length) or by using the projected length resulting from the loaded member and the global project coordinate system. It is only considered if the global project coordinate system is used, and if the action is of type IfcStructuralLinearAction or IfcStructuralPlanarAction."
         },
-        "description": "Instances of the entity IfcStructuralPlanarAction are used to define constant planar actions. Structural loads applicable to planar actions are IfcStructuralLoadPlanarForce and IfcStructuralLoadTemperature.",
+        "description": "Instances of the entity IfcStructuralPlanarAction are used to define constant planar actions. Structural loads applicable to planar actions are IfcStructuralLoadPlanarForce and IfcStructuralLoadTemperature. The structural load, defining the planar action is given by the attribute AppliedLoad at the supertype IfcStructuralActivity. The coordinate system, in which the AppliedLoad is defined is given by the attribute ObjectPlacement at the supertype IfcProduct. *Topology Use Definition* Special case: If applied to building elements, placement and representation of the structural action are often implied by those of the building elements and are therefore optional for the actions. Standard case: If applied to structural items, instances of IfcStructuralPlanarAction shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". Placement The placement for IfcStructuralPlanarAction is determined at its supertype IfcProduct. It is defined by the optional IfcObjectPlacement, referenced by ObjectPlacement at IfcProduct, which establishes, if given, the object coordinate system that is referenced by the applied load. - If the ObjectPlacement attribute is omitted, then all topological representations are given directly in world coordinates. - If the ObjectPlacement attribute is provided, then it establishes an object coordinate system for all topological representations which are given object coordinates. If the PlacementRelTo relationship of IfcLocalPlacement is omitted, the object coordinate system is established within the world coordinate system. If the PlacementRelTo relationship of IfcLocalPlacement is given, it shall point to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. Topology Representation Instances of IfcStructuralPlanarAction shall have a topology representation given by a face with an optional additional geometric representation of the included surface. It can be provided by either - IfcFace - IfcFaceSurface which should be the single item of IfcTopologyRepresentation.Items.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralplanaraction.htm"
     },
     "IfcStructuralPlanarActionVarying": {
@@ -4851,11 +4851,11 @@
             "VaryingAppliedLoadLocation": "A shape aspect, containing a list of shape representations, each defining either one Cartesian point or one point on curve (by parameter values) which are needed to provide the positions of the VaryingAppliedLoads. The values contained in the list of IfcShapeAspect.ShapeRepresentations correspond to the values at the same position in the list VaryingAppliedLoads.",
             "VaryingAppliedLoads": "Derived list of all varying applied loads by pushing the inherited AppliedLoad value to the beginning of the list of SubsequentAppliedLoads. IfcAddToBeginOfList(SELF\\IfcStructuralActivity.AppliedLoad, SubsequentAppliedLoads)"
         },
-        "description": "Instances of the entity IfcStructuralPlanarActionVarying are used to define varying planar actions. IfcStructuralPlanarActionVarying inherits the needed attributes and applicable structural load types from its superclass IfcStructuralLinearAction.",
+        "description": "Instances of the entity IfcStructuralPlanarActionVarying are used to define varying planar actions. IfcStructuralPlanarActionVarying inherits the needed attributes and applicable structural load types from its superclass IfcStructuralLinearAction. *Topology Use Definition* Instances of IfcStructuralPlanarActionVarying shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". The definition of the topological representation is given at the supertype IfcStructuralPlanarAction. *Shape Aspect Use Definition* The attribute VaryingAppliedLoadLocation reference a shape aspect, that has a list of ShapeRepresentations. Each individual IfcShapeRepresentation within that list shall have a single item within its list of Items. The type of the item shall be either: - IfcCartesianPoint, or - IfcPointOnSurface Each list member within the list of ShapeRepresentations corresponds to the list member (at same position) of the list VaryingAppliedLoads, and provides the position of the applied load. At least three applied load values shall be given, the distribution of the applied planar loads across the surface of the planar action is constructed by triangulation. The following examples shows a definition of a varying applied loads by four Cartesian points.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralplanaractionvarying.htm"
     },
     "IfcStructuralPointAction": {
-        "description": "Instances of the entity IfcStructuralPointAction are used to define point actions. Structural loads applicable to point actions are IfcStructuralLoadSingleForce (and subtype), and IfcStructuralLoadSingleDisplacement (and subtype).",
+        "description": "Instances of the entity IfcStructuralPointAction are used to define point actions. Structural loads applicable to point actions are IfcStructuralLoadSingleForce (and subtype), and IfcStructuralLoadSingleDisplacement (and subtype). The structural load, defining the point action is given by the attribute AppliedLoad at the supertype IfcStructuralActivity. The coordinate system, in which the AppliedLoad is defined is given by the attribute ObjectPlacement at the supertype IfcProduct. *Topology Use Definition* Special case: If applied to building elements, placement and representation of the structural action are often implied by those of the building elements and are therefore optional for the actions. Standard case: If applied to structural items, instances of IfcStructuralPointAction shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". Placement The placement for IfcStructuralPointAction is determined at its supertype IfcProduct. It is defined by the optional IfcObjectPlacement, referenced by ObjectPlacement at IfcProduct, which establishes, if given, the object coordinate system that is referenced by the applied load. - If the ObjectPlacement attribute is omitted, then all topological representations are given directly in world coordinates. - If the ObjectPlacement attribute is provided, then it establishes an object coordinate system for all topological representations which are given object coordinates. If the PlacementRelTo relationship of IfcLocalPlacement is omitted, the object coordinate system is established within the world coordinate system. If the PlacementRelTo relationship of IfcLocalPlacement is given, it shall point to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. Topology Representation Instances of IfcStructuralPointAction may have a topology representation given by a vertex with an optional additional geometric representation by a Cartesian point. It can be provided by either - IfcVertex - IfcVertexPoint which should be the single item of IfcTopologyRepresentation.Items. If no topology representation is given, the location of the placement is taken as the vertex at which the point actions acts upon the structural item.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralpointaction.htm"
     },
     "IfcStructuralPointConnection": {
@@ -4863,7 +4863,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralpointconnection.htm"
     },
     "IfcStructuralPointReaction": {
-        "description": "Instances of the entity IfcStructuralPointReaction are used to define point reactions. IfcStructuralPointReaction inherits all needed attributes from its superclass IfcStructuralReaction.",
+        "description": "Instances of the entity IfcStructuralPointReaction are used to define point reactions. IfcStructuralPointReaction inherits all needed attributes from its superclass IfcStructuralReaction. The structural load, defining the point reaction is given by the attribute AppliedLoad at the supertype IfcStructuralActivity. The coordinate system, in which the AppliedLoad is defined is given by the attribute ObjectPlacement at the supertype IfcProduct. *Topology Use Definition* Instances of IfcStructuralPointReaction shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". Placement The placement for IfcStructuralPointReaction is determined at its supertype IfcProduct. It is defined by the optional IfcObjectPlacement, referenced by ObjectPlacement at IfcProduct, which establishes, if given, the object coordinate system that is referenced by the applied load. - Ifc the ObjectPlacement attribute is omitted, then all topological representations are given directly in world coordinates. - Ifc the ObjectPlacement attribute is provided, then it establishes an object coordinate system for all topological representations which are given object coordinates. If the PlacementRelTo relationship of IfcLocalPlacement is omitted, the object coordinate system is established within the world coordinate system. If the PlacementRelTo relationship of IfcLocalPlacement is given, it shall point to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. Topology Representation Instances of IfcStructuralPointReaction may have a topology representation given by a vertex with an optional additional geometric representation by a Cartesian point. It can be provided by either - IfcVertex - IfcVertexPoint which should be the single item of IfcTopologyRepresentation.Items. If no topology representation is given, the location of the placement is taken as the vertex at which the point reaction takes place.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralpointreaction.htm"
     },
     "IfcStructuralProfileProperties": {
@@ -4885,7 +4885,7 @@
             "TorsionalSectionModulus": "Torsional resistance (about the profiles X-axis). Usually measured in [mm3].",
             "WarpingConstant": "Warping constant of the profile for torsional action. Usually measured in [mm6]."
         },
-        "description": "Definition from IAI: This is a collection of structural properties applicable to all linear structural members having a profile definition. For the structural profile properties a further material dependent specialization is given for taking into account specific profile properties applicable only in the context of a specific building material.",
+        "description": "Definition from IAI: This is a collection of structural properties applicable to all linear structural members having a profile definition. For the structural profile properties a further material dependent specialization is given for taking into account specific profile properties applicable only in the context of a specific building material. The center of gravity is measured from the origin of the geometric profile definition (see subtypes of IfcProfileDef). The CentreOfGravityInX defines the distance along the geometric x axis of the geometric profile definition, the CentreOfGravityInY defines the distance along the geometric y axis. - For parameterized profiles: Center of gravity is measured from the center of the profile definition, which is the center of the bounding box of that profile geometry. - For arbitrary profiles: Center of gravity is measured from the 0.,0. local origin of the underlying 2D coordinate system of the explicit profile definition. The shear center is measured from the gravity center and is given in the structural coordinates, defined by: * origin = center of gravity * y axis = negative x axis of the geometric coordinate system * z axis = negative y axis of the geometric coordinate system Illustration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcstructuralprofileproperties.htm"
     },
     "IfcStructuralReaction": {
@@ -4923,7 +4923,7 @@
         "attributes": {
             "Thickness": "Defines the typically understood thickness of the structural face member, i.e. the smallest spatial dimension of the element."
         },
-        "description": "Instances of the entity IfcStructuralSurfaceMember shall be used to describe planar structural elements.",
+        "description": "Instances of the entity IfcStructuralSurfaceMember shall be used to describe planar structural elements. The material properties are defined by IfcMechanicalMaterialProperties (and subtypes) and they are connected through IfcMaterial and IfcRelAssociatesMaterial and are accessible via the inherited inverse relationship HasAssociations. *Topology Use Definition* Instances of IfcStructuralSurfaceMember shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". Placement The placement for IfcStructuralSurfaceMember is determined at its supertype IfcProduct. It is defined by the optional IfcObjectPlacement, referenced by ObjectPlacement at IfcProduct, which establishes, if given, the object coordinate system that is referenced by all topological representations of that product. - If the ObjectPlacement attribute is omitted, then all topological representations are given directly in world coordinates. - If the ObjectPlacement attribute is provided, then it establishes an object coordinate system for all topological representations which are given object coordinates. If the PlacementRelTo relationship of IfcLocalPlacement is omitted, the object coordinate system is established within the world coordinate system. If the PlacementRelTo relationship of IfcLocalPlacement is given, it shall point to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. Topology Representation Instances of IfcStructuralSurfaceMember shall have a topology representation given by a face with an optional additional geometric representation of the included surface. It can be provided by either - IfcFace - IfcFaceSurface which should be the single item of IfcTopologyRepresentation.Items.",
         "predefined_types": {
             "BENDING_ELEMENT": "",
             "MEMBRANE_ELEMENT": "",
@@ -4939,15 +4939,15 @@
             "VaryingThickness": "Derived list of all varying thickness values by pushing the inherited starting thickness to the beginning of the list of SubsequentThickness. IfcAddToBeginOfList(SELF\\IfcStructuralSurfaceMember.Thickness, SubsequentThickness)",
             "VaryingThicknessLocation": "A shape aspect, containing a list of shape representations, each defining either one Cartesian point or one point on surface (by parameter values) which are needed to provide the positions of the VaryingThickness. The values contained in the list of IfcShapeAspect.ShapeRepresentations correspond to the values at the same position in the list VaryingThickness. The locations shall be along the outer bounds of the face (or surface) only."
         },
-        "description": "Instances of the entity IfcStructuralSurfaceMemberVarying shall be used to describe planar structural elements with a varying thickness.",
+        "description": "Instances of the entity IfcStructuralSurfaceMemberVarying shall be used to describe planar structural elements with a varying thickness. The inherited Thickness attribute shall be given, the additional, subsequent thickness values are given by the SubsequentThickness list. The derived list VaryingThickness is created by pushing the_Thickness_ attribute at the beginning of the SubsequentThickness list. *Topology Use Definition* Instances of IfcStructuralSurfaceMemberVarying shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type \"IfcTopologyRepresentation\". The guidelines on using the location and topological representation capabilities are identical with those at the supertype IfcStructuralSurfaceMember. *Shape Aspect Use Definition* The attribute VaryingThicknessLocation references a shape aspect that has a list of ShapeRepresentations. Each individual IfcShapeRepresentation within that list shall have a single item within its list of Items. The type of the item shall be either: - IfcCartesianPoint, or - IfcPointOnSurface Each list member within the list of ShapeRepresentations corresponds to the list member (at same position) of the list VaryingThickness, and provides the thickness at that location. At least three thickness values shall be given, the analytical volume is constructed by triangulation. The following example shows a definition of a varying thickness by four Cartesian points.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfacemembervarying.htm"
     },
     "IfcStructuredDimensionCallout": {
-        "description": "The structured dimension callout represents a special type of a draughting callout, which identifies the various components of the dimension text. This is done by ensuring the correct Name attribute values for the annotation text occurrences used within the callout.",
+        "description": "The structured dimension callout represents a special type of a draughting callout, which identifies the various components of the dimension text. This is done by ensuring the correct Name attribute values for the annotation text occurrences used within the callout. Illustration from ISO 10303-202 page 497:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcstructureddimensioncallout.htm"
     },
     "IfcStyleModel": {
-        "description": "The IfcStyleModel represents the concept of a particular presentation style defined for a material (or other characteristic) of a product or a product component within a representation context. This representation context may (but has not to be) a geometric representation context. ",
+        "description": "The IfcStyleModel represents the concept of a particular presentation style defined for a material (or other characteristic) of a product or a product component within a representation context. This representation context may (but has not to be) a geometric representation context. The IfcStyleModel can be a style representation (presentation style) of a material (via IfcMaterialDefinitionRepresentation), potentially differentiated for different representation contexts (e.g. different material hatching depending on the scale of the target representation context).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcstylemodel.htm"
     },
     "IfcStyledItem": {
@@ -4956,11 +4956,11 @@
             "Name": "The word, or group of words, by which the styled item is referred to.",
             "Styles": "Representation style assignments which are assigned to an item. NOTE: In current IFC release only one presentation style assignment shall be assigned."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: The styled item is an assignment of style for presentation to a geometric representation item as it is used in a representation.",
+        "description": "Definition from ISO/CD 10303-46:1992: The styled item is an assignment of style for presentation to a geometric representation item as it is used in a representation. Definition from IAI: The IfcStyledItem holds presentation style information for products, either explicitly for an IfcGeometricRepresentationItem being part of an IfcShapeRepresentation assigned to a product, or by assigning presentation information to IfcMaterial being assigned as other representation for a product.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcstyleditem.htm"
     },
     "IfcStyledRepresentation": {
-        "description": "Definition from IAI: The IfcStyledRepresentation represents the concept of a styled presentation being a representation of a product or a product component, like material. within a representation context. This representation context does not need to be (but may be) a geometric representation context.",
+        "description": "Definition from IAI: The IfcStyledRepresentation represents the concept of a styled presentation being a representation of a product or a product component, like material. within a representation context. This representation context does not need to be (but may be) a geometric representation context. A styled representation has to include one or several styled items or annotation occurrences with the associated style information (curve, symbol, text, fill area, or surface styles). It may also contain the geometric representation items that are styled.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcstyledrepresentation.htm"
     },
     "IfcSubContractResource": {
@@ -4968,18 +4968,18 @@
             "JobDescription": "The description of the jobs that this subcontract should complete.",
             "SubContractor": "The actor performing the role of the subcontracted resource."
         },
-        "description": "An IfcSubContractResource is a construction resource needed in a construction process that represents a type of sub-contractor.",
+        "description": "An IfcSubContractResource is a construction resource needed in a construction process that represents a type of sub-contractor. An IfcSubContractResource can be used in cost estimating and work planning without specifying the subcontractor. However, it can be associated with an actor fulfilling the subcontractor role when detailed work planning is performed. The type of subcontractor can also be identified in a construction crew resource.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifcsubcontractresource.htm"
     },
     "IfcSubedge": {
         "attributes": {
             "ParentEdge": "The Edge, or Subedge, which contains the Subedge."
         },
-        "description": "Definition from ISO/DIS 10303-42:1999(E): A subedge is an edge whose domain is a connected portion of the domain of an existing edge. The topological constraints on a subedge are the same as those on an edge.",
+        "description": "Definition from ISO/DIS 10303-42:1999(E): A subedge is an edge whose domain is a connected portion of the domain of an existing edge. The topological constraints on a subedge are the same as those on an edge. Informal propositions: - The domain of the subedge is formally defined to be the domain of the parent edge, as trimmed by the subedge start vertex and subedge end vertex. - The start vertex and end vertex shall be within the union of the domains of the vertices of the parent edge and the domain of the parent edge.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcsubedge.htm"
     },
     "IfcSurface": {
-        "description": "Definition from ISO/CD 10303-42:1992: A surface can be envisioned as a set of connected points in 3-dimensional space which is always locally 2-dimensional, but need not be a manifold.",
+        "description": "Definition from ISO/CD 10303-42:1992: A surface can be envisioned as a set of connected points in 3-dimensional space which is always locally 2-dimensional, but need not be a manifold. Informal proposition: - A surface has non zero area. - A surface is arcwise connected.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcsurface.htm"
     },
     "IfcSurfaceCurveSweptAreaSolid": {
@@ -4989,7 +4989,7 @@
             "ReferenceSurface": "The surface containing the Directrix.",
             "StartParam": "The parameter value on the Directrix at which the sweeping operation commences."
         },
-        "description": "Definition from ISO/DIS 10303-42:1999(E): A surface curve swept area solid is a type of swept area solid which is the result of sweeping a face along a Directrix lying on a ReferenceSurface. The orientation of the SweptArea is related to the direction of the surface normal.",
+        "description": "Definition from ISO/DIS 10303-42:1999(E): A surface curve swept area solid is a type of swept area solid which is the result of sweeping a face along a Directrix lying on a ReferenceSurface. The orientation of the SweptArea is related to the direction of the surface normal. The SweptArea is required to be a curve bounded surface lying in the plane z = 0 and this is swept along the Directrix in such a way that the origin of the local coordinate system used to define the SweptArea is on the Directrix and the local x-axis is in the direction of the normal to the ReferenceSurface at the current point. The resulting solid has the property that the cross section of the surface by the normal plane to the Directrix at any point is a copy of the SweptArea. The orientation of the SweptArea as it sweeps along the Directrix is precisely defined by a CartesianTransformationOperator3d with attributes: - LocalOrigin as point (0; 0; 0), - Axis1 as the normal N to the ReferenceSurface at the point of the Directrix with parameter u. - Axis3 as the direction of the tangent vector t at the point of the Directrix with parameter u. The remaining attributes are defaulted to define a corresponding transformation matrix T(u), which varies with the Directrix parameter u. The swept face is given by IfcProfileDef (or subtypes), the profile definition is given within a 2D coordinate system, which is inserted into the XY plane of the Position coordinate system inherited from the supertype IfcSweptAreaSolid. The attributes of the CartesianTransformationOperator3d (as given above) should apply to the Position coordinate system, in which the profile is inserted. Informal propositions: - The SweptArea shall lie in the plane z = 0. - The directrix shall lie on the ReferenceSurface.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsurfacecurvesweptareasolid.htm"
     },
     "IfcSurfaceOfLinearExtrusion": {
@@ -4998,7 +4998,7 @@
             "ExtrudedDirection": "The direction of the extrusion.",
             "ExtrusionAxis": "The extrusion axis defined as vector. IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector (ExtrudedDirection, Depth)"
         },
-        "description": "Definition from ISO/CD 10303-42:1992: This surface is a simple swept surface or a generalized cylinder obtained by sweeping a curve in a given direction. The parameterization is as follows where the curve has a parameterization l(u):",
+        "description": "Definition from ISO/CD 10303-42:1992: This surface is a simple swept surface or a generalized cylinder obtained by sweeping a curve in a given direction. The parameterization is as follows where the curve has a parameterization l(u): Informal propositions: - The surface shall not self-intersect",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcsurfaceoflinearextrusion.htm"
     },
     "IfcSurfaceOfRevolution": {
@@ -5006,7 +5006,7 @@
             "AxisLine": "The line coinciding with the axis of revolution. IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(AxisPosition.Location,    IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(AxisPosition.Z,1.0))",
             "AxisPosition": "A point on the axis of revolution and the direction of the axis of revolution."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A surface of revolution (IfcSurfaceOfRevolution) is the surface obtained by rotating a curve one complete revolution about an axis. The data shall be interpreted as below.",
+        "description": "Definition from ISO/CD 10303-42:1992: A surface of revolution (IfcSurfaceOfRevolution) is the surface obtained by rotating a curve one complete revolution about an axis. The data shall be interpreted as below. The parameterization is as follows where the curve has a parameterization l(u): For a surface of revolution the parametric range is 0 < u < 360 degree. The parameterization range for v is defined by referenced curve. Informal propositions: - The surface shall not self-intersect - The swept curve shall not be coincident with the axis line for any finite part of its legth.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcsurfaceofrevolution.htm"
     },
     "IfcSurfaceStyle": {
@@ -5024,7 +5024,7 @@
             "ReflectanceColour": "A coefficient that determines the extent that the light falling onto a surface is fully or partially reflected.  > The factor can be measured physically and has three ratios for the red, green and blue part of the light.",
             "TransmissionColour": "Describes how the light falling on a body is totally or partially transmitted.  > The factor can be measured physically and has three ratios for the red, green and blue part of the light."
         },
-        "description": "IfcSurfaceStyleLighting is a container class for properties for calculation of physically exact illuminance related to a particular surface style.",
+        "description": "IfcSurfaceStyleLighting is a container class for properties for calculation of physically exact illuminance related to a particular surface style. The illustration above shows the reflection and transmission components from an incident ray. The sum of the components for reflection and transmission is a value of 1.0 denoting that the incident ray is completely decomposed into reflection and transmission components. Each value of reflection and transmission is therefore within the range 0.0 to 1.0. All these factors can be measured physically and are ratios for the red, green and blue part of the light. These properties are defined in the model as Type IfcColorRGB with a factor for each colour.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestylelighting.htm"
     },
     "IfcSurfaceStyleRefraction": {
@@ -5046,21 +5046,21 @@
             "TransmissionColour": "The transmissive part of the reflectance equation can be given as either a colour or a scalar factor. It only applies to materials which Transparency field is greater than zero. The transmissive colour field specifies the colour that passes through a transparant material (like the colour that shines through a glass). The transmissive factor defines the transmissive part, the transmissive colour is then defined by surface colour \\* transmissive factor.",
             "Transparency": "Definition from ISO/CD 10303-46: The degree of transparency is indicated by the percentage of light traversing the surface. Definition from VRML97 - ISO/IEC 14772-1:1997: The transparency field specifies how \"clear\" an object is, with 1.0 being completely transparent, and 0.0 completely opaque. If not given, the value 0.0 (opaque) is assumed."
         },
-        "description": "IfcSurfaceStyleRendering holds the properties for visualization related to a particular surface side style.",
+        "description": "IfcSurfaceStyleRendering holds the properties for visualization related to a particular surface side style. It allows rendering properties to be defined by: - a transparency component (Transparency attribute) - a colour component (SurfaceColour attribute inherited from IfcSurfaceStyleShading) - a reflectance component, given either by applying reflectance factors to the surface colour: diffuse component (SurfaceColour * DiffuseFactor) transmission component (SurfaceColour * TransmissionFactor ) diffuse transmission component (SurfaceColour * DiffuseTransmissionFactor) reflection component (SurfaceColour * ReflectionFactor) specular component (SurfaceColour * SpecularFactor attribute together with SpecularHighlight) explicitly defining such factors as colours (DiffuseColour, TransmissionColour, DiffuseTransmissionColour, ReflectionColour and SpecularColour) - a displacement component, currently only given by a texture map with the TextureType = bump - a coverage component, currently only given by the alpha component of the texture map (2 or 4 component colour texture)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestylerendering.htm"
     },
     "IfcSurfaceStyleShading": {
         "attributes": {
             "SurfaceColour": "The colour used to render the surface. The surface colour for visualisation is defined by specifying the intensity of red, green and blue."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: The surface style rendering allows the realistic visualization of surfaces referring to rendering techniques based on the laws of physics and mathematics.",
+        "description": "Definition from ISO/CD 10303-46:1992: The surface style rendering allows the realistic visualization of surfaces referring to rendering techniques based on the laws of physics and mathematics. The entity IfcSurfaceStyleShading allows for colour information used for shading, whereas subtypes provide data for more sophisticated rendering techniques. The surface colour is used for colouring or simple shading of the assigned surfaces.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestyleshading.htm"
     },
     "IfcSurfaceStyleWithTextures": {
         "attributes": {
             "Textures": "The textures applied to the surface. Only one image map with the same image map type shall be applied."
         },
-        "description": "Definition from IAI: The entity IfcSurfaceStyleWithTextures allows for the assignment of image textures to surface styles. These image textures can be applied repeating across the surface or mapped with a particular scale upon the surface.",
+        "description": "Definition from IAI: The entity IfcSurfaceStyleWithTextures allows for the assignment of image textures to surface styles. These image textures can be applied repeating across the surface or mapped with a particular scale upon the surface. The entity IfcSurfaceStyleWithTextures is part of the surface style table for presentation information assigned to surfaces for shading, rendering and lighting with textures. The mapping of the texture onto the surface or the solid is determined by the texture coordinates, each IfcAnnotationSurfaceOccurrence has a TextureCoordinates attribute, referencing the texture coordinates for the occurrence of the IfcSurfaceStyleWithTextures.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestylewithtextures.htm"
     },
     "IfcSurfaceTexture": {
@@ -5070,7 +5070,7 @@
             "TextureTransform": "These parameters support changes to the size, orientation, and position of textures on shapes. Note that these operations appear reversed when viewed on the surface of geometry. For example, a scale value of (2 2) will scale the texture coordinates and have the net effect of shrinking the texture size by a factor of 2 (texture coordinates are twice as large and thus cause the texture to repeat). A translation of (0.5 0.0) translates the texture coordinates +.5 units along the S-axis and has the net effect of translating the texture -0.5 along the S-axis on the geometry's surface. A rotation of PI/2 of the texture coordinates results in a -PI/2 rotation of the texture on the geometry.",
             "TextureType": "Identifies the predefined types of image map from which the type required may be set."
         },
-        "description": "Definition from IAI: An IfcSurfaceTexture provides a 2-dimensional image-based texture map. It can either be given by referencing an external image file through an URL reference (IfcImageTexture), or by explicitly including an array of pixels (IfcPixelTexture).",
+        "description": "Definition from IAI: An IfcSurfaceTexture provides a 2-dimensional image-based texture map. It can either be given by referencing an external image file through an URL reference (IfcImageTexture), or by explicitly including an array of pixels (IfcPixelTexture). The following additional definitions from ISO/IEC FCD 19775:200x, the Extensible 3D (X3D) specification, apply: - Texture: An image used in a texture map to create visual appearance effects when applied to geometry nodes. - Texture map: A texture plus the general parameters necessary for mapping the texture to geometry. Texture maps are defined by 2D images that contain an array of colour values describing the texture. The texture map values are interpreted differently depending on the number of components in the texture map and the specifics of the image format. In general, texture maps may be described using one of the following forms: - Intensity textures (one-component) - Intensity plus alpha opacity textures (two-component) - Full RGB textures (three-component) - Full RGB plus alpha opacity textures (four-component)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacetexture.htm"
     },
     "IfcSweptAreaSolid": {
@@ -5078,7 +5078,7 @@
             "Position": "Position coordinate system for the swept area.",
             "SweptArea": "The surface defining the area to be swept. It is given as a profile definition within the xy plane of the position coordinate system."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: The swept area solid entity collects the entities which are defined procedurally by sweeping action on planar bounded surfaces. The position is space of the swept solid will be dependent upon the position of the swept area. The swept area will be a face of the resulting swept area solid, except for the case of a revolved area solid with angle equal to 2 p (or 360 degrees).",
+        "description": "Definition from ISO/CD 10303-42:1992: The swept area solid entity collects the entities which are defined procedurally by sweeping action on planar bounded surfaces. The position is space of the swept solid will be dependent upon the position of the swept area. The swept area will be a face of the resulting swept area solid, except for the case of a revolved area solid with angle equal to 2 p (or 360 degrees). The swept area is defined by a cross section (also referred to as profile), which is given as a closed two-dimensional boundary on an implicit plane. The swept area is defined in the xy plane of the position coordinate system, which is given for the swept area solid.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsweptareasolid.htm"
     },
     "IfcSweptDiskSolid": {
@@ -5102,7 +5102,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcsweptsurface.htm"
     },
     "IfcSwitchingDeviceType": {
-        "description": "An IfcSwitchingDeviceType defines a particular type of switch which is a mechanically operated contactor.",
+        "description": "An IfcSwitchingDeviceType defines a particular type of switch which is a mechanically operated contactor. *Use Definitions* An IfcSwitchingDeviceType is a subtype of IfcFlowControllerType that provides for all forms of switch. Usage of IfcSwitchingDeviceType defines the parameters for one or more occurrences of IfcFlowController. Parameters are specified through property sets that are enumerated in the IfcSwitchingDeviceTypeEnum data type. *Property Set Use Definition*: The property sets relating to the IfcSwitchingDeviceType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcSwitchingDeviceType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available - Pset_SwitchingDeviceTypeCommon: property set for properties that are common to all types of switching device, if available - Pset_SwitchingDeviceTypeContactor: specific property set for the properties of a contactor , if available - Pset_SwitchingDeviceTypeEmergencyStop: specific property set for the properties of an emergency stop device, if available - Pset_SwitchingDeviceTypeStarter: specific property set for the properties of a starter, if available - Pset_SwitchingDeviceTypeSwitchDisconnector: specific property set for the properties of a switch disconnector, if available - Pset_SwitchingDeviceTypeToggleSwitch: specific property set for the properties of a toggle switch, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "CONTACTOR": "An electrical device used to control the flow of power in a circuit on or off.",
             "EMERGENCYSTOP": "An emergency stop device acts to remove as quickly as possible any danger that may have arisen unexpectedly.",
@@ -5129,7 +5129,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcsystem.htm"
     },
     "IfcSystemFurnitureElementType": {
-        "description": "An IfcSystemFurnitureElementType defines a particular type of component or element of systems or modular furniture.",
+        "description": "An IfcSystemFurnitureElementType defines a particular type of component or element of systems or modular furniture. *Use Definitions* An IfcSystemFurnitureElementType provides for all types of elements of system furniture. Occurrences of a type of system furniture element are specified through IfcFurnishingElement. An occurrence of a complete IfcFurnishingElement made up of system furniture elements is created using IfcRelNests (if only the system furniture elements are specified) or IfcRelAggregates (in cases where both the system furniture elements, means of joining together the elements and other accessories such as cable tray and wiring etc. are included). *Property Set Use Definition*: The property sets relating to an IfcSystemFurnitureElementType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcSystemFurnitureElementType are part of this IFC release: - Pset_SystemFurnitureElementTypeCommon: property set for the properties common to all types of system furniture element, if available - Pset_SystemFurnitureElementTypePanel: specific property set for the properties of a system furniture panel, if available - Pset_SystemFurnitureElementTypeWorkSurface: specific property set for the properties of a system furniture work surface, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem. *Name Use Definitions*The name of the type of system furniture element is defined through the IfcSystemFurnitureElementType.Name attribute (through inheritance from IfcRoot). For further indormation on usage, refer to IfcFurnitureType",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcsystemfurnitureelementtype.htm"
     },
     "IfcTShapeProfileDef": {
@@ -5145,7 +5145,7 @@
             "WebSlope": "Slope of flange of the profile. If it is not given, zero is assumed.",
             "WebThickness": "Constant wall thickness of web (= ts)."
         },
-        "description": "Definition from IAI: The IfcTShapeProfileDef defines a section profile that provides the defining parameters of a T-shaped section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
+        "description": "Definition from IAI: The IfcTShapeProfileDef defines a section profile that provides the defining parameters of a T-shaped section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box. The centre of gravity, if given, is located in x direction within the center of the bounding box, and in y-direction along the positive y axis, the offset value is given by the offset parameter CentreOfGravityInY. Illustration: Table: Parameters of T-shape profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifctshapeprofiledef.htm"
     },
     "IfcTable": {
@@ -5156,7 +5156,7 @@
             "NumberOfHeadings": "The number of headings in a table. This is restricted by WR3 to max. one. SIZEOF(QUERY( Temp <* Rows | Temp.IsHeading))",
             "Rows": "Reference to information content of rows."
         },
-        "description": "A data structure for the provision of information in the form of rows and columns. Each instance may have a heading row with titles or descriptions for each column. The rows of information are stored as a list of IfcTableRow objects.",
+        "description": "A data structure for the provision of information in the form of rows and columns. Each instance may have a heading row with titles or descriptions for each column. The rows of information are stored as a list of IfcTableRow objects. Limitation: In this release of IFC the rows of an IfcTable object are constrained to have the same number of cells. The first Row of the table provides the number of cells. All other rows are forced to include the same number of cells. This is enforced by the WR2.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifctable.htm"
     },
     "IfcTableRow": {
@@ -5165,11 +5165,11 @@
             "OfTable": "Reference to the IfcTable, in which the IfcTableRow is defined (or contained).",
             "RowCells": "The value of information by row and column using the units defined. NOTE - The row value identifies both the actual value and the units in which it is recorded. Each cell (unique row and column) may have a different value AND different units. If the row is a heading row, then the row values are strings defined by the IfcString."
         },
-        "description": "The information content of each row within the table (other than the heading row). A table contains a number of rows which record information concerning the instance of the type of information recorded within the table.",
+        "description": "The information content of each row within the table (other than the heading row). A table contains a number of rows which record information concerning the instance of the type of information recorded within the table. Limitation: Within this release of IFC all IfcTableRow objects referenced by an IfcTable shall have the same number of Row Cells. The actual number of Cells shall be taken from the number of cells of the first IfcTableRow for that table. The number of Cells is calculated by the derived attribute NumberOfCellsInRow in the associated IfcTable.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifctablerow.htm"
     },
     "IfcTankType": {
-        "description": "The element type IfcTankType defines a list of commonly shared property set definitions of a tank and an optional set of product representations. It is used to define a tank specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcTankType defines a list of commonly shared property set definitions of a tank and an optional set of product representations. It is used to define a tank specification (i.e. the specific product information, that is common to all occurrences of that product type). A tank type is used to define the common properties of a Tank that may be applied to many occurrences of that type. A tank is a device used to hold gasses and liquids. Tank types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcTankType are represented by instances of IfcFlowStorageDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_TankTypeCommon: common property set for all tank types Pset_TankTypeExpansion: property set for expansion tank types Pset_TankTypePreformed: property set for preformed tank types Pset_TankTypePressureVessel: property set for pressure vessel tank types Pset_TankTypeSectional: property set for sectional tank types",
         "predefined_types": {
             "EXPANSION": "A closed container used in a closed fluid distribution system to mitigate the effects of thermal expansion or water hammer. The tank is typically constructed with a diaphragm dividing the tank into two sections, with fluid on one side of the diaphragm and air on the other. One example application is when connected to the primary circuit of a hot water system to accommodate the increase in volume of the water when it is heated.",
             "NOTDEFINED": "Undefined tank type.",
@@ -5188,7 +5188,7 @@
             "TaskId": "An identifying designation given to a task.",
             "WorkMethod": "The method of work used in carrying out a task."
         },
-        "description": "An IfcTask is an identifiable unit of work to be carried out independently of any other units of work in a construction project.",
+        "description": "An IfcTask is an identifiable unit of work to be carried out independently of any other units of work in a construction project. Use Definitions Work is identified as tasks (i.e. IfcTask) that are capable of either containing other tasks or being sub-items of other tasks. A task can be used to describe a process for the construction or installation of products. Each instance of IfcTask is given a name that is indicative of its content. A textual description of the the task may be be provided. Instances of IfcTask may be assigned to an IfcWorkControl (either a work plan or a work schedule) through the IfcRelAssignsTasks relationship class. The installation of a number of items of equipment within a particular space may be the subject of a single task which is identified as e.g. \u2018fix equipment in space 123\u2019. IfcTask represents the occurrence of a work performance of a type of process in a construction plan. A task can nest other tasks as sub-items; the nesting relationship is modeled by IfcRelNests. For example, the construction of a stud wall may be designated as a nesting task named \u2018install wall #1\u2019 including other tasks such as \u2018install dry wall\u2019, \u2018install studs\u2019, \u2018wall taping\u2019, and \u2018erect wall\u2019 as sub-processes. Special information relating to a task is asserted using IfcTask.ObjectType (inherited from IfcObject). Examples that may be used include fixed duration, fixed unit, fixed work. The sequential relationships between tasks are represented by IfcRelSequence in IfcKernel schema. Resource used by tasks are assigned by IfcRelAssignsToProcess. Quantities of resources consumed by the task are dealt with by defining the IfcElementQuantity for the resource and not at the instance of IfcTask. An IfcTask may be assigned a Work Breakdown Structure (WBS) code. A WBS code is dealt with as a classification of task and is associated to a task occurrence using the IfcRelAssociatesClassification relationship class. As well as being to designate the code, the classification structure of the IFC model also enables the source of the work breakdown structure classification to be identified.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifctask.htm"
     },
     "IfcTelecomAddress": {
@@ -5212,7 +5212,7 @@
             "PreStress": "The prestress to be applied on the tendon.",
             "TensionForce": "The maximum allowed tension force that can be applied on the tendon."
         },
-        "description": "A steel element such as a wire, cable, bar, rod, or strand used to impart prestress to concrete when the element is tensioned.",
+        "description": "A steel element such as a wire, cable, bar, rod, or strand used to impart prestress to concrete when the element is tensioned. Geometry Use Definitions: The geometric representation of IfcTendon is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcBuildingElementComponent. Standard Geometric Representation using Swept Solid Representation The standard geometric representation of IfcTendon is defined using the swept solid representation. The RepresentationType attribute of IfcShapeRepresentation should have the value 'SweptSolid'. The solid is formed from a cross section approximated as a circular disk swept along any arbitrary curve. Given this, the following constraints apply to the standard representation: - Solid: IfcSweptDiskSolid introduced in IFC Release 2x2 shall be supported. - Profile: The circular disk cross section approximation is defined by the Radius attribute of IfcSweptDiskSolid. - Extrusion: The extrusion along any arbitrary curve is defined by the Directrix attribute of IfcSweptDiskSolid. Simplified Geometric Representation Simplified geometric representations may be used based on local agreements.",
         "predefined_types": {
             "BAR": "The tendon is configured as a bar.",
             "COATED": "The tendon is coated.",
@@ -5224,7 +5224,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifctendon.htm"
     },
     "IfcTendonAnchor": {
-        "description": "In prestressed or posttensioned concrete, the end connection for the tendons.",
+        "description": "In prestressed or posttensioned concrete, the end connection for the tendons. Geometry Use Definitions: The geometric representation of IfcTendonAnchor is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are: Local Placement The use of local placement is defined at the supertype IfcBuildingElementComponent. Standard Geometric Representation The use of Standard Geometric Representations is defined at the supertype IfcBuildingElementComponent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifctendonanchor.htm"
     },
     "IfcTerminatorSymbol": {
@@ -5257,7 +5257,7 @@
             "TextFontStyle": "The style applied to the text font for its visual appearance.   It defines the font family, font style, weight and size.",
             "TextStyle": "The style applied to the text block for its visual appearance.   It defines the text block characteristics, either for vector based or monospace text fonts (see select item _IfcTextStyleWithBoxCharacteristics_), or for true type text fonts (see select item _IfcTextStyleTextModel_."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: The text style is a presentation style for annotation text..",
+        "description": "Definition from ISO/CD 10303-46:1992: The text style is a presentation style for annotation text.. Definition from IAI: The IfcTextStyle provides the text style table for presentation information assigned to text literals. The style is defined by color, text font characteristics, and text box characteristics. The definitions are based upon: - definitions from ISO/IS 10303-46:1994 for (old) vector based and monospace text. - definitions from Cascading Style Sheets, level 1, W3C Recommendation 17 Dec 1996, revised 11 Jan 1999, CSS1, for all true type text. The use of the CSS1 definitions is the preferred way to represent text styles. An IfcTextStyle, when representing (old) vector based and monospace text, is instantiated with: * TextCharacterAppearance:: IfcTextStyleForDefinedFont (with BackgroundColour = NIL) * TextStyle:: IfcTextStyleWithBoxCharacteristics * TextFontStyle:: IfcDraughtingPreDefinedTextFont or IfcExternallyDefinedTextFont An IfcTextStyle, when representing (new) true type text, based on CSS1 definitions, is instantiated with: * TextCharacterAppearance:: IfcTextStyleForDefinedFont * TextStyle:: IfcTextStyleTextModel * TextFontStyle:: IfcTextStyleFontModel An IfcTextStyle can be assigned to IfcTextLiteral via the IfcPresentationStyleAssignment through an intermediate IfcAnnotationTextOccurrence.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextstyle.htm"
     },
     "IfcTextStyleFontModel": {
@@ -5268,7 +5268,7 @@
             "FontVariant": "The font variant property selects between normal and small-caps.    > NOTE  It has been introduced for later compliance to full CSS1 support.",
             "FontWeight": "The font weight property selects the weight of the font.    > NOTE  Values other then 'normal' and 'bold' have been introduced for later compliance to full CSS1 support."
         },
-        "description": "Definition from CSS1 (W3C Recommendation): Setting font properties will be among the most common uses of style sheets. Unfortunately, there exists no well-defined and universally accepted taxonomy for classifying fonts, and terms that apply to one font family may not be appropriate for others. E.g. 'italic' is commonly used to label slanted text, but slanted text may also be labeled as being Oblique, Slanted, Incline, Cursive or Kursiv. Therefore it is not a simple problem to map typical font selection properties to a specific font.",
+        "description": "Definition from CSS1 (W3C Recommendation): Setting font properties will be among the most common uses of style sheets. Unfortunately, there exists no well-defined and universally accepted taxonomy for classifying fonts, and terms that apply to one font family may not be appropriate for others. E.g. 'italic' is commonly used to label slanted text, but slanted text may also be labeled as being Oblique, Slanted, Incline, Cursive or Kursiv. Therefore it is not a simple problem to map typical font selection properties to a specific font. Font matching Because there is no accepted, universal taxonomy of font properties, matching of properties to font faces must be done carefully. The properties are matched in a well-defined order to insure that the results of this matching process are as consistent as possible across user agents (assuming that the same library of font faces is presented to each of them). - The user agent makes (or accesses) a database of relevant CSS1 properties of all the fonts of which the UA is aware. The UA may be aware of a font because it has been installed locally or it has been previously downloaded over the web. If there are two fonts with exactly the same properties, one of them is ignored. - At a given element and for each character in that element, the UA assembles the font-properties applicable to that element. Using the complete set of properties, the UA uses the 'font-family' property to choose a tentative font family. The remaining properties are tested against the family according to the matching criteria described with each property. If there are matches for all the remaining properties, then that is the matching font face for the given element. - If there is no matching font face within the 'font-family' being processed by step 2, and if there is a next alternative 'font-family' in the font set, then repeat step 2 with the next alternative 'font-family'. - If there is a matching font face, but it doesn't contain a glyph for the current character, and if there is a next alternative 'font-family' in the font sets, then repeat step 2 with the next alternative 'font-family'. - If there is no font within the family selected in 2, then use a UA-dependent default 'font-family' and repeat step 2, using the best match that can be obtained within the default font. (The above algorithm can be optimized to avoid having to revisit the CSS1 properties for each character.) The per-property matching rules from (2) above are as follows: - 'font-style' is tried first. 'italic' will be satisfied if there is either a face in the UA's font database labeled with the CSS keyword 'italic' (preferred) or 'oblique'. Otherwise the values must be matched exactly or font-style will fail. - 'font-variant' is tried next. 'normal' matches a font not labeled as 'small-caps'; 'small-caps' matches (1) a font labeled as 'small-caps', (2) a font in which the small caps are synthesized, or (3) a font where all lowercase letters are replaced by upper case letters. A small-caps font may be synthesized by electronically scaling uppercase letters from a normal font. - 'font-weight' is matched next, it will never fail. (See 'font-weight' below.) - 'font-size' must be matched within a UA-dependent margin of tolerance. (Typically, sizes for scalable fonts are rounded to the nearest whole pixel, while the tolerance for bitmapped fonts could be as large as 20%.) Further computations, are based on the 'font-size' value that is used, not the one that is specified. Definition from IAI: The inherited Name attribute is used to define the font name, particularly in cases, where no (list of) font families are provided.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifctextstylefontmodel.htm"
     },
     "IfcTextStyleForDefinedFont": {
@@ -5276,7 +5276,7 @@
             "BackgroundColour": "This property sets the background color of an element.",
             "Colour": "This property describes the text color of an element (often referred to as the foreground color)."
         },
-        "description": "Definition from ISO/CD 10303-46:1992: A text style for defined font is a character glyph style for pre-defined or externally defined text fonts.",
+        "description": "Definition from ISO/CD 10303-46:1992: A text style for defined font is a character glyph style for pre-defined or externally defined text fonts. Definition from CSS1 (W3C Recommendation): These properties describe the color (often called foreground color) and background of an element (i.e. the surface onto which the content is rendered). One can set a background color. Definition from IAI: The IfcTextStyleForDefinedFont combines the text font color with an optional background color, that fills the text box, defined by the planar extent given to the text literal.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextstylefordefinedfont.htm"
     },
     "IfcTextStyleTextModel": {
@@ -5289,7 +5289,7 @@
             "TextTransform": "This property describes how text characters may transform to upper case, lower case, or capitalized case, independent of the character case used in the text literal.    > NOTE  It has been introduced for later compliance to full CSS1 support.",
             "WordSpacing": "The length unit indicates an addition to the default space between words. Values can be negative, but there may be implementation-specific limits. The user agent is free to select the exact spacing algorithm. The word spacing may also be influenced by justification (which is a value of the 'text-align' property).    > NOTE  It has been introduced for later compliance to full CSS1 support."
         },
-        "description": "Definition from CSS1 (W3C Recommendation): The properties defined in the text model affect the visual presentation of characters, spaces, words, and paragraphs.",
+        "description": "Definition from CSS1 (W3C Recommendation): The properties defined in the text model affect the visual presentation of characters, spaces, words, and paragraphs. Definition from IAI: The IfcTextStyleTextModel combines all text style properties, that affect the presentation of a text literal within a given extent. It includes the spacing between characters and words, the horizontal and vertical alignment of the text within the planar box of the extent, decorations (like underline), transformations of the literal (like uppercase), and the height of each text line within a multi-line text block.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextstyletextmodel.htm"
     },
     "IfcTextStyleWithBoxCharacteristics": {
@@ -5300,7 +5300,7 @@
             "BoxWidth": "It is the width scaling factor in the definition of a character glyph.",
             "CharacterSpacing": "The distance between the character boxes of adjacent characters."
         },
-        "description": "Definition from IAI: The text style with box characteristics allows the presentation of annotated text by specifying the characteristics of the character boxes of the text and the spacing between the character boxes.",
+        "description": "Definition from IAI: The text style with box characteristics allows the presentation of annotated text by specifying the characteristics of the character boxes of the text and the spacing between the character boxes. The IfcTextStyleWithBoxCharacteristics is mainly used to provide some compatibility with ISO10303. Its usage is restricted to monospace text fonts (having uniform character boxes) and simple vector based text fonts. For true text fonts however the use of IfcTextStyleTextModel is required.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextstylewithboxcharacteristics.htm"
     },
     "IfcTextureCoordinate": {
@@ -5315,21 +5315,21 @@
             "Mode": "The mode describes the algorithm used to compute texture coordinates.",
             "Parameter": "The parameter used by the function as specified by Mode."
         },
-        "description": "Definition from IAI: The IfcTextureCoordinateGenerator describes a procedurally defined mapping function with input parameter to map 2D texture coordinates to 3D geometry vertices. The allowable Mode values and input Parameter need to be agreed upon in implementer agreements.",
+        "description": "Definition from IAI: The IfcTextureCoordinateGenerator describes a procedurally defined mapping function with input parameter to map 2D texture coordinates to 3D geometry vertices. The allowable Mode values and input Parameter need to be agreed upon in implementer agreements. The following additional definitions from ISO/IEC FCD 19775:200x, the Extensible 3D (X3D) specification, apply:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctexturecoordinategenerator.htm"
     },
     "IfcTextureMap": {
         "attributes": {
             "TextureMaps": "Reference to a list of texture vertex assignment to coordinates within a vertex based geometry."
         },
-        "description": "Definition from IAI: An IfcTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to vertex based geometry models, such as",
+        "description": "Definition from IAI: An IfcTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to vertex based geometry models, such as - IfcFacetedBrep - IfcFacetedBrepWithVoids - IfcFaceBasedSurfaceModel - IfcShellBasedSurfaceModel The IfcTextureMap provides a set of TextureMaps, each IfcVertexBasedTextureMap holds a corresponding pair of lists: - a list of TexturePoints, currently of type IfcCartesianPoint, and - a list of TexturesVertices of type IfcTextureVertex. Each IfcTextureVertex (given as S, T coordinates of 2 dimension) corresponds to the geometric coordinates of the IfcCartesianPoint (given as X, Y, and Z coordinates of 3 dimensions). Informal propositions: - All TexturePoints in the list TextureMaps of IfcVertexBasedTextureMap shall be used by the vertex based geometry, to which this texture map is assigned to by using the IfcAnnotationSurface.Item attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctexturemap.htm"
     },
     "IfcTextureVertex": {
         "attributes": {
             "Coordinates": "The first coordinate[1] is the S, the second coordinate[2] is the T parameter value."
         },
-        "description": "Definition from IAI: An IfcTextureVertex is a list of 2 (S, T) texture coordinates.",
+        "description": "Definition from IAI: An IfcTextureVertex is a list of 2 (S, T) texture coordinates. The following additional definitions from ISO/IEC FCD 19775:200x, the Extensible 3D (X3D) specification, apply:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctexturevertex.htm"
     },
     "IfcThermalMaterialProperties": {
@@ -5354,7 +5354,7 @@
             "Unit": "The unit to be assigned to all values within the time series. Note that mixing units is not allowed. If the value is not given, the global unit for the type of _IfcValue_, as defined at _IfcProject.UnitsInContext_ is used.",
             "UserDefinedDataOrigin": "Value of the data origin if DataOrigin attribute is USERDEFINED."
         },
-        "description": "A time series is a set of a time-stamped data entries. It allows a natural association of data collected over intervals of time. Time series can be regular or irregular. In regular time series data arrive predictably at predefined intervals. In irregular time series some or all time stamps do not follow a repetitive pattern and unpredictable bursts of data may arrive at unspecified points in time.",
+        "description": "A time series is a set of a time-stamped data entries. It allows a natural association of data collected over intervals of time. Time series can be regular or irregular. In regular time series data arrive predictably at predefined intervals. In irregular time series some or all time stamps do not follow a repetitive pattern and unpredictable bursts of data may arrive at unspecified points in time. The modeling of buildings and their performance involves data that are generated and recorded over a period of time. Such data cover a large spectrum, from weather data to schedules of all kinds to status measurements to reporting to everything else that has a time related aspect. Their correct placement in time is essential for their proper understanding and use, and the IfcTimeSeries subtypes provide the appropriate data structures to accommodate these types of data.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifctimeseries.htm"
     },
     "IfcTimeSeriesReferenceRelationship": {
@@ -5371,14 +5371,14 @@
             "TimeSeries": "The time series is used to represent the values at discrete points in time that define the schedule. For example, a 24-hour occupancy schedule would be a regular time series with a start time at midnight, end time at (the following) midnight, and with 24 values indicating the occupancy load for each hour of the 24-hour period.",
             "TimeSeriesScheduleType": "Defines the type of schedule, such as daily, weekly, monthly or annually."
         },
-        "description": "The IfcTimeSeriesSchedule defines a time-series that is applicable to to one or more calendar dates. It typically contains a periodically repetitive time series used to define the schedule, facilitating the capture of hours of operation, occupancy loads, etc.",
+        "description": "The IfcTimeSeriesSchedule defines a time-series that is applicable to to one or more calendar dates. It typically contains a periodically repetitive time series used to define the schedule, facilitating the capture of hours of operation, occupancy loads, etc. Informal proposition: - If Intent : IfcConstraintIntentEnum is set to value UserDefined, then the intent shall be given by using inherited attribute IfcObject.ObjectType.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccontrolextension/lexical/ifctimeseriesschedule.htm"
     },
     "IfcTimeSeriesValue": {
         "attributes": {
             "ListValues": "A list of time-series values. At least one value is required."
         },
-        "description": "A time series value is a list of values that comprise the time series. At least one value must be supplied. Applications are expected to normalize values by applying the following three rules:",
+        "description": "A time series value is a list of values that comprise the time series. At least one value must be supplied. Applications are expected to normalize values by applying the following three rules: - All time (universal, local, daylight savings, and solar) is normalized against the ISO 8601 standard GMT/UTC (Universal Coordinated Time). - Any rollover is handled by the application providing the data. Rollover occurs, for example, when the measurement device resets itself while measuring and the recording data do not include the data measured before the reset. - The normalized data refer to the preceding time unit. The time series example shown in the figure below contains four time points: Time \"a\" indicates the beginning of the time series and the associated datum has no relevance. Data at time points \"b,\" \"c\" and \"d\" are associated with values 1, 2 and 3, respectively.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifctimeseriesvalue.htm"
     },
     "IfcTopologicalRepresentationItem": {
@@ -5386,11 +5386,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifctopologicalrepresentationitem.htm"
     },
     "IfcTopologyRepresentation": {
-        "description": "Definition from IAI: The IfcTopologyRepresentation represents the concept of a particular topological representation of a product or a product component within a representation context. This representation context does not need to be (but may be) a geometric representation context. Several representation types for shape representation are included as predefined types:",
+        "description": "Definition from IAI: The IfcTopologyRepresentation represents the concept of a particular topological representation of a product or a product component within a representation context. This representation context does not need to be (but may be) a geometric representation context. Several representation types for shape representation are included as predefined types: The representation type is given as a string value at the inherited attribute 'RepresentationType'.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifctopologyrepresentation.htm"
     },
     "IfcTransformerType": {
-        "description": "An IfcTransformerType defines a particular type of transformer that is an inductive stationary device that transfers electrical energy from one circuit to another.",
+        "description": "An IfcTransformerType defines a particular type of transformer that is an inductive stationary device that transfers electrical energy from one circuit to another. *Use Definitions* An IfcTransformerType is a subtype of IfcEnergyConversionDeviceType that provides for all forms of transformer. Usage of IfcTransformerType defines the parameters for one or more occurrences of IfcEnergyConversionDevice. Parameters are specified through a common property set. *Property Set Use Definition*: The property sets relating to the IfcTransformerType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcTransformerType are part of this IFC release: - Pset_ElectricalDeviceCommon: property set for properties that are common to all types of electrical devices, if available - Pset_TransformerTypeCommon: property set for properties that are common to all types of transformer, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "CURRENT": "A transformer that changes the current between circuits.",
             "FREQUENCY": "A transformer that changes the frequency between circuits.",
@@ -5406,11 +5406,11 @@
             "CapacityByWeight": "Capacity of the transport element measured by weight.",
             "OperationType": "Predefined type for transport element."
         },
-        "description": "Generalization of all transport related objects that move people, animals or goods within a building or building complex. The IfcTransportElement defines the occurrence of a covering type, that (if given) is expressed by the IfcTransportElementType.",
+        "description": "Generalization of all transport related objects that move people, animals or goods within a building or building complex. The IfcTransportElement defines the occurrence of a covering type, that (if given) is expressed by the IfcTransportElementType. *Property Set Use Definition*: The property sets relating to the IfcTransportElement are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcTransportElement are part of this IFC release: - Pset_TransportElementCommon: common property set for all transport element occurrences - Pset_TransportElementElevator: specific property set for all occurrences of transport elements with the PredefinedType: ELEVATOR *Geometry Use Definitions*: The geometric representation of IfcTransportElement is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Local Placement The local placement for IfcTransportElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement , which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. SurfaceModel Representation Any IfcTransportElement (so far no further constraints are defined at the level of its subtypes) may be represented as a single or multiple surface models, based on either shell or face based models. Then the following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'SurfaceModel' Brep Representation Any IfcTransportElement (so far no further constraints are defined at the level of its subtypes) may be represented as a single or multiple Boundary Representation elements (which are restricted to faceted Brep with or without voids). Then the following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'Brep' MappedRepresentation The new mapped item, IfcMappedItem, should be used if appropriate as it allows for reusing the geometry definition of the property element type at occurrences of the same equipment type. Then the following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: - RepresentationIdentifier : 'Body' - RepresentationType : 'MappedRepresentation'",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifctransportelement.htm"
     },
     "IfcTransportElementType": {
-        "description": "The element type (IfcTransportElementType) defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type (IfcTransportElementType) defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A transport element type is used to define the common properties of a certain type of a transport element that may be applied to many instances of that type to assign a specific style. Transport element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcTransportElementType are represented by instances of IfcTransportElement (or its subtypes).",
         "predefined_types": {
             "ELEVATOR": "Elevator or lift being a transport device to move people of good vertically.",
             "ESCALATOR": "Escalator being a transport device to move people. It consists of individual linked steps that move up and down on tracks while keeping the threads horizontal.",
@@ -5427,7 +5427,7 @@
             "TopXOffset": "Offset from the beginning of the top line to the bottom line, measured along the implicit x-axis.",
             "YDim": "The extent of the distance between the parallel bottom and top lines measured along the implicit y-axis."
         },
-        "description": "Definition from IAI: The IfcTrapeziumProfileDef defines a trapezium as the profile definition used by the swept surface geometry or the swept area solid. It is given by its Top X and Bottom X extent and its Y extent as well as by the offset of the Top X extend, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, i.e. in the center of the bounding box.",
+        "description": "Definition from IAI: The IfcTrapeziumProfileDef defines a trapezium as the profile definition used by the swept surface geometry or the swept area solid. It is given by its Top X and Bottom X extent and its Y extent as well as by the offset of the Top X extend, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, i.e. in the center of the bounding box. Illustration: Table: Parameter of trapezium profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifctrapeziumprofiledef.htm"
     },
     "IfcTrimmedCurve": {
@@ -5438,11 +5438,11 @@
             "Trim1": "The first trimming point which may be specified as a Cartesian point, as a real parameter or both.",
             "Trim2": "The second trimming point which may be specified as a Cartesian point, as a real parameter or both."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A trimmed curve is a bounded curve which is created by taking a selected portion, between two identified points, of the associated basis curve. The basis curve itself is unaltered and more than one trimmed curve may reference the same basis curve. Trimming points for the curve may be identified by:",
+        "description": "Definition from ISO/CD 10303-42:1992: A trimmed curve is a bounded curve which is created by taking a selected portion, between two identified points, of the associated basis curve. The basis curve itself is unaltered and more than one trimmed curve may reference the same basis curve. Trimming points for the curve may be identified by: - parametric value - geometric position - both of the above At least one of these shall be specified at each end of the curve. The SenseAgreement makes it possible to unambiguously define any segment of a closed curve such as a circle. The combinations of sense and ordered end points make it possible to define four distinct directed segments connecting two different points on a circle or other closed curve. For this purpose cyclic properties of the parameter range are assumed; for example, 370 degrees is equivalent to 10 degrees. The IfcTrimmedCurve has a parameterization which is inherited from the particular basis curve reference. More precisely the parameter s of the trimmed curve is derived from the parameter of the basis curve as follows: - if SenseAgreement is TRUE: s = t - t~1~ - if SenseAgreement is FALSE: s = t~2~ - t In the above equations t~1~ is the value given by Trim1 or the parameter value corresponding to point 1 and t~2~ is the value given by Trim2 or the parameter value corresponding to point 2. The resultant IfcTrimmedCurve has a parameter ranging from 0 at the first trimming point to |t~2~ - t~1~| at the second trimming point. Informal Propositions: - Where both the parameter value and the Cartesian point exist for Trim1 and Trim2 they shall be consistent. (i.e., the BasisCurve evaluated at the parameter value shall coincide with the specified point). - When a Cartesian point is specified by Trim1 or by Trim2 it shall lie on the BasisCurve. - Except the case of a closed BasisCurve where both parameter 1 and parameter 2 exist, they shall be consistent with the sense flag, i.e., (sense = parameter 1 < parameter 2). Or, for every open curve where both parameter 1 and parameter 2 exist, they shall be consistent with the SenseAgreement, i.e., SenseAgreement = (parameter 1 < parameter 2). - If both parameter 1 and parameter 2 exist, then parameter 1 <> parameter 2. For a closed base curve, e.g. IfcCircle or IfcEllipse, this also applies to the cyclic properties, as 360' is equal to 0', parameter 1 = 360' and parameter 2 = 0' are treated as being equal and therefore violating this proposition. - When a parameter value is specified by Trim1 or Trim2 it shall lie within the parametric range of the BasisCurve. Additional illustration from IAI:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifctrimmedcurve.htm"
     },
     "IfcTubeBundleType": {
-        "description": "The element type IfcTubeBundleType defines a list of commonly shared property set definitions of a tube buncle and an optional set of product representations. It is used to define a tube bundle specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcTubeBundleType defines a list of commonly shared property set definitions of a tube buncle and an optional set of product representations. It is used to define a tube bundle specification (i.e. the specific product information, that is common to all occurrences of that product type). A tube bundle type is used to define the common properties of a tube bundle that may be applied to many occurrences of that type. A tube bundle is a device consisting of tubes and bundles of tubes used for heat transfer and contained typically within other energy conversion devices, such as a chiller or coil. The occurrences of the IfcTubeBundleType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_TubeBundleTypeCommon: common property set for all tube bundle types Pset_TubeBundleTypeFinned: property set for finned tube bundle types",
         "predefined_types": {
             "FINNED": "Finned tube bundle type.",
             "NOTDEFINED": "Undefined tube bundle type.",
@@ -5463,7 +5463,7 @@
             "HasPropertySets": "Set ~~list~~ of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type.",
             "ObjectTypeOf": "Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type."
         },
-        "description": "The object type (IfcTypeObject) defines the specific information about a type. It refers to the specific level of the well recognized generic - specific - occurrence modeling paradigm.",
+        "description": "The object type (IfcTypeObject) defines the specific information about a type. It refers to the specific level of the well recognized generic - specific - occurrence modeling paradigm. The object style is represented by a list of property set definitions, where the order in the list implies a decreasing generality. The list of property sets describes the available specific information about the object type. Thereby the object type is used to define the common properties of a certain type (or style) of an object that may be applied to multiple instances of the same type. The IfcTypeObject gets assigned to the individual object instances (the occurrences) via the IfcRelDefinesByType relationship. Object types may be exchanged without being already assigned to objects. An object type may have an indication of the library (or catalogue) from which its definition originates. This association is handled by the inherited HasAssociations relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifctypeobject.htm"
     },
     "IfcTypeProduct": {
@@ -5471,7 +5471,7 @@
             "RepresentationMaps": "List of unique representation maps. Each representation map describes a block definition of the shape of the product style. By providing more than one representation map, a multi-view block definition can be given.",
             "Tag": "The tag (or label) identifier at the particular type of a product, e.g. the article number (like the EAN). It is the identifier at the specific level."
         },
-        "description": "The product type (IfcTypeProduct) defines a list of property set definitions of a product and an optional set of product representations. It is used to define a product specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The product type (IfcTypeProduct) defines a list of property set definitions of a product and an optional set of product representations. It is used to define a product specification (i.e. the specific product information, that is common to all occurrences of that product type). A product type is used to define the common properties of a certain type or style of an object that may be applied to instances of those products to assign a specific style to them. Product types may be exchanges without being already assigned to products.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifctypeproduct.htm"
     },
     "IfcUShapeProfileDef": {
@@ -5485,7 +5485,7 @@
             "FlangeWidth": "Flange lengths, see illustration above (= b).",
             "WebThickness": "Constant wall thickness of web (= ts)."
         },
-        "description": "The IfcUShapeProfileDef defines a section profile that provides the defining parameters of a U-shape (channel) section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the\\^profiles centre of the ~~gravity~~ bounding box.",
+        "description": "The IfcUShapeProfileDef defines a section profile that provides the defining parameters of a U-shape (channel) section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the\\^profiles centre of the ~~gravity~~ bounding box. The centre of gravity, if given, is located in y direction within the center of the bounding box, and in x-direction along the negative x axis, the offset value is given by the offset parameter CentreOfGravityInX. Illustration: Table: Parameters of U-shape profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcushapeprofiledef.htm"
     },
     "IfcUnitAssignment": {
@@ -5496,7 +5496,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcunitassignment.htm"
     },
     "IfcUnitaryEquipmentType": {
-        "description": "The element type IfcUnitaryEquipmentType defines a list of commonly shared property set definitions of a unitary equipment element and an optional set of product representations. It is used to define a unitary equipment element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcUnitaryEquipmentType defines a list of commonly shared property set definitions of a unitary equipment element and an optional set of product representations. It is used to define a unitary equipment element specification (i.e. the specific product information, that is common to all occurrences of that product type). A unitary equipment type is used to define the common properties of unitary equipment that may be applied to many occurrences of that type. Unitary equipment typically combine a number of components into a single product, such as pre-packaged rooftop air-conditioning units, split systems, etc. Unitary equipment types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcUnitaryEquipmentType are represented by instances of IfcEnergyConversionDevice or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release:",
         "predefined_types": {
             "AIRCONDITIONINGUNIT": "A unitary packaged air-conditioning unit typically used in residential or light commercial applications.",
             "AIRHANDLER": "A unitary air handling unit typically containing a fan, economizer, and coils.",
@@ -5508,7 +5508,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcunitaryequipmenttype.htm"
     },
     "IfcValveType": {
-        "description": "The element type IfcValveType defines a list of commonly shared property set definitions of a valve and an optional set of product representations. It is used to define a valve specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcValveType defines a list of commonly shared property set definitions of a valve and an optional set of product representations. It is used to define a valve specification (i.e. the specific product information, that is common to all occurrences of that product type). A valve type is used to define the common properties of a valve that may be applied to many occurrences of that type. Valves are typically is used in a building services piping distribution system to control or modulate the flow of the fluid. Valve types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcValveType are represented by instances of IfcFlowController or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_ValveTypeCommon: common property set for all valve types Pset_ValveTypeAirRelease: property set for air release valve types Pset_ValveTypeDrawOffCock: property set for draw off cock valve types Pset_ValveTypeFaucet: property set for faucet valve types Pset_ValveTypeFlushing: property set for flushing valve types Pset_ValveTypeGasTap: property set for gas tap valve types Pset_ValveTypeIsolating: property set for isolating valve types Pset_ValveTypeMixing: property set for mixing valve types Pset_ValveTypePressureReducing: property set for pressure reducing valve types Pset_ValveTypePressureRelief: property set for pressure relief valve types",
         "predefined_types": {
             "AIRRELEASE": "Valve used to release air from a pipe or fitting.",
             "ANTIVACUUM": "Valve that opens to admit air if the pressure falls below atmospheric pressure.",
@@ -5546,7 +5546,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcvector.htm"
     },
     "IfcVertex": {
-        "description": "Definition from ISO/CD 10303-42:1992: A vertex is the topological construct corresponding to a point. It has dimensionality 0 and extent 0. The domain of a vertex, if present, is a point in m dimensional real space R^M^; this is represented by the vertex point subtype.",
+        "description": "Definition from ISO/CD 10303-42:1992: A vertex is the topological construct corresponding to a point. It has dimensionality 0 and extent 0. The domain of a vertex, if present, is a point in m dimensional real space R^M^; this is represented by the vertex point subtype. Informal proposition: - The vertex has dimensionality 0. This is a fundamental property of the vertex. - The extent of a vertex is defined to be zero.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcvertex.htm"
     },
     "IfcVertexBasedTextureMap": {
@@ -5554,25 +5554,25 @@
             "TexturePoints": "Reference to a list of polyloop's defining a face bound of a face within a vertex based geometry.",
             "TextureVertices": "List of texture vertex coordinates, each texture vertex refers to the Cartesian point within the polyloop (corresponding lists). The first coordinate[1] is the S, the second coordinate[2] is the T parameter value."
         },
-        "description": "Definition from IAI: An IfcVertexBasedTextureMap provides the mapping of the 2-dimensional texture coordinates (S, T) to the vertices of a single surface onto which it is mapped. For each vertex coordinates, provided by IfcCartesianPoin, a set of 2 (S, T) texture coordinates are given.",
+        "description": "Definition from IAI: An IfcVertexBasedTextureMap provides the mapping of the 2-dimensional texture coordinates (S, T) to the vertices of a single surface onto which it is mapped. For each vertex coordinates, provided by IfcCartesianPoin, a set of 2 (S, T) texture coordinates are given. The IfcVertexBasedTextureMap provides two corresponding lists: - a list of TexturePoints, given by min. of 3 IfcCartesianPoint's. - a list of TextureVertices, given by min. of 3 IfcTextureVertex's. These corresponding lists are: Each texture vertex (given as S, T coordinates of 2 dimension) corresponds to the geometric coordinates (given as X, Y, and Z coordinates of 3 dimensions) of the Cartesian point, All Cartesian points within the list of shall lie within a plane. Informal propositions: - The list of TextureVertices shall correspond to the list of TexturePoints. - All Cartesian points of the list of _TexturePoints_shall lie in one plane - The references points shall be part of the vertex based geometry to which the annotation surface with textures is assigned.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcvertexbasedtexturemap.htm"
     },
     "IfcVertexLoop": {
         "attributes": {
             "LoopVertex": "The vertex which defines the entire loop."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A vertex_loop is a loop of zero genus consisting of a single vertex. A vertex can exist independently of a vertex loop. The topological data shall satisfy the following constraint:",
+        "description": "Definition from ISO/CD 10303-42:1992: A vertex_loop is a loop of zero genus consisting of a single vertex. A vertex can exist independently of a vertex loop. The topological data shall satisfy the following constraint: Informal propositions: - A vertex loop has zero extent and dimensionality. - The vertex loop has genus 0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcvertexloop.htm"
     },
     "IfcVertexPoint": {
         "attributes": {
             "VertexGeometry": "The geometric point, which defines the position in geometric space of the vertex."
         },
-        "description": "Definition from ISO/CD 10303-42:1992: A vertex point is a vertex which has its geometry defined as a point.",
+        "description": "Definition from ISO/CD 10303-42:1992: A vertex point is a vertex which has its geometry defined as a point. Informal proposition: - The domain of the vertex is formally defined to be the domain of its vertex point.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcvertexpoint.htm"
     },
     "IfcVibrationIsolatorType": {
-        "description": "The element type IfcVibrationIsolatorType defines a list of commonly shared property set definitions of a vibration isolator and an optional set of product representations. It is used to define a vibration isolator specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcVibrationIsolatorType defines a list of commonly shared property set definitions of a vibration isolator and an optional set of product representations. It is used to define a vibration isolator specification (i.e. the specific product information, that is common to all occurrences of that product type). A vibration isolator type is used to define the common properties of an isolator that may be applied to many occurrences of that type. A vibration isolator is a device used to minimize the effects of vibration transmissibility in a building. Isolator types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcVibrationIsolatorType are represented by instances of IfcEquipmentElement or its subtypes. *Property Set Use Definition*: The property sets relating to this entity are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to this entity are part of this IFC release: - Pset_VibrationIsolatorTypeCommon: common property set for all vibration isolator types",
         "predefined_types": {
             "COMPRESSION": "Compression type vibration isolator.",
             "NOTDEFINED": "Undefined vibration isolator type.",
@@ -5582,7 +5582,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcvibrationisolatortype.htm"
     },
     "IfcVirtualElement": {
-        "description": "A special element used to provide imaginary boundaries, such as between two adjacent, but not separated, spaces. Virtual elements are usually not displayed and does not have quantities and other measures. Therefore IfcVirtualElement does not have material information and quantities attached.",
+        "description": "A special element used to provide imaginary boundaries, such as between two adjacent, but not separated, spaces. Virtual elements are usually not displayed and does not have quantities and other measures. Therefore IfcVirtualElement does not have material information and quantities attached. *Geometry Use Definitions* The geometric representation of any IfcVirtualElement is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. Local Placement The local placement for IfcVirtualElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level. - If the relative placement is not used, the absolute placement is defined within the world coordinate system. Geometric Representations Currently, the use of 'FootPrint' and 'Surface' representation is supported. Two-dimensional Representation using foot print representation The 2D geometric representation of IfcVirtualElement is defined using the 'FootPrint' or 'Surface' representation. The following attribute values should be inserted - IfcShapeRepresentation.RepresentationIdentifier = 'FootPrint'. - IfcShapeRepresentation.RepresentationType = 'Curve2D' or 'GeometricCurveSet' . The following constraints apply to the 2D curve representation: - Curve: IfcPolyline, IfcTrimmedCurve or IfcCompositeCurve Three-dimensional Representation using surface model representation The 3D geometric representation of IfcVirtualElement is defined using the 'SurfaceModel' geometry. The following attribute values should be inserted - IfcShapeRepresentation.RepresentationIdentifier = 'Surface'. - IfcShapeRepresentation.RepresentationType = 'GeometricSet . The following constraints apply to the 3D surface representation: - Surface: IfcSurfaceOfLinearExtrusion - Profile: IfcArbitraryOpenProfileDef - Extrusion: The extrusion direction shall be vertically, i.e., along the positive Z Axis of the co-ordinate system of the containing spatial structure element.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcvirtualelement.htm"
     },
     "IfcVirtualGridIntersection": {
@@ -5590,7 +5590,7 @@
             "IntersectingAxes": "Two grid axes which intersects at exactly one intersection (see also informal proposition at IfcGrid). If attribute OffsetDistances is omitted, the intersection defines the placement or ref direction of a grid placement directly. If OffsetDistances are given, the intersection is defined by the offset curves to the grid axes.",
             "OffsetDistances": "Offset distances to the grid axes. If given, it defines virtual offset curves to the grid axes. The intersection of the offset curves specify the virtual grid intersection."
         },
-        "description": "The IfcVirtualGridIntersection defines the derived location of the intersection between two grid axes. Offset values may be given to set an offset distance to the grid axis for the calculation of the virtual grid intersection.",
+        "description": "The IfcVirtualGridIntersection defines the derived location of the intersection between two grid axes. Offset values may be given to set an offset distance to the grid axis for the calculation of the virtual grid intersection. The two intersecting axes (IntersectingAxes) define the intersection point, which exact location (in terms of the Cartesian point representing the intersection) has to be calculated from the geometric representation of the two participating curves. Offset values may be given (OffsetDistances). If given, the position within the list of OffsetDistances corresponds with the position within the list of IntersectingAxes. Therefore: - OffsetDistances[1] sets the offset to IntersectingAxes[1], - OffsetDistances[2] sets the offset to IntersectingAxes[2], and - OffsetDistances[3] sets the offset to the virtual intersection in direction of the orientation of the cross product of IntersectingAxes[1] and the orthogonal complement of the IntersectingAxes[1] (which is the positive or negative direction of the z axis of the design grid position). *Geometry use definitions*: The following figures explain the usage of the OffsetDistances and IntersectingAxes attributes. The distance of the offset curve (OffsetDistances[n]) is measured from the basis curve. The distance may be positive, negative or zero. A positive value of distance defines an offset in the direction which is normal to the curve in the sense of an anti-clockwise rotation through 90 degrees from the tangent vector T at the given point. (This is in the direction of orthogonal complement(T).) This can be reverted by the SameSense attribute at IfcGridAxis which may switch the sense of the AxisCurve. Illustration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcvirtualgridintersection.htm"
     },
     "IfcWall": {
@@ -5598,11 +5598,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwall.htm"
     },
     "IfcWallStandardCase": {
-        "description": "The standard wall (IfcWallStandardCase) defines a wall with certain constraints for the provision of parameters and with certain constraints for the geometric representation. The IfcWallStandardCase handles all cases of walls, that are extruded vertically ",
+        "description": "The standard wall (IfcWallStandardCase) defines a wall with certain constraints for the provision of parameters and with certain constraints for the geometric representation. The IfcWallStandardCase handles all cases of walls, that are extruded vertically - along the positive z axis of the wall local placement coordinate system, and - along the positive z axis of the global (world) coordinate system and have a single thickness along the path, i.e.: - parallel sides for straight walls - co-centric sides for curved walls. The following parameter shall be given: - Wall height, taken from the depth of extrusion, provided by the geometric representation. - Wall thickness, taken from the material layer set usage, attached to the wall - Wall offset from axis, taken from the material layer set usage, attached to the wall The material of the wall is defined by the IfcMaterialLayerSetUsage and is attached by the IfcRelAssociatesMaterial objectified relationship. It is accessible by the inverse HasAssociations relationship. The material layer set usage has to be given (enforced by where rule). *Type Use Definition* The type information relating to the IfcWallStandardCase is defined at the supertype IfcWall. As an additional use agreement for standard walls, the IfcWallType should have a unique IfcMaterialLayerSet, that is referenced by the IfcMaterialLayerSetUsage assigned to all occurrences of this IfcWallType. *Property Set Use Definition*: The property sets relating to the IfcWallStandardCase are defined at the supertype IfcWall. *Quantity Use Definition*: The quantities relating to the IfcWallStandardCase are defined at the supertype IfcWall. *Geometry Use Definitions*: The geometric representation of IfcWallStandardCase is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Included are: Local Placement The use of local placement is defined at the supertype IfcWall. Geometric Representation The standard geometric representation of IfcWallStandardCase is defined using the following multiple shape representations for its definition: - Axis: A two-dimensional open curve (IfcBoundedCurve) defining the axis for the standard wall. The material layer offset is measured from the wall axis. - Body: A Swept Solid Representation or a CSG representation defining the 3D shape of the standard wall First representation: Curve2D representation of wall axis The wall axis is represented by a two-dimensional open curve within a particular shape representation. The wall axis is used to apply the parameter to the wall geometry. The following attribute values shall be used Second representation: SweptSolid or Clipping representation of wall body The body of the IfcWallStandardCase is defined by using 'SweptSolid' representation for walls without clippings or 'Clipping' representation for walls with clippings (e.g. under sloped roof slabs). SweptSolid representation The standard geometric representation (for body) of IfcWallStandardCase is defined using the 'SweptSolid' representation. The following additional constraints apply to the swept solid representation: - Solid: IfcExtrudedAreaSolid is required, - Profile: IfcArbitraryClosedProfileDef and IfcRectangleProfileDef shall be supported. - Extrusion: The profile shall be extruded vertically, i.e., in the direction of the z-axis of the co-ordinate system of the referred spatial structure element. It might be further constraint to be in the direction of the global z-axis in implementers agreements. The extrusion axis shall be perpendicular to the swept profile, i.e. pointing into the direction of the z-axis of the Position of the IfcExtrudedAreaSolid. The advanced geometric representation (for body) of IfcWallStandardCase is defined using the 'Clipping' representation. The following additional constraints apply to the swept solid representation: - Solid: see standard geometric representation - Profile: see standard geometric representation - Extrusion: see standard geometric representation - Boolean result: The IfcBooleanClippingResult shall be supported, allowing for Boolean differences between the swept solid (here IfcExtrudedAreaSolid) and one or several IfcHalfSpaceSolid (or subtypes).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwallstandardcase.htm"
     },
     "IfcWallType": {
-        "description": "The element type (IfcWallType) defines a list of commonly shared property set definitions of a wall and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type (IfcWallType) defines a list of commonly shared property set definitions of a wall and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). An IfcWallType is used to define the common properties of a certain type of a wall that may be applied to many instances of that type to assign a specific style. Wall types may be exchanged without being already assigned to occurrences. The IfcWallType can have common material (using the inverse relationship HasAssociations) or property set information (using HasPropertySets) assigned. If present, it does apply equally to all occurrences of the IfcWallType. Property set information may be overridden at the occurrence. The occurrences of the IfcWallType are represented by instances of IfcWall and IfcWallStandardCase. Informal proposition: - The material assignment, if provided using the IfcRelAssociatesMaterial relationship, shall not reference the IfcMaterialLayerSetUsage.",
         "predefined_types": {
             "ELEMENTEDWALL": "A stud wall framed with studs and faced with sheetings, sidings, wallboard, or plasterwork.",
             "NOTDEFINED": "Undefined wall element.",
@@ -5615,7 +5615,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwalltype.htm"
     },
     "IfcWasteTerminalType": {
-        "description": "The IfcWasteTerminalType defines a particular type of sanitary flow that has the purpose of collecting or intercepting waste from one or more sanitary terminals or other fluid waste generating equipment and discharging it into a single waste/drainage system.",
+        "description": "The IfcWasteTerminalType defines a particular type of sanitary flow that has the purpose of collecting or intercepting waste from one or more sanitary terminals or other fluid waste generating equipment and discharging it into a single waste/drainage system. *Use Definitions* An IfcWasteTerminalType provides for all forms of trap, waste point and interceptor that collects discharge from a sanitary terminal and discharges it into a waste/drainage subsystem or that collects waste from several terminals and passes it into a single waste/drainage subsystem. This includes the P and S traps from soil sanitary terminals, sinks, basins etc. as well as floor wastes, gully traps and interceptors that provide collection points. An IfcWasteTerminalType may be included into the spatial context of the building model through an (or multiple) instances of IfcFlowTerminal. The parameters of the waste terminal type are defined through the type driven property sets referred to by the predefined type attribute of IfcWasteTerminalType. *Property Set Use Definition*: The property sets relating to the IfcWasteTerminalType_are defined by the _IfcPropertySet and attached by the IfcRelDefinesByType relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to an IfcWasteTerminalType are part of this IFC release: - Pset_WasteTerminalTypeFloorTrap: specific property set for the properties of a floor trap, if available - Pset_WasteTerminalTypeFloorWaste: specific property set for the properties of a floor waste unit, if available - Pset_WasteTerminalTypeGreaseInterceptor: specific property set for the properties of a grease interceptor, if available - Pset_WasteTerminalTypeGullySump: specific property set for the properties of a gully sump, if available - Pset_WasteTerminalTypeGullyTrap: specific property set for the properties of a gully trap, if available - Pset_WasteTerminalTypeOilInterceptor: specific property set for the properties of an oil interceptor, if available - Pset_WasteTerminalTypePetrolInterceptor: specific property set for the properties of a petrol interceptor, if available - Pset_WasteTerminalTypeRoofDrain: specific property set for the properties of a roof drain, if available - Pset_WasteTerminalTypeWasteDisposalUnit: specific property set for the properties of a waste disposal unit, if available - Pset_WasteTerminalTypeWasteTrap: specific property set for the properties of a waste trap, if available *Geometry Use Definitions* Representations of the type are defined as representation maps (at the level of the supertype IfcTypeProduct). These are assigned at the occurrence through the IfcShapeRepresentation.Item being an IfcMappedItem.",
         "predefined_types": {
             "FLOORTRAP": "Pipe fitting, set into the floor, that retains liquid to prevent the passage of foul air",
             "FLOORWASTE": "Pipe fitting, set into the floor, that collects waste water and discharges it to a separate trap.",
@@ -5665,7 +5665,7 @@
             "ShapeAspectStyle": "Optional link to a shape aspect definition, which points to the part of the geometric representation of the window style, which is used to represent the lining.",
             "TransomThickness": "Thickness of the transom (horizontal separator of window panels within a window), measured parallel to the window elevation plane. The transom is part of the lining and the transom depth is assumed to be identical to the lining depth."
         },
-        "description": "The window lining is the frame which enables the window to be fixed in position. The window lining is used to hold the window panels or other casements. The parameter of the window lining (IfcWindowLiningProperties) define the geometrically relevant parameter of the lining.",
+        "description": "The window lining is the frame which enables the window to be fixed in position. The window lining is used to hold the window panels or other casements. The parameter of the window lining (IfcWindowLiningProperties) define the geometrically relevant parameter of the lining. The IfcWindowLiningProperties are included in the list of properties (HasPropertySets) of the IfcWindowStyle. More information about the window lining can be included in the same list of the IfcWindowStyle using the IfcPropertySet for dynamic extensions. *Geometry Use Definitions* The IfcWindowLiningProperties does not hold an own geometric representation. However it defines parameter, which can be used to create the shape of the window style (which is inserted by the IfcWindow into the spatial context of the project). Interpretation of parameter The parameters at the IfcWindowLiningProperties define a standard window lining, including (if given) a mullion and a transom (for horizontal and vertical splits). The outer boundary of the lining is determined by the occurrence parameter assigned to the IfcWindow, which inserts the IfcWindowStyle. NOTE - All offsets are given as a normalized ratio measure.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowliningproperties.htm"
     },
     "IfcWindowPanelProperties": {
@@ -5676,7 +5676,7 @@
             "PanelPosition": "Position of this panel within the overall window style.",
             "ShapeAspectStyle": "Optional link to a shape aspect definition, which points to the part of the geometric representation of the window style, which is used to represent the panel."
         },
-        "description": "A description of the window panel. A window panel is a casement, i.e. a component, fixed or opening, consisting essentially of a frame and the infilling. The infilling of a window panel is normally glazing. The way of operation is defined in the operation type.",
+        "description": "A description of the window panel. A window panel is a casement, i.e. a component, fixed or opening, consisting essentially of a frame and the infilling. The infilling of a window panel is normally glazing. The way of operation is defined in the operation type. The IfcWindowPanelProperties are included in the list of properties (HasPropertySets) of the IfcWindowStyle. More information about the window panel can be included in the same list of the IfcWindowStyle using the IfcPropertySet for dynamic extensions. *Geometry Use Definitions* The IfcWindowPanelProperties does not hold an own geometric representation. However it defines parameter, which can be used to create the shape of the IfcWindowStyle (which is inserted by the IfcWindow into the spatial context of the project). Interpretation of parameter The parameters at the IfcWindowPanelProperties define a standard window panel. The outer boundary of the panel is determined by the occurrence parameter assigned to the IfcWindow, which inserts the IfcWindowStyle. It has to take the lining parameter into account as well. The position of the window panel within the overall window is determined by the PanelPosition attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowpanelproperties.htm"
     },
     "IfcWindowStyle": {
@@ -5686,7 +5686,7 @@
             "ParameterTakesPrecedence": "The Boolean value reflects, whether the parameter given in the attached lining and panel properties exactly define the geometry (TRUE), or whether the attached style shape take precedence (FALSE). In the last case the parameter have only informative value.",
             "Sizeable": "The Boolean indicates, whether the attached ShapeStyle can be sized (using scale factor of transformation), or not (FALSE). If not, the ShapeStyle should be inserted by the IfcWindow (using IfcMappedItem) with the scale factor = 1."
         },
-        "description": "The window style defines a particular style of windows, which may be included into the spatial context of the building model through an (or multiple) instances of IfcWindow. A window style defines the overall parameter of the window style and refers to the particular parameter of the lining and one (or several) panels through the IfcWindowLiningProperties and the IfcWindowPanelProperties.",
+        "description": "The window style defines a particular style of windows, which may be included into the spatial context of the building model through an (or multiple) instances of IfcWindow. A window style defines the overall parameter of the window style and refers to the particular parameter of the lining and one (or several) panels through the IfcWindowLiningProperties and the IfcWindowPanelProperties. The window entity (IfcWindow) defines a particular occurrence of a window inserted in the spatial context of a project. The actual parameter of the window and/or its shape is defined at the IfcWindowStyle, to which the IfcWindow related by the inverse relationship IsDefinedBy pointing to IfcRelDefinesByType. The IfcWindowStyle also defines the particular attributes for the lining (IfcWindowLiningProperties) and panels (IfcWindowPanelProperties). *Geometry Use Definitions*: The IfcWindowStyle defines the baseline geometry, or the representation map, for all occurrences of the window style, given by the IfcWindow, pointing to this style. The representation of the window style may be given by the agreed set of minimal parameters, defined for the window lining and the window panel(s), or it my be given by a geometric representation used by the IfcRepresentationMap. The attribute ParameterTakesPrecedence decides, whether the set of parameters can be used to exactly represent the shape of the window style (TRUE), or whether the attached IfcRepresentationMap holds the exact representation (FALSE). Interpretation of parameters The IfcWindowStyleOperationTypeEnum defines the general layout of the window style. Depending on the enumerator, the appropriate instances of IfcWindowLiningProperties and IfcWindowPanelProperties are attached in the list of HasPropertySets. See geometry use definitions there.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowstyle.htm"
     },
     "IfcWorkControl": {
@@ -5702,15 +5702,15 @@
             "UserDefinedControlType": "A user defined work control type.",
             "WorkControlType": "Predefined work control types from which that required may be set."
         },
-        "description": "An IfcWorkControl is an abstract supertype which captures information that is common to both IfcWorkPlan and IfcWorkSchedule",
+        "description": "An IfcWorkControl is an abstract supertype which captures information that is common to both IfcWorkPlan and IfcWorkSchedule Use Definitions A work control may have resources assigned to it, this is handled by the IfcRelAssignsToControl relationship. The assignment of tasks to the work control is handled by the IfcRelAssignsTasks relationship. The inherited attributes have the following meaning: IfcControl.Controls - references to the IfcRelAssignsTasks, that assign instances of IfcTask including time schedule controls. IfcObject.HasAssignments - references to the IfcRelAssignsToResources, that assigns an instance of IfcResource to the IfcWorkControl. The attribute IfcWorkControl.Purpose is used to define the purpose of either a work schedule or a work plan. In the case of IfcWorkPlan, the purpose attribute can be used to determine if the work plan is for cost estimating, task scheduling or some other defined purpose.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcworkcontrol.htm"
     },
     "IfcWorkPlan": {
-        "description": "An IfcWorkPlan represents work plans in a construction or a facilities management project.",
+        "description": "An IfcWorkPlan represents work plans in a construction or a facilities management project. Use Definitions A work plan contains a set of work schedules for different purposes (including construction and facilities management). Through inheritance from IfcWorkControl, it also have references to all the activities (i.e. IfcTask) and resources used in the work schedules. A work plan has information such as start date, finish date, total free float, and so on. IfcWorkPlan can also refer to the construction project represented by the single IfcProject instance.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcworkplan.htm"
     },
     "IfcWorkSchedule": {
-        "description": "An IfcWorkSchedule represents a task schedule in a work plan, which in turn can contain a set of schedules for different purposes.",
+        "description": "An IfcWorkSchedule represents a task schedule in a work plan, which in turn can contain a set of schedules for different purposes. Use Definitions An IfcWorkSchedule includes a set of elements (created through relating schedule time controls to tasks) with references to the resources used for the tasks included in the work schedule. Additionally, through the IfcWorkControl abstract supertype, the actors creating the schedule can be specified and schedule time information such as start time, finish time, and total float of the schedule can also be specified. IfcWorkSchedule can reference a project (i.e. the single IfcProject instance). The documents of the IfcWorkSchedule can be referenced by the IfcRelAssociatesDocuments relationship. Moreover, a work schedule can include other work schedules as sub-items through IfcRelNests relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcworkschedule.htm"
     },
     "IfcZShapeProfileDef": {
@@ -5722,11 +5722,11 @@
             "FlangeWidth": "Flange length, see illustration above (= b).",
             "WebThickness": "Constant wall thickness of web, see illustration above (= ts)."
         },
-        "description": "Definition from IAI: The IfcZShapeProfileDef defines a section profile that provides the defining parameters of a Z-shape section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the gravity bounding box.",
+        "description": "Definition from IAI: The IfcZShapeProfileDef defines a section profile that provides the defining parameters of a Z-shape section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the gravity bounding box. Illustration: Table: Parameters of Z-shape profile definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifczshapeprofiledef.htm"
     },
     "IfcZone": {
-        "description": "A zone (IfcZone) is an aggregation of spaces, partial spaces or other zones. Zone structures may not be hierarchical (in contrary to the spatial structure of a project - see IfcSpatialStructureElement), i.e. one individual IfcSpace may be associated with zero, one, or several IfcZone's. IfcSpace's are aggregated into an IfcZone by using the objectified relationship IfcRelAssignsToGroup as specified at the supertype IfcGroup.",
+        "description": "A zone (IfcZone) is an aggregation of spaces, partial spaces or other zones. Zone structures may not be hierarchical (in contrary to the spatial structure of a project - see IfcSpatialStructureElement), i.e. one individual IfcSpace may be associated with zero, one, or several IfcZone's. IfcSpace's are aggregated into an IfcZone by using the objectified relationship IfcRelAssignsToGroup as specified at the supertype IfcGroup. Additional classifications of the IfcZone, as provided by a national classification system, can be assigned by using the IfcRelAssociatesClassification relationship. *Property Set Use Definition*: The property sets relating to the IfcZone are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcZone are part of this IFC release: - Pset_ZoneCommon: common property set for all types of zone - Pset_SpaceFireSafetyRequirements: common property set for all types of zones to capture the fire safety requirements - Pset_SpaceLightingRequirements: common property set for all types of zones to capture the lighting requirements - Pset_SpaceOccupancyRequirements: common property set for all types of zones to capture the occupancy requirements - Pset_SpaceThermalRequirements: common property set for all types of zones to capture the thermal requirements",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifczone.htm"
     }
 }
\ No newline at end of file
diff --git a/src/ifcopenshell-python/ifcopenshell/util/schema/ifc2x3_types.json b/src/ifcopenshell-python/ifcopenshell/util/schema/ifc2x3_types.json
index 3f7f7919da..3c8403c259 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/schema/ifc2x3_types.json
+++ b/src/ifcopenshell-python/ifcopenshell/util/schema/ifc2x3_types.json
@@ -1,10 +1,10 @@
 {
     "IfcAbsorbedDoseMeasure": {
-        "description": "A measure of the absorbed radioactivity dose.",
+        "description": "A measure of the absorbed radioactivity dose. Usually measured in Gray (Gy, J/kg). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcabsorbeddosemeasure.htm"
     },
     "IfcAccelerationMeasure": {
-        "description": "A measure of acceleration.",
+        "description": "A measure of acceleration. Usually measured in m/s2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcaccelerationmeasure.htm"
     },
     "IfcActionSourceTypeEnum": {
@@ -12,43 +12,43 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcactionsourcetypeenum.htm"
     },
     "IfcActionTypeEnum": {
-        "description": "This enumeration type is used to distinguish between possible action types at a high level. It can be used for an automated definition of load combinations and for dimensioning. The contained items and their acronyms are adopted from the Eurocode standard.",
+        "description": "This enumeration type is used to distinguish between possible action types at a high level. It can be used for an automated definition of load combinations and for dimensioning. The contained items and their acronyms are adopted from the Eurocode standard. The IfcActionTypeEnum type is referenced by the entity IfcStructuralLoadGroup which shall normally be of the type LOAD_COMBINATION_GROUP (see also IfcLoadGroupTypeEnum). If an enumeration item is missing for an appropriate definition of a load group, the item USERDEFINED shall be used instead. In this case, a meaning can be given by using the IfcActionSourceTypeEnum.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcactiontypeenum.htm"
     },
     "IfcActorSelect": {
-        "description": "The actor select type allows a person and/or organization to be referenced.",
+        "description": "The actor select type allows a person and/or organization to be referenced. SELECT - IfcOrganization An organization. - IfcPerson A person. - IfcPersonAndOrganization A person related to an organization.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcactorselect.htm"
     },
     "IfcActuatorTypeEnum": {
-        "description": "The IfcActuatorTypeEnum defines the range of different types of actuator that can be specified.",
+        "description": "The IfcActuatorTypeEnum defines the range of different types of actuator that can be specified. Enumeration See property set of actuator common attributes for specification of properties for hand operated actuators.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcactuatortypeenum.htm"
     },
     "IfcAddressTypeEnum": {
-        "description": "Identifies the logical location of the address.",
+        "description": "Identifies the logical location of the address. ENUMERATION - OFFICE An office address. - SITE A site address. - HOME A home address. - DISTRIBUTIONPOINT A postal distribution point address. - USERDEFINED A user defined address type to be provided.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcaddresstypeenum.htm"
     },
     "IfcAheadOrBehind": {
-        "description": "An enumeration type that is used to specify whether a local time is ahead or behind of the coordinated universal time.",
+        "description": "An enumeration type that is used to specify whether a local time is ahead or behind of the coordinated universal time. ENUMERATION - AHEAD The time is ahead of coordinated universal time. - BEHIND The time is behind of coordinated universal time",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifcaheadorbehind.htm"
     },
     "IfcAirTerminalBoxTypeEnum": {
-        "description": "This enumeration identifies different types of air terminal boxes.",
+        "description": "This enumeration identifies different types of air terminal boxes. Valid enumerations are: - CONSTANTFLOW: Terminal box does not include a means to reset the volume automatically to an outside signal such as thermostat. - VARIABLEFLOWPRESSUREDEPENDANT: terminal box includes a means to reset the volume automatically to a different control point in response to an outside signal such as thermostat: air-flow rate depends on supply pressure. - VARIABLEFLOWPRESSUREINDEPENDANT: terminal box includes a means to reset the volume automatically to a different control point in response to an outside signal such as thermostat: air-flow rate is independant of supply pressure. - USERDEFINED: User-defined terminal box. - NOTDEFINED: Undefined terminal box.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcairterminalboxtypeenum.htm"
     },
     "IfcAirTerminalTypeEnum": {
-        "description": "Enumeration defining the functional types of air terminals. The IfcAirTerminalTypeEnum contains the following:",
+        "description": "Enumeration defining the functional types of air terminals. The IfcAirTerminalTypeEnum contains the following: - GRILLE: A covering for any area through which air passes. - REGISTER: A grille typically equipped with a damper or control valve. - DIFFUSER: An outlet discharging supply air in various directions and planes. - EYEBALL: A small, circular diffuser. - IRIS: An iris-shaped diffuser. - LINEARGRILLE: A rectilinear grille. - LINEARDIFFUSER: a rectilinear diffuser. - USERDEFINED: User-defined air terminal type. - NOTDEFINED: Undefined air terminal type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcairterminaltypeenum.htm"
     },
     "IfcAirToAirHeatRecoveryTypeEnum": {
-        "description": "Defines general types of pumps. The IfcPumpTypeEnum contains the following:",
+        "description": "Defines general types of pumps. The IfcPumpTypeEnum contains the following: - FIXEDPLATECOUNTERFLOWEXCHANGER: Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with primary air enters at secondary air outlet location and exits at secondary air inlet location. - FIXEDPLATECROSSFLOWEXCHANGER: Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with secondary air flow in the direction perpendicular to primary air flow. - FIXEDPLATEPARALLELFLOWEXCHANGER: Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with primary air enters at secondary air inlet location and exits at secondary air outlet location. - ROTARYWHEEL: A heat wheel with a revolving cylinder filled with an air-permeable medium having a large internal surface area. - RUNAROUNDCOILLOOP: A typical coil energy recovery loop places extended surface, finned tube water coils in the supply and exhaust airstreams of a building. - HEATPIPE: A passive energy recovery device with a heat pipe divided into evaporator and condenser sections. - TWINTOWERENTHALPYRECOVERYLOOPS: An air-to-liquid, liquid-to-air enthalpy recovery system with a sorbent liquid circulates continuously between supply and exhaust airstreams, alternately contacting both airstreams directly in contactor towers. - THERMOSIPHONSEALEDTUBEHEATEXCHANGERS: Sealed systems that consist of an evaporator, a condenser, interconnecting piping, and an intermediate working fluid that is present in both liquid and vapor phases where the evaporator and the condenser are usually at opposite ends of a bundle of straight, individual thermosiphon tubes and the exhaust and supply ducts are adjacent to each other. - THERMOSIPHONCOILTYPEHEATEXCHANGERS: Sealed systems that consist of an evaporator, a condenser, interconnecting piping, and an intermediate working fluid that is present in both liquid and vapor phases where the evaporator and condensor coils are installed independently in the ducts and are interconnected by the working fluid piping. - USERDEFINED: User-defined air to air heat recovery type. - NOTDEFINED: Undefined air to air heat recovery type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcairtoairheatrecoverytypeenum.htm"
     },
     "IfcAlarmTypeEnum": {
-        "description": "The IfcAlarmTypeEnum defines the range of different types of alarm that can be specified.",
+        "description": "The IfcAlarmTypeEnum defines the range of different types of alarm that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcalarmtypeenum.htm"
     },
     "IfcAmountOfSubstanceMeasure": {
-        "description": "An amount of substance measure is the value for the quantity of a substance when compared with the number of atoms in 0.012kilogram of carbon 12.",
+        "description": "An amount of substance measure is the value for the quantity of a substance when compared with the number of atoms in 0.012kilogram of carbon 12. Usually measure in mole (mol). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcamountofsubstancemeasure.htm"
     },
     "IfcAnalysisModelTypeEnum": {
@@ -60,23 +60,23 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcanalysistheorytypeenum.htm"
     },
     "IfcAngularVelocityMeasure": {
-        "description": "A measure of the velocity of a body measured in terms of angle subtended per unit time.",
+        "description": "A measure of the velocity of a body measured in terms of angle subtended per unit time. Usually measured in radians/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcangularvelocitymeasure.htm"
     },
     "IfcAppliedValueSelect": {
-        "description": "The IfcAppliedValueSelect defines the selection of whether a value (expressed as a ratio) or an amount should be used as the value for an IfcAppliedValue.",
+        "description": "The IfcAppliedValueSelect defines the selection of whether a value (expressed as a ratio) or an amount should be used as the value for an IfcAppliedValue. Select from: - IfcMeasureWithUnit - IfcMonetaryMeasure - IfcRatioMeasure Use Definitions Selecting IfcMeasureWithUnit allows the specification of both the actual figure for the value together with the currency (for a cost value) or an environmental measurement unit (in the case of an environmental impact value) in which the value is represented. Selecting IfcMonetaryMeasure allows the specification only of the value, the currency being as set by the global context Selecting IfcRatioMeasure assumes that the amount is a percentage or other REAL number. Note that if the amount is normally specified as -20%, then this figure will need to be converted to a multiplier of 0.8",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcappliedvalueselect.htm"
     },
     "IfcAreaMeasure": {
-        "description": "An area measure is the value of the extent of a surface.",
+        "description": "An area measure is the value of the extent of a surface. Usually measured in square metre (m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcareameasure.htm"
     },
     "IfcArithmeticOperatorEnum": {
-        "description": "The IfcArithmeticOperatorEnum specifies the form of arithmetical operation implied by the relationship.",
+        "description": "The IfcArithmeticOperatorEnum specifies the form of arithmetical operation implied by the relationship. Enumeration - ADD - DIVIDE - MULTIPLY - SUBTRACT Use Definitions There can be only one arithmetic operator for each applied value relationship. This is to enforce arithmetic consistency. Given this consistency, the cardinality of the IfcAppliedValueRelationship.Components attribute is a set of one to many applied values that are components of an applied value.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcarithmeticoperatorenum.htm"
     },
     "IfcAssemblyPlaceEnum": {
-        "description": "Enumeration defining where the assembly is intended to take place, either in a factory or on the building site.",
+        "description": "Enumeration defining where the assembly is intended to take place, either in a factory or on the building site. Enumeration - SITE - this assembly is assembled at site - FACTORY - this assembly is assembled in a factory",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcassemblyplaceenum.htm"
     },
     "IfcAxis2Placement": {
@@ -84,55 +84,55 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcaxis2placement.htm"
     },
     "IfcBSplineCurveForm": {
-        "description": "This type is used to indicate that the B-spline curve represents a part of a curve of some specific form.",
+        "description": "This type is used to indicate that the B-spline curve represents a part of a curve of some specific form. Enumeration: - polyline form: A connected sequence of line segments represented by degree 1 B-spline basis functions. - circular arc: An arc of a circle, or a complete circle represented by a B-spline curve. - elliptic arc: An arc of an ellipse, or a complete ellipse, represented by a B-spline curve. - parabolic arc: An arc of finite length of a parabola represented by a B-spline curve. - hyperbolic arc: An arc of finite length of one branch of a hyperbola represented by a B-spline curve. - unspecified: A B-spline curve for which no particular form is specified.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcbsplinecurveform.htm"
     },
     "IfcBeamTypeEnum": {
-        "description": "This enumeration defines the different types of linear elements an IfcBeamType object can fulfill:",
+        "description": "This enumeration defines the different types of linear elements an IfcBeamType object can fulfill: - BEAM: A standard beam usually used horizontally. - JOIST: A beam used to support a floor or ceiling. - LINTEL: A beam or horizontal piece of material over an opening (e.g. door, window). - T_BEAM: A T-shape beam that forms part of a slab construction. - USERDEFINED: User-defined linear beam element. - NOTDEFINED: Undefined linear beam element",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcbeamtypeenum.htm"
     },
     "IfcBenchmarkEnum": {
-        "description": "An IfcBenchmarkEnum is an enumeration used to identify the logical comparators that can be applied in conjunction with constraint values.",
+        "description": "An IfcBenchmarkEnum is an enumeration used to identify the logical comparators that can be applied in conjunction with constraint values. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcbenchmarkenum.htm"
     },
     "IfcBoilerTypeEnum": {
-        "description": "Enumeration defining the typical types of boilers. The IfcBoilerTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of boilers. The IfcBoilerTypeEnum contains the following: - WATER: Water boiler. - STEAM: Steam boiler. - USERDEFINED: User-defined Boiler type. - NOTDEFINED: Undefined Boiler type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcboilertypeenum.htm"
     },
     "IfcBoolean": {
-        "description": "A defined data type of simple data type Boolean. (Required since a select type, i.e. IfcSimpleValue, cannot include directly simple types in its select list). A boolean type can have value TRUE or FALSE.",
+        "description": "A defined data type of simple data type Boolean. (Required since a select type, i.e. IfcSimpleValue, cannot include directly simple types in its select list). A boolean type can have value TRUE or FALSE. Type: BOOLEAN",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcboolean.htm"
     },
     "IfcBooleanOperand": {
-        "description": "This select type identifies all those types of entities which may participate in a Boolean operation to form a CSG solid.",
+        "description": "This select type identifies all those types of entities which may participate in a Boolean operation to form a CSG solid. CSG primitives are out of scope for the current IFC Release. Only faceted B-reps, swept area solids and half space solids are available as Boolean operands. Boolean results themselves can be used as operands thus enabling nested Boolean operations.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcbooleanoperand.htm"
     },
     "IfcBooleanOperator": {
-        "description": "This type defines the three Boolean operators used in the definition of CSG solids.",
+        "description": "This type defines the three Boolean operators used in the definition of CSG solids. - Union: The operation of constructing the regularized set theoretic union of the volumes defined by two solids. - Intersection: The set theoretic difference between volumes defined by two solids. - Difference: The operation of constructing the regularized set theoretic intersection of the volumes defined by two solids.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcbooleanoperator.htm"
     },
     "IfcBoxAlignment": {
-        "description": "Definition from IAI: The box alignment specifies the alignment of the text box relative to its position. The following string values shall be used:",
+        "description": "Definition from IAI: The box alignment specifies the alignment of the text box relative to its position. The following string values shall be used: - top-left - top-middle - top-right - middle-left - center - middle-right - bottom-left - bottom-middle - bottom-right",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcboxalignment.htm"
     },
     "IfcBuildingElementProxyTypeEnum": {
-        "description": "This enumeration defines the available generic types for IfcBuildingElementProxyType.",
+        "description": "This enumeration defines the available generic types for IfcBuildingElementProxyType. Enumeration - USERDEFINED - NOTDEFINED",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingelementproxytypeenum.htm"
     },
     "IfcCableCarrierFittingTypeEnum": {
-        "description": "The IfcCableCarrierFittingTypeEnum defines the range of different types of cable carrier fitting that can be specified.",
+        "description": "The IfcCableCarrierFittingTypeEnum defines the range of different types of cable carrier fitting that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifccablecarrierfittingtypeenum.htm"
     },
     "IfcCableCarrierSegmentTypeEnum": {
-        "description": "The IfcCableCarrierSegmentTypeEnum defines the range of different types of cable carrier segment that can be specified.",
+        "description": "The IfcCableCarrierSegmentTypeEnum defines the range of different types of cable carrier segment that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifccablecarriersegmenttypeenum.htm"
     },
     "IfcCableSegmentTypeEnum": {
-        "description": "The IfcCableSegmentTypeEnum defines the range of different types of cable segment that can be specified.",
+        "description": "The IfcCableSegmentTypeEnum defines the range of different types of cable segment that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifccablesegmenttypeenum.htm"
     },
     "IfcChangeActionEnum": {
-        "description": "Enumeration identifying the type of change that might have occurred to the object during the last session (e.g., unchanged, added, deleted, etc.). This information is required in a partial model exchange scenario so that an application or model server will know how an object might have been affected by the previous application. Valid enumerations are:",
+        "description": "Enumeration identifying the type of change that might have occurred to the object during the last session (e.g., unchanged, added, deleted, etc.). This information is required in a partial model exchange scenario so that an application or model server will know how an object might have been affected by the previous application. Valid enumerations are: - NOCHANGE: Object has not been modified. This is the default state. - MODIFIED: A modification to the object has been made by the user and application defined by the LastModifyingUser and LastModifyingApplication respectively. - ADDED: The object has been added by the user and application defined by the LastModifyingUser and LastModifyingApplication respectively. - DELETED: The object has been deleted by the user and application defined by the LastModifyingUser and LastModifyingApplication respectively. - MODIFIEDADDED: The object has been added and modified by the user and application defined by the LastModifyingUser and LastModifyingApplication respectively. - MODIFIEDDELETED: The object has been modified and deleted by the user and application defined by the LastModifyingUser and LastModifyingApplication respectively. Note that only the first four enumerations should be used. The MODIFIEDADDED and MODIFIEDDELETED are left for compatibility purposes but should not be used. Consider Application A receives an IFC dataset, adds a new object and sets IfcChangeActionEnum to ADDED. Application B then receives this IFC dataset but doesn't do anything to the object added by Application A. Consequently, the object's IfcChangeActionEnum remains set at ADDED. Consequently, the intent is that an application only modifies the value of IfcChangeActionEnum when it does something to the object, with the further intent that a model server is responsible for clearing the IfcChangeActionEnum back to UNCHANGED when it is checked back into the repository.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifcchangeactionenum.htm"
     },
     "IfcCharacterStyleSelect": {
@@ -140,15 +140,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccharacterstyleselect.htm"
     },
     "IfcChillerTypeEnum": {
-        "description": "Enumeration defining the typical types of Chillers classified by their method of heat rejection. The IfcChillerTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of Chillers classified by their method of heat rejection. The IfcChillerTypeEnum contains the following: - AIRCOOLED: Air cooled chiller. - WATERCOOLED: Water cooled chiller. - HEATRECOVERY: Heat recovery chiller. - USERDEFINED: User-defined chiller type. - NOTDEFINED: Undefined chiller type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcchillertypeenum.htm"
     },
     "IfcClassificationNotationSelect": {
-        "description": "IfcClassificationNotationSelect enables selection of whether a classification notation is to be contained within an IFC model or is to be referenced from an external source (or classification server).",
+        "description": "IfcClassificationNotationSelect enables selection of whether a classification notation is to be contained within an IFC model or is to be referenced from an external source (or classification server). Select From: - IfcClassificationNotation (for notation used from a reference) - IfcClassificationReference (for reference into a classification system or source)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationnotationselect.htm"
     },
     "IfcCoilTypeEnum": {
-        "description": "Enumeration defining the typical types of coils. The IfcCoilTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of coils. The IfcCoilTypeEnum contains the following: - DXCOOLINGCOIL: Cooling coil using a refrigerant to cool the air stream directly. - WATERCOOLINGCOIL: Cooling coil using chilled water to cool the air stream. - STEAMHEATINGCOIL: Heating coil using steam as heating source. - WATERHEATINGCOIL: Heating coil using hot water as a heating source. - ELECTRICHEATINGCOIL: Heating coil using electricity as a heating source. - GASHEATINGCOIL: Heating coil using gas as a heating source. - USERDEFINED: User-defined coil type. - NOTDEFINED: Undefined coil type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccoiltypeenum.htm"
     },
     "IfcColour": {
@@ -160,27 +160,27 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccolourorfactor.htm"
     },
     "IfcColumnTypeEnum": {
-        "description": "This enumeration defines the different types of linear elements an IfcColumnType object can fulfill:",
+        "description": "This enumeration defines the different types of linear elements an IfcColumnType object can fulfill: - COLUMN: A standard column element usually used vertically. - USERDEFINED: User-defined linear element. - NOTDEFINED: Undefined linear element",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifccolumntypeenum.htm"
     },
     "IfcComplexNumber": {
-        "description": "Representation of a complex number expressed as an array with two elements. The first element (index 1) denotes the real component, i.e. the numerical component of a complex number whose square roots can be calculated explicitly. The second element (index 2) denotes the imaginary component, i.e. numerical component of a complex number whose square roots cannot be determined other than through the provision of the square of the imaginary number j where j\\^2 = -1. Note that the imaginary component may be referred to as i in certain references.",
+        "description": "Representation of a complex number expressed as an array with two elements. The first element (index 1) denotes the real component, i.e. the numerical component of a complex number whose square roots can be calculated explicitly. The second element (index 2) denotes the imaginary component, i.e. numerical component of a complex number whose square roots cannot be determined other than through the provision of the square of the imaginary number j where j\\^2 = -1. Note that the imaginary component may be referred to as i in certain references. Type: ARRAY [1:2] OF REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifccomplexnumber.htm"
     },
     "IfcCompoundPlaneAngleMeasure": {
-        "description": "A compound measure of plane angle in degrees, minutes, seconds, and optionally millionth-seconds of arc.",
+        "description": "A compound measure of plane angle in degrees, minutes, seconds, and optionally millionth-seconds of arc. Type: LIST [3:4] OF INTEGER The first integer measure is the number of degrees in the range The second integer measure is the number of minutes in the range The third integer measure is the number of seconds in the range The optional fourth integer measure is the number of millionth-seconds in the range",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifccompoundplaneanglemeasure.htm"
     },
     "IfcCompressorTypeEnum": {
-        "description": "Types of compressors. The IfcCompressorTypeEnum contains the following:",
+        "description": "Types of compressors. The IfcCompressorTypeEnum contains the following: - DYNAMIC: The pressure of refrigerant vapor is increased by a continuous transfer of angular momentum from a rotating member to the vapor followed by conversion of this momentum into static pressure. - RECIPROCATING: Positive-displacement compressor using a piston driven by a connecting rod from a crankshaft. - ROTARY: Positive-displacement compressor using a roller or rotor device. - SCROLL: Positive-displacement compressor using two inter-fitting, spiral-shaped scroll members. - TROCHOIDAL: Positive-displacement compressor using a rolling motion of one circle outside or inside the circumference of a basic circle and produce either epitrochoids or hypotrochoids. - SINGLESTAGE: Positive-displacement reciprocating compressor where vapor is compressed in a single stage. - BOOSTER: Positive-displacement reciprocating compressor where pressure is increased by a booster. - OPENTYPE: Positive-displacement reciprocating compressor where the shaft extends through a seal in the crankcase for an external drive. - HERMETIC: Positive-displacement reciprocating compressor where the motor and compressor are contained within the same housing, with the motor shaft integral with the compressor crankshaft and the motor in contact with refrigerant. - SEMIHERMETIC: Positive-displacement reciprocating compressor where the hermetic compressors use bolted construction amenable to field repair. - WELDEDSHELLHERMETIC: Positive-displacement reciprocating compressor where the motor compressor is mounted inside a steel shell, which, in turn is sealed by welding. - ROLLINGPISTON: Positive-displacement rotary compressor using a roller mounted on the eccentric of a shaft with a single vane in the nonrotating cylindrical housing. - ROTARYVANE: Positive-displacement rotary compressor using a roller mounted on the eccentric of a shaft with multiple vanes in the nontotating cylindrical housing. - SINGLESCREW: Positive-displacement rotary compressor using a single cylindrical main rotor that works with a pair of gate rotors. - TWINSCREW: Positive-displacement rotary compressor using two mating helically grooved rotors, male (lobes) and female (flutes) in a stationary housing with inlet and outlet gas ports. - USERDEFINED: User-defined compressor type. - NOTDEFINED: Undefined compressor type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccompressortypeenum.htm"
     },
     "IfcCondenserTypeEnum": {
-        "description": "Enumeration defining the typical types of condensers. The IfcCondenserTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of condensers. The IfcCondenserTypeEnum contains the following: - WATERCOOLEDSHELLTUBE: Water-cooled condenser with cooling water circulated through one or more tubes contained within the shell. - WATERCOOLEDSHELLCOIL: Water-cooled condenser with cooling water circulated through one or more continuous or assembled coils contained within the shell. - WATERCOOLEDTUBEINTUBE: Water-cooled condenser consisting of one or more assemblies of two tubes, one within the other. - WATERCOOLEDBRAZEDPLATE: Water-cooled condenser condenser with plates brazed together to form an assembly of separate channels. - AIRCOOLED: A condenser in which heat is transferred to an air-stream. - EVAPORATIVECOOLED: A condenser that is cooled evaporatively. - USERDEFINED: User-defined condenser type. - NOTDEFINED: Undefined condenser type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccondensertypeenum.htm"
     },
     "IfcConditionCriterionSelect": {
-        "description": "An IfcConditionCriterionSelect enables the selection of the criterion that is to be measured or assessed to establish the condition of an artifact(s).",
+        "description": "An IfcConditionCriterionSelect enables the selection of the criterion that is to be measured or assessed to establish the condition of an artifact(s). Select From: - IfcLabel (for an observed or assessed criterion) - IfcMeasureWithUnit (for a measured criterion)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcconditioncriterionselect.htm"
     },
     "IfcConnectionTypeEnum": {
@@ -188,43 +188,43 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcconnectiontypeenum.htm"
     },
     "IfcConstraintEnum": {
-        "description": "An IfcConstraintEnum is an enumeration used to qualify a constraint.",
+        "description": "An IfcConstraintEnum is an enumeration used to qualify a constraint. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcconstraintenum.htm"
     },
     "IfcContextDependentMeasure": {
-        "description": "Is the value of a physical quantity as defined by an application context.",
+        "description": "Is the value of a physical quantity as defined by an application context. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifccontextdependentmeasure.htm"
     },
     "IfcControllerTypeEnum": {
-        "description": "The IfcControllerTypeEnum defines the range of different types of controller that can be specified.",
+        "description": "The IfcControllerTypeEnum defines the range of different types of controller that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifccontrollertypeenum.htm"
     },
     "IfcCooledBeamTypeEnum": {
-        "description": "Enumeration defining the typical types of cooled beams. The IfcCooledBeamTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of cooled beams. The IfcCooledBeamTypeEnum contains the following: - ACTIVE: An active or ventilated cooled beam provides cooling (and heating) but can also function as an air terminal in a ventilation system. - PASSIVE: A passive or static cooled beam provides cooling (and heating) to a room or zone. - USERDEFINED: User-defined cooled beam type. - NOTDEFINED: Undefined cooled beam type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccooledbeamtypeenum.htm"
     },
     "IfcCoolingTowerTypeEnum": {
-        "description": "Enumeration defining the typical types of cooling towers. The IfcCoolingTowerTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of cooling towers. The IfcCoolingTowerTypeEnum contains the following: - NATURALDRAFT: Air flow is produced naturally. - MECHANICALINDUCEDDRAFT: Air flow is produced by a mechanical device, typically one or more fans, located on the air outlet side of the cooling tower. - MECHANICALFORCEDDRAFT: Air flow is produced by a mechanical device, typically one or more fans, located on the inlet air side of the cooling tower. - USERDEFINED: User-defined cooling tower type. - NOTDEFINED: Undefined cooling tower type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccoolingtowertypeenum.htm"
     },
     "IfcCostScheduleTypeEnum": {
-        "description": "An IfcCostScheduleTypeEnum is a list of the available types of cost schedule from which that required may be selected.",
+        "description": "An IfcCostScheduleTypeEnum is a list of the available types of cost schedule from which that required may be selected. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifccostscheduletypeenum.htm"
     },
     "IfcCountMeasure": {
-        "description": "A count measure is the value of a count.",
+        "description": "A count measure is the value of a count. Type: NUMBER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifccountmeasure.htm"
     },
     "IfcCoveringTypeEnum": {
-        "description": "This enumeration defines the range of different types of covering that can further specify an IfcCovering or an IfcCoveringType.",
+        "description": "This enumeration defines the range of different types of covering that can further specify an IfcCovering or an IfcCoveringType. Enumeration - CEILING: the covering is used to represent a ceiling - FLOORING: the covering is used to represent a flooring - CLADDING: the covering is used to represent a cladding - ROOFING: the covering is used to represent a roof - INSULATION: the covering is used to insulate an element for thermal or acoustic purposes. - MEMBRANE: an impervious layer that could be used for e.g. roof covering (below tiling - that may be known as sarking etc.) or as a damp proof course membrane - SLEEVING: the covering is used to isolate a distribution element from a space in which it is contained. - WRAPPING: the covering is used for wrapping particularly of distribution elements using tape. - USERDEFINED: user defined type of covering - NOTDEFINED: undefined type of covering",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifccoveringtypeenum.htm"
     },
     "IfcCsgSelect": {
-        "description": "This type identifies the types of entity which may be selected as the root of a CSG tree including a single CSG primitive as a special case (currently not in IFC).",
+        "description": "This type identifies the types of entity which may be selected as the root of a CSG tree including a single CSG primitive as a special case (currently not in IFC). In the current IFC Release only Boolean result (IfcBooleanResult) is defined for being a root tree expression (at IfcCsgSolid). CSG primitives are out of scope for the current IFC Release.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifccsgselect.htm"
     },
     "IfcCurrencyEnum": {
-        "description": "An enumeration of the international abbreviations of currencies used of various countries.",
+        "description": "An enumeration of the international abbreviations of currencies used of various countries. ENUMERATION - AED United Arab Emirates - AES Argentina - ATS Austria - AUD Australia - BBD Barbados - BEG Belgium - BGL Bulgaria - BHD Bahrain - BMD Bermuda - BND Brunei - BRL Brazil - BSD Bahamas - BWP Botswana - BZD Belize - CAD Canada - CBD Carribean - CHF Switzerland - CLP Chile - CNY China - CYS Cyprus - CZK Czech Republic - DDP Dominican Republic - DEM Germany - DKK Denmark - EGL Egypt - EST Spain - EUR A currency adopted by a number of countries within the European Union from January 1st 1999. The zone in which the currency operates is termed 'Euroland' in financial transactions - FAK Faroe Islands - FIM Finland - FJD Fiji - FKP Falkland Islands - FRF France - GBP United Kingdom - GIP Gibraltar - GMD Gambia - GRX Greece - HKD Hong Kong - HUF Hungary - ICK Iceland - IDR Indonesia - ILS Israel - INR India - IRP Ireland - ITL Italy - JMD Jamaica - JOD Jordan - JPY Japan - KES Kenya - KRW Republic of Korea - KWD Kuwait - KYD Cayman Islands - LKR Sri Lanka - LUF Luxembourg - MTL Malta - MUR Mauritius - MXN Mexico - MYR Malaysia - NLG Netherlands - NOK Norway - NZD New Zealand - OMR Oman - PGK Papua New Guinea - PHP Philipines - PKR Pakistan - PLN Poland - PTN Portugal - QAR Qatar - RUR Russia - SAR Saudi Arabia - SCR Seychelles - SEK Sweden - SGD Singapore - SKP St.Helena - THB Thailand - TRL Turkey - TTD Trinidad and Tobago - TWD Taiwan - USD United States of America - VEB Venezuela - VND Viet-Nam - XEU Europe (States of the European Union) - ZAR South Africa - ZWD Zimbabwe",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifccurrencyenum.htm"
     },
     "IfcCurtainWallTypeEnum": {
@@ -232,7 +232,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifccurtainwalltypeenum.htm"
     },
     "IfcCurvatureMeasure": {
-        "description": "A measure for curvature, which is defined as the change of slope per length. This is typically a computed value in structural analysis. It is usually measured in rad/m.",
+        "description": "A measure for curvature, which is defined as the change of slope per length. This is typically a computed value in structural analysis. It is usually measured in rad/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifccurvaturemeasure.htm"
     },
     "IfcCurveFontOrScaledCurveFontSelect": {
@@ -248,23 +248,23 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccurvestylefontselect.htm"
     },
     "IfcDamperTypeEnum": {
-        "description": "This enumeration defines the various types of damper:",
+        "description": "This enumeration defines the various types of damper: - CONTROLDAMPER: Control damper used to automatically modulate the flow of air by adjusting the position of the blades. - FIREDAMPER: Fire damper used to prevent the spread of fire for a specified duration. - SMOKEDAMPER: Smoke damper used to prevent the spread of smoke. - FIRESMOKEDAMPER: Combination fire and smoke damper used to preven the spread of fire and smoke. - BACKDRAFTDAMPER: Backdraft damper used to restrict the movement of air in one direction. - RELIEFDAMPER: Relief damper used to allow air to move upon a buildup of a specified pressure differential. - BLASTDAMPER: Blast damper. - GRAVITYDAMPER: Gravity damper closes from the force of gravity. - GRAVITYRELIEFDAMPER: Gravity-relief damper used to allow air to move upon a buildup of enough pressure to overcome the gravitational force exerted upon the damper blades. - FUMEHOODEXHAUST: Fume hood exhaust damper. - BALANCINGDAMPER: Damper used for purposes of manually balancing pressure differences. - USERDEFINED: User-defined damper. - NOTDEFINED: Undefined damper.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcdampertypeenum.htm"
     },
     "IfcDataOriginEnum": {
-        "description": "The IfcTimeSeriesDataGeneratedByEnum identifies the origin of the time series data:",
+        "description": "The IfcTimeSeriesDataGeneratedByEnum identifies the origin of the time series data: - MEASURED: The origin of the time series data is a measurement device. - PREDICTED: The time series data are a prediction. - SIMULATED: The origin of the time series data is a simulation. - USERDEFINED: User-defined time series data origin. - NOTDEFINED: The origin of the time series data is undefined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifcdataoriginenum.htm"
     },
     "IfcDateTimeSelect": {
-        "description": "Allows a date (IfcCalendarDate) and/or local time (IfcDateAndTime, IfcLocalTime) to be referenced.",
+        "description": "Allows a date (IfcCalendarDate) and/or local time (IfcDateAndTime, IfcLocalTime) to be referenced. SELECT - IfcLocalTime A local time. - IfcCalendarDate A calendar date. - IfcDateAndTime A combined time and date.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifcdatetimeselect.htm"
     },
     "IfcDayInMonthNumber": {
-        "description": "The position of the specified day in a month.",
+        "description": "The position of the specified day in a month. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifcdayinmonthnumber.htm"
     },
     "IfcDaylightSavingHour": {
-        "description": "The positive integer value by which clock time is offset from solar time at the particular location.",
+        "description": "The positive integer value by which clock time is offset from solar time at the particular location. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifcdaylightsavinghour.htm"
     },
     "IfcDefinedSymbolSelect": {
@@ -272,19 +272,19 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcdefinedsymbolselect.htm"
     },
     "IfcDerivedMeasureValue": {
-        "description": "A select type for selecting between derived measure types.",
+        "description": "A select type for selecting between derived measure types. SELECT - IfcAbsorbedDoseMeasure - IfcAccelerationMeasure - IfcAngularVelocityMeasure - IfcCompoundPlaneAngleMeasure - IfcDoseEquivalentMeasure - IfcDynamicViscosityMeasure - IfcElectricCapacitanceMeasure - IfcElectricChargeMeasure - IfcElectricConductanceMeasure - IfcElectricResistanceMeasure - IfcElectricVoltageMeasure - IfcEnergyMeasure - IfcForceMeasure - IfcFrequencyMeasure - IfcHeatFluxDensityMeasure - IfcIlluminanceMeasure - IfcInductanceMeasure - IfcIntegerCountRateMeasure - IfcIsothermalMoisturecapacityMeasure - IfcKinematicViscosityMeasure - IfcLinearForceMeasure - IfcLinearMomentMeasure - IfcLinearStiffnessMeasure - IfcLinearVelocityMeasure - IfcLuminousFluxMeasure - IfcMagneticFluxDensityMeasure - IfcMagneticFluxMeasure - IfcMassDensityMeasure - IfcMassFlowRateMeasure - IfcModulusOfElasticityMeasure - IfcModulusOfSubgradeReactionMeasure - IfcMoistureDiffusivityMeasure - IfcMolecularWeightMeasure - IfcMomentOfInertiaMeasure - IfcMonetaryMeasure - IfcPlanarForceMeasure - IfcPowerMeasure - IfcPressureMeasure - IfcRadioActivityMeasure - IfcRotationalFrequencyMeasure - IfcRotationalStiffnessMeasure - IfcShearModulusMeasure - IfcSpecificHeatCapacityMeasure - IfcThermalAdmittanceMeasure - IfcThermalConductivityMeasure - IfcThermalResistanceMeasure - IfcThermalTransmittanceMeasure - IfcTimeStamp - IfcTorqueMeasure - IfcVaporPermeabilityMeasure - IfcVolumetricFlowRateMeasure - IfcCurvatureMeasure - IfcMassPerLengthMeasure - IfcRotationalMassMeasure - IfcSectionalAreaIntegralMeasure - IfcSectionModulusMeasure - IfcTemperatureGradientMeasure - IfcWarpingConstantMeasure - IfcWarpingMomentMeasure - IfcThermalExpansionCoefficientMeasure - IfcModulusOfLinearSubgradeReactionMeasure - IfcModulusOfRotationalSubgradeReactionMeasure - IfcLuminousIntensityDistributionMeasure - IfcSoundPowerMeasure - IfcSoundPressureMeasure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcderivedmeasurevalue.htm"
     },
     "IfcDerivedUnitEnum": {
-        "description": "An enumeration type for allowed types of derived units.",
+        "description": "An enumeration type for allowed types of derived units. ENUMERATION - ACCELERATIONUNIT - ANGULARVELOCITYUNIT - COMPOUNDPLANEANGLEUNIT - DYNAMICVISCOSITYUNIT - HEATFLUXDENSITYUNIT - INTEGERCOUNTRATEUNIT - ISOTHERMALMOISTURECAPACITYUNIT - KINEMATICVISCOSITYUNIT - LINEARFORCEUNIT - LINEARMOMENTUNIT - LINEARSTIFFNESSUNIT - LINEARVELOCITYUNIT - MASSDENSITYUNIT - MASSFLOWRATEUNIT - MODULUSOFELASTICITYUNIT - MODULUSOFSUBGRADEREACTIONUNIT - MOISTUREDIFFUSIVITYUNIT - MOLECULARWEIGHTUNIT - MOMENTORINERTIAUNIT - PLANARFORCEUNIT - ROTATIONALFREQUENCYUNIT - ROTATIONALSTIFFNESSUNIT - SHEARMODULUSUNIT - SPECIFICHEATCAPACITYUNIT - THERMALADMITTANCEUNIT - THERMALCONDUCTANCEUNIT - THERMALRESISTANCEUNIT - THERMALTRANSMITTANCEUNIT - TORQUEUNIT - VAPORPERMEABILITYUNIT - VOLUMETRICFLOWRATEUNIT - CURVATUREUNIT - HEATINGVALUEUNIT - IONCONCENTRATIONUNIT - LUMINOUSINTENSITYDISTRIBUTIONUNIT - MASSPERLENGTHUNIT - MODULUSOFLINEARSUBGRADEREACTIONUNIT - MODULUSOFROTATIONALSUBGRADEREACTIONUNIT - PHUNIT - ROTATIONALMASSUNIT - SECTIONAREAINTEGRALUNIT - SECTIONMODULUSUNIT - SOUNDPOWERUNIT - SOUNDPRESSUREUNIT - TEMPERATUREGRADIENTUNIT - THERMALEXPANSIONCOEFFICIENTUNIT - WARPINGCONSTANTUNIT - WARPINGMOMENTUNIT - USERDEFINED User defined derived unit.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcderivedunitenum.htm"
     },
     "IfcDescriptiveMeasure": {
-        "description": "A descriptive measure is a human interpretable definition of a quantifiable value.",
+        "description": "A descriptive measure is a human interpretable definition of a quantifiable value. Type: STRING",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcdescriptivemeasure.htm"
     },
     "IfcDimensionCount": {
-        "description": "A dimension count is a positive integer used to define the coordinate space dimensionality.",
+        "description": "A dimension count is a positive integer used to define the coordinate space dimensionality. The IfcDimensionCount is restricted to have the dimensionality of either 1, 2, or 3 - the WR1 had been added as an addition to the STEP P42 entity dimension_count. In contrary to the STEP P42 constraint, that all geometric representation items within a geometric representation context are forced to have the same dimension count, the IFC geometry allows mixed dimensions, particularly when defining the boundary of planar surfaces.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcdimensioncount.htm"
     },
     "IfcDimensionExtentUsage": {
@@ -292,19 +292,19 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdimensionextentusage.htm"
     },
     "IfcDirectionSenseEnum": {
-        "description": "Enumeration denoting whether sense of direction is positive or negative along the given axis.",
+        "description": "Enumeration denoting whether sense of direction is positive or negative along the given axis. ENUMERATION - POSITIVE Direction defined to be positive. - NEGATIVE Direction defined to be negative.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcdirectionsenseenum.htm"
     },
     "IfcDistributionChamberElementTypeEnum": {
-        "description": "The This enumeration identifies different types of distribution chambers.",
+        "description": "The This enumeration identifies different types of distribution chambers. Valid enumerations are: - FORMEDDUCT: Space formed in the ground for the passage of pipes, cables, ducts. (BS6100 100 3410) - INSPECTIONCHAMBER: Chamber constructed on a drain, sewer or pipeline and with a removable cover, that permits visble inspection.. - INSPECTIONPIT: Recess or chamber formed to permit access for inspection of substructure and services. (BS6100 221 4128 - modified) - MANHOLE: Chamber constructed on a drain, sewer or pipeline and with a removable cover, that permits the entry of a person. - METERCHAMBER: Chamber that houses a meter(s) (BS6100 250 6224 - modified) - SUMP: Recess or small chamber into which liquid is drained to facilitate its removal (BS6100 100 3431) - TRENCH: Excavation, the length of which greatly exceeds the width. (BS6100 221 4118) - VALVECHAMBER: Chamber that houses a valve(s) (BS6100 250 6224) - USERDEFINED: User-defined terminal box. - NOTDEFINED: Undefined terminal box.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionchamberelementtypeenum.htm"
     },
     "IfcDocumentConfidentialityEnum": {
-        "description": "IfcDocumentConfidentialityEnum enables selection of the level of confidentiality of document information from a list of choices.",
+        "description": "IfcDocumentConfidentialityEnum enables selection of the level of confidentiality of document information from a list of choices. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcdocumentconfidentialityenum.htm"
     },
     "IfcDocumentSelect": {
-        "description": "IfcDocumentSelect enables selection of whether document information is to be contained within an IFC model or is to be referenced from an external source.",
+        "description": "IfcDocumentSelect enables selection of whether document information is to be contained within an IFC model or is to be referenced from an external source. Select From: - IfcDocumentInformation (for \"metadata\" of an external document) - IfcDocumentReference (for reference to the location of a document)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcdocumentselect.htm"
     },
     "IfcDocumentStatusEnum": {
@@ -312,11 +312,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcdocumentstatusenum.htm"
     },
     "IfcDoorPanelOperationEnum": {
-        "description": "This enumeration defines the basic ways how individual door panels operate.",
+        "description": "This enumeration defines the basic ways how individual door panels operate. The opening direction of the door panels is given by the local placement of the IfcDoor. The positive y-axis determines the direction as shown in the figure. NOTE - Figures (symbolic representation) depend on the national building code - These figures are only shown as illustrations",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorpaneloperationenum.htm"
     },
     "IfcDoorPanelPositionEnum": {
-        "description": "This enumeration defines the basic ways to describe the location of a door panel within a door lining.",
+        "description": "This enumeration defines the basic ways to describe the location of a door panel within a door lining. Illustration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorpanelpositionenum.htm"
     },
     "IfcDoorStyleConstructionEnum": {
@@ -324,11 +324,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorstyleconstructionenum.htm"
     },
     "IfcDoorStyleOperationEnum": {
-        "description": "This enumeration defines the basic ways to describe how doors operate.",
+        "description": "This enumeration defines the basic ways to describe how doors operate. Illustration NOTE - Figures are shown in the ground view. - Figures (symbolic representation) depend on the national building code. - These figures are only shown as illustrations, the actual representation in the ground view might differ. - Open to the outside is declared as open into the direction of the positive y-axis, determined by the ObjectPlacement at IfcDoor - The location of the panel relative to the wall thickness is defined by the ObjectPlacement at IfcDoor, and the IfcDoorLiningProperties.LiningOffset parameter.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorstyleoperationenum.htm"
     },
     "IfcDoseEquivalentMeasure": {
-        "description": "A measure of the radioactive dose equivalent.",
+        "description": "A measure of the radioactive dose equivalent. Usually measured in Sievert (Sv, J/kg). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcdoseequivalentmeasure.htm"
     },
     "IfcDraughtingCalloutElement": {
@@ -336,51 +336,51 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdraughtingcalloutelement.htm"
     },
     "IfcDuctFittingTypeEnum": {
-        "description": "This enumeration is used to identify the primary purpose of a duct fitting. This is a very basic categorization mechanism to generically identify the duct fitting type. Subcategories of duct fittings are not enumerated. The IfcDuctFittingTypeEnum contains the following:",
+        "description": "This enumeration is used to identify the primary purpose of a duct fitting. This is a very basic categorization mechanism to generically identify the duct fitting type. Subcategories of duct fittings are not enumerated. The IfcDuctFittingTypeEnum contains the following: - BEND: A fitting with typically two ports used to change the direction of flow between connected elements. - CONNECTOR: Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two duct segments). - ENTRY: Entry fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., an outside air duct system intake opening). - EXIT: Exit fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., an exhaust air discharge opening). - JUNCTION: A fitting with typically more than two ports used to redistribute flow among the ports and/or to change the direction of flow between connected elements (e.g, tee, cross, wye, etc.). - OBSTRUCTION: A fitting with typically two ports used to obstruct or restrict flow between the connected elements (e.g., screen, perforated plate, etc.). - TRANSITION: A fitting with typically two ports having different shapes or sizes. Can also be used to change the direction of flow between connected elements. - USERDEFINED: User-defined fitting. - NOTDEFINED: Undefined fitting.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcductfittingtypeenum.htm"
     },
     "IfcDuctSegmentTypeEnum": {
-        "description": "This enumeration is used to identify the primary purpose of a duct segment. This is a very basic categorization mechanism to generically identify the duct segment type. Subcategories of duct segments are not enumerated. The IfcDuctSegmentTypeEnum contains the following:",
+        "description": "This enumeration is used to identify the primary purpose of a duct segment. This is a very basic categorization mechanism to generically identify the duct segment type. Subcategories of duct segments are not enumerated. The IfcDuctSegmentTypeEnum contains the following: - RIGIDSEGMENT: A rigid segment is continuous linear segment of duct that cannot be deformed. - FLEXIBLESEGMENT: A flexible segment is a continuous non-linear segment of duct that can be deformed and change the direction of flow. - USERDEFINED: User-defined segment. - NOTDEFINED: Undefined segment.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcductsegmenttypeenum.htm"
     },
     "IfcDuctSilencerTypeEnum": {
-        "description": "Enumeration defining the typical types of duct silencers. The IfcDuctSilencerTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of duct silencers. The IfcDuctSilencerTypeEnum contains the following: - FLATOVAL: Flat-oval shaped duct silencer type. - RECTANGULAR: Rectangular shaped duct silencer type. - ROUND: Round duct silencer type. - USERDEFINED: User-defined duct silencer type. - NOTDEFINED: Undefined duct silencer type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcductsilencertypeenum.htm"
     },
     "IfcDynamicViscosityMeasure": {
-        "description": "A measure of the viscous resistance of a medium.",
+        "description": "A measure of the viscous resistance of a medium. Usually measured in Pascal second (Pa s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcdynamicviscositymeasure.htm"
     },
     "IfcElectricApplianceTypeEnum": {
-        "description": "The IfcElectricApplianceTypeEnum defines the range of different types of electrical appliance that can be specified.",
+        "description": "The IfcElectricApplianceTypeEnum defines the range of different types of electrical appliance that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricappliancetypeenum.htm"
     },
     "IfcElectricCapacitanceMeasure": {
-        "description": "A measure of the electric capacitance.",
+        "description": "A measure of the electric capacitance. Usually measured in Farad (F, C/V = A s/V). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcelectriccapacitancemeasure.htm"
     },
     "IfcElectricChargeMeasure": {
-        "description": "A measure of the electric charge.",
+        "description": "A measure of the electric charge. Usually measured in Coulomb (C, A s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcelectricchargemeasure.htm"
     },
     "IfcElectricConductanceMeasure": {
-        "description": "A measure of the electric conductance.",
+        "description": "A measure of the electric conductance. Usually measured in Siemens (S, 1/Ohm = A/V). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcelectricconductancemeasure.htm"
     },
     "IfcElectricCurrentEnum": {
-        "description": "This enumeration defines the different types of available electrical current:",
+        "description": "This enumeration defines the different types of available electrical current: - ALTERNATING: Alternating current (AC). - DIRECT: Direct current (DC). - NOTDEFINED: Undefined electrical current.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcelectriccurrentenum.htm"
     },
     "IfcElectricCurrentMeasure": {
-        "description": "The value for the movement of electrically charged particles.",
+        "description": "The value for the movement of electrically charged particles. Usually measured in Ampere (A). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcelectriccurrentmeasure.htm"
     },
     "IfcElectricDistributionPointFunctionEnum": {
-        "description": "The IfcElectricDistributionPointTypeEnum defines the range of different functions that an electric distribution point can fulfil.",
+        "description": "The IfcElectricDistributionPointTypeEnum defines the range of different functions that an electric distribution point can fulfil. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricdistributionpointfunctionenum.htm"
     },
     "IfcElectricFlowStorageDeviceTypeEnum": {
-        "description": "The IfcElectricFlowStorageDeviceTypeEnum defines the range of different types of electrical flow storage device available.",
+        "description": "The IfcElectricFlowStorageDeviceTypeEnum defines the range of different types of electrical flow storage device available. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricflowstoragedevicetypeenum.htm"
     },
     "IfcElectricGeneratorTypeEnum": {
@@ -388,55 +388,55 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricgeneratortypeenum.htm"
     },
     "IfcElectricHeaterTypeEnum": {
-        "description": "The IfcElectricHeaterTypeEnum defines the range of types of electric heater available.",
+        "description": "The IfcElectricHeaterTypeEnum defines the range of types of electric heater available. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricheatertypeenum.htm"
     },
     "IfcElectricMotorTypeEnum": {
-        "description": "The IfcElectricMotorTypeEnum defines the range of different types of electric motor that can be specified.",
+        "description": "The IfcElectricMotorTypeEnum defines the range of different types of electric motor that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricmotortypeenum.htm"
     },
     "IfcElectricResistanceMeasure": {
-        "description": "A measure of the electric resistance.",
+        "description": "A measure of the electric resistance. Usually measured in Ohm (V/A). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcelectricresistancemeasure.htm"
     },
     "IfcElectricTimeControlTypeEnum": {
-        "description": "The IfcElectricTimeControlTypeEnum defines the range of types of electrical time control available.",
+        "description": "The IfcElectricTimeControlTypeEnum defines the range of types of electrical time control available. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectrictimecontroltypeenum.htm"
     },
     "IfcElectricVoltageMeasure": {
-        "description": "A measure of electromotive force.",
+        "description": "A measure of electromotive force. Usually measured in Volts (V, W/A). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcelectricvoltagemeasure.htm"
     },
     "IfcElementAssemblyTypeEnum": {
-        "description": "An enumeration defining the basic configuration types for element assemblies.",
+        "description": "An enumeration defining the basic configuration types for element assemblies. Enumeration - ACCESSORY_ASSEMBLY: Assembled accessories or components - ARCH: A curved structure - BEAM_GRID: Interconnected beams, located in one (typically horizontal) plane - BRACED_FRAME: A rigid frame with additional bracing members - GIRDER: A beam-like superstructure - REINFORCEMENT_UNIT: Assembled reinforcement elements - RIGID_FRAME: A structure built up of beams, columns, etc. with moment-resisting joints - SLAB_FIELD: Slabs, laid out in one plane - TRUSS: A structure built up of members with (quasi) pinned joints - USERDEFINED: User-defined element assembly - NOTDEFINED: Undefined element assembly",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelementassemblytypeenum.htm"
     },
     "IfcElementCompositionEnum": {
-        "description": "Enumeration that provides an indication, whether the spatial structure element or proxy represents a:",
+        "description": "Enumeration that provides an indication, whether the spatial structure element or proxy represents a: - COMPLEX - a group or aggregation of similar elements - ELEMENT - a (undivided) element itself - PARTIAL - a subelement or part",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelementcompositionenum.htm"
     },
     "IfcEnergyMeasure": {
-        "description": "A measure of energy required or used.",
+        "description": "A measure of energy required or used. Usually measured in Joules, (J, Nm). Type: REAL > HISTORY New type in IFC Release 2.0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcenergymeasure.htm"
     },
     "IfcEnergySequenceEnum": {
-        "description": "This enumeration is used to identify the sequence of usage of the energy source. The IfcEnergySequenceEnum contains the following:",
+        "description": "This enumeration is used to identify the sequence of usage of the energy source. The IfcEnergySequenceEnum contains the following: - PRIMARY: Primary energy source. - SECONDARY: Secondary energy source. - TERTIARY: Tertiary energy source. - AUXILIARY: Auxiliary. - USERDEFINED: User-defined energy sequence. - NOTDEFINED: Undefined energy sequence.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcenergysequenceenum.htm"
     },
     "IfcEnvironmentalImpactCategoryEnum": {
-        "description": "The IfcEnvironmentalImpactCategoryEnum defines the range of categories into which an environmental impact can be broken down and from which the category required may be selected.",
+        "description": "The IfcEnvironmentalImpactCategoryEnum defines the range of categories into which an environmental impact can be broken down and from which the category required may be selected. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcenvironmentalimpactcategoryenum.htm"
     },
     "IfcEvaporativeCoolerTypeEnum": {
-        "description": "Enumeration defining the typical types of evaporative coolers. The IfcEvaporativeCoolerTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of evaporative coolers. The IfcEvaporativeCoolerTypeEnum contains the following: - DIRECTEVAPORATIVERANDOMMEDIAAIRCOOLER: Direct evaporative random media air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers with evaporative pads, usually of aspen wood or plastic fiber/foam. - DIRECTEVAPORATIVERIGIDMEDIAAIRCOOLER: Direct evaporative rigid media air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers with sheets of rigid, corrugated material as the wetted surface. - DIRECTEVAPORATIVESLINGERSPACKAGEDAIRCOOLER: Direct evaporative slingers packaged air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers with a water slinger in an evaporative cooling section and a fan section. - DIRECTEVAPORATIVEPACKAGEDROTARYAIRCOOLER: Direct evaporative packaged rotary air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers that wet and wash the evaporative pad by rotating it through a water bath. - DIRECTEVAPORATIVEAIRWASHER: Direct evaporative air washer: Cools the air stream by evaporating water dircectly into the air stream using coolers with spray-type air washer consist of a chamber or casing containing spray nozzles, and tank for collecting spray water, and an eliminator section for removing entrained drops of water from the air. - INDIRECTEVAPORATIVEPACKAGEAIRCOOLER: Indirect evaporative package air cooler: Cools the air stream by evaporating water indirectly and without adding moisture into the air stream. On one side of the heat exchanger, the secondary air stream is cooled by evaporation, while on the other side of heat exchanger, the primary air stream (conditioned air to be supplied to the room) is sensibly cooled by the heat exchanger surfaces. - INDIRECTEVAPORATIVEWETCOIL: Indirect evaporative wet coil: Cools the air stream by evaporating water indirectly and without adding moisture into the air stream. Water is sprayed directly on the tubes of the heat exchanger where latent cooling takes place and the vaporization of the water on the outside of the heat exchanger tubes allows the simultaneous heat and mass transfer which removes heat from the supply air on the tube side. - INDIRECTEVAPORATIVECOOLINGTOWERORCOILCOOLER: Indirect evaporative cooling tower or coil cooler: Cools the air stream by evaporating water indirectly and without adding moisture into the air stream using a combination of a cooling tower or other evaporative water cooler with a water-to-air heat exchanger coil and water circulating pump. - INDIRECTDIRECTCOMBINATION: Indirect/Direct combination: Cools the air stream by evaporating water indirectly and without adding moisture into the air stream using a two-stage cooler with a first-stage indirect evaporative cooler and second-stage direct evaporative cooler. - USERDEFINED: User-defined evaporative cooler type. - NOTDEFINED: Undefined evaporative cooler type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcevaporativecoolertypeenum.htm"
     },
     "IfcEvaporatorTypeEnum": {
-        "description": "Enumeration defining the typical types of evaporators. The IfcEvaporatorTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of evaporators. The IfcEvaporatorTypeEnum contains the following: - DIRECTEXPANSIONSHELLANDTUBE: Direct-expansion evaporator where a refrigerant evaporates inside a series of baffles that channel the fluid throughout the shell side. - DIRECTEXPANSIONTUBEINTUBE: Direct-expansion evaporator where a refrigerant evaporates inside one or more pairs of coaxial tubes. - DIRECTEXPANSIONBRAZEDPLATE: Direct-expansion evaporator where a refrigerant evaporates inside plates brazed or welded together to make up an assembly of separate channels. - FLOODEDSHELLANDTUBE: Evaporator in which refrigerant evaporates outside tubes. - SHELLANDCOIL: Evaporator in which refrigerant evaporates inside a simple coiled tube immersed in the fluid to be cooled. - USERDEFINED: User-defined evaporator type. - NOTDEFINED: Undefined evaporator type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcevaporatortypeenum.htm"
     },
     "IfcFanTypeEnum": {
-        "description": "Enumeration defining the typical types of fans. The IfcFanTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of fans. The IfcFanTypeEnum contains the following: - CENTRIFUGALFORWARDCURVED: Air flows through the impeller radially using blades that are forward curved. - CENTRIFUGALRADIAL: Air flows through the impeller radially using blades that are uncurved or slightl forward curved. - CENTRIFUGALBACKWARDINCLINEDCURVED: Air flows through the impeller radially using blades that are backward curved. - CENTRIFUGALAIRFOIL: Air flows through the impeller radially using blades are airfoil shaped. - TUBEAXIAL: Air flows through the impeller axially with reduced tip clearance and operating at higher tip speeds. - VANEAXIAL: Air flows through the impeller axially with guide vanes and reduced running blade tip clearance. - PROPELLORAXIAL: Air flows through the impeller axially and small hub-to-tip ratio impeller mounted in an orifice plate or inlet ring. - USERDEFINED: User-defined fan type. - NOTDEFINED: Undefined fan type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcfantypeenum.htm"
     },
     "IfcFillAreaStyleTileShapeSelect": {
@@ -448,55 +448,55 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcfillstyleselect.htm"
     },
     "IfcFilterTypeEnum": {
-        "description": "This enumeration defines the various types of filter typically used within building services distribution systems:",
+        "description": "This enumeration defines the various types of filter typically used within building services distribution systems: - AIRPARTICLEFILTER: An air filter removing particulates from air. - ODORFILTER: An air filter used to remove odors from air. - OILFILTER: A filter used to remove particulates in from oil. - STRAINER: A filter used to remove particulates from a fluid. - WATERFILTER: A filter used to remove particulates from water. - USERDEFINED: User-defined filter type. - NOTDEFINED: Undefined filter type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcfiltertypeenum.htm"
     },
     "IfcFireSuppressionTerminalTypeEnum": {
-        "description": "The IfcFireSuppressionTerminalTypeEnum defines the range of different types of fire suppression terminal that can be specified.",
+        "description": "The IfcFireSuppressionTerminalTypeEnum defines the range of different types of fire suppression terminal that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcplumbingfireprotectiondomain/lexical/ifcfiresuppressionterminaltypeenum.htm"
     },
     "IfcFlowDirectionEnum": {
-        "description": "This enumeration defines the flow direction at a connection point as either a Source, Sink, or both SourceAndSink:",
+        "description": "This enumeration defines the flow direction at a connection point as either a Source, Sink, or both SourceAndSink: - SOURCE: A source of flow (e.g., it flows out of the connection) - SINK: A flow sink (e.g., it flows into the connection) - SOURCEANDSINK: Both a source and sink (e.g., it flows both into and out of the connection simultaneously) - NOTDEFINED: Undefined flow direction",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowdirectionenum.htm"
     },
     "IfcFlowInstrumentTypeEnum": {
-        "description": "The IfcFlowInstrumentTypeEnum defines the range of different types of flow instrument that can be specified.",
+        "description": "The IfcFlowInstrumentTypeEnum defines the range of different types of flow instrument that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcflowinstrumenttypeenum.htm"
     },
     "IfcFlowMeterTypeEnum": {
-        "description": "This enumeration defines various types of flow meter:",
+        "description": "This enumeration defines various types of flow meter: - ELECTRICMETER: Electric meter - ENERGYMETER: Energy meter - FLOWMETER: Flow meter - GASMETER: Gas meter - OILMETER: Oil meter - WATERMETER: Water meter - USERDEFINED: User-defined meter type - NOTDEFINED: Undefined meter type",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcflowmetertypeenum.htm"
     },
     "IfcFontStyle": {
-        "description": "Definition from CSS1 (W3C Recommendation): The font-style property selects between normal (sometimes referred to as \"roman\" or \"upright\"), italic and oblique faces within a font family. Values are:",
+        "description": "Definition from CSS1 (W3C Recommendation): The font-style property selects between normal (sometimes referred to as \"roman\" or \"upright\"), italic and oblique faces within a font family. Values are: - normal - italic - oblique A value of 'normal' selects a font that is classified as 'normal' in the user agents font database, while 'oblique' selects a font that is labeled 'oblique'. A value of 'italic' selects a font that is labeled 'italic', or, if that is not available, one labeled 'oblique'. The font that is labeled 'oblique' in the user agents font database may actually have been generated by electronically slanting a normal font. Fonts with Oblique, Slanted or Incline in their names will typically be labeled 'oblique' in the user agents font database. Fonts with Italic, Cursive or Kursiv in their names will typically be labeled 'italic'.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcfontstyle.htm"
     },
     "IfcFontVariant": {
-        "description": "Definition from CSS1 (W3C Recommendation): The font-style property selects between normal and small-caps within a font family. Values are:",
+        "description": "Definition from CSS1 (W3C Recommendation): The font-style property selects between normal and small-caps within a font family. Values are: - normal - small-caps Another type of variation within a font family is the small-caps. In a small-caps font the lower case letters look similar to the uppercase ones, but in a smaller size and with slightly different proportions. The 'font-variant' property selects that font. A value of 'normal' selects a font that is not a small-caps font, 'small-caps' selects a small-caps font. It is acceptable (but not required) in CSS1 if the small-caps font is a created by taking a normal font and replacing the lower case letters by scaled uppercase characters. As a last resort, uppercase letters will be used as replacement for a small-caps font.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcfontvariant.htm"
     },
     "IfcFontWeight": {
-        "description": "Definition from CSS1 (W3C Recommendation): The 'font-weight' property selects the weight of the font. The values '100' to '900' form an ordered sequence, where each number indicates a weight that is at least as dark as its predecessor. The keyword 'normal' is synonymous with '400', and 'bold' is synonymous with '700'. Keywords other than 'normal' and 'bold' have been shown to be often confused with font names and a numerical scale was therefore chosen for the 9-value list. Values are:",
+        "description": "Definition from CSS1 (W3C Recommendation): The 'font-weight' property selects the weight of the font. The values '100' to '900' form an ordered sequence, where each number indicates a weight that is at least as dark as its predecessor. The keyword 'normal' is synonymous with '400', and 'bold' is synonymous with '700'. Keywords other than 'normal' and 'bold' have been shown to be often confused with font names and a numerical scale was therefore chosen for the 9-value list. Values are: - normal - bold - 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 Fonts (the font data) typically have one or more properties whose values are names that are descriptive of the \"weight\" of a font. There is no accepted, universal meaning to these weight names. Their primary role is to distinguish faces of differing darkness within a single font family. Usage across font families is quite variant; for example a font that you might think of as being bold might be described as being Regular, Roman, Book, Medium, Semi- or DemiBold, Bold, or Black, depending on how black the \"normal\" face of the font is within the design. Because there is no standard usage of names, the weight property values in CSS1 are given on a numerical scale in which the value '400' (or 'normal') corresponds to the \"normal\" text face for that family. The weight name associated with that face will typically be Book, Regular, Roman, Normal or sometimes Medium. The association of other weights within a family to the numerical weight values is intended only to preserve the ordering of darkness within that family. However, the following heuristics tell how the assignment is done in typical cases: - If the font family already uses a numerical scale with nine values (like e.g. OpenType does), the font weights should be mapped directly. - If there is both a face labeled Medium and one labeled Book, Regular, Roman or Normal, then the Medium is normally assigned to the '500'. - The font labeled \"Bold\" will often correspond to the weight value '700'. - If there are fewer then 9 weights in the family, the default algorithm for filling the \"holes\" is as follows. If '500' is unassigned, it will be assigned the same font as '400'. If any of the values '600', '700', '800' or '900' remains unassigned, they are assigned to the same face as the next darker assigned keyword, if any, or the next lighter one otherwise. If any of '300', '200' or '100' remains unassigned, it is assigned to the next lighter assigned keyword, if any, or the next darker otherwise. The following two examples illustrate the process. Assume four weights in the \"Example1\" family, from lightest to darkest: Regular, Medium, Bold, Heavy. And assume six weights in the \"Example2\" family: Book, Medium, Bold, Heavy, Black, ExtraBlack. Note how in the second example it has been decided not to assign \"Example2 ExtraBlack\" to anything.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcfontweight.htm"
     },
     "IfcFootingTypeEnum": {
-        "description": "Definition from         IAI: Enumeration defining the generic footing type.",
+        "description": "Definition from IAI: Enumeration defining the generic footing type. ENUMERATION - FOOTING_BEAM Footing elements that are in bending and are supported clear of the ground. They will normally span between piers, piles or pile caps. They are distinguished from beams in the building superstructure since they will normally require a lower grade of finish. They are distinguished from STRIP_FOOTING since they are clear of the ground surface and hence require support to the lower face while the concrete is curing. - PAD_FOOTING An element that transfers the load of a single column (possibly two) to the ground. - PILE_CAP An element that transfers the load from a column or group of columns to a pier or pile or group of piers or piles. - STRIP_FOOTING A linear element that transfers loads into the ground from either a continuous element, such as a wall, or from a series of elements, such as columns. - USERDEFINED Special types of footings which meet specific local requirements. - NOTDEFINED The type of footing is not defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcfootingtypeenum.htm"
     },
     "IfcForceMeasure": {
-        "description": "A measure of the force.",
+        "description": "A measure of the force. Usually measured in Newton (N, kg m/s2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcforcemeasure.htm"
     },
     "IfcFrequencyMeasure": {
-        "description": "A measure of the number of times that an item vibrates in unit time.",
+        "description": "A measure of the number of times that an item vibrates in unit time. Usually measured in cycles/s or Herz (Hz). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcfrequencymeasure.htm"
     },
     "IfcGasTerminalTypeEnum": {
-        "description": "Enumeration defining the functional type of gas terminal. The IfcGasTerminalTypeEnum contains the following:",
+        "description": "Enumeration defining the functional type of gas terminal. The IfcGasTerminalTypeEnum contains the following: - GASAPPLIANCE: Gas appliance gas terminal type - GASBOOSTER: Gas booster gas terminal type - GASTERMINAL: Gas terminal gas terminal type - USERDEFINED: User-defined gas terminal type. - NOTDEFINED: Undefined gas terminal type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcgasterminaltypeenum.htm"
     },
     "IfcGeometricProjectionEnum": {
-        "description": "Definition from IAI: The IfcGeometricProjectionEnum defines the various representation types that can be semantically distinguished. Often different levels of detail of the shape representation are controlled by the representation type.",
+        "description": "Definition from IAI: The IfcGeometricProjectionEnum defines the various representation types that can be semantically distinguished. Often different levels of detail of the shape representation are controlled by the representation type. - GRAPH_VIEW: Geometric display representation that shows an abstract, often 1D element representation, e.g. representing a wall by its axis line. - SKETCH_VIEW: Geometric display representation that shows an abstract, often 2D element representation, e.g. representing a wall by its two foot print edges, surpressing any inner layer representation. - MODEL_VIEW: Geometric display representation that shows a full 3D element representation, e.g. representing a wall by its volumetric body. - PLAN_VIEW: Geometric display representation that shows a full 2D element representation, the level of detail often depends on the target scale, e.g. representing a wall by its two foot print edges and the edges of all inner layers. The projection is shown in ground view as seen from above. - REFLECTED_PLAN_VIEW: Geometric display representation that shows a full 2D element representation, the level of detail often depends on the target scale, e.g. representing a wall by its two foot print edges and the edges of all inner layers. The projection is shown in ground view as seen from below. - SECTION_VIEW: Geometric display representation that shows a full 2D element representation, the level of detail often depends on the target scale, e.g. representing a wall by its two inner/outer edges and the edges of all inner layers, if the element is cut by the section line. - ELEVATION_VIEW: Geometric display representation that shows a full 2D element representation, the level of detail often depends on the target scale, e.g. representing a wall by its bounding edges if the element is within an elevation view. - USERDEFINED: A user defined specification is given by the value of the UserDefinedTargetView attribute. - NOTDEFINED: No specification given.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcgeometricprojectionenum.htm"
     },
     "IfcGeometricSetSelect": {
@@ -508,7 +508,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcglobalorlocalenum.htm"
     },
     "IfcGloballyUniqueId": {
-        "description": "Holds an identifier that is unique throughout the software world. This is also known as a Globally Unique Identifier (GUID) or Universal Unique Identifier (UUID) by the Open Group. The identifier is generated using an algorithm published by the Object Management Group. The algorithm is explained at the open group website. The Microsoft Foundation Class (MFC) function \"CoCreateGuid\", which is an implementation of the above algorithm, has been used by many IFC implementers to create an identifier.",
+        "description": "Holds an identifier that is unique throughout the software world. This is also known as a Globally Unique Identifier (GUID) or Universal Unique Identifier (UUID) by the Open Group. The identifier is generated using an algorithm published by the Object Management Group. The algorithm is explained at the open group website. The Microsoft Foundation Class (MFC) function \"CoCreateGuid\", which is an implementation of the above algorithm, has been used by many IFC implementers to create an identifier. An identifier is a unique 128-bit number. Since this identifier is required for all IFC object instances, it is desirable to compress the identifier size to reduce overhead. Beginning in IFC R1.5.1, IFC implementers agreed to compress the identifier down to 20 characters using an algorithm developed by IAI Implementers. This algorithm maps the identifier bits onto a base 85 digit encoded from the following character set: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&\\^|*+,-./:;<=>?\\~`@_ An index (0-84) into this character set string determines the \"value\" for each character (e.g. \"A\" has a value of 10, \"@\" has a value of 83, etc.). Note that all characters are case-sensitive. In order to prevent possible problems with some parsers, implementers have agreed not to use the \"/*\" and \"*/\" character combinations in the identifier string and instead to use \"\\*\" and \"*\\\". The implementation of the compression algorithm has changed in IFC R2x in order to prevent conflicts with special characters in the ISO 10303-21 exchange file and the W3C XML file (such as '<*', '*>', '<' and '>'). Using 64 characters for the base rather than 85, the resulting compressed string now needs 22 characters. The encoding of the base 64 character set is shown below: The following code example in C is given as a guideline for creating the base 64 compressed strings and for mapping the previous base 85 strings to the base 64 strings. This code is provided \"as-is\" with no support or guarantee of suitability provided by the IAI. Use of the code example is at the sole risk of the user. - CreateGuid_64.h - CreateGuid_64.c The resulting string is a fixed 22 character length string to be exchanged within the IFC exchange file structure.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifcgloballyuniqueid.htm"
     },
     "IfcHatchLineDistanceSelect": {
@@ -516,11 +516,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifchatchlinedistanceselect.htm"
     },
     "IfcHeatExchangerTypeEnum": {
-        "description": "Enumeration defining the typical types of heat exchangers. The IfcHeatExchangerTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of heat exchangers. The IfcHeatExchangerTypeEnum contains the following: - PLATE: Plate heat exchanger. - SHELLANDTUBE: Shell and Tube heat exchanger. - USERDEFINED: User-defined heat exchanger type. - NOTDEFINED: Undefined heat exchanger type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcheatexchangertypeenum.htm"
     },
     "IfcHeatFluxDensityMeasure": {
-        "description": "A measure of the density of heat flux within a body.",
+        "description": "A measure of the density of heat flux within a body. Usually measured in W/m2 (J/s m2). Type: REAL > HISTORY New type in IFC Release 2.0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcheatfluxdensitymeasure.htm"
     },
     "IfcHeatingValueMeasure": {
@@ -528,39 +528,39 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcheatingvaluemeasure.htm"
     },
     "IfcHourInDay": {
-        "description": "The hour element of a specified time on a 24 hour clock.",
+        "description": "The hour element of a specified time on a 24 hour clock. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifchourinday.htm"
     },
     "IfcHumidifierTypeEnum": {
-        "description": "Enumeration defining the typical types of humidifiers. The IfcHumidifierTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of humidifiers. The IfcHumidifierTypeEnum contains the following: - STEAMINJECTION: Water vapor is added into the airstream through direction steam injection. - ADIABATICAIRWASHER: Water vapor is added into the airstream through adiabatic evaporation using an air washing element. - ADIABATICPAN: Water vapor is added into the airstream through adiabatic evaporation using a pan. - ADIABATICWETTEDELEMENT: Water vapor is added into the airstream through adiabatic evaporation using a wetted element. - ADIABATICATOMIZING: Water vapor is added into the airstream through adiabatic evaporation using an atomizing element. - ADIABATICULTRASONIC: Water vapor is added into the airstream through adiabatic evaporation using an ultrasonic element. - ADIABATICRIGIDMEDIA: Water vapor is added into the airstream through adiabatic evaporation using a rigid media. - ADIABATICCOMPRESSEDAIRNOZZLE: Water vapor is added into the airstream through adiabatic evaporation using a compressed air nozzle. - ASSISTEDELECTRIC: Water vapor is added into the airstream through water heated evaporation using an electric heater. - ASSISTEDNATURALGAS: Water vapor is added into the airstream through water heated evaporation using a natural gas heater. - ASSISTEDPROPANE: Water vapor is added into the airstream through water heated evaporation using a propane heater. - ASSISTEDBUTANE: Water vapor is added into the airstream through water heated evaporation using a butane heater. - ASSISTEDSTEAM: Water vapor is added into the airstream through water heated evaporation using a steam heater. - USERDEFINED: User-defined humidifier type. - NOTDEFINED: Undefined humidifier type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifchumidifiertypeenum.htm"
     },
     "IfcIdentifier": {
-        "description": "An identifier is an alphanumeric string which allows an individual thing to be identified. It may not provide natural-language meaning.",
+        "description": "An identifier is an alphanumeric string which allows an individual thing to be identified. It may not provide natural-language meaning. Type: STRING - it should be restricted to max. 255 characters.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcidentifier.htm"
     },
     "IfcIlluminanceMeasure": {
-        "description": "A measure of the illuminance.",
+        "description": "A measure of the illuminance. Usually measured in Lux (lx, Lumen/m2 = Candela Steradian/m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcilluminancemeasure.htm"
     },
     "IfcInductanceMeasure": {
-        "description": "A measure of the inductance.",
+        "description": "A measure of the inductance. Usually measure in Henry (H, Weber/A = V s/A). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcinductancemeasure.htm"
     },
     "IfcInteger": {
-        "description": "A defined type of simple data type Integer. (Required since a select type, i.e. IfcSimpleValue, cannot include directly simple types in its select list).",
+        "description": "A defined type of simple data type Integer. (Required since a select type, i.e. IfcSimpleValue, cannot include directly simple types in its select list). In principle, the domain of IfcInteger (being an Integer) is all integer numbers. Here the number of bits used for the IfcInteger representation is unconstrained, but in practice it is implementation specific. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcinteger.htm"
     },
     "IfcIntegerCountRateMeasure": {
-        "description": "A measure of the integer number of units flowing per unit time.",
+        "description": "A measure of the integer number of units flowing per unit time. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcintegercountratemeasure.htm"
     },
     "IfcInternalOrExternalEnum": {
-        "description": "This enumeration defines the different types of spaces or space boundaries in terms of either being inside the building or outside the building.",
+        "description": "This enumeration defines the different types of spaces or space boundaries in terms of either being inside the building or outside the building. Enumeration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcinternalorexternalenum.htm"
     },
     "IfcInventoryTypeEnum": {
-        "description": "IfcInventoryTypeEnum defines the types of inventory that can be defined.",
+        "description": "IfcInventoryTypeEnum defines the types of inventory that can be defined. Enumeration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcinventorytypeenum.htm"
     },
     "IfcIonConcentrationMeasure": {
@@ -568,7 +568,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcionconcentrationmeasure.htm"
     },
     "IfcIsothermalMoistureCapacityMeasure": {
-        "description": "A measure of isothermal moisture capacity.",
+        "description": "A measure of isothermal moisture capacity. Usually measured in m3/kg. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcisothermalmoisturecapacitymeasure.htm"
     },
     "IfcJunctionBoxTypeEnum": {
@@ -576,175 +576,175 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcjunctionboxtypeenum.htm"
     },
     "IfcKinematicViscosityMeasure": {
-        "description": "A measure of the viscous resistance of a medium to a moving body.",
+        "description": "A measure of the viscous resistance of a medium to a moving body. Usually measured in m2/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifckinematicviscositymeasure.htm"
     },
     "IfcLabel": {
-        "description": "A label is the term by which something may be referred to. It is a string which represents the human-interpretable name of something and shall have a natural-language meaning.",
+        "description": "A label is the term by which something may be referred to. It is a string which represents the human-interpretable name of something and shall have a natural-language meaning. Type: STRING - it should be restricted to max. 255 characters.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifclabel.htm"
     },
     "IfcLampTypeEnum": {
-        "description": "The IfcLampTypeEnum defines the range of different types of lamp available.",
+        "description": "The IfcLampTypeEnum defines the range of different types of lamp available. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifclamptypeenum.htm"
     },
     "IfcLayerSetDirectionEnum": {
-        "description": "Identification of the axis of element geometry denoting the layer set thickness direction.",
+        "description": "Identification of the axis of element geometry denoting the layer set thickness direction. ENUMERATION - AXIS1 Usually x-axis. - AXIS2 Usually y-axis. - AXIS3 Usually z-axis.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifclayersetdirectionenum.htm"
     },
     "IfcLayeredItem": {
-        "description": "The layered things type selects those things, which can be grouped in layers.",
+        "description": "The layered things type selects those things, which can be grouped in layers. It is the collection of all those items, that are assigned to a single layer. These items are representation items or complete representations (IfcRepresentationItem, IfcRepresentation). If an IfcRepresentation is referenced, all IfcRepresentationItem within its set of Items are assigned to the same layer.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclayereditem.htm"
     },
     "IfcLengthMeasure": {
-        "description": "A length measure is the value of a distance.",
+        "description": "A length measure is the value of a distance. Usually measured in millimeters (mm). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifclengthmeasure.htm"
     },
     "IfcLibrarySelect": {
-        "description": "An IfcLibrarySelect enables selection of whether library information is to be contained within an IFC model or is to be referenced from an external source.",
+        "description": "An IfcLibrarySelect enables selection of whether library information is to be contained within an IFC model or is to be referenced from an external source. Select From: - IfcLibraryInformation (for library information) - IfcLibraryReference (for reference into a library of information by location)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifclibraryselect.htm"
     },
     "IfcLightDistributionCurveEnum": {
-        "description": "There are three kinds of light distribution curves:",
+        "description": "There are three kinds of light distribution curves: - Type A Photometry - Type B Photometry - Type C Photometry. The following applies (Definitions according to Standard CEN TC 169, prEN 13032-1, CIE 121 ): - Type A is basically not used. For completeness the Type A Photometry equals the Type B rotated 90\u00b0 around the Z-Axis counter clockwise. - Type B is sometimes used for floodlights. The B-Plane System has a horizontal axis. B-Angles are valid from -180\u00b0 to +180\u00b0 with B 0\u00b0 at the bottom and B180\u00b0/B-180\u00b0 at the top, \u03b2-Angles are valid from -90\u00b0 to +90\u00b0. (See the pictures below.) - Type C is the recommended standard system. The C-Plane system equals a globe with a vertical axis. C-Angles are valid from 0\u00b0 to 360\u00b0, \u03b3-Angles are valid from 0\u00b0 (south pole) to 180\u00b0 (north pole). (See the pictures below.)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightdistributioncurveenum.htm"
     },
     "IfcLightDistributionDataSourceSelect": {
-        "description": "A goniometric light gets its intensity distribution function (how much light goes in any one direction) from one of two sources: (i) an industry-standard file, (ii) from distribution data passed directly via the IfcLightIntensityDistribution.",
+        "description": "A goniometric light gets its intensity distribution function (how much light goes in any one direction) from one of two sources: (i) an industry-standard file, (ii) from distribution data passed directly via the IfcLightIntensityDistribution. The light distribution provides the luminous intensity distribution according to some standardized light distribution curves. Select:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightdistributiondatasourceselect.htm"
     },
     "IfcLightEmissionSourceEnum": {
-        "description": "The IfcLightEmissionSourceEnum defines the range of different types of light emitter available.",
+        "description": "The IfcLightEmissionSourceEnum defines the range of different types of light emitter available. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightemissionsourceenum.htm"
     },
     "IfcLightFixtureTypeEnum": {
-        "description": "The IfcLightFixtureTypeEnum defines the range of different types of light fixture available.",
+        "description": "The IfcLightFixtureTypeEnum defines the range of different types of light fixture available. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifclightfixturetypeenum.htm"
     },
     "IfcLinearForceMeasure": {
-        "description": "A measure of linear force.",
+        "description": "A measure of linear force. Usually measured in N/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifclinearforcemeasure.htm"
     },
     "IfcLinearMomentMeasure": {
-        "description": "A measure of linear moment.",
+        "description": "A measure of linear moment. Usually measured in Nm/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifclinearmomentmeasure.htm"
     },
     "IfcLinearStiffnessMeasure": {
-        "description": "A measure of linear stiffness.",
+        "description": "A measure of linear stiffness. Usually measured in N/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifclinearstiffnessmeasure.htm"
     },
     "IfcLinearVelocityMeasure": {
-        "description": "A measure of the velocity of a body measured in terms of distance moved per unit time.",
+        "description": "A measure of the velocity of a body measured in terms of distance moved per unit time. Usually measured in m/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifclinearvelocitymeasure.htm"
     },
     "IfcLoadGroupTypeEnum": {
-        "description": "This type definition is used to distinguish between different kinds and purposes of load grouping. It allows to differentiate between load groups, load cases, load combination groups and load combinations. Normally, these enumeration types shall be used in the following context :",
+        "description": "This type definition is used to distinguish between different kinds and purposes of load grouping. It allows to differentiate between load groups, load cases, load combination groups and load combinations. Normally, these enumeration types shall be used in the following context : - LOAD_GROUP groups instances of IfcStructuralAction or its subclasses. It shall be used as a container for loads grouped together for specific purposes. Optionally, an overall load factor can be assigned. - LOAD_CASE groups LOAD_GROUPs and instances of IfcStructuralAction or its subclasses. It shall be used as a container for loads with the same origin, and to assign a common load factor. - LOAD_COMBINATION_GROUP shall be used to group LOAD_CASEs and to assign a common load combination factor. The grouping of LOAD_GROUPs and instances of IfcStructuralAction or its subclasses is also possible, but off the traditional way. - LOAD_COMBINATION shall be used to group all loads belonging to a specific load combination. Normally only LOAD_COMBINATION_GROUPs with all needed load factors are used to create load combinations. The IfcLoadGroupTypeEnum type is referenced by the entity IfcStructuralLoadGroup.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcloadgrouptypeenum.htm"
     },
     "IfcLogical": {
-        "description": "A defined type of simple type logical. (Required since a select type, i.e. IfcSimpleValue, cannot include directly simple types in its select list). Logical datatype can have values TRUE, FALSE or UNKNOWN.",
+        "description": "A defined type of simple type logical. (Required since a select type, i.e. IfcSimpleValue, cannot include directly simple types in its select list). Logical datatype can have values TRUE, FALSE or UNKNOWN. Type: LOGICAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifclogical.htm"
     },
     "IfcLogicalOperatorEnum": {
-        "description": "IfcLogicalOperatorEnum is an enumeration that defines the logical operators that may be applied for the satisfaction of more than one constraint at a time.",
+        "description": "IfcLogicalOperatorEnum is an enumeration that defines the logical operators that may be applied for the satisfaction of more than one constraint at a time. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifclogicaloperatorenum.htm"
     },
     "IfcLuminousFluxMeasure": {
-        "description": "A measure of the luminous flux.",
+        "description": "A measure of the luminous flux. Usually measured in Lumen (lm, Candela Steradian). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcluminousfluxmeasure.htm"
     },
     "IfcLuminousIntensityDistributionMeasure": {
-        "description": "A measure of the luminous intensity of a light source that changes according to the direction of the ray. It is normally based on some standardized distribution light distribution curves.",
+        "description": "A measure of the luminous intensity of a light source that changes according to the direction of the ray. It is normally based on some standardized distribution light distribution curves. Usually measured in Candela/Lumen (cd/lm) or (cd/klm). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcluminousintensitydistributionmeasure.htm"
     },
     "IfcLuminousIntensityMeasure": {
-        "description": "A luminous intensity measure is the value for the brightness of a body.",
+        "description": "A luminous intensity measure is the value for the brightness of a body. Usually measured in candela (cd). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcluminousintensitymeasure.htm"
     },
     "IfcMagneticFluxDensityMeasure": {
-        "description": "A measure of the magnetic flux density.",
+        "description": "A measure of the magnetic flux density. Usually measured in Tesla (T, Weber/m2 = V s/m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmagneticfluxdensitymeasure.htm"
     },
     "IfcMagneticFluxMeasure": {
-        "description": "A measure of the magnetic flux.",
+        "description": "A measure of the magnetic flux. Usually measured in Weber (Wb, V s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmagneticfluxmeasure.htm"
     },
     "IfcMassDensityMeasure": {
-        "description": "A measure of the density of a medium.",
+        "description": "A measure of the density of a medium. Usually measured in kg/m3. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmassdensitymeasure.htm"
     },
     "IfcMassFlowRateMeasure": {
-        "description": "A measure of the mass of a medium flowing per unit time.",
+        "description": "A measure of the mass of a medium flowing per unit time. Usually measured in kg/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmassflowratemeasure.htm"
     },
     "IfcMassMeasure": {
-        "description": "A mass measure is the value of the amount of matter that a body contains.",
+        "description": "A mass measure is the value of the amount of matter that a body contains. Usually measure in kilograms (kg) or grams (g). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmassmeasure.htm"
     },
     "IfcMassPerLengthMeasure": {
-        "description": "A measure for mass per length. For example for rolled steel profiles the weight of an imaginary beam is usually expressed by kg/m length for cost calculation and structural analysis purposes.",
+        "description": "A measure for mass per length. For example for rolled steel profiles the weight of an imaginary beam is usually expressed by kg/m length for cost calculation and structural analysis purposes. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmassperlengthmeasure.htm"
     },
     "IfcMaterialSelect": {
-        "description": "Selection of whether a material, a material layer, material layer set (with or without usage information) or a material list is assigned to an element.",
+        "description": "Selection of whether a material, a material layer, material layer set (with or without usage information) or a material list is assigned to an element. SELECT - IfcMaterial - IfcMaterialList - IfcMaterialLayer - IfcMaterialLayerSet - IfcMaterialLayerSetUsage",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmaterialselect.htm"
     },
     "IfcMeasureValue": {
-        "description": "A measure value is a value as defined in ISO 31-0 (clause 2).",
+        "description": "A measure value is a value as defined in ISO 31-0 (clause 2). SELECT - IfcAmountOfSubstanceMeasure - IfcAreaMeasure - IfcContextDependentMeasure - IfcCountMeasure - IfcDescriptiveMeasure - IfcElectricCurrentMeasure - IfcLengthMeasure - IfcLuminousIntensityMeasure - IfcMassMeasure - IfcNormalisedRatioMeasure - IfcNumericMeasure - IfcParameterValue - IfcPlaneAngleMeasure - IfcPositiveLengthMeasure - IfcPositivePlaneAngleMeasure - IfcPositiveRatioMeasure - IfcRatioMeasure - IfcSolidAngleMeasure - IfcThermodynamicTemperatureMeasure - IfcTimeMeasure - IfcVolumeMeasure - IfcComplexNumber",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmeasurevalue.htm"
     },
     "IfcMemberTypeEnum": {
-        "description": "This enumeration defines the different types of linear elements an IfcMemberType object can fulfill:",
+        "description": "This enumeration defines the different types of linear elements an IfcMemberType object can fulfill: - BRACE: A linear element (usually sloped) often used for bracing of a girder or truss. - CHORD: Upper or lower longitudinal member of a truss, used horizontally or sloped. - COLLAR: A linear element (usually used horizontally) within a roof structure to connect rafters and posts. - MEMBER: A linear element within a girder or truss with no further meaning. - MULLION: A linear element within a curtain wall system to connect two (or more) panels. - PLATE: A linear continuous horizontal element in wall framing, e.g. a head piece or a sole plate. - POST: A linear member (usually used vertically) within a roof structure to support purlins. - PURLIN: A linear element (usually used horizontally) within a roof structure to support rafters - RAFTER: A linear elements used to support roof slabs or roof covering, usually used with slope. - STRINGER: A linear element used to support stair or ramp flights, usually used with slope. - STRUT: A linear element often used within a girder or truss. - STUD: Vertical element in wall framing. - USERDEFINED: User-defined linear element. - NOTDEFINED: Undefined linear element",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcmembertypeenum.htm"
     },
     "IfcMetricValueSelect": {
-        "description": "An IfcMetricValueSelect is a select type that enables selection of the data type for the value component of an IfcMetric.",
+        "description": "An IfcMetricValueSelect is a select type that enables selection of the data type for the value component of an IfcMetric. HISTORY: New type in IFC Release 2.0 Select - IfcCostValue - IfcDateTimeSelect - IfcMetricBoundedValue - IfcMeasureWithUnit - IfcTable - IfcText - IfcTimeSeries",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcmetricvalueselect.htm"
     },
     "IfcMinuteInHour": {
-        "description": "The minute element of a specified time.",
+        "description": "The minute element of a specified time. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifcminuteinhour.htm"
     },
     "IfcModulusOfElasticityMeasure": {
-        "description": "A measure of modulus of elasticity.",
+        "description": "A measure of modulus of elasticity. Usually measured in N/m2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmodulusofelasticitymeasure.htm"
     },
     "IfcModulusOfLinearSubgradeReactionMeasure": {
-        "description": "A measure for modulus of linear subgrade reaction, which expresses the elastic bedding of a linear structural element per length, e.g. a beam. It is typically measured in N/m\\^2.",
+        "description": "A measure for modulus of linear subgrade reaction, which expresses the elastic bedding of a linear structural element per length, e.g. a beam. It is typically measured in N/m\\^2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmodulusoflinearsubgradereactionmeasure.htm"
     },
     "IfcModulusOfRotationalSubgradeReactionMeasure": {
-        "description": "A measure for modulus of rotational subgrade reaction, which expresses the rotational elastic bedding of a linear structural element per length, e.g. a beam. It is typically measured in Nm/(m*rad).",
+        "description": "A measure for modulus of rotational subgrade reaction, which expresses the rotational elastic bedding of a linear structural element per length, e.g. a beam. It is typically measured in Nm/(m*rad). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmodulusofrotationalsubgradereactionmeasure.htm"
     },
     "IfcModulusOfSubgradeReactionMeasure": {
-        "description": "A geotechnical measure describing         interaction between foundation structures and the soil. May also be known as         bedding measure.",
+        "description": "A geotechnical measure describing interaction between foundation structures and the soil. May also be known as bedding measure. Usually measured in N/m3. Type: REAL Illustration: Figure: Elastic support of a planar member.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmodulusofsubgradereactionmeasure.htm"
     },
     "IfcMoistureDiffusivityMeasure": {
-        "description": "A measure of moisture diffusivity.",
+        "description": "A measure of moisture diffusivity. Usually measured in m3/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmoisturediffusivitymeasure.htm"
     },
     "IfcMolecularWeightMeasure": {
-        "description": "A measure of molecular weight of material (typically gas).",
+        "description": "A measure of molecular weight of material (typically gas). Usually measured in g/mole. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmolecularweightmeasure.htm"
     },
     "IfcMomentOfInertiaMeasure": {
-        "description": "A measure of moment of inertia.",
+        "description": "A measure of moment of inertia. Usually measured in m4. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmomentofinertiameasure.htm"
     },
     "IfcMonetaryMeasure": {
-        "description": "A monetary measure is the value of an amount of money without regard to its currency.",
+        "description": "A monetary measure is the value of an amount of money without regard to its currency. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmonetarymeasure.htm"
     },
     "IfcMonthInYearNumber": {
-        "description": "The position of the specified month in a year as defined in ISO 8601 (subcaluse 5.2.1).",
+        "description": "The position of the specified month in a year as defined in ISO 8601 (subcaluse 5.2.1). Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifcmonthinyearnumber.htm"
     },
     "IfcMotorConnectionTypeEnum": {
-        "description": "The IfcMotorConnectionTypeEnum defines the range of different types of motor connection that can be specified.",
+        "description": "The IfcMotorConnectionTypeEnum defines the range of different types of motor connection that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcmotorconnectiontypeenum.htm"
     },
     "IfcNormalisedRatioMeasure": {
-        "description": "Dimensionless measure to express ratio values ranging from 0.0 to 1.0",
+        "description": "Dimensionless measure to express ratio values ranging from 0.0 to 1.0 Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcnormalisedratiomeasure.htm"
     },
     "IfcNullStyle": {
@@ -752,7 +752,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcnullstyle.htm"
     },
     "IfcNumericMeasure": {
-        "description": "A numeric measure is the numeric value of a physical quantity.",
+        "description": "A numeric measure is the numeric value of a physical quantity. Type: NUMBER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcnumericmeasure.htm"
     },
     "IfcObjectReferenceSelect": {
@@ -764,11 +764,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcobjecttypeenum.htm"
     },
     "IfcObjectiveEnum": {
-        "description": "An IfcObjectiveEnum is an enumeration used to determine the objective for which purpose the constraint needs to be satisfied.",
+        "description": "An IfcObjectiveEnum is an enumeration used to determine the objective for which purpose the constraint needs to be satisfied. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcobjectiveenum.htm"
     },
     "IfcOccupantTypeEnum": {
-        "description": "IfcOccupantTypeEnum defines the types of occupant from which the type required can be selected.",
+        "description": "IfcOccupantTypeEnum defines the types of occupant from which the type required can be selected. Enumeration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcoccupanttypeenum.htm"
     },
     "IfcOrientationSelect": {
@@ -776,7 +776,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcorientationselect.htm"
     },
     "IfcOutletTypeEnum": {
-        "description": "The IfcOutletTypeEnum defines the range of different types of outlet that can be specified.",
+        "description": "The IfcOutletTypeEnum defines the range of different types of outlet that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcoutlettypeenum.htm"
     },
     "IfcPHMeasure": {
@@ -784,63 +784,63 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcphmeasure.htm"
     },
     "IfcParameterValue": {
-        "description": "A parameter value is the value which specifies the amount of a parameter in some parameter space.",
+        "description": "A parameter value is the value which specifies the amount of a parameter in some parameter space. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcparametervalue.htm"
     },
     "IfcPermeableCoveringOperationEnum": {
-        "description": "Enumeration defining the valid types of permeable coverings.",
+        "description": "Enumeration defining the valid types of permeable coverings. Enumeration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcarchitecturedomain/lexical/ifcpermeablecoveringoperationenum.htm"
     },
     "IfcPhysicalOrVirtualEnum": {
-        "description": "This enumeration defines the different types of space boundaries in terms of its physical manifestation. A space boundary can either be physically dividing or can be a virtual divider.",
+        "description": "This enumeration defines the different types of space boundaries in terms of its physical manifestation. A space boundary can either be physically dividing or can be a virtual divider. Enumeration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcphysicalorvirtualenum.htm"
     },
     "IfcPileConstructionEnum": {
-        "description": "Enumeration defining the construction type for piles. The type is mainly based on how the piles are used and manufactured. Some material information is mixed in because this affects the way the piles are used.",
+        "description": "Enumeration defining the construction type for piles. The type is mainly based on how the piles are used and manufactured. Some material information is mixed in because this affects the way the piles are used. ENUMERATION - CAST_IN_PLACE Piles and piers that are excavated and poured in place. - COMPOSITE Piles that are a mix of components, such as a steel outer casing which is driven into the ground with a cast-in-place concrete core. - PRECAST_CONCRETE Piles that are entirely of precast concrete (possibly with some steel or other fixtures). - PREFAB_STEEL Prefabricated piles made entirely out of steel. It will also include steel sheet piles where these are not part of another construction element. - USERDEFINED Special types of pile construction which meet specific local requirements. - NOTDEFINED The type of pile construction is not defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcpileconstructionenum.htm"
     },
     "IfcPileTypeEnum": {
-        "description": "Enumeration defining the pile type according to function.",
+        "description": "Enumeration defining the pile type according to function. ENUMERATION - COHESION A cohesion pile. - FRICTION A friction pile. - SUPPORT A support pile. - USERDEFINED The type of pile function is user defined. - NOTDEFINED The type of pile function is not defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcpiletypeenum.htm"
     },
     "IfcPipeFittingTypeEnum": {
-        "description": "This enumeration is used to identify the primary purpose of a pipe fitting. This is a very basic categorization mechanism to generically identify the pipe fitting type. Subcategories of pipe fittings are not enumerated. The IfcpipeFittingTypeEnum contains the following:",
+        "description": "This enumeration is used to identify the primary purpose of a pipe fitting. This is a very basic categorization mechanism to generically identify the pipe fitting type. Subcategories of pipe fittings are not enumerated. The IfcpipeFittingTypeEnum contains the following: - BEND: A fitting with typically two ports used to change the direction of flow between connected elements. - CONNECTOR: Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two pipe segments). - ENTRY: Entry fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., a breeching inlet). - EXIT: Exit fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., a hose bibb). - JUNCTION: A fitting with typically more than two ports used to redistribute flow among the ports and/or to change the direction of flow between connected elements (e.g, tee, cross, wye, etc.). - OBSTRUCTION: A fitting with typically two ports used to obstruct or restrict flow between the connected elements (e.g., screen, perforated plate, etc.). - TRANSITION: A fitting with typically two ports having different shapes or sizes. Can also be used to change the direction of flow between connected elements. - USERDEFINED: User-defined fitting. - NOTDEFINED: Undefined fitting.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcpipefittingtypeenum.htm"
     },
     "IfcPipeSegmentTypeEnum": {
-        "description": "This enumeration is used to identify the primary purpose of a pipe segment. This is a very basic categorization mechanism to generically identify the pipe segment type. Subcategories of pipe segments are not enumerated. The IfcPipeSegmentTypeEnum contains the following:",
+        "description": "This enumeration is used to identify the primary purpose of a pipe segment. This is a very basic categorization mechanism to generically identify the pipe segment type. Subcategories of pipe segments are not enumerated. The IfcPipeSegmentTypeEnum contains the following: - RIGIDSEGMENT: A rigid segment is continuous linear segment of pipe that cannot be deformed. - FLEXIBLESEGMENT: A flexible segment is a continuous non-linear segment of pipe that can be deformed and change the direction of flow. - GUTTER: A gutter segment is a continuous open-channel segment of pipe. - SPOOL: A type of rigid segment that is typically shorter and used for providing connectivity within a piping network. - USERDEFINED: User-defined segment. - NOTDEFINED: Undefined segment.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcpipesegmenttypeenum.htm"
     },
     "IfcPlanarForceMeasure": {
-        "description": "A measure of force on an area.",
+        "description": "A measure of force on an area. Usually measured in N/m2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcplanarforcemeasure.htm"
     },
     "IfcPlaneAngleMeasure": {
-        "description": "A plane angle measure is the value of an angle in a plane.",
+        "description": "A plane angle measure is the value of an angle in a plane. Usually measured in radian (rad, m/m = 1), but also grads may be used. The grad unit may be declared as a conversion based unit based on radian unit. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcplaneanglemeasure.htm"
     },
     "IfcPlateTypeEnum": {
-        "description": "This enumeration defines the different types of planar elements an IfcPlateType object can fulfill:",
+        "description": "This enumeration defines the different types of planar elements an IfcPlateType object can fulfill: - CURTAIN_PANEL: A planar element within a curtain wall, often consisting of a frame with fixed glazing. - SHEET: A planar, flat and thin element, comes usually as metal sheet, and is often used as an additonal part within an assembly. - USERDEFINED: User-defined linear element. - NOTDEFINED: Undefined linear element",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcplatetypeenum.htm"
     },
     "IfcPointOrVertexPoint": {
-        "description": "The IfcPointOrVertexPoint provides the option to either select a geometric point (IfcPoint and subtypes) within a geometric model, or a vertex with associated point coordinates (IfcVertexPoint) within a topological model.",
+        "description": "The IfcPointOrVertexPoint provides the option to either select a geometric point (IfcPoint and subtypes) within a geometric model, or a vertex with associated point coordinates (IfcVertexPoint) within a topological model. SELECT * IfcPoint, * IfcVertexPoint",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcpointorvertexpoint.htm"
     },
     "IfcPositiveLengthMeasure": {
-        "description": "A positive length measure is a length measure that is greater than zero.",
+        "description": "A positive length measure is a length measure that is greater than zero. Type: IfcLengthMeasure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcpositivelengthmeasure.htm"
     },
     "IfcPositivePlaneAngleMeasure": {
-        "description": "A positive plaPositive plane angle measure is a plane angle measure that is greater than zero.",
+        "description": "A positive plaPositive plane angle measure is a plane angle measure that is greater than zero. Type: IfcPlaneAngleMeasure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcpositiveplaneanglemeasure.htm"
     },
     "IfcPositiveRatioMeasure": {
-        "description": "A positive ratio measure is a ratio measure that is greater than zero.",
+        "description": "A positive ratio measure is a ratio measure that is greater than zero. Type: IfcRatioMeasure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcpositiveratiomeasure.htm"
     },
     "IfcPowerMeasure": {
-        "description": "A measure of power required or used.",
+        "description": "A measure of power required or used. Usually measured in Watts (W, J/s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcpowermeasure.htm"
     },
     "IfcPresentableText": {
@@ -852,75 +852,75 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcpresentationstyleselect.htm"
     },
     "IfcPressureMeasure": {
-        "description": "A measure of the quantity of a medium acting on a unit area.",
+        "description": "A measure of the quantity of a medium acting on a unit area. Usually measured in Pascals (Pa, N/m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcpressuremeasure.htm"
     },
     "IfcProcedureTypeEnum": {
-        "description": "The IfcProcedureTypeEnum defines the range of different types of procedure that can be specified.",
+        "description": "The IfcProcedureTypeEnum defines the range of different types of procedure that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcproceduretypeenum.htm"
     },
     "IfcProfileTypeEnum": {
-        "description": "Definition from IAI: The enumeration defines whether the definition of a profile shape shall be geometrically resolved into a curve or into a surface.",
+        "description": "Definition from IAI: The enumeration defines whether the definition of a profile shape shall be geometrically resolved into a curve or into a surface. Enumeration values: Curve The resulting geometric item is of type curve and closed (with the only exception of the curve created by the IfcArbitraryOpenProfileDef which resolves into an open curve). The resulting geometry after applying a sweeping operation is a swept surface. This can be used to define shapes with thin sheets, such as ducts, where the thickness is not appropriate for geometric representation. Area The resulting geometric item is of type surface. The resulting geometry after applying a sweeping operation is a swept solid with defined volume.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcprofiletypeenum.htm"
     },
     "IfcProjectOrderRecordTypeEnum": {
-        "description": "An IfcProjectOrderRecordTypeEnum is a designation of the type of event being recorded.",
+        "description": "An IfcProjectOrderRecordTypeEnum is a designation of the type of event being recorded. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcprojectorderrecordtypeenum.htm"
     },
     "IfcProjectOrderTypeEnum": {
-        "description": "An IfcProjectOrderTypeEnum is a list of the types of project order that may be identified.",
+        "description": "An IfcProjectOrderTypeEnum is a list of the types of project order that may be identified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcprojectordertypeenum.htm"
     },
     "IfcProjectedOrTrueLengthEnum": {
-        "description": "This enumeration type is needed for load definition and is only considered if the load values are given as global actions and if they define linear or planar loads.",
+        "description": "This enumeration type is needed for load definition and is only considered if the load values are given as global actions and if they define linear or planar loads. The IfcProjectedOrTrueLengthEnum type is referenced by the entity IfcStructuralAction and its respective subclasses. It also depends on the attribute value_GlobalOrLocal_ of supertype IfcStructuralActivity and should only take effect if GlobalOrLocal is set to GLOBAL_COORDS.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcprojectedortruelengthenum.htm"
     },
     "IfcPropertySourceEnum": {
-        "description": "This enumeration is used to qualify the life-cycle or design state of the properties contained in the entity and contains the following:",
+        "description": "This enumeration is used to qualify the life-cycle or design state of the properties contained in the entity and contains the following: - DESIGN: Properties are all design values. - DESIGNMAXIMUM: Properties are all maximum design values. - DESIGNMINIMUM: Properties are all minimum design values. - SIMULATED: Property values are all the results of a simulation. - ASBUILT: Properties are all AS-BUILT values. - COMMISSIONING: Properties are all commissioning values. - MEASURED: Property values are all the results of a measurement device, either automated or manual. - USERDEFINED: Property values are defined by the user. - NOTDEFINED: Property values are not defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcpropertysourceenum.htm"
     },
     "IfcProtectiveDeviceTypeEnum": {
-        "description": "The IfcProtectiveDeviceTypeEnum defines the range of different types of protective device available.",
+        "description": "The IfcProtectiveDeviceTypeEnum defines the range of different types of protective device available. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcprotectivedevicetypeenum.htm"
     },
     "IfcPumpTypeEnum": {
-        "description": "Defines general types of pumps. The IfcPumpTypeEnum contains the following:",
+        "description": "Defines general types of pumps. The IfcPumpTypeEnum contains the following: - CIRCULATOR: Circulator. - ENDSUCTION: End suction. - SPLITCASE: Split case. - VERTICALINLINE: Vertical inline. - VERTICALTURBINE: Vertical turbine. - USERDEFINED: User-defined pump type. - NOTDEFINED: Pump type has not been defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcpumptypeenum.htm"
     },
     "IfcRadioActivityMeasure": {
-        "description": "A measure of activity of radionuclide.",
+        "description": "A measure of activity of radionuclide. Usually measured in Becquerel (Bq, 1/s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcradioactivitymeasure.htm"
     },
     "IfcRailingTypeEnum": {
-        "description": "Enumeration defining the valid types of railings that can be predefined using the enumeration values.",
+        "description": "Enumeration defining the valid types of railings that can be predefined using the enumeration values. Enumeration - HANDRAIL: A type of railing designed to serve as an optional structural support for loads applied by human occupants (at hand height). Generally located adjacent to ramps and stairs. Generally floor or wall mounted. - GUARDRAIL: A type of railing designed to guard human occupants from falling off a stair, ramp or landing where there is a vertical drop at the edge of such floors/landings. - BALUSTRADE: Similar to the definitions of a guardrail except the location is at the edge of a floor, rather then a stair or ramp. Examples are balustrates at roof-tops or balconies. - USERDEFINED: User-defined railing element, a term to identify the user type is given by the attribute IfcRailing.ObjectType. - NOTDEFINED: Undefined railing element, no type information available.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrailingtypeenum.htm"
     },
     "IfcRampFlightTypeEnum": {
-        "description": "This enumeration defines the different types of linear elements an IfcRampFlightType object can fulfill:",
+        "description": "This enumeration defines the different types of linear elements an IfcRampFlightType object can fulfill: - STRAIGHT: A ramp flight with a straight walking line. - SPIRAL: A ramp flight with a circular or elliptic walking line. - USERDEFINED: User-defined ramp flight. - NOTDEFINED: Undefined ramp flight.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrampflighttypeenum.htm"
     },
     "IfcRampTypeEnum": {
-        "description": "This enumeration defines the basic configuration of the ramp type in terms of the number and shape of ramp flights. The type also distinguished turns by landings. In addition the subdivision of the straight and changing direction ramps is included. The ramp configurations are given for ramps without and with one and two landings.",
+        "description": "This enumeration defines the basic configuration of the ramp type in terms of the number and shape of ramp flights. The type also distinguished turns by landings. In addition the subdivision of the straight and changing direction ramps is included. The ramp configurations are given for ramps without and with one and two landings. Ramps which are subdivided into more than two landings have to be defined by the geometry only. Also ramps with non-regular shapes have to be defined by the geometry only. The type of such ramps is USERDEFINED. Illustration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcramptypeenum.htm"
     },
     "IfcRatioMeasure": {
-        "description": "A ratio measure is the value of the relation between two physical quantities that are of the same kind.",
+        "description": "A ratio measure is the value of the relation between two physical quantities that are of the same kind. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcratiomeasure.htm"
     },
     "IfcReal": {
-        "description": "A defined type of simple data type REAL (required since a select type, i.e. IfcSimpleValue, cannot include directly simple types in its select list). In principle, the domain of IfcReal (being a Real) is all rational, irrational and scientific real numbers. Here the precision is unconstrained, but in practice it is implementation specific.",
+        "description": "A defined type of simple data type REAL (required since a select type, i.e. IfcSimpleValue, cannot include directly simple types in its select list). In principle, the domain of IfcReal (being a Real) is all rational, irrational and scientific real numbers. Here the precision is unconstrained, but in practice it is implementation specific. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcreal.htm"
     },
     "IfcReflectanceMethodEnum": {
-        "description": "The IfcReflectanceMethodEnum defines the range of different reflectance methods available.",
+        "description": "The IfcReflectanceMethodEnum defines the range of different reflectance methods available. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcreflectancemethodenum.htm"
     },
     "IfcReinforcingBarRoleEnum": {
-        "description": "Enumeration defining standard types for the role, purpose or usage of the bar, i.e. the kind of loads and stresses they are intended to carry.",
+        "description": "Enumeration defining standard types for the role, purpose or usage of the bar, i.e. the kind of loads and stresses they are intended to carry. ENUMERATION - MAIN The reinforcing bar is a main bar. - SHEAR The reinforcing bar is a shear bar. - LINK The reinforcing bar is a link (stirrup). - STUD The reinforcing bar is a stud. - PUNCHING Punching reinforcement. - EDGE Edge reinforcement. - RING Ring reinforcement. - ANCHORING Anchoring reinforcement. - USERDEFINED The type of reinforcement is user defined. - NOTDEFINED The type of reinforcement is not defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcreinforcingbarroleenum.htm"
     },
     "IfcReinforcingBarSurfaceEnum": {
-        "description": "Enumeration indicating whether the bar has a plain or textured (ribbed) surface.",
+        "description": "Enumeration indicating whether the bar has a plain or textured (ribbed) surface. ENUMERATION - PLAIN The reinforcing bar surface is plain. - TEXTURED The reinforcing bar surface is textured (ribbed).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcreinforcingbarsurfaceenum.htm"
     },
     "IfcResourceConsumptionEnum": {
@@ -932,55 +932,55 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcribplatedirectionenum.htm"
     },
     "IfcRoleEnum": {
-        "description": "Roles which may be played by an actor.",
+        "description": "Roles which may be played by an actor. ENUMERATION - SUPPLIER - MANUFACTURER - CONTRACTOR - SUBCONTRACTOR - ARCHITECT - STRUCTURALENGINEER - COSTENGINEER - CLIENT - BUILDINGOWNER - BUILDINGOPERATOR - MECHANICALENGINEER - ELECTRICALENGINEER - PROJECTMANAGER - FACILITIESMANAGER - CIVILENGINEER - COMISSIONINGENGINEER - ENGINEER - OWNER - CONSULTANT - CONSTRUCTIONMANAGER - FIELDCONSTRUCTIONMANAGER - RESELLER - USERDEFINED User defined value to be provided.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcroleenum.htm"
     },
     "IfcRoofTypeEnum": {
-        "description": "This enumeration defines the basic configuration of the roof in terms of the different roof shapes.",
+        "description": "This enumeration defines the basic configuration of the roof in terms of the different roof shapes. Roofs which are subdivided into more than these basic shapes have to be defined by the geometry only. Also roofs with non-regular shapes (free form roof ) have to be defined by the geometry only. The type of such roofs is FREEFORM. Illustration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrooftypeenum.htm"
     },
     "IfcRotationalFrequencyMeasure": {
-        "description": "A measure of the number of cycles that an item revolves in unit time.",
+        "description": "A measure of the number of cycles that an item revolves in unit time. Usually measured in cycles/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcrotationalfrequencymeasure.htm"
     },
     "IfcRotationalMassMeasure": {
-        "description": "The rotational mass measure denotes the inertia of a body with respect to angular acceleration.",
+        "description": "The rotational mass measure denotes the inertia of a body with respect to angular acceleration. It is usually measured in kg*m\\^2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcrotationalmassmeasure.htm"
     },
     "IfcRotationalStiffnessMeasure": {
-        "description": "A measure of rotational stiffness.",
+        "description": "A measure of rotational stiffness. Usually measured in Nm/rad. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcrotationalstiffnessmeasure.htm"
     },
     "IfcSIPrefix": {
-        "description": "An SI prefix is the name of a prefix that may be associated with an SI unit. The definitions of SI prefixes are specified in ISO 1000 (clause 3).",
+        "description": "An SI prefix is the name of a prefix that may be associated with an SI unit. The definitions of SI prefixes are specified in ISO 1000 (clause 3). ENUMERATION - EXA 10\\^18. - PETA 10\\^15. - TERA 10\\^12. - GIGA 10\\^9. - MEGA 10\\^6. - KILO 10\\^3. - HECTO 10\\^2. - DECA 10. - DECI 10\\^-1. - CENTI 10\\^-2. - MILLI 10\\^-3. - MICRO 10\\^-6. - NANO 10\\^-9. - PICO 10\\^-12. - FEMTO 10\\^-15. - ATTO 10\\^-18.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsiprefix.htm"
     },
     "IfcSIUnitName": {
-        "description": "An SI unit name is the name of an SI unit. The definitions of the names of SI units are specified in ISO 1000 (clause 2).",
+        "description": "An SI unit name is the name of an SI unit. The definitions of the names of SI units are specified in ISO 1000 (clause 2). ENUMERATION - AMPERE Unit for electric current. - BECQUEREL Unit for radioactivity. - CANDELA Unit for luminousintensity. - COULOMB Unit for electric charge. - CUBIC_METRE Unit for volume. - DEGREE_CELSIUS Unit for thermodynamic temperature. - FARAD Unit for electric capacitance. - GRAM Unit for mass. - GRAY Unit for absorbed radioactive dose. - HENRY Unit for inductance. - HERTZ Unit for frequency. - JOULE Unit for energy. - KELVIN Unit for thermodynamic temperature. - LUMEN Unit for luminous flux. - LUX Unit for illuminance. - METRE Unit for length. - MOLE Unit for amount of substance. - NEWTON Unit for force. - OHM Unit for electric resistance. - PASCAL Unit for pressure. - RADIAN Unit for plane angle. - SECOND Unit for time. - SIEMENS Unit for electric conductance. - SIEVERT Unit for radioactive dose equivalent. - SQUARE_METRE Unit for area. - STERADIAN Unit for solid angle. - TESLA Unit for magnetic flux density. - VOLT Unit for electric voltage. - WATT Unit for power. - WEBER Unit for magnetic flux.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsiunitname.htm"
     },
     "IfcSanitaryTerminalTypeEnum": {
-        "description": "The IfcSanitaryTerminalTypeEnum defines the range of different types of sanitary terminal that can be specified.",
+        "description": "The IfcSanitaryTerminalTypeEnum defines the range of different types of sanitary terminal that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcplumbingfireprotectiondomain/lexical/ifcsanitaryterminaltypeenum.htm"
     },
     "IfcSecondInMinute": {
-        "description": "The second element of a specified time.",
+        "description": "The second element of a specified time. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifcsecondinminute.htm"
     },
     "IfcSectionModulusMeasure": {
-        "description": "A measure for the resistance of a cross section against bending or torsional moment. It is usually measured in m\\^3.",
+        "description": "A measure for the resistance of a cross section against bending or torsional moment. It is usually measured in m\\^3. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsectionmodulusmeasure.htm"
     },
     "IfcSectionTypeEnum": {
-        "description": "An enumeration indicating whether a specific piece of a cross section is uniform or tapered in longitudinal direction.",
+        "description": "An enumeration indicating whether a specific piece of a cross section is uniform or tapered in longitudinal direction. ENUMERATION - UNIFORM The section is uniform in longitudinal direction. - TAPERED The section is tapered in longitudinal direction.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcsectiontypeenum.htm"
     },
     "IfcSectionalAreaIntegralMeasure": {
-        "description": "The sectional area integral measure is typically used in torsional analysis. It is usually measured in m\\^5.",
+        "description": "The sectional area integral measure is typically used in torsional analysis. It is usually measured in m\\^5. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsectionalareaintegralmeasure.htm"
     },
     "IfcSensorTypeEnum": {
-        "description": "The IfcSensorTypeEnum defines the range of different types of sensor that can be specified.",
+        "description": "The IfcSensorTypeEnum defines the range of different types of sensor that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcsensortypeenum.htm"
     },
     "IfcSequenceEnum": {
@@ -988,27 +988,27 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcsequenceenum.htm"
     },
     "IfcServiceLifeFactorTypeEnum": {
-        "description": "An IfcServiceLifeFactorTypeEnum is an enumerated list of the types of service life factor that can be applied and that modify the extent of the service life.",
+        "description": "An IfcServiceLifeFactorTypeEnum is an enumerated list of the types of service life factor that can be applied and that modify the extent of the service life. Enumeration: Note that the values given in the enumeration list are those indicated in the ISO standard relating to service life. In the standard, service life modification factors are identified as A to G inclusive. In the enumeration list, the A to G values are retained for conformance to the standard. However, each factor is also named according to its purpose. This semantic name is placed after an 'underscore' character immediately following the ISO factor.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcservicelifefactortypeenum.htm"
     },
     "IfcServiceLifeTypeEnum": {
-        "description": "An IfcServiceLifeTypeEnum is an enumerated list of the types of service life of an artefact",
+        "description": "An IfcServiceLifeTypeEnum is an enumerated list of the types of service life of an artefact Enumeration:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcservicelifetypeenum.htm"
     },
     "IfcShearModulusMeasure": {
-        "description": "A measure of shear modulus.",
+        "description": "A measure of shear modulus. Usually measured in N/m2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcshearmodulusmeasure.htm"
     },
     "IfcShell": {
-        "description": "This type collects together, for reference when constructing more complex models, the subtypes which have the characteristics of a shell. A shell is a connected object of fixed dimensionality d = 0; 1; or 2, typically used to bound a region. The domain of a shell, if present, includes its bounds and 0 \u00a3X<\u00a5 .",
+        "description": "This type collects together, for reference when constructing more complex models, the subtypes which have the characteristics of a shell. A shell is a connected object of fixed dimensionality d = 0; 1; or 2, typically used to bound a region. The domain of a shell, if present, includes its bounds and 0 \u00a3X<\u00a5 . - A shell of dimensionality 0 is represented by a graph consisting of a single vertex. The vertex shall not have any associated edges. - A shell of dimensionality 1 is represented by a connected graph of dimensionality 1. - A shell of dimensionality 2 is a topological entity constructed by joining faces along edges. Its domain, if present, is a connected, orientable 2-manifold with boundary, that is, a connected, oriented, finite, non-self-intersecting surface, which may be closed or open. Shells of dimensionality 0 and 1 are not part of the current IFC release.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcshell.htm"
     },
     "IfcSimpleValue": {
-        "description": "A select type for selecting between simple value types.",
+        "description": "A select type for selecting between simple value types. SELECT - IfcInteger Defined type of simple type INTEGER. - IfcReal Defined type of simple type REAL. - IfcBoolean Defined type of simple type BOOLEAN. - IfcLogical Defined type of simple type LOGICAL. - IfcIdentifier Defined type of simple type STRING for identification purposes. - IfcLabel Defined type of simple type STRING for naming purposes. - IfcText Defined type of simple type STRING for descriptive purposes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsimplevalue.htm"
     },
     "IfcSizeSelect": {
-        "description": "The size select is a selection of a specific positive length measure.",
+        "description": "The size select is a selection of a specific positive length measure. Definition from ISO: The size (or width) measure value is given in the global drawing length units.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsizeselect.htm"
     },
     "IfcSlabTypeEnum": {
@@ -1016,35 +1016,35 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcslabtypeenum.htm"
     },
     "IfcSolidAngleMeasure": {
-        "description": "A solid angle measure is the value of an angle in a solid.",
+        "description": "A solid angle measure is the value of an angle in a solid. Usually measured in Steradians, (sr, m2/m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsolidanglemeasure.htm"
     },
     "IfcSoundPowerMeasure": {
-        "description": "A sound power measure is a measure of total radiated noise with units of decibels with a reference value of picowatts.",
+        "description": "A sound power measure is a measure of total radiated noise with units of decibels with a reference value of picowatts. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsoundpowermeasure.htm"
     },
     "IfcSoundPressureMeasure": {
-        "description": "A sound pressure measure is a measure of the pressure fluctuations superimposed over the ambient pressure level with units of decibels with a reference value of micropascals.",
+        "description": "A sound pressure measure is a measure of the pressure fluctuations superimposed over the ambient pressure level with units of decibels with a reference value of micropascals. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsoundpressuremeasure.htm"
     },
     "IfcSoundScaleEnum": {
-        "description": "This enumeration defines the different sound scales:",
+        "description": "This enumeration defines the different sound scales: - DBA: Decibels in an A-weighted scale - DBB: Decibels in an B-weighted scale - DBC: Decibels in an C-weighted scale - NC: Noise criteria - NR: Noise rating - USERDEFINED: User-defined sound scale - NOTDEFINED: Undefined sound scale",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcsoundscaleenum.htm"
     },
     "IfcSpaceHeaterTypeEnum": {
-        "description": "Enumeration defining the functional type of space heater. The IfcSpaceHeaterTypeEnum contains the following:",
+        "description": "Enumeration defining the functional type of space heater. The IfcSpaceHeaterTypeEnum contains the following: - SECTIONALRADIATOR: Sectional type radiator typically fabricated from welded sheet metal sections and resembling free standing cast-iron radiators. - PANELRADIATOR: Panel type radiator typically fabricated with flat panels, with or without an exposed extended fin surface attached to the rear for increased output. - TUBULARRADIATOR: Tubular type radiator consisting of supply and return headers with interconnecting parallel tubes in a wide variety of lengths and heights. - CONVECTOR: A heat-distributing unit that operates with gravity-circulated air. - BASEBOARDHEATER: Baseboard heater designed for installation along the bottom of walls in place of the conventional baseboard. - FINNEDTUBEUNIT: Fin-tube heater typically fabricated from metallic tubing, with metallic fins bonded to the tube. - UNITHEATER: An assembly typically consisting of a fan, a motor, and a heating element. - USERDEFINED: User-defined space heater type. - NOTDEFINED: Undefined space heater type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcspaceheatertypeenum.htm"
     },
     "IfcSpaceTypeEnum": {
-        "description": "This enumeration defines the available generic types for IfcSpaceType.",
+        "description": "This enumeration defines the available generic types for IfcSpaceType. Enumeration - USERDEFINED - NOTDEFINED",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcspacetypeenum.htm"
     },
     "IfcSpecificHeatCapacityMeasure": {
-        "description": "Defines the specific heat of material: The heat energy absorbed per temperature unit.",
+        "description": "Defines the specific heat of material: The heat energy absorbed per temperature unit. Usually measured in J / kg Kelvin. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcspecificheatcapacitymeasure.htm"
     },
     "IfcSpecularExponent": {
-        "description": "The IfcSpecularExponent defines the datatype for exponent determining the sharpness of the 'reflection'. reflection is made sharper with large values of the exponent, such as 10.0. Small values, such as 1.0, decrease the specular fall-off.",
+        "description": "The IfcSpecularExponent defines the datatype for exponent determining the sharpness of the 'reflection'. reflection is made sharper with large values of the exponent, such as 10.0. Small values, such as 1.0, decrease the specular fall-off. IfcSpecularExponent is of type REAL.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcspecularexponent.htm"
     },
     "IfcSpecularHighlightSelect": {
@@ -1052,23 +1052,23 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcspecularhighlightselect.htm"
     },
     "IfcSpecularRoughness": {
-        "description": "The IfcSpecularRoughness defines the datatype for the reflection resulting from the roughness of a surface through the height of surface impurities where the specular highlight is made sharper with small values for the roughness, such as 0.1.",
+        "description": "The IfcSpecularRoughness defines the datatype for the reflection resulting from the roughness of a surface through the height of surface impurities where the specular highlight is made sharper with small values for the roughness, such as 0.1. Applies to \"glass\", \"metal\", \"mirror\" and \"plastic\" reflection models. Larger values, close to 1.0 decrease the specular fall-off. IfcSpecularRoughness is of type REAL. It is constraint to values between (and including) 0 and 1.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcspecularroughness.htm"
     },
     "IfcStackTerminalTypeEnum": {
-        "description": "An IfcStackTerminalTypeEnum defines the range of different types of stack terminal that can be specified for use at the top of a vertical stack subsystem.",
+        "description": "An IfcStackTerminalTypeEnum defines the range of different types of stack terminal that can be specified for use at the top of a vertical stack subsystem. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcplumbingfireprotectiondomain/lexical/ifcstackterminaltypeenum.htm"
     },
     "IfcStairFlightTypeEnum": {
-        "description": "This enumeration defines the different types of stair flights an IfcStairFlightType object can fulfill:",
+        "description": "This enumeration defines the different types of stair flights an IfcStairFlightType object can fulfill: - STRAIGHT: A stair flight with a straight walking line. - WINDER: A stair flight with a straight walking line. - SPIRAL: A stair flight with a circular or elliptic walking line. - CURVED: A stair flight with a curved walking line. - FREEFORM: A stair flight with a free form walking line (and outer boundaries). - USERDEFINED: User-defined stair flight . - NOTDEFINED: Undefined stair flight .",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcstairflighttypeenum.htm"
     },
     "IfcStairTypeEnum": {
-        "description": "This enumeration defines the basic configuration of the stair type in terms of the number of stair flights and the number of landings. The type also distinguished turns by windings or by landings. In addition the subdivision of the straight and changing direction stairs is included. The stair configurations are given for stairs without and with one, two or three landings.",
+        "description": "This enumeration defines the basic configuration of the stair type in terms of the number of stair flights and the number of landings. The type also distinguished turns by windings or by landings. In addition the subdivision of the straight and changing direction stairs is included. The stair configurations are given for stairs without and with one, two or three landings. Stairs which are subdivided into more than three landings have to be defined by the geometry only. Also stairs with non-regular shapes have to be defined by the geometry only. The type of such stairs is OTHEROPERATION. Illustration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcstairtypeenum.htm"
     },
     "IfcStateEnum": {
-        "description": "Enumeration identifying the state or accessibility of the object (e.g., read/write, locked, etc.). This concept was initially introduced in IFC 2.0 as IfcModifiedFlag of type BINARY(3) FIXED and has been modified in R2x to an enumeration. It was initially introduced as a first step towards providing facilities for partial model exchange from a server as requested by the IFC implementers. It is intended for use primarily by a model server so that an application can identify the state of the object.",
+        "description": "Enumeration identifying the state or accessibility of the object (e.g., read/write, locked, etc.). This concept was initially introduced in IFC 2.0 as IfcModifiedFlag of type BINARY(3) FIXED and has been modified in R2x to an enumeration. It was initially introduced as a first step towards providing facilities for partial model exchange from a server as requested by the IFC implementers. It is intended for use primarily by a model server so that an application can identify the state of the object. Valid enumerations are: - READWRITE: Object is in a Read-Write state. It may be modified by an application. - READONLY: Object is in a Read-Only state. It may be viewed but not modified by an application. - LOCKED: Object is in a Locked state. It may not be accessed by an application. - READWRITELOCKED: Object is in a Read-Write-Locked state. It may not be accessed by an application. - READONLYLOCKED: Object is in a Read-Only-Locked state. It may not be accessed by an application.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifcstateenum.htm"
     },
     "IfcStructuralActivityAssignmentSelect": {
@@ -1076,31 +1076,31 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralactivityassignmentselect.htm"
     },
     "IfcStructuralCurveTypeEnum": {
-        "description": "This type definition shall be used to distinguish between different types of structural 'curve' members, such as cables. The IfcStructuralCurveTypeEnum type is referenced by the entity IfcStructuralCurveMember.",
+        "description": "This type definition shall be used to distinguish between different types of structural 'curve' members, such as cables. The IfcStructuralCurveTypeEnum type is referenced by the entity IfcStructuralCurveMember. - RIGID_JOINED_MEMBER: A member with capacity to carry transverse and axial loads, i.e. a beam. Its actual joints may be rigid or pinned. Typically used in rigid frames. - PIN_JOINED_MEMBER: A member with capacity to carry axial loads only, i.e. a link. Typically used in trusses. - CABLE: A tension member which is able to carry transverse loads only under large deflection. - TENSION_MEMBER: A member without compressional stiffness. - COMPRESSION_MEMBER: A member without tensional stiffness. - USERDEFINED: A specially defined member. - NOTDEFINED: A member without further categorization.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralcurvetypeenum.htm"
     },
     "IfcStructuralSurfaceTypeEnum": {
-        "description": "This type definition shall be used to distinguish between different types of structural surface members, such as the typical mechanical function of walls, slabs and shells.",
+        "description": "This type definition shall be used to distinguish between different types of structural surface members, such as the typical mechanical function of walls, slabs and shells. - BENDING_ELEMENT: A member with capacity to carry out-of-plane loads, i.e. a plate. - MEMBRANE_ELEMENT: A member with capacity to carry in-plane loads, for example a shear wall. - SHELL: A member with capacity to carry in-plane and out-of-plane loads, i.e. a combination of bending element and membrane element. - USERDEFINED: A specially defined member. - NOTDEFINED: A member without further categorization.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfacetypeenum.htm"
     },
     "IfcSurfaceOrFaceSurface": {
-        "description": "The IfcSurfaceOrFaceSurface provides the option to either select a geometric surface (IfcSurface and subtypes) within a geometric model, or a face with associated surface geometry and coordinates (IfcFaceSurface) within a topological model.",
+        "description": "The IfcSurfaceOrFaceSurface provides the option to either select a geometric surface (IfcSurface and subtypes) within a geometric model, or a face with associated surface geometry and coordinates (IfcFaceSurface) within a topological model. SELECT * IfcSurface * IfcFaceSurface * IfcFaceBasedSurfaceModel(a connected face set, representing a faceted surface as an approximation of a non planar, non rectangular bounded surface)_",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcsurfaceorfacesurface.htm"
     },
     "IfcSurfaceSide": {
-        "description": "Denotion of whether negative, positive or both sides of a surface are being referenced.",
+        "description": "Denotion of whether negative, positive or both sides of a surface are being referenced. ENUMERATION - POSITIVE: The side of a surface which is in the same direction as the surface normal derived from the mathematical definition. - NEGATIVE: The side of a surface which is in the opposite direction than the surface normal derived from the mathematical definition. - BOTH: Both, positive and negative side.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfaceside.htm"
     },
     "IfcSurfaceStyleElementSelect": {
-        "description": "The surface style element select is a selection of the different surface styles to use in the presentation of the side of a surface.",
+        "description": "The surface style element select is a selection of the different surface styles to use in the presentation of the side of a surface. The select type only includes the IfcSurfaceStyleRendering (which is the equivalent to surface_style_rendering) from the select type surface_style_element_select. In addition it has the IfcSurfaceStyleLighting, which holds the exact physically based lighting properties for lighting based calculation algorithms (as the opposite to the rendering based calculation), the IfcSurfaceStyleRefraction (for more advanced refraction indices) and IfcSurfaceStyleWithTextures (to allow for image textures applied to surfaces). In addition an IfcExternallyDefinedSurfaceStyle can be selected that points into an external material library.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestyleelementselect.htm"
     },
     "IfcSurfaceTextureEnum": {
-        "description": "The IfcSurfaceTextureEnum defines the range of different types of image or pixel maps available.",
+        "description": "The IfcSurfaceTextureEnum defines the range of different types of image or pixel maps available. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacetextureenum.htm"
     },
     "IfcSwitchingDeviceTypeEnum": {
-        "description": "The IfcSwitchingDeviceTypeEnum defines the range of different types of switch that can be specified.",
+        "description": "The IfcSwitchingDeviceTypeEnum defines the range of different types of switch that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcswitchingdevicetypeenum.htm"
     },
     "IfcSymbolStyleSelect": {
@@ -1108,31 +1108,31 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsymbolstyleselect.htm"
     },
     "IfcTankTypeEnum": {
-        "description": "Enumeration defining the typical types of tanks. The IfcTankTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of tanks. The IfcTankTypeEnum contains the following: - PREFORMED: Tank is preformed. - SECTIONAL: Tank is sectional. - USERDEFINED: User-defined tank type. - NOTDEFINED: Undefined tank type. - EXPANSION: Tank is an expansion tank. - PRESSUREVESSEL: Tank is a pressure vessel.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifctanktypeenum.htm"
     },
     "IfcTemperatureGradientMeasure": {
-        "description": "The temperature gradient measures the difference of a temperature per lenght, as for instance used in an external wall or its layers. It is usually measured in K/m.",
+        "description": "The temperature gradient measures the difference of a temperature per lenght, as for instance used in an external wall or its layers. It is usually measured in K/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifctemperaturegradientmeasure.htm"
     },
     "IfcTendonTypeEnum": {
-        "description": "Enumeration defining the types of tendons.",
+        "description": "Enumeration defining the types of tendons. ENUMERATION - STRAND The tendon is a strand. - WIRE The tendon is a wire. - BAR The tendon is configured as a bar. - COATED The tendon is coated. - USERDEFINED The type of tendon is user defined. - NOTDEFINED The type of tendon is not defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifctendontypeenum.htm"
     },
     "IfcText": {
-        "description": "A text is an alphanumeric string of characters which is intended to be read and understood by a human being. It is for information purposes only.",
+        "description": "A text is an alphanumeric string of characters which is intended to be read and understood by a human being. It is for information purposes only. Type: STRING",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifctext.htm"
     },
     "IfcTextAlignment": {
-        "description": "Definition from CSS1 (W3C Recommendation): This property describes how text is aligned within the element. The actual justification algorithm used is user agent and human language dependent. If 'justify' is not supported, the user agent will supply a replacement. Typically, this will be 'left' for western languages. Values are:",
+        "description": "Definition from CSS1 (W3C Recommendation): This property describes how text is aligned within the element. The actual justification algorithm used is user agent and human language dependent. If 'justify' is not supported, the user agent will supply a replacement. Typically, this will be 'left' for western languages. Values are: - left - right - center - justify",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextalignment.htm"
     },
     "IfcTextDecoration": {
-        "description": "Definition from CSS1 (W3C Recommendation): This property describes decorations that are added to the text of an element. A value of 'blink' causes the text to blink.. Values are:",
+        "description": "Definition from CSS1 (W3C Recommendation): This property describes decorations that are added to the text of an element. A value of 'blink' causes the text to blink.. Values are: - none - underline - overline - line-through - blink User agents must recognize the keyword 'blink', but are not required to support the blink effect.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextdecoration.htm"
     },
     "IfcTextFontName": {
-        "description": "Definition from CSS1 (W3C Recommendation): The value is a  font family name and/or generic family name. Values are:",
+        "description": "Definition from CSS1 (W3C Recommendation): The value is a font family name and/or generic family name. Values are: It is encouraged to offer a generic font family as a last alternative.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifctextfontname.htm"
     },
     "IfcTextFontSelect": {
@@ -1144,79 +1144,79 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctextpath.htm"
     },
     "IfcTextStyleSelect": {
-        "description": "Definition from IAI: The text style select allows for the selection of styles to be assigned to an annotated text. The text style determines the text model that affect the visual presentation of characters, spaces, words, and paragraphs. There are two choices:",
+        "description": "Definition from IAI: The text style select allows for the selection of styles to be assigned to an annotated text. The text style determines the text model that affect the visual presentation of characters, spaces, words, and paragraphs. There are two choices: - _IfcTextStyleWithBoxCharacteristics_for definitions from ISO/IS 10303-46:1994 for (old) vector based and monospace text. - IfcTextStyleTextModel for definitions from Cascading Style Sheets, level 1, W3C Recommendation 17 Dec 1996, revised 11 Jan 1999, CSS1, for all true type text. The use of the CSS1 definitions is the preferred way to represent text styles.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextstyleselect.htm"
     },
     "IfcTextTransformation": {
-        "description": "Definition from CSS1 (W3C Recommendation): This property describes how the cases of characters are handled. Values are:",
+        "description": "Definition from CSS1 (W3C Recommendation): This property describes how the cases of characters are handled. Values are: - capitalize: uppercases the first character of each word - uppercase: uppercases all letters of the element - lowercase: lowercases all letters of the element - none",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctexttransformation.htm"
     },
     "IfcThermalAdmittanceMeasure": {
-        "description": "The measure of the ability of a surface to smooth out temperature variations.",
+        "description": "The measure of the ability of a surface to smooth out temperature variations. Usually measured in Watt / m2 Kelvin. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcthermaladmittancemeasure.htm"
     },
     "IfcThermalConductivityMeasure": {
-        "description": "A measure of thermal conductivity.",
+        "description": "A measure of thermal conductivity. Usually measured in Watt / m Kelvin. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcthermalconductivitymeasure.htm"
     },
     "IfcThermalExpansionCoefficientMeasure": {
-        "description": "A measure of the thermal expansion coefficient of a material, which expresses its elongation (as a ratio) per temperature difference. It is usually measured in 1/K. A positive elongation per (positive) rise of temperature is expressed by a positive value.",
+        "description": "A measure of the thermal expansion coefficient of a material, which expresses its elongation (as a ratio) per temperature difference. It is usually measured in 1/K. A positive elongation per (positive) rise of temperature is expressed by a positive value. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcthermalexpansioncoefficientmeasure.htm"
     },
     "IfcThermalLoadSourceEnum": {
-        "description": "This enumeration defines the various sources of thermal gains or losses for spaces or zones, derived from various use cases:",
+        "description": "This enumeration defines the various sources of thermal gains or losses for spaces or zones, derived from various use cases: - PEOPLE: Heat gains and losses from people. - LIGHTING: Lighting loads. - EQUIPMENTSENSIBLE: Heat gains and losses from equipment. - VENTILATIONINDOORAIR: Ventilation loads from indoor air. - VENTILATIONOUTSIDEAIR: Ventilation loads from outside air. - RECIRCULATEDAIR: Loads from recirculated air. - EXHAUSTAIR: Loads from exhaust air. - AIREXCHANGERATE: Loads from the air exchange rate. - DRYBULBTEMPERATURE: Loads from the dry bulb temperature. - RELATIVEHUMIDITY: Loads from the relative humidity. - INFILTRATIONSENSIBLE: Heat gains and losses from infiltration. - USERDEFINED: User-defined thermal load type. - NOTDEFINED: Undefined thermal load type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcthermalloadsourceenum.htm"
     },
     "IfcThermalLoadTypeEnum": {
-        "description": "This enumeration defines the type of thermal load for spaces or zones, as derived from various use cases:",
+        "description": "This enumeration defines the type of thermal load for spaces or zones, as derived from various use cases: - SENSIBLE: Energy added or removed from air that affects its temperature. - LATENT: Energy added or removed from air that affects its humidity or concentration of water vapor. - RADIANT: Electromagnetic energy added or removed by emission or absorption. - NOTDEFINED: Undefined thermal load type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcthermalloadtypeenum.htm"
     },
     "IfcThermalResistanceMeasure": {
-        "description": "A measure of the resistance offered by a body to the flow of energy.",
+        "description": "A measure of the resistance offered by a body to the flow of energy. Usually measured in m2 Kelvin/Watt.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcthermalresistancemeasure.htm"
     },
     "IfcThermalTransmittanceMeasure": {
-        "description": "A measure of the rate at which energy is transmitted through a body.",
+        "description": "A measure of the rate at which energy is transmitted through a body. Usually measured in Watts/m2 Kelvin. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcthermaltransmittancemeasure.htm"
     },
     "IfcThermodynamicTemperatureMeasure": {
-        "description": "A thermodynamic temperature measure is the value for the degree of heat of a body.",
+        "description": "A thermodynamic temperature measure is the value for the degree of heat of a body. Usually measured in degrees Kelvin (K). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcthermodynamictemperaturemeasure.htm"
     },
     "IfcTimeMeasure": {
-        "description": "A time measure is the value of the duration of periods.",
+        "description": "A time measure is the value of the duration of periods. Usually measured in seconds (s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifctimemeasure.htm"
     },
     "IfcTimeSeriesDataTypeEnum": {
-        "description": "The IfcTimeSeriesDataTypeEnum describes a type of time series data and is used to determine a value during the time series which is not explicitly specified:",
+        "description": "The IfcTimeSeriesDataTypeEnum describes a type of time series data and is used to determine a value during the time series which is not explicitly specified: - CONTINUOUS: The time series data is continuous. - DISCRETE: The time series data is discrete. - DISCRETEBINARY: The time series data is discrete binary. - PIECEWISEBINARY: The time series data is piecewise binary. - PIECEWISECONSTANT: The time series data is piecewise constant. - PIECEWISECONTINUOUS: The time series data is piecewise continuous. - NOTDEFINED: The time series data is not defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifctimeseriesdatatypeenum.htm"
     },
     "IfcTimeSeriesScheduleTypeEnum": {
-        "description": "Defines the type of time series schedule, such as daily, weekly, monthly or annually.",
+        "description": "Defines the type of time series schedule, such as daily, weekly, monthly or annually. ENUMERATION - ANNUAL An annual time series schedule. - MONTHLY A monthly time series schedule. - WEEKLY A weekly time series schedule. - DAILY A daily time series schedule. - USERDEFINED A user defined time series schedule type to be provided. - NOTDEFINED Time series schedule type not defined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccontrolextension/lexical/ifctimeseriesscheduletypeenum.htm"
     },
     "IfcTimeStamp": {
-        "description": "An indication of date and time by measuring the number of seconds which have elapsed since the beginning of the year 1970.",
+        "description": "An indication of date and time by measuring the number of seconds which have elapsed since the beginning of the year 1970. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifctimestamp.htm"
     },
     "IfcTorqueMeasure": {
-        "description": "A measure of the torque or moment of a couple.",
+        "description": "A measure of the torque or moment of a couple. Usually measured in N m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifctorquemeasure.htm"
     },
     "IfcTransformerTypeEnum": {
-        "description": "The IfcTransformerTypeEnum defines the range of different types of transformer that can be specified.",
+        "description": "The IfcTransformerTypeEnum defines the range of different types of transformer that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifctransformertypeenum.htm"
     },
     "IfcTransitionCode": {
-        "description": "This type conveys the continuity properties of a composite curve or surface. The continuity referred to is geometric, not parametric continuity. For example, in ContSameGradient the tangent vectors of successive segments will have the same direction, but may have different magnitude.",
+        "description": "This type conveys the continuity properties of a composite curve or surface. The continuity referred to is geometric, not parametric continuity. For example, in ContSameGradient the tangent vectors of successive segments will have the same direction, but may have different magnitude. Figure quoted from ISO/CD 10303-42:1992, p. 55 ENUMERATION - Discontinuous: The segments do not join. This is permitted only at the boundary of the curve or surface to indicate that it is not closed. - Continuous: The segments join but no condition on their tangents is implied. - ContSameGradient: The segments join and their tangent vectors or tangent planes are parallel and have the same direction at the joint: equality of derivatives is not required. - ContSameGradientSameCurvature: For a curve, the segments join, their tangent vectors are parallel and in the same direction and their curvatures are equal at the joint: equality of derivatives is not required. For a surface this implies that the principle curvatures are the same and the principle directions are coincident along the common boundary.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifctransitioncode.htm"
     },
     "IfcTransportElementTypeEnum": {
-        "description": "This enumeration is used to identify primary transport element types. The IfcTransportElementTypeEnum contains the following:",
+        "description": "This enumeration is used to identify primary transport element types. The IfcTransportElementTypeEnum contains the following: - ELEVATOR: Elevator. - ESCALATOR: Escalator. - MOVINGWALKWAY: Moving walkway.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifctransportelementtypeenum.htm"
     },
     "IfcTrimmingPreference": {
-        "description": "This type is used to describe the preferred way of trimming a parametric curve where the trimming is multiply defined.",
+        "description": "This type is used to describe the preferred way of trimming a parametric curve where the trimming is multiply defined. ENUMERATION - Cartesian Indicates that trimming by Cartesian point is preferred. - Parameter Indicates the preference for the parameter value. - Unspecified Indicates that no preference is communicated.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifctrimmingpreference.htm"
     },
     "IfcTrimmingSelect": {
@@ -1224,31 +1224,31 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifctrimmingselect.htm"
     },
     "IfcTubeBundleTypeEnum": {
-        "description": "Enumeration defining the typical types of tube bundles. The IfcTubeBundleTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of tube bundles. The IfcTubeBundleTypeEnum contains the following: - FINNED: Finned tube bundle type. - USERDEFINED: User-defined tube bundle type. - NOTDEFINED: Undefined tube bundle type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifctubebundletypeenum.htm"
     },
     "IfcUnit": {
-        "description": "A unit is a physical quantity, with a value of one, which is used as a standard in terms of which other quantities are expressed.",
+        "description": "A unit is a physical quantity, with a value of one, which is used as a standard in terms of which other quantities are expressed. SELECT - IfcNamedUnit A unit which is identified by a name. - IfcDerivedUnit A unit which is derived from an expression of units. - IfcMonetaryUnit A unit for defining currencies.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcunit.htm"
     },
     "IfcUnitEnum": {
-        "description": "An enumeration type for allowed unit types of IfcNamedUnit.",
+        "description": "An enumeration type for allowed unit types of IfcNamedUnit. ENUMERATION - ABSORBEDDOSEUNIT - AMOUNTOFSUBSTANCEUNIT - AREAUNIT - DOSEEQUIVALENTUNIT - ELECTRICCAPACITANCEUNIT - ELECTRICCHARGEUNIT - ELECTRICCONDUCTANCEUNIT - ELECTRICCURRENTUNIT - ELECTRICRESISTANCEUNIT - ELECTRICVOLTAGEUNIT - ENERGYUNIT - FORCEUNIT - FREQUENCYUNIT - ILLUMINANCEUNIT - INDUCTANCEUNIT - LENGTHUNIT - LUMINOUSFLUXUNIT - LUMINOUSINTENSITYUNIT - MAGNETICFLUXDENSITYUNIT - MAGNETICFLUXUNIT - MASSUNIT - PLANEANGLEUNIT - POWERUNIT - PRESSUREUNIT - RADIOACTIVITYUNIT - SOLIDANGLEUNIT - THERMODYNAMICTEMPERATUREUNIT - TIMEUNIT - VOLUMEUNIT - USERDEFINED User defined unit.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcunitenum.htm"
     },
     "IfcUnitaryEquipmentTypeEnum": {
-        "description": "Enumeration defining the functional type of unitary equipment. The IfcUnitaryEquipmentTypeEnum contains the following:",
+        "description": "Enumeration defining the functional type of unitary equipment. The IfcUnitaryEquipmentTypeEnum contains the following: - AIRHANDLER: A unitary air handling unit typically containing a fan, economizer, and coils. - AIRCONDITIONINGUNIT: A unitary packaged air-conditioning unit typically used in residential or light commercial applications. - SPLITSYSTEM: A system which separates the compressor from the evaporator, but acts as a unitary component typically within residential or light commercial applications. - ROOFTOPUNIT: A packaged assembly that is either field-erected or manufactured atop the roof of a large residential or commercial building and acts as a unitary component. - USERDEFINED: User-defined unitary equipment type. - NOTDEFINED: Undefined unitary equipment type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcunitaryequipmenttypeenum.htm"
     },
     "IfcValue": {
-        "description": "A select type for selecting between more specialised select types IfcSimpleValue, IfcMeasureValue and IfcDerivedMeasureValue.",
+        "description": "A select type for selecting between more specialised select types IfcSimpleValue, IfcMeasureValue and IfcDerivedMeasureValue. SELECT - IfcSimpleValue A select type for basic defined types of simple data type. - IfcMeasureValue A select type for basic measure types of ISO/CD 10303-41. - IfcDerivedMeasureValue A select type for derived measure types.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcvalue.htm"
     },
     "IfcValveTypeEnum": {
-        "description": "The IfcValveTypeEnum defines the range of different types of valve that can be specified. These are typically used in conjunction with Pset_ValveTypeCommon, which contains common properties for all valve types. The IfcValveTypeEnum contains:",
+        "description": "The IfcValveTypeEnum defines the range of different types of valve that can be specified. These are typically used in conjunction with Pset_ValveTypeCommon, which contains common properties for all valve types. The IfcValveTypeEnum contains: - AIRRELEASE: Valve used to release air from a pipe or fitting. - ANTIVACUUM: Valve that opens to admit air if the pressure falls below atmospheric pressure (BS6100 330 4104) - CHANGEOVER: Valve that enables flow to be switched between pipelines (3 or 4 port). - CHECK: Valve that permits water to flow in one direction only and is enclosed when there is no flow (2 port). - COMMISSIONING: Valve used to facilitate commissioning of a system (2 port). - DIVERTING: Valve that enables flow to be diverted from one branch of a pipeline to another (3 port). - DOUBLECHECK: An assembly that incorporates two valves used to prevent backflow (BS6100 330 4106). - DOUBLEREGULATING: Valve used to facilitate regulation of fluid flow in a system. - DRAWOFFCOCK: A valve used to remove fluid from a piping system. - FAUCET: Faucet valve typically used as a flow discharge. - FLUSHING: Valve that flushes a predetermined quantity of water to cleanse a toilet, urinal, etc. - GASCOCK: Valve that is used for controlling the flow of gas. - GASTAP: Gas tap typically used for venting or discharging gas from a system. - ISOLATING: Valve that closes off flow in a pipeline. - MIXING: Valve that enables flow from two branches of a pipeline to be mixed together (3 port). - PRESSUREREDUCING: Valve that reduces the pressure of a fluid immediately downstream of its position in a pipeline to a preselected value or by a predetermined ratio. - PRESSURERELIEF: Spring or weight loaded valve that automatically discharges to a safe place fluid that has built up to excessive pressure in pipes or fittings - REGULATING: Valve used to facilitate regulation of fluid flow in a system. - SAFETYCUTOFF: Valve that closes under the action of a safety mechanism such as a drop weight, solenoid etc. - STEAMTRAP: Valve that restricts flow of steam while allowing condensate to pass through. - STOPCOCK: An isolating valve used on a domestic water service. - USERDEFINED: User-defined valve type. - NOTDEFINED: Undefined valve type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcvalvetypeenum.htm"
     },
     "IfcVaporPermeabilityMeasure": {
-        "description": "A measure of vapor permeability.",
+        "description": "A measure of vapor permeability. Usually measured in kg / s m Pascal. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcvaporpermeabilitymeasure.htm"
     },
     "IfcVectorOrDirection": {
@@ -1256,39 +1256,39 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcvectorordirection.htm"
     },
     "IfcVibrationIsolatorTypeEnum": {
-        "description": "Enumeration defining the typical types of vibration isolators. The IfcVibrationIsolatorTypeEnum contains the following:",
+        "description": "Enumeration defining the typical types of vibration isolators. The IfcVibrationIsolatorTypeEnum contains the following: - COMPRESSION: Compression type vibration isolator. - SPRING: Spring type vibration isolator. - USERDEFINED: User-defined vibration isolator type. - NOTDEFINED: Undefined vibration isolator type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcvibrationisolatortypeenum.htm"
     },
     "IfcVolumeMeasure": {
-        "description": "A volume measure is the value of the solid content of a body.",
+        "description": "A volume measure is the value of the solid content of a body. Usually measured in cubic metre (m3). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcvolumemeasure.htm"
     },
     "IfcVolumetricFlowRateMeasure": {
-        "description": "A measure of the volume of a medium flowing per unit time.",
+        "description": "A measure of the volume of a medium flowing per unit time. Usually measured in m3/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcvolumetricflowratemeasure.htm"
     },
     "IfcWallTypeEnum": {
-        "description": "This enumeration defines the different types of walls an IfcWallType object can fulfill:",
+        "description": "This enumeration defines the different types of walls an IfcWallType object can fulfill: - STANDARD: A standard wall, extruded vertically with a constant thickness along the wall path. - POLYGONAL: A polygonal wall, extruded vertically, where the wall thickness changes along the wall path. - SHEAR: A shear wall, having a non-rectangular cross section. - USERDEFINED: User-defined wall element. - NOTDEFINED: Undefined wall element",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwalltypeenum.htm"
     },
     "IfcWarpingConstantMeasure": {
-        "description": "A measure for the warping constant or warping resistance of a cross section under torsional loading. It is usually measured in m\\^6.",
+        "description": "A measure for the warping constant or warping resistance of a cross section under torsional loading. It is usually measured in m\\^6. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcwarpingconstantmeasure.htm"
     },
     "IfcWarpingMomentMeasure": {
-        "description": "The warping moment measure is a measure for the warping moment, which occurs in warping torsional analysis. It is usually measured in kN*m\\^2.",
+        "description": "The warping moment measure is a measure for the warping moment, which occurs in warping torsional analysis. It is usually measured in kN*m\\^2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcwarpingmomentmeasure.htm"
     },
     "IfcWasteTerminalTypeEnum": {
-        "description": "IfcWasteTerminalTypeEnum",
+        "description": "IfcWasteTerminalTypeEnum The IfcWasteTerminalTypeEnum defines the range of different types of waste terminal that can be specified. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcplumbingfireprotectiondomain/lexical/ifcwasteterminaltypeenum.htm"
     },
     "IfcWindowPanelOperationEnum": {
-        "description": "This enumeration defines the basic ways to describe how window panels operate.",
+        "description": "This enumeration defines the basic ways to describe how window panels operate. Illustration The opening direction of the window panels is given by the local placement of the IfcWindow. The positive y-axis determines the direction as shown in the figure. NOTE - Figures are shown as viewed from the outside (in direction of the positive y-axis). - Figures (symbolic representation) depend on the national building code - These figures are only shown as illustrations",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowpaneloperationenum.htm"
     },
     "IfcWindowPanelPositionEnum": {
-        "description": "This enumeration defines the basic configuration of the window type in terms of the location of window panels. The window configurations are given for windows with one, two or three panels (including fixed panels). It corresponds to the OperationType of the IfcWindowStyle definition, which references the IfcWindowPanelProperties.",
+        "description": "This enumeration defines the basic configuration of the window type in terms of the location of window panels. The window configurations are given for windows with one, two or three panels (including fixed panels). It corresponds to the OperationType of the IfcWindowStyle definition, which references the IfcWindowPanelProperties. Windows which are subdivided into more than three panels have to be defined by the geometry only. The type of such windows is given by an IfcWindowStyle.OperationType = USERDEFINED or NOTDEFINED (see IfcWindowStyleOperationEnum for details). Illustration NOTE - The figures are shown as elevations in the XZ plane of the local placement of the window, looking into the direction of the positive Y axis. - These figures are only shown as illustrations.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowpanelpositionenum.htm"
     },
     "IfcWindowStyleConstructionEnum": {
@@ -1296,15 +1296,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowstyleconstructionenum.htm"
     },
     "IfcWindowStyleOperationEnum": {
-        "description": "This enumeration defines the basic configuration of the window type in terms of the number of window panels and the subdivision of the total window. The window configurations are given for windows with one, two or three panels (including fixed panels).",
+        "description": "This enumeration defines the basic configuration of the window type in terms of the number of window panels and the subdivision of the total window. The window configurations are given for windows with one, two or three panels (including fixed panels). Windows which are subdivided into more than three panels have to be defined by the geometry only. The type of such windows is USERDEFINED. Illustration NOTE - The way how each panel operates is defined at the_IfcWindowPanelProperties.OperationType_. - The reference from the window panel to the location of that panel in the window style configuration is handled by the IfcWindowPanelProperties.PanelPosition. - The figures are shown as elevations in the XZ plane of the local placement of the window, looking into the direction of the positive Y axis. - These figures are only shown as illustrations",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowstyleoperationenum.htm"
     },
     "IfcWorkControlTypeEnum": {
-        "description": "An IfcWorkControlTypeEnum is an enumeration data type that specifies the types of work control from which the relevant control can be selected.",
+        "description": "An IfcWorkControlTypeEnum is an enumeration data type that specifies the types of work control from which the relevant control can be selected. Enumeration",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcworkcontroltypeenum.htm"
     },
     "IfcYearNumber": {
-        "description": "The year as defined in Gregorian Calendar.",
+        "description": "The year as defined in Gregorian Calendar. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifcyearnumber.htm"
     }
 }
\ No newline at end of file
diff --git a/src/ifcopenshell-python/ifcopenshell/util/schema/ifc4_entities.json b/src/ifcopenshell-python/ifcopenshell/util/schema/ifc4_entities.json
index 12a4241937..b988daac10 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/schema/ifc4_entities.json
+++ b/src/ifcopenshell-python/ifcopenshell/util/schema/ifc4_entities.json
@@ -4,7 +4,7 @@
             "LongDescription": "Detailed description of the permit.",
             "Status": "The status currently assigned to the request.  Possible values include:   Hold: wait to see if further requests are received before deciding on action   NoAction: no action is required on this request   Schedule: plan action to take place as part of maintenance or other task planning/scheduling   Urgent: take action immediately"
         },
-        "description": "A request is the act or instance of asking for something, such as a request for information, bid submission, or performance of work.",
+        "description": "A request is the act or instance of asking for something, such as a request for information, bid submission, or performance of work. Requests may take many forms depending on the need including fault reports for maintenance, requests for small works, and purchase requests (where these are to be made through a help desk or buying function).",
         "predefined_types": {
             "EMAIL": "Request was made through email.",
             "FAX": "Request was made through facsimile.",
@@ -48,7 +48,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcbuildingcontrolsdomain/lexical/ifcactuator.htm"
     },
     "IfcActuatorType": {
-        "description": "The distribution control element type IfcActuatorType defines commonly shared information for occurrences of actuators. The set of shared information may include:",
+        "description": "The distribution control element type IfcActuatorType defines commonly shared information for occurrences of actuators. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a actuator type specification indicating the specific product information that is common to all occurrences of that product type. The IfcActuatorType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcActuatorType are represented by instances of IfcActuator. Refer to the documentation at IfcActuator for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "ELECTRICACTUATOR": "A device that electrically actuates a control element.",
             "HANDOPERATEDACTUATOR": "A device that manually actuates a control element.",
@@ -72,18 +72,18 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcactorresource/lexical/ifcaddress.htm"
     },
     "IfcAdvancedBrep": {
-        "description": "An advanced B-rep is a boundary representation model in which all faces, edges and vertices are explicitly represented. It is a solid with explicit topology and elementary or free-form geometry. The faces of the B-rep are of type IfcAdvancedFace. An advanced B-rep has to meet the same topological constraints as the manifold solid B-rep.",
+        "description": "An advanced B-rep is a boundary representation model in which all faces, edges and vertices are explicitly represented. It is a solid with explicit topology and elementary or free-form geometry. The faces of the B-rep are of type IfcAdvancedFace. An advanced B-rep has to meet the same topological constraints as the manifold solid B-rep. Informal Propositions: - each face is a face surface; - each face surface has its geometry defined by an elementary surface, swept surface or a b-spline surface; - the edges used to define the boundaries of the face shall all reference an edge curve - each curve used to define the geometry of the faces and face bounds shall be either a conic, or a line or a polyline or a b-spline curve - the edges used to define the face boundaries shall all be trimmed by vertices of type vertex point - no loop used to define a face bound shall be of the oriented subtype",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcadvancedbrep.htm"
     },
     "IfcAdvancedBrepWithVoids": {
         "attributes": {
             "Voids": ""
         },
-        "description": "The IfcAdvancedBrepWithVoids is a specialization of an advanced B-rep which contains one or more voids in its interior. The voids are represented as closed shells which are defined so that the shell normal point into the void.",
+        "description": "The IfcAdvancedBrepWithVoids is a specialization of an advanced B-rep which contains one or more voids in its interior. The voids are represented as closed shells which are defined so that the shell normal point into the void. Informal Propositions: - Each void shell shall be disjoint from the outer shell and from every other void shell - Each void shell shall be enclosed within the outer shell but not within any other void shell. In particular the outer shell is not in the set of void shells - Each shell in the IfcManifoldSolidBrep shall be referenced only once. - All the faces of all the shells in the IfcAdvancedBrep and the IfcAdvancedBrepWithVoids.Voids shall be of type IfcAdvancedFace.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcadvancedbrepwithvoids.htm"
     },
     "IfcAdvancedFace": {
-        "description": "An advanced face is a specialization of a face surface that has to meet requirements on using particular topological and geometric representation items for the definition of the faces, edges and vertices.",
+        "description": "An advanced face is a specialization of a face surface that has to meet requirements on using particular topological and geometric representation items for the definition of the faces, edges and vertices. An IfcAdvancedFace is restricted to: - have a face surface geometry of type IfcElementarySurface, IfcSweptSurface or IfcBSplineSurface, - have one IfcFaceOuterBound as the bound of the face, with the exception of closed surfaces, - have all faces to be bound by IfcEdgeLoop or IfcVertexLoop, - have all edges to have an edge curve geometry, - have the edge curve geometry restricted to IfcLine, IfcConic, IfcPolyline, or IfcBSplineCurve In case of closed faces with periodic surfaces, such as cylindrical or spherical surfaces, the following applies: - the edges of the closed surface, in case of a cylindrical surface the upper and lower cap, refer to the same instance of IfcVertexPoint twice, - no IfcFaceOuterBound is provided, or the IfcFaceOuterBound is constructed using an IfcSeamCurve at the periodic end of the underlying closed surface, in case of a cylindrical surface at 0./360. degree.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcadvancedface.htm"
     },
     "IfcAirTerminal": {
@@ -110,7 +110,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcairterminalbox.htm"
     },
     "IfcAirTerminalBoxType": {
-        "description": "The flow controller type IfcAirTerminalBoxType defines commonly shared information for occurrences of air terminal boxes. The set of shared information may include:",
+        "description": "The flow controller type IfcAirTerminalBoxType defines commonly shared information for occurrences of air terminal boxes. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define an air terminal box type specification indicating the specific product information that is common to all occurrences of that product type. The IfcAirTerminalBoxType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcAirTerminalBoxType are represented by instances of IfcAirTerminalBox. Refer to the documentation at IfcAirTerminalBox for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CONSTANTFLOW": "Terminal box does not include a means to reset the volume automatically to an outside signal such as thermostat.",
             "NOTDEFINED": "Undefined terminal box.",
@@ -121,7 +121,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcairterminalboxtype.htm"
     },
     "IfcAirTerminalType": {
-        "description": "The flow terminal type IfcAirTerminalType defines commonly shared information for occurrences of air terminals. The set of shared information may include:",
+        "description": "The flow terminal type IfcAirTerminalType defines commonly shared information for occurrences of air terminals. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define an air terminal type specification indicating the specific product information that is common to all occurrences of that product type. The IfcAirTerminalType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcAirTerminalType are represented by instances of IfcAirTerminal. Refer to the documentation at IfcAirTerminal for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "DIFFUSER": "An outlet discharging supply air in various directions and planes.",
             "GRILLE": "A covering for any area through which air passes.",
@@ -150,7 +150,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcairtoairheatrecovery.htm"
     },
     "IfcAirToAirHeatRecoveryType": {
-        "description": "The energy conversion device type IfcAirToAirHeatRecoveryType defines commonly shared information for occurrences of air to air heat recoverys. The set of shared information may include:",
+        "description": "The energy conversion device type IfcAirToAirHeatRecoveryType defines commonly shared information for occurrences of air to air heat recoverys. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define an air to air heat recovery type specification indicating the specific product information that is common to all occurrences of that product type. The IfcAirToAirHeatRecoveryType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcAirToAirHeatRecoveryType are represented by instances of IfcAirToAirHeatRecovery. Refer to the documentation at IfcAirToAirHeatRecovery for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "FIXEDPLATECOUNTERFLOWEXCHANGER": "Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with primary air entering at secondary air outlet location and exiting at secondary air inlet location.",
             "FIXEDPLATECROSSFLOWEXCHANGER": "Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with secondary air flow in the direction perpendicular to primary air flow.",
@@ -167,7 +167,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcairtoairheatrecoverytype.htm"
     },
     "IfcAlarm": {
-        "description": "An alarm is a device that signals the existence of a condition or situation that is outside the boundaries of normal expectation or that activates such a device.",
+        "description": "An alarm is a device that signals the existence of a condition or situation that is outside the boundaries of normal expectation or that activates such a device. Alarms include the provision of break glass buttons and manual pull boxes that are used to activate alarms.",
         "predefined_types": {
             "BELL": "An audible alarm.",
             "BREAKGLASSBUTTON": "An alarm activation mechanism in which a protective glass has to be broken to enable a button to be pressed.",
@@ -181,7 +181,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcbuildingcontrolsdomain/lexical/ifcalarm.htm"
     },
     "IfcAlarmType": {
-        "description": "The distribution control element type IfcAlarmType defines commonly shared information for occurrences of alarms. The set of shared information may include:",
+        "description": "The distribution control element type IfcAlarmType defines commonly shared information for occurrences of alarms. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a alarm type specification indicating the specific product information that is common to all occurrences of that product type. The IfcAlarmType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcAlarmType are represented by instances of IfcAlarm. Refer to the documentation at IfcAlarm for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BELL": "An audible alarm.",
             "BREAKGLASSBUTTON": "An alarm activation mechanism in which a protective glass has to be broken to enable a button to be pressed.",
@@ -198,7 +198,7 @@
         "attributes": {
             "ContainedInStructure": "Relationship to a spatial structure element, to which the associate is primarily associated."
         },
-        "description": "An annotation is a graphical representation within the geometric (and spatial) context of a project, that adds a note or meaning to the objects which constitutes the project model. Annotations include additional points, curves, text, dimensioning, hatching and other forms of graphical notes. It also include symbolic representations of additional model components, not representing products or spatial structures, such as survey points, contour lines or similar.",
+        "description": "An annotation is a graphical representation within the geometric (and spatial) context of a project, that adds a note or meaning to the objects which constitutes the project model. Annotations include additional points, curves, text, dimensioning, hatching and other forms of graphical notes. It also include symbolic representations of additional model components, not representing products or spatial structures, such as survey points, contour lines or similar. If available, the annotation should be related to the spatial context of the project, by containing the annotation within the appropriate level of the building structure (site, building, storey, or space). This is handled by the IfcRelContainedInSpatialStructure relationship. The IfcAnnotation can provide specific 0D, 1D, and 2D geometric items as representation of the annotation, offering annotation point, curves, and surfaces. The following values shall be used for the ObjectType. - 'Annotation point' is an annotation provided by a point that has additional semantic. The inherited attribute ObjectType should be used to capture the type of point annotation, some predefined values are: 'SurveyPoint: A single survey point represented by a Cartesian point. A property set may add the conditions (method, accurracy, etc. to the survey point). 'SurveyArea': A set of survey points represented by Cartesian point. These coordinates are determined relative to the coordinates of a reference point, which acts as the datum for the survey. Properties attached apply equally to all points. The difference in elevation of the survey points enables terrain to be determined. - 'Annotation curve' is an annotation provided by a curve that has additional semantic. The inherited attribute ObjectType should be used to capture the type of curve annotation, some predefined values are: 'ContourLine': A line of constant elevation typically used on geographic maps where the spacing of lines at constant intervals of elevation may be used as an indication of slope. 'IsoBar': A line of constant pressure typically used on weather maps or to show pressure gradient in spaces, chambers or externally. 'IsoLux': A line of constant illumination typically used to show the distribution of illumination levels and/or daylighting in a space or externally. 'IsoTherm': A line of constant temperature typically used to show the distribution and effect of heating or cooling within a space or to show temperature distribution on a geographic map. - 'Annotation surface' is an annotation provided by a surface that has additional semantic. The inherited attribute ObjectType should be used to capture the type of surface annotation, some predefined values are: 'SurveyArea': A surface patch based on survey points.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcannotation.htm"
     },
     "IfcAnnotationFillArea": {
@@ -206,7 +206,7 @@
             "InnerBoundaries": "A set of inner curves that define the inner boundaries of the fill area. The areas defined by the inner boundaries are excluded from applying the fill area style.",
             "OuterBoundary": "A closed curve that defines the outer boundary of the fill area. The areas defined by the outer boundary (minus potentially defined inner boundaries) is filled by the fill area style."
         },
-        "description": "The IfcAnnotationFillArea defines an area by a definite OuterBoundary, that might include InnerBoundaries. The areas defined by the InnerBoundaries are excluded from applying the fill area style. The InnerBoundaries shall not intersect with the OuterBoundary nor being outside of the OuterBoundary.",
+        "description": "The IfcAnnotationFillArea defines an area by a definite OuterBoundary, that might include InnerBoundaries. The areas defined by the InnerBoundaries are excluded from applying the fill area style. The InnerBoundaries shall not intersect with the OuterBoundary nor being outside of the OuterBoundary. The fill area style that is applied to the IfcAnnotationFillArea is declared using the IfcFillAreaStyle, associated to the area by an IfcStyledItem. Applicable fill area styles are a solid color, a hatching, tiles, or a combination of those styles. Figure 1 illustrates annotation fill area. Informal Propositions: - Any curve that describes an inner boundary shall not intersect with, nor include, another curve defining an inner boundary. - The curve defining the outer boundary shall not intersect with any curve defining an inner boundary, nor shall it be surrounded by a curve defining an inner boundary.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationdefinitionresource/lexical/ifcannotationfillarea.htm"
     },
     "IfcApplication": {
@@ -233,7 +233,7 @@
             "Name": "A name or additional clarification given to a cost value.",
             "UnitBasis": "The number and unit of measure on which the unit cost is based.  Note: As well as the normally expected units of measure such as length, area, volume etc., costs may be based on units of measure which need to be defined e.g. sack, drum, pallet, item etc. Unit costs may be based on quantities greater (or lesser) than a unitary value of the basis measure. For instance, timber may have a unit cost rate per X meters where X > 1; similarly for cable, piping and many other items. The basis number may be either an integer or a real value.  Note: This attribute should be asserted for all circumstances where the cost to be applied is per unit quantity. It may be asserted even for circumstances where an item price is used, in which case the unit cost basis should be by item (or equivalent definition)."
         },
-        "description": "This entity captures a value driven by a formula, with additional qualifications including unit basis, valid date range, and categorization.",
+        "description": "This entity captures a value driven by a formula, with additional qualifications including unit basis, valid date range, and categorization. The extent of the IfcAppliedValue is determined by the AppliedValue attribute which may be defined either as an IfcMeasureWithUnit or as an IfcMonetaryMeasure or as an IfcRatioMeasure via the IfcAppliedValueSelect type. Optionally, an IfcAppliedValue may have an applicable date. This is intended to fix the date on which the value became relevant for use. It may be the date on which the value was set in the model or it may be a prior or future date when the value becomes operable. Similarly, an IfcAppliedValue may have a 'fixed until' date. This is intended to fix the date on which the value ceases to be relevant for use. An instance of IfcAppliedValue may have a unit basis asserted. This is defined as an IfcMeasureWithUnit that determines the extent of the unit value for application purposes. It is assumed that when this attribute is asserted, then the value given to IfcAppliedValue is that for unit quantity. This is not enforced within the schema and thus needs to be controlled within an application. Applied values may be referenced from a document (such as a price list). The relationship between one or more occurrences of IfcAppliedValue (or its subtypes) is achieved through the use of the IfcExternalReferenceRelationship in which the document provides the IfcExternalReferenceRelationship.RelatingExtReference and the value occurrences are the IfcExternalReferenceRelationship.RelatedResourceObjects.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifccostresource/lexical/ifcappliedvalue.htm"
     },
     "IfcApproval": {
@@ -268,21 +268,21 @@
         "attributes": {
             "OuterCurve": "Bounded curve, defining the outer boundaries of the arbitrary profile."
         },
-        "description": "The closed profile IfcArbitraryClosedProfileDef defines an arbitrary two-dimensional profile for the use within the swept surface geometry, the swept area solid or a sectioned spine. It is given by an outer boundary from which the surface or solid can be constructed.",
+        "description": "The closed profile IfcArbitraryClosedProfileDef defines an arbitrary two-dimensional profile for the use within the swept surface geometry, the swept area solid or a sectioned spine. It is given by an outer boundary from which the surface or solid can be constructed. Informal Propositions: - The OuterCurve has to be a closed curve. - The OuterCurve shall not intersect. Figure 1 illustrates the arbitrary closed profile definition. The OuterCurve is defined in the underlying coordinate system. The underlying coordinate system is defined by the swept surface or swept area solid that uses the profile definition. It is the xy plane of either: - IfcSweptSurface.Position - IfcSweptAreaSolid.Position or in case of sectioned spines the xy plane of each list member of IfcSectionedSpine.CrossSectionPositions. The OuterCurve attribute defines a two dimensional closed bounded curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcarbitraryclosedprofiledef.htm"
     },
     "IfcArbitraryOpenProfileDef": {
         "attributes": {
             "Curve": "Open bounded curve defining the profile."
         },
-        "description": "The open profile IfcArbitraryOpenProfileDef defines an arbitrary two-dimensional open profile for the use within the swept surface geometry. It is given by an open boundary from which the surface can be constructed.",
+        "description": "The open profile IfcArbitraryOpenProfileDef defines an arbitrary two-dimensional open profile for the use within the swept surface geometry. It is given by an open boundary from which the surface can be constructed. Informal Propositions: - The Curve has to be an open curve. Figure 1 illustrates the arbitrary open profile definition. The Curve is defined in the underlying coordinate system. The underlying coordinate system is defined by the swept surface that uses the profile definition. It is the xy plane of: - IfcSweptSurface.Position The Curve attribute defines a two dimensional open bounded curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcarbitraryopenprofiledef.htm"
     },
     "IfcArbitraryProfileDefWithVoids": {
         "attributes": {
             "InnerCurves": "Set of bounded curves, defining the inner boundaries of the arbitrary profile."
         },
-        "description": "The IfcArbitraryProfileDefWithVoids defines an arbitrary closed two-dimensional profile with holes. It is given by an outer boundary and inner boundaries. A common usage of IfcArbitraryProfileDefWithVoids is as the cross section for the creation of swept surfaces or swept solids.",
+        "description": "The IfcArbitraryProfileDefWithVoids defines an arbitrary closed two-dimensional profile with holes. It is given by an outer boundary and inner boundaries. A common usage of IfcArbitraryProfileDefWithVoids is as the cross section for the creation of swept surfaces or swept solids. Informal Propositions: - The outer curve and all inner curves shall be closed curves. - The outer curve shall enclose all inner curves. - No inner curve shall intersect with the outer curve or any other inner curve. That is, no two curves of the profile definition shall have a point or segment in common, taken into account the geometric precision factor of the geometric representation context. In other words, curves must neither cross nor touch each other. - No inner curve may enclose another inner curve. Figure 1 illustrates the arbitrary closed profile definition with voids. The OuterCurve, defined at the supertype IfcArbitraryClosedProfileDef and the inner curves are defined in the same underlying coordinate system. The common underlying coordinate system is defined by the swept area solid that uses the profile definition. It is the xy plane of: - IfcSweptAreaSolid.Position or in case of sectioned spines the xy plane of each list member of IfcSectionedSpine.CrossSectionPositions. The OuterCurve attribute defines a two dimensional closed bounded curve, the InnerCurves define a set of two dimensional closed bounded curves.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcarbitraryprofiledefwithvoids.htm"
     },
     "IfcAsset": {
@@ -297,7 +297,7 @@
             "TotalReplacementCost": "The total cost of replacement of the asset.",
             "User": "The name of the person or organization that 'uses' the asset."
         },
-        "description": "An asset is a uniquely identifiable grouping of elements acting as a single entity that has a financial value or that can be operated on as a single unit.",
+        "description": "An asset is a uniquely identifiable grouping of elements acting as a single entity that has a financial value or that can be operated on as a single unit. An asset is generally the level of granularity at which maintenance operations are undertaken. An asset is a group that can contain one or more elements. Whilst the financial value of a component or element can be defined, financial value is also defined for accounting purposes at the level of the asset. There are a number of actors that can be associated with an asset, each actor having a role. Actors within the scope of the project are indicated using the IfcRelAssignsToActor relationship in which case roles should be defined through the IfcActorRole class; otherwise principal actors are identified as attributes of the class. In the existence of both, direct attributes take precedence. There are a number of costs that can be associated with an asset, each cost having a role. These are specified through the OriginalValue, CurrentValue, TotalReplacementCost and DepreciatedValue attributes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedfacilitieselements/lexical/ifcasset.htm"
     },
     "IfcAsymmetricIShapeProfileDef": {
@@ -315,11 +315,11 @@
             "TopFlangeWidth": "Extent of the top flange, defined parallel to the x axis of the position coordinate system.",
             "WebThickness": "Thickness of the web of the I-shape. The web is centred on the x-axis and the y-axis of the position coordinate system."
         },
-        "description": "IfcAsymmetricIShapeProfileDef defines a section profile that provides the defining parameters of a singly symmetric I-shaped section. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box.",
+        "description": "IfcAsymmetricIShapeProfileDef defines a section profile that provides the defining parameters of a singly symmetric I-shaped section. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box. The overall width of the profile is implicitly given by the maximum of the bottom flange width and the top flange width. IfcAsymmetricIShapeProfileDef can also be used to model rail profiles if the application scenario does not require a full explicit shape model of the rail profile. Alternatively, IfcArbitraryClosedProfileDef can be used to provide the exact shape of rail profiles. Either way, a reference to an external document or library should be provided to further define the profile as described at IfcProfileDef. Figure 1 illustrates parameters of the asymmetric I-shaped section definition. The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept area solid that uses the profile definition. It is the xy plane of: - IfcSweptAreaSolid.Position By using offsets of the position location, the parameterized profile can be positioned centric (using x,y offsets = 0.), or at any position relative to the profile. The parameterized profile is defined by a set of parameter attributes. In the illustrated example, the 'CentreOfGravityInY' property in IfcExtendedProfileProperties, if provided, is negative.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcasymmetricishapeprofiledef.htm"
     },
     "IfcAudioVisualAppliance": {
-        "description": "An audio-visual appliance is a device that displays, captures, transmits, or receives audio or video.",
+        "description": "An audio-visual appliance is a device that displays, captures, transmits, or receives audio or video. Audio-visual appliances may be fixed in place or may be able to be moved from one space to another. They may require an electrical supply that may be supplied either by an electrical circuit or provided from a local battery source. Audio-visual appliances may be connected to data circuits including specialist circuits for audio visual purposes only.",
         "predefined_types": {
             "AMPLIFIER": "A device that receives an audio signal and amplifies it to play through speakers.",
             "CAMERA": "A device that records images, either as a still photograph or as moving images known as videos or movies.  Note that a camera may operate with light from the visible spectrum or from other parts of the electromagnetic spectrum such as infrared or ultraviolet.",
@@ -338,7 +338,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcaudiovisualappliance.htm"
     },
     "IfcAudioVisualApplianceType": {
-        "description": "The flow terminal type IfcAudioVisualApplianceType defines commonly shared information for occurrences of audio visual appliances. The set of shared information may include:",
+        "description": "The flow terminal type IfcAudioVisualApplianceType defines commonly shared information for occurrences of audio visual appliances. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a audio visual appliance type specification indicating the specific product information that is common to all occurrences of that product type. The IfcAudioVisualApplianceType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcAudioVisualApplianceType are represented by instances of IfcAudioVisualAppliance. Refer to the documentation at IfcAudioVisualAppliance for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "AMPLIFIER": "A device that receives an audio signal and amplifies it to play through speakers.",
             "CAMERA": "A device that records images, either as a still photograph or as moving images known as videos or movies.  Note that a camera may operate with light from the visible spectrum or from other parts of the electromagnetic spectrum such as infrared or ultraviolet.",
@@ -378,7 +378,7 @@
             "P": "The normalized directions of the placement X Axis (P[1]) and the placement Y Axis (P[2]) and the placement Z Axis (P[3]). IfcBuildAxes(Axis, RefDirection)",
             "RefDirection": "The direction used to determine the direction of the local X Axis. If necessary an adjustment is made to maintain orthogonality to the Axis direction. If Axis and/or RefDirection is omitted, these directions are taken from the geometric coordinate system."
         },
-        "description": "The IfcAxis2Placement3D provides location and orientations to place items in a three-dimensional space. The attribute Axis defines the Z direction, RefDirection the X direction. The Y direction is derived.",
+        "description": "The IfcAxis2Placement3D provides location and orientations to place items in a three-dimensional space. The attribute Axis defines the Z direction, RefDirection the X direction. The Y direction is derived. If the attribute values for Axis and RefDirection are not given, the placement defaults to P[1] (x-axis) as [1.,0.,0.], P[2] (y-axis) as [0.,1.,0.] and P[3] (z-axis) as [0.,0.,1.].",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcaxis2placement3d.htm"
     },
     "IfcBSplineCurve": {
@@ -391,7 +391,7 @@
             "SelfIntersect": "Indication whether the curve self-intersects or not; it is for information only.",
             "UpperIndexOnControlPoints": "The upper index on the array of control points; the lower index is 0. This value is derived from the control points list. (SIZEOF(ControlPointsList) - 1)"
         },
-        "description": "The IfcBSplineCurve is a spline curve parameterized by spline functions.",
+        "description": "The IfcBSplineCurve is a spline curve parameterized by spline functions. Figure 1 illustrates a B-spline curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcbsplinecurve.htm"
     },
     "IfcBSplineCurveWithKnots": {
@@ -434,7 +434,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcbsplinesurfacewithknots.htm"
     },
     "IfcBeam": {
-        "description": "An IfcBeam is a horizontal, or nearly horizontal, structural member that is capable of withstanding load primarily by resisting bending. It represents such a member from an architectural point of view. It is not required to be load bearing.",
+        "description": "An IfcBeam is a horizontal, or nearly horizontal, structural member that is capable of withstanding load primarily by resisting bending. It represents such a member from an architectural point of view. It is not required to be load bearing. There are two main representations for beam occurrences: - IfcBeam with IfcMaterialProfileSetUsage is used for all occurrences of beams, that have a profile defined that is swept along a directrix. The profile might be changed uniformly by a taper definition along the directrix. The profile parameter and its cardinal point of insertion can be fully described by the IfcMaterialProfileSetUsage. These beams are always represented geometricly by an 'Axis' and a 'SweptSolid' or 'AdvancedSweptSolid' shape representation (or by a 'Clipping' geometry based on the swept solid), if a 3D geometric representation is assigned. NOTE The entity IfcBeamStandardCase has been deprecated, IfcBeam with IfcMaterialProfileSetUsage is used instead. - IfcBeam without IfcMaterialProfileSetUsage is used for all other occurrences of beams, particularly for beams with non-uniformly changing profile sizes along the sweep, or beams having only 'AdvancedBrep', 'Brep', or 'SurfaceModel' geometry, or if a more parametric representation is not intended.",
         "predefined_types": {
             "BEAM": "A standard beam usually used horizontally.",
             "HOLLOWCORE": "A wide often prestressed beam with a hollow-core profile that usually serves as a slab component.",
@@ -448,11 +448,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcbeam.htm"
     },
     "IfcBeamStandardCase": {
-        "description": "The standard beam, IfcBeamStandardCase, defines a beam with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcBeamStandardCase handles all cases of beams, that:",
+        "description": "The standard beam, IfcBeamStandardCase, defines a beam with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcBeamStandardCase handles all cases of beams, that: - have a reference to the IfcMaterialProfileSetUsage defining the material profile association of the beam with the cardinal point of its insertion relative to the local placement. - are consistent in using the correct cardinal point offset of the profile as compared to the 'Axis' and 'Body' shape representation - are based on a sweep of a planar profile, or set of profiles, as defined by the IfcMaterialProfileSet - have an 'Axis' shape representation with constraints provided below in the geometry use definition - have a 'Body' shape representation with constraints provided below in the geometry use definition are extruded perpendicular to the profile definition plane have a start profile, or set of profiles, that is swept the sweeping operation can be linear extrusion, circular rotation, or a sweep along a directrix the start profile, or set of profiles can be swept unchanged, or might be changed uniformly by a taper definition - NOTE View definitions and implementer agreements may further constrain the applicable geometry types, e.g. by excluding tapering from an IfcBeamStandardCase implementation. Geometric Representations The geometric representation of IfcBeamStandardCase is defined using the following multiple shape representations for its definition: - Axis: A three dimensional open curve (subtype of IfcBoundedCurve) defining the axis for the standard beam. The cardinal point is determined by the beam axis. - Body: A Swept Solid Representation or a CSG clipping representation defining the 3D shape of the standard beam.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcbeamstandardcase.htm"
     },
     "IfcBeamType": {
-        "description": "The element type IfcBeamType defines commonly shared information for occurrences of beams. The set of shared information may include:",
+        "description": "The element type IfcBeamType defines commonly shared information for occurrences of beams. The set of shared information may include: - common properties within shared property sets - common material information - common profile definitions - common shape representations It is used to define a beam specification, or beam style (the specific product information that is common to all occurrences of that beam type). Beam types may be exchanged without being already assigned to occurrences. Occurrences of the IfcBeamType within building models are represented by instances of IfcBeamStandardCase if the IfcBeamType has a single associated IfcMaterialProfileSet; otherwise they are represented by instances of IfcBeam. Occurrences of the IfcBeamType within structural analysis models are represented by instances of IfcStructuralCurveMember, or its applicable subtypes.",
         "predefined_types": {
             "BEAM": "A standard beam usually used horizontally.",
             "HOLLOWCORE": "A wide often prestressed beam with a hollow-core profile that usually serves as a slab component.",
@@ -470,7 +470,7 @@
             "RasterCode": "Blob, given as a single binary, to capture the texture within one popular file (compression) format. The file format is provided by the _RasterFormat_ attribute.",
             "RasterFormat": "The format of the _RasterCode_ often using a compression."
         },
-        "description": "An IfcBlobTexture provides a 2-dimensional distribution of the lighting parameters of a surface onto which it is mapped. The texture itself is given as a single binary blob, representing the content of a pixel format file. The file format of the pixel file is given by the RasterFormat attribute and allowable formats are guided by where rule SupportedRasterFormat.",
+        "description": "An IfcBlobTexture provides a 2-dimensional distribution of the lighting parameters of a surface onto which it is mapped. The texture itself is given as a single binary blob, representing the content of a pixel format file. The file format of the pixel file is given by the RasterFormat attribute and allowable formats are guided by where rule SupportedRasterFormat. For interpretation of the texture nodes see IfcImageTexture definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcblobtexture.htm"
     },
     "IfcBlock": {
@@ -479,11 +479,11 @@
             "YLength": "The size of the block along the placement Y axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[2]_.",
             "ZLength": "The size of the block along the placement Z axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[3]_."
         },
-        "description": "The IfcBlock is a Construction Solid Geometry (CSG) 3D primitive. It is defined by a position and a positve distance along the three orthogonal axes. The inherited Position attribute has the IfcAxisPlacement3D type and provides:",
+        "description": "The IfcBlock is a Construction Solid Geometry (CSG) 3D primitive. It is defined by a position and a positve distance along the three orthogonal axes. The inherited Position attribute has the IfcAxisPlacement3D type and provides: - SELF\\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcCsgPrimitive3D.Position.Location: The block has one vertex at location and the edges are aligned with the placement axes in the positive sense. The XLength, YLength, and ZLength attributes define the size of the IfcBlock along the three axes. Texture definition On each side face, textures are aligned facing upright. On the top and bottom faces, textures are aligned facing front-to-back. Textures are stretched or repeated to the extent of each face according to RepeatS and RepeatT. Figure 2 illustrates default texture mapping with a clamped texture (RepeatS=False and RepeatT=False). The image on the left shows the texture where the S axis points to the right and the T axis points up. The image on the right shows the texture applied to the geometry where the X axis points back to the right, the Y axis points back to the left, and the Z axis points up.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcblock.htm"
     },
     "IfcBoiler": {
-        "description": "A boiler is a closed, pressure-rated vessel in which water or other fluid is heated using an energy source such as natural gas, heating oil, or electricity. The fluid in the vessel is then circulated out of the boiler for use in various processes or heating applications.",
+        "description": "A boiler is a closed, pressure-rated vessel in which water or other fluid is heated using an energy source such as natural gas, heating oil, or electricity. The fluid in the vessel is then circulated out of the boiler for use in various processes or heating applications. IfcBoiler is a vessel solely used for heating of water or other fluids. Storage vessels, such as for drinking water storage are considered as tanks and use the IfcTank entity.",
         "predefined_types": {
             "NOTDEFINED": "Undefined Boiler type.",
             "STEAM": "Steam boiler.",
@@ -493,7 +493,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcboiler.htm"
     },
     "IfcBoilerType": {
-        "description": "The energy conversion device type IfcBoilerType defines commonly shared information for occurrences of boilers. The set of shared information may include:",
+        "description": "The energy conversion device type IfcBoilerType defines commonly shared information for occurrences of boilers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a boiler type specification indicating the specific product information that is common to all occurrences of that product type. The IfcBoilerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcBoilerType are represented by instances of IfcBoiler. Refer to the documentation at IfcBoiler for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "NOTDEFINED": "Undefined Boiler type.",
             "STEAM": "Steam boiler.",
@@ -503,7 +503,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcboilertype.htm"
     },
     "IfcBooleanClippingResult": {
-        "description": "A clipping result is defined as a special subtype of the general IfcBooleanResult. It constrains the operands and the operator of the Boolean result.",
+        "description": "A clipping result is defined as a special subtype of the general IfcBooleanResult. It constrains the operands and the operator of the Boolean result. A clipping result is the Boolean difference between a swept solid and a half space solid, or between the result of the Boolean difference and a half space solid. Hence more than one difference operation can be applied to achieve the final Boolean result.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcbooleanclippingresult.htm"
     },
     "IfcBooleanResult": {
@@ -536,7 +536,7 @@
             "TranslationalStiffnessByLengthY": "Translational stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.",
             "TranslationalStiffnessByLengthZ": "Translational stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object."
         },
-        "description": "Describes linearly elastic support conditions or connection conditions.",
+        "description": "Describes linearly elastic support conditions or connection conditions. Applicability: - Curve supports and connections.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcboundaryedgecondition.htm"
     },
     "IfcBoundaryFaceCondition": {
@@ -545,7 +545,7 @@
             "TranslationalStiffnessByAreaY": "Translational stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.",
             "TranslationalStiffnessByAreaZ": "Translational stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object."
         },
-        "description": "Describes linearly elastic support conditions or connection conditions.",
+        "description": "Describes linearly elastic support conditions or connection conditions. Applicability: - Surface supports and connections.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcboundaryfacecondition.htm"
     },
     "IfcBoundaryNodeCondition": {
@@ -557,22 +557,22 @@
             "TranslationalStiffnessY": "Translational stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.",
             "TranslationalStiffnessZ": "Translational stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object."
         },
-        "description": "Describes linearly elastic support conditions or connection conditions.",
+        "description": "Describes linearly elastic support conditions or connection conditions. Applicability: - Point supports and connections.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcboundarynodecondition.htm"
     },
     "IfcBoundaryNodeConditionWarping": {
         "attributes": {
             "WarpingStiffness": "Defines the warping stiffness value."
         },
-        "description": "Describes linearly elastic support conditions or connection conditions, including linearly elastic warping restraints.",
+        "description": "Describes linearly elastic support conditions or connection conditions, including linearly elastic warping restraints. Applicability: - Point supports and connections.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcboundarynodeconditionwarping.htm"
     },
     "IfcBoundedCurve": {
-        "description": "An IfcBoundedCurve is a curve of finite length.",
+        "description": "An IfcBoundedCurve is a curve of finite length. Informal Propositions: - A bounded curve has finite arc length. - A bounded curve has a start point and an end point.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcboundedcurve.htm"
     },
     "IfcBoundedSurface": {
-        "description": "An IfcBoundedSurface is a surface of finite area.",
+        "description": "An IfcBoundedSurface is a surface of finite area. Informal Propositions: - A bounded surface has finite non-zero surface area. - A bounded surface has boundary curves.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcboundedsurface.htm"
     },
     "IfcBoundingBox": {
@@ -590,7 +590,7 @@
         "attributes": {
             "Enclosure": "The box which bounds the resulting solid of the Boolean operation involving the half space solid for computational purposes only."
         },
-        "description": "The IfcBoxedHalfSpace is used (as its supertype IfcHalfSpaceSolid) only within Boolean operations. It divides the domain into exactly two subsets, where the domain in question is that of the attribute Enclosure.",
+        "description": "The IfcBoxedHalfSpace is used (as its supertype IfcHalfSpaceSolid) only within Boolean operations. It divides the domain into exactly two subsets, where the domain in question is that of the attribute Enclosure. The purpose of the attribute Enclosure is to provide a search box for the other operand in the Boolean operation. It shall be sufficiently large to fully enclose the resulting solid after the Boolean operation with the half space. It however does not alter the final result. The result of the Boolean operation would be the same, as if executed by the supertype IfcHalfSpaceSolid. See Figure 1 below. The IfcBoundingBox that provides the enclosure is given for the convenience of the receiving application to enable the use of size box comparison for efficiency (for example, to check first whether size boxes intersect, if not no calculations has to be done to check whether the solids of the entities intersect).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcboxedhalfspace.htm"
     },
     "IfcBuilding": {
@@ -599,15 +599,15 @@
             "ElevationOfRefHeight": "Elevation above sea level of the reference height used for all storey elevation measures, equals to height 0.0. It is usually the ground floor level.",
             "ElevationOfTerrain": "Elevation above the minimal terrain level around the foot print of the building, given in elevation above sea level."
         },
-        "description": "A building represents a structure that provides shelter for its occupants or contents and stands in one place. The building is also used to provide a basic element within the spatial structure hierarchy for the components of a building project (together with site, storey, and space).",
+        "description": "A building represents a structure that provides shelter for its occupants or contents and stands in one place. The building is also used to provide a basic element within the spatial structure hierarchy for the components of a building project (together with site, storey, and space). A building is (if specified) associated to a site. A building may span over several connected or disconnected buildings. Therefore building complex provides for a collection of buildings included in a site. A building can also be decomposed in (vertical) parts, where each part defines a building section. This is defined by the composition type attribute of the supertype IfcSpatialStructureElements which is interpreted as follow: - COMPLEX: building complex - ELEMENT: building - PARTIAL: building section The IfcBuilding is used to build the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). The spatial structure elements are linked together by using the objectified relationship IfcRelAggregates. Figure 1 shows the IfcBuilding as part of the spatial structure. It also serves as the spatial container for building and other elements. Systems, such as building service or electrical distribution systems, zonal systems, or structural analysis systems, relate to IfcBuilding by using the objectified relationship IfcRelServicesBuildings. Figure 2 describes the heights and elevations of the IfcBuilding. It is used to provide the height above sea level of the project height datum for this building, that is, the internal height 0.00. The height 0.00 is often used as a building internal reference height and equal to the floor finish level of the ground floor. - base elevation of building provided by: IfcBuilding.ElevationOfRefHeight, it is usually the top of construction slab - base elevation of terrain at the perimeter of the building provided by: IfcBuilding.ElevationOfTerrain, it is usually the minimum elevation is sloped terrain - total height of building, also referred to as ridge height (top of roof structure, e.g the ridge against terrain): provided by BaseQuantity with Name=\"TotalHeight\" - eaves height of building (base of roof structure, e.g the eaves against terrain): provided by BaseQuantity with Name=\"EavesHeight\"",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcbuilding.htm"
     },
     "IfcBuildingElement": {
-        "description": "The building element comprises all elements that are primarily part of the construction of a building, i.e., its structural and space separating system. Building elements are all physically existent and tangible things",
+        "description": "The building element comprises all elements that are primarily part of the construction of a building, i.e., its structural and space separating system. Building elements are all physically existent and tangible things This IfcBuildingElement is a generalization of all elements that participate in a building system. Typical examples of IfcBuildingElement's are (among others): - building elements within a space separation systems - building elements within an enclosure system (such as a facade) - building elements within a fenestration system - building elements within a load bearing system - building elements within a foundation system The IfcBuildingElement is an abstract entity that cannot be instantiated. For arbitrary building elements, that cannot be expressed by a subtype of IfcBuildingElement, use IfcBuildingElementProxy.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcbuildingelement.htm"
     },
     "IfcBuildingElementPart": {
-        "description": "IfcBuildingElementPart represents major components as subordinate parts of a building element. Typical usage examples include precast concrete sandwich walls, where the layers may have different geometry representations. In this case the layered material representation does not sufficiently describe the element. Each layer is represented by an own instance of the IfcBuildingElementPart with its own geometry description.",
+        "description": "IfcBuildingElementPart represents major components as subordinate parts of a building element. Typical usage examples include precast concrete sandwich walls, where the layers may have different geometry representations. In this case the layered material representation does not sufficiently describe the element. Each layer is represented by an own instance of the IfcBuildingElementPart with its own geometry description. The kind of building element part is further specified by a corresponding instance of IfcBuildingElementPartType, referred to by IfcRelDefinesByType.",
         "predefined_types": {
             "INSULATION": "The part provides thermal insulation, for example as insulation layer between wall panels in sandwich walls or as infill in stud walls.",
             "NOTDEFINED": "Undefined accessory.",
@@ -627,7 +627,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedcomponentelements/lexical/ifcbuildingelementparttype.htm"
     },
     "IfcBuildingElementProxy": {
-        "description": "The IfcBuildingElementProxy is a proxy definition that provides the same functionality as subtypes of IfcBuildingElement, but without having a predefined meaning of the special type of building element, it represents.",
+        "description": "The IfcBuildingElementProxy is a proxy definition that provides the same functionality as subtypes of IfcBuildingElement, but without having a predefined meaning of the special type of building element, it represents. Proxies can also be used as spatial place holders or provisions, that are later replaced by special types of elements. One use of the proxy object is a provision for voids, i.e. where a particular volume of space is requested by an engineering function that might later be accepted or rejected. If accepted it is transformed into a void within a building element, like a wall opening, or a slab opening. The provision for voids is exchanged as an IfcBuildingElementProxy with the PredefinedType = ProvisionForVoid. Such proxy shall have a swept solid geometry, where the profile of the swept solid lies on/near the surface of the referred building element and the extrusion depths is equal to or bigger then (in case of round or otherwise irregular element shape) the thickness of the building element. The appropriate property set should be attached. In addition to the provision for voids, the building element proxy can also represent a provision for space, often the necessary space allocation for mechanical equipment that will be determined in a later design phase. The provision for space is exchanged as an IfcBuildingElementProxy with the PredefinedType = ProvisionForSpace. Other usages of IfcBuildingElementProxy include: - The IfcBuildingElementProxy can be used to exchange special types of building elements for which the current specification does not yet provide a semantic definition. - The IfcBuildingElementProxy can also be used to represent building elements for which the participating applications can not provide a semantic definition.",
         "predefined_types": {
             "COMPLEX": "Not used - kept for upward compatibility.",
             "ELEMENT": "Not used - kept for upward compatibility.",
@@ -640,7 +640,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcbuildingelementproxy.htm"
     },
     "IfcBuildingElementProxyType": {
-        "description": "IfcBuildingElementProxyType defines a list of commonly shared property set definitions of a building element proxy and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "IfcBuildingElementProxyType defines a list of commonly shared property set definitions of a building element proxy and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A building element proxy type is used to define the common properties of a certain type of a building element proxy that may be applied to many instances of that type to assign a specific style. Building element proxy types may be exchanged without being already assigned to occurrences. The occurrences of the IfcBuildingElementProxyType are represented by instances of IfcBuildingElementProxy.",
         "predefined_types": {
             "COMPLEX": "Not used - kept for upward compatibility.",
             "ELEMENT": "Not used - kept for upward compatibility.",
@@ -653,21 +653,21 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcbuildingelementproxytype.htm"
     },
     "IfcBuildingElementType": {
-        "description": "The IfcBuildingElementType provides the type information for IfcBuildingElement occurrences.",
+        "description": "The IfcBuildingElementType provides the type information for IfcBuildingElement occurrences. A building element type is used to define the common properties of a certain type of building element that are applied to all occurrences of that type. It is used to define a building element specification (i.e. the specific product information, that is common to all occurrences of that product type). Building element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The IfcBuildingElementType is an abstract type that cannot be instantiated. For arbitrary building element types, that cannot be expressed by a subtype of IfcBuildingElementType, use IfcBuildingElementProxyType. Occurrences of subtypes of the IfcBuildingElementType are represented by instances of the appropriate subtypes of IfcBuildingElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcbuildingelementtype.htm"
     },
     "IfcBuildingStorey": {
         "attributes": {
             "Elevation": "Elevation of the base of this storey, relative to the 0,00 internal reference height of the building. The 0.00 level is given by the absolute above sea level height by the _ElevationOfRefHeight_ attribute given at _IfcBuilding_.  > NOTE  If the geometric data is provided (_ObjectPlacement_ is specified), the _Elevation_ value shall either not be included, or be equal to the local placement Z value."
         },
-        "description": "The building storey has an elevation and typically represents a (nearly) horizontal aggregation of spaces that are vertically bound.",
+        "description": "The building storey has an elevation and typically represents a (nearly) horizontal aggregation of spaces that are vertically bound. A storey is (if specified) associated to a building. A storey may span over several connected storeys. Therefore storey complex provides for a collection of storeys included in a building. A storey can also be decomposed in (horizontical) parts, where each part defines a partial storey. This is defined by the composition type attribute of the supertype IfcSpatialStructureElements which is interpreted as follow: - COMPLEX: building storey complex - ELEMENT: building storey - PARTIAL: partial building storey The IfcBuildingStorey is used to build the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). The spatial structure elements are linked together by using the objectified relationship IfcRelAggregates. Figure 1 shows the IfcBuildingStorey as part of the s patial structure. It also serves as the spatial container for building and other elements. Figure 2 describes the heights and elevations of the IfcBuildingStorey. - elevation of storey provided by: IfcBuildingStorey.Elevation as a local height value relative to IfcBuilding.ElevationOfRefHeight, it is usually the top of construction slab - net height of storey, also referred to as total height or system height (top of construction slab to top of construction slab above): provided by BaseQuantity with Name=\"GrossHeight\" - net height of storey (top of construction slab to bottom of construction slab above): provided by BaseQuantity with Name=\"NetHeight\"",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcbuildingstorey.htm"
     },
     "IfcBuildingSystem": {
         "attributes": {
             "LongName": "Long name for a building system, used for informal purposes. It should be used, if available, in conjunction with the inherited _Name_ attribute. > NOTE  In many scenarios the _Name_ attribute refers to the short name or number of a building system, and the _LongName_ refers to a descriptive name."
         },
-        "description": "A building system is a group by which building elements are grouped according to a common function within the building.",
+        "description": "A building system is a group by which building elements are grouped according to a common function within the building. The group IfcBuildingSystem defines the occurrence of a specialized system for use within the context of a building and finishing fabric. Important functionalities for the description of a building system are derived from supertypes: - From IfcSystem it inherits the ability to couple the building system via IfcRelServicesBuildings to one or more IfcSpatialElement subtypes as necessary. - From IfcGroup it inherits the inverse attribute IsGroupedBy, pointing to the relationship class IfcRelAssignsToGroup. This allows to group building elements (instances of IfcBuildingElement subtypes, IfcFurnishingElement subtype, IfcElementAssembly and IfcTransportElement). - From IfcObjectDefinition it inherits the inverse attribute IsDecomposedBy pointing to the relationship class IfcRelAggregates. It provides the hierarchy between the separate (partial) building systems.",
         "predefined_types": {
             "FENESTRATION": "System of doors, windows, and other fillings in opening in a building envelop that are designed to permit the passage of air or light.",
             "FOUNDATION": "System of shallow and deep foundation element that transmit forces to the supporting ground.",
@@ -689,7 +689,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcburner.htm"
     },
     "IfcBurnerType": {
-        "description": "The energy conversion device type IfcBurnerType defines commonly shared information for occurrences of burners. The set of shared information may include:",
+        "description": "The energy conversion device type IfcBurnerType defines commonly shared information for occurrences of burners. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a burner type specification indicating the specific product information that is common to all occurrences of that product type. The IfcBurnerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcBurnerType are represented by instances of IfcBurner. Refer to the documentation at IfcBurner for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "NOTDEFINED": "Undefined burner type.",
             "USERDEFINED": "User-defined burner type."
@@ -704,7 +704,7 @@
             "WallThickness": "Constant wall thickness of profile (= ts).",
             "Width": "Profile width, see illustration above (= b)."
         },
-        "description": "IfcCShapeProfileDef defines a section profile that provides the defining parameters of a C-shaped section to be used by the swept area solid. This section is typically produced by cold forming steel. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box.",
+        "description": "IfcCShapeProfileDef defines a section profile that provides the defining parameters of a C-shaped section to be used by the swept area solid. This section is typically produced by cold forming steel. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box. Figure 1 illustrates parameters of the C-shape profile definition. The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept area solid that uses the profile definition. It is the xy plane of: - IfcSweptAreaSolid.Position By using offsets of the position location, the parameterized profile can be positioned centric (using x,y offsets = 0.), or at any position relative to the profile. The parameterized profile is defined by a set of parameter attributes. In the illustrated example, the 'CentreOfGravityInX' property in IfcExtendedProfileProperties, if provided, is negative.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifccshapeprofiledef.htm"
     },
     "IfcCableCarrierFitting": {
@@ -720,7 +720,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifccablecarrierfitting.htm"
     },
     "IfcCableCarrierFittingType": {
-        "description": "The flow fitting type IfcCableCarrierFittingType defines commonly shared information for occurrences of cable carrier fittings. The set of shared information may include:",
+        "description": "The flow fitting type IfcCableCarrierFittingType defines commonly shared information for occurrences of cable carrier fittings. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a cable carrier fitting type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCableCarrierFittingType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCableCarrierFittingType are represented by instances of IfcCableCarrierFitting. Refer to the documentation at IfcCableCarrierFitting for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BEND": "A fitting that changes the route of the cable carrier.",
             "CROSS": "A fitting at which two branches are taken from the main route of the cable carrier simultaneously.",
@@ -744,7 +744,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifccablecarriersegment.htm"
     },
     "IfcCableCarrierSegmentType": {
-        "description": "The flow segment type IfcCableCarrierSegmentType defines commonly shared information for occurrences of cable carrier segments. The set of shared information may include:",
+        "description": "The flow segment type IfcCableCarrierSegmentType defines commonly shared information for occurrences of cable carrier segments. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a cable carrier segment type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCableCarrierSegmentType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCableCarrierSegmentType are represented by instances of IfcCableCarrierSegment. Refer to the documentation at IfcCableCarrierSegment for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CABLELADDERSEGMENT": "An open carrier segment on which cables are carried on a ladder structure.",
             "CABLETRAYSEGMENT": "A (typically) open carrier segment onto which cables are laid.",
@@ -769,7 +769,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifccablefitting.htm"
     },
     "IfcCableFittingType": {
-        "description": "The flow fitting type IfcCableFittingType defines commonly shared information for occurrences of cable fittings. The set of shared information may include:",
+        "description": "The flow fitting type IfcCableFittingType defines commonly shared information for occurrences of cable fittings. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a cable fitting type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCableFittingType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCableFittingType are represented by instances of IfcCableFitting. Refer to the documentation at IfcCableFitting for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CONNECTOR": "A fitting that joins two cable segments of the same connector type (though potentially different gender).",
             "ENTRY": "A fitting that begins a cable segment at a non-electrical element such as a grounding clamp attached to a pipe.",
@@ -782,7 +782,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifccablefittingtype.htm"
     },
     "IfcCableSegment": {
-        "description": "A cable segment is a flow segment used to carry electrical power, data, or telecommunications signals.",
+        "description": "A cable segment is a flow segment used to carry electrical power, data, or telecommunications signals. A cable segment is used to typically join two sections of an electrical network or a network of components carrying the electrical service.",
         "predefined_types": {
             "BUSBARSEGMENT": "Electrical conductor that makes a common connection between several electrical circuits. Properties of a busbar are the same as those of a cable segment and are captured by the cable segment property set.",
             "CABLESEGMENT": "Cable with a specific purpose to lead electric current within a circuit or any other electric construction. Includes all types of electric cables, mainly several core segments or conductor segments wrapped together.",
@@ -794,7 +794,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifccablesegment.htm"
     },
     "IfcCableSegmentType": {
-        "description": "The flow segment type IfcCableSegmentType defines commonly shared information for occurrences of cable segments. The set of shared information may include:",
+        "description": "The flow segment type IfcCableSegmentType defines commonly shared information for occurrences of cable segments. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a cable segment type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCableSegmentType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCableSegmentType are represented by instances of IfcCableSegment. Refer to the documentation at IfcCableSegment for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BUSBARSEGMENT": "Electrical conductor that makes a common connection between several electrical circuits. Properties of a busbar are the same as those of a cable segment and are captured by the cable segment property set.",
             "CABLESEGMENT": "Cable with a specific purpose to lead electric current within a circuit or any other electric construction. Includes all types of electric cables, mainly several core segments or conductor segments wrapped together.",
@@ -824,14 +824,14 @@
         "attributes": {
             "CoordList": "Two-dimensional list of Cartesian points provided by two coordinates."
         },
-        "description": "The IfcCartesianPointList2D defines an ordered collection of two-dimentional Cartesian points. Each Cartesian point is provided as an two-dimensional point by a fixed list of two coordinates. The attribute CoordList is a two-dimensional list, where",
+        "description": "The IfcCartesianPointList2D defines an ordered collection of two-dimentional Cartesian points. Each Cartesian point is provided as an two-dimensional point by a fixed list of two coordinates. The attribute CoordList is a two-dimensional list, where - first dimension is an unbounded list representing each 2D Cartesian point; - second dimension is a fixed list of two list members, where [1] is the x-coordinate, and [2] the y-coordinate of the Cartesian point.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifccartesianpointlist2d.htm"
     },
     "IfcCartesianPointList3D": {
         "attributes": {
             "CoordList": "Two-dimensional list of Cartesian points provided by three coordinates."
         },
-        "description": "The IfcCartesianPointList3D defines an ordered collection of three-dimentional Cartesian points. Each Cartesian point is provided as an three-dimensional point by a fixed list of three coordinates. The attribute CoordList is a two-dimensional list, where",
+        "description": "The IfcCartesianPointList3D defines an ordered collection of three-dimentional Cartesian points. Each Cartesian point is provided as an three-dimensional point by a fixed list of three coordinates. The attribute CoordList is a two-dimensional list, where - first dimension is an unbounded list representing each 3D Cartesian point; - second dimension is a fixed list of three list members, where [1] is the x-coordinate, [2] the y-coordinate and [3] the z-coordinate of the Cartesian point.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifccartesianpointlist3d.htm"
     },
     "IfcCartesianTransformationOperator": {
@@ -858,7 +858,7 @@
             "Scale2": "The scaling value specified for the transformation along the axis 2. This is normally the y scale factor.",
             "Scl2": "The derived scale S(2) of the transformation along the axis 2 (normally the y axis), equal to Scale2 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. NVL(Scale2, SELF\\IfcCartesianTransformationOperator.Scl)"
         },
-        "description": "A Cartesian transformation operator 2d non uniform defines a geometric transformation in two-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by two different scaling factors:",
+        "description": "A Cartesian transformation operator 2d non uniform defines a geometric transformation in two-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by two different scaling factors: - SELF\\IfcCartesianTransformationOperator.Scale: the x axis scale factor - Scale2: the y axis scale factor If the Scale factor (at supertype IfcCartesianTransformationOperator) is omitted, it defaults to 1.0. If the Scale2 factor is omitted, it defaults to the value of Scale (the x axis scale factor).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifccartesiantransformationoperator2dnonuniform.htm"
     },
     "IfcCartesianTransformationOperator3D": {
@@ -876,14 +876,14 @@
             "Scl2": "The derived scale S(2) of the transformation along the axis 2 (normally the y axis), equal to Scale2 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. NVL(Scale2, SELF\\IfcCartesianTransformationOperator.Scl)",
             "Scl3": "The derived scale S(3) of the transformation along the axis 3 (normally the z axis), equal to Scale3 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. NVL(Scale3, SELF\\IfcCartesianTransformationOperator.Scl)"
         },
-        "description": "A Cartesian transformation operator 3d non uniform defines a geometric transformation in three-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by three different scaling factors:",
+        "description": "A Cartesian transformation operator 3d non uniform defines a geometric transformation in three-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by three different scaling factors: - SELF\\IfcCartesianTransformationOperator.Scale: the x axis scale factor - Scale2: the y axis scale factor - Scale3: the z axis scale factor If the Scale factor (at supertype IfcCartesianTransformationOperator) is omitted, it defaults to 1.0. If the Scale2 or the Scale3 factor is omitted, it defaults to the value of Scale (the x axis scale factor).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifccartesiantransformationoperator3dnonuniform.htm"
     },
     "IfcCenterLineProfileDef": {
         "attributes": {
             "Thickness": "Constant thickness applied along the center line."
         },
-        "description": "The profile IfcCenterLineProfileDef defines an arbitrary two-dimensional open, not self intersecting profile for the use within the swept solid geometry. It is given by an area defined by applying a constant thickness to a centerline, generating an area from which the solid can be constructed.",
+        "description": "The profile IfcCenterLineProfileDef defines an arbitrary two-dimensional open, not self intersecting profile for the use within the swept solid geometry. It is given by an area defined by applying a constant thickness to a centerline, generating an area from which the solid can be constructed. Among else, IfcCenterLineProfileDef is used to model cold-formed steel or aluminium sections (Sigma, Zeta, Omega, and similar sections which are not covered by subtypes of IfcParameterizedProfileDef). However, since IfcCenterLineProfileDef does not provide shape parameters except for the thickness, there is generally a need to further specify the profile definition by means of - the name, - external reference to a document or library, - profile properties, or a combination of them. See IfcProfileDef for guidance on external references for profiles. Informal Propositions: - The Curve has to be an open curve. - The Curve has to be a non-intersecting curve. Figure 1 illustrates the center line profile definition. The Curve is defined in the underlying coordinate system. The underlying coordinate system is defined by the swept surface that uses the profile definition. It is the xy plane of: - IfcSweptSurface.Position The Curve attribute defines a two dimensional open bounded curve. The Thickness attribute defines a constant thickness along the curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifccenterlineprofiledef.htm"
     },
     "IfcChiller": {
@@ -898,7 +898,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcchiller.htm"
     },
     "IfcChillerType": {
-        "description": "The energy conversion device type IfcChillerType defines commonly shared information for occurrences of chillers. The set of shared information may include:",
+        "description": "The energy conversion device type IfcChillerType defines commonly shared information for occurrences of chillers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a chiller type specification indicating the specific product information that is common to all occurrences of that product type. The IfcChillerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcChillerType are represented by instances of IfcChiller. Refer to the documentation at IfcChiller for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "AIRCOOLED": "Air cooled chiller.",
             "HEATRECOVERY": "Heat recovery chiller.",
@@ -917,7 +917,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcchimney.htm"
     },
     "IfcChimneyType": {
-        "description": "The building element type IfcChimneyType defines commonly shared information for occurrences of chimneys. The set of shared information may include:",
+        "description": "The building element type IfcChimneyType defines commonly shared information for occurrences of chimneys. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a chimney type specification indicating the specific product information that is common to all occurrences of that product type. The IfcChimneyType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcChimneyType are represented by instances of IfcChimney. Refer to the documentation at IfcChimney for supported property sets, materials, and composition.",
         "predefined_types": {
             "NOTDEFINED": "",
             "USERDEFINED": ""
@@ -928,29 +928,29 @@
         "attributes": {
             "Radius": "The radius of the circle, which shall be greater than zero."
         },
-        "description": "An IfcCircle is a curve consisting of a set of points having equal distance from the center.",
+        "description": "An IfcCircle is a curve consisting of a set of points having equal distance from the center. Figure 1 illustrates the definition of IfcCircle within a three-dimensional position coordinate system placed within the object coordinate system of an element. The IfcCircle ia parameterized using numeric values in correspondence to the plane angle unit provided within the IfcUnitAssignment. If the plane angle unit is 'Degree' the parametric range of a circle is 0 \u2264 u \u2264 360, if the plane angle unit is radians, the parametric range is 0 \u2264 u \u2264 2\u03c0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifccircle.htm"
     },
     "IfcCircleHollowProfileDef": {
         "attributes": {
             "WallThickness": "Thickness of the material, it is the difference between the outer and inner radius."
         },
-        "description": "IfcCircleHollowProfileDef defines a section profile that provides the defining parameters of a circular hollow section (tube) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profile's centre of the bounding box (for symmetric profiles identical with the centre of gravity).",
+        "description": "IfcCircleHollowProfileDef defines a section profile that provides the defining parameters of a circular hollow section (tube) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profile's centre of the bounding box (for symmetric profiles identical with the centre of gravity). Figure 1 illustrates parameters of the circular hollow profile definition. The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept area solid that uses the profile definition. It is the xy plane of: - IfcSweptAreaSolid.Position By using offsets of the position location, the parameterized profile can be positioned centric (using x,y offsets = 0.), or at any position relative to the profile. Explicit coordinate offsets are used to define cardinal points (for example, upper-left bound). The parameterized profile is defined by a set of parameter attributes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifccirclehollowprofiledef.htm"
     },
     "IfcCircleProfileDef": {
         "attributes": {
             "Radius": "The radius of the circle."
         },
-        "description": "IfcCircleProfileDef defines a circle as the profile definition used by the swept surface geometry or by the swept area solid. It is given by its Radius attribute and placed within the 2D position coordinate system, established by the Position attribute.",
+        "description": "IfcCircleProfileDef defines a circle as the profile definition used by the swept surface geometry or by the swept area solid. It is given by its Radius attribute and placed within the 2D position coordinate system, established by the Position attribute. Figure 1 illustrates parameters for the circle profile definition. The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept surface or swept area solid that uses the profile definition. It is the xy plane of either: - IfcSweptSurface.Position - IfcSweptAreaSolid.Position Or in case of sectioned spines, it is the xy plane of each list member of IfcSectionedSpine.CrossSectionPositions. By using offsets of the position location, the parameterized profile can be positioned centric (using x,y offsets = 0.), or at any position relative to the profile. Explicit coordinate offsets are used to define cardinal points (e.g. upper-left bound). The Position attribute defines the 2D position coordinate system of the circle. The Radius attribute defines the radius of the circle.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifccircleprofiledef.htm"
     },
     "IfcCivilElement": {
-        "description": "An IfcCivilElement is a generalization of all elements within a civil engineering works. It includes in particular all occurrences of typical linear construction works, such as road segments, bridge segments, pavements, etc. Depending on the context of the construction project, included building work, such as buildings or factories, are represented as a collection of IfcBuildingElement's, distribution systems, such as piping or drainage, are represented as a collection of IfcDistributionElement's, and other geographic elements, such as trees, light posts, traffic signs etc. are represented as IfcGeographicElement's.",
+        "description": "An IfcCivilElement is a generalization of all elements within a civil engineering works. It includes in particular all occurrences of typical linear construction works, such as road segments, bridge segments, pavements, etc. Depending on the context of the construction project, included building work, such as buildings or factories, are represented as a collection of IfcBuildingElement's, distribution systems, such as piping or drainage, are represented as a collection of IfcDistributionElement's, and other geographic elements, such as trees, light posts, traffic signs etc. are represented as IfcGeographicElement's. Civil elements are typically horizontally organized using a spatial structure expressed by spatial zones, therefore IfcCivilElement is spatially contained by default within an IfcSpatialZone.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifccivilelement.htm"
     },
     "IfcCivilElementType": {
-        "description": "An IfcCivilElementType is used to define an element specification of an element used within civil engineering works. Civil element types include for different types of element that may be used to represent information for construction works external to a building. IfcCivilElementType's may include:",
+        "description": "An IfcCivilElementType is used to define an element specification of an element used within civil engineering works. Civil element types include for different types of element that may be used to represent information for construction works external to a building. IfcCivilElementType's may include: - linear elements such as sections of a roadway (including carriageway/pavement, verge, median, marker line, kerb etc.); - elements for connections and junctions including traffic roundabouts, T junctions, 4 way junctions; - elements for supporting structures such as piers, piles, pylons, and similar. The specification of the specific types is provided by the inherited attribute IfcElementType.ElementType given as an IfcLabel.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifccivilelementtype.htm"
     },
     "IfcClassification": {
@@ -965,7 +965,7 @@
             "ReferenceTokens": "The delimiter tokens that are used to mark the boundaries of individual facets (substrings) in a classification reference.       This typically applies then the _IfcClassification_ is used in conjuction with _IfcClassificationReference_'s. If only one _ReferenceToken_ is provided, it applies to all boundaries of individual facets, if more than one _ReferenceToken_ are provided, the first token applies to the first boundary, the second token to the second boundary, and the n^th^ token to the n^th^ and any additional boundary.   > NOTE  Tokens are typically recommended within the classification itself and each token will have a particular role.  > EXAMPLE 1 To indicate that the facet delimiter used for DIN277-2 reference key \"2.1\" (\"Office rooms\") is \".\", a single _ReferenceToken_ ['.'] is provided. To indicate that the facet delimiter used for Omniclass Table 13 (space by function) reference key \"13-15 11 34 11\" (\"Office\") are \"-\" and \" \", two _ReferenceToken_'s ['-', ' '] are provided.  > EXAMPLE 2 The use of _ReferenceTokens_ can also be extended to include masks. The use need to be agreed in view definitions or implementer agreements that stipulates a \"mask syntax\" that should be used.",
             "Source": "Source (or publisher) for this classification. > NOTE  that the source of the classification means the person or organization that was the original author or the person or organization currently acting as the publisher."
         },
-        "description": "An IfcClassification is used for the arrangement of objects into a class or category according to a common purpose or their possession of common characteristics. A classification in the sense of IfcClassification is taxonomy, or taxonomic scheme, arranged in a hierarchical structure. A category of objects relates to other categories in a generalization-specialization relationship. Therefore the classification items in an classification are organized in a tree structure.",
+        "description": "An IfcClassification is used for the arrangement of objects into a class or category according to a common purpose or their possession of common characteristics. A classification in the sense of IfcClassification is taxonomy, or taxonomic scheme, arranged in a hierarchical structure. A category of objects relates to other categories in a generalization-specialization relationship. Therefore the classification items in an classification are organized in a tree structure. The IfcClassification identifies the classification system or source to which a classification reference refers to. Each classification reference may reference an instance of IfcClassification. A classification system declared may be either formally published, or it may be a locally defined method of classifiying information. There are two methods to define and reference a classification system: - Including the classification system structure within the dataset: Here a hierarchical tree of IfcClassificationReference's is included that defines the classification system including the relationship between the classification items. The ReferencedSource attribute of IfcClassificationReference links the classification item to the parent item, and the parent item finally to the IfcClassification. - Referencing the classification system by a classification key or id: Here the IfcClassificationReference is used to assign a classification id or key as Identification attribute and it may link by ReferencedSource attribute directly to the IfcClassification.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifcclassification.htm"
     },
     "IfcClassificationReference": {
@@ -976,15 +976,15 @@
             "ReferencedSource": "The classification system or source that is referenced.",
             "Sort": "Optional identifier to sort the set of classification references within the referenced source (either a classification facet of higher level, or the classification system itself)."
         },
-        "description": "An IfcClassificationReference is a reference into a classification system or source (see IfcClassification) for a specific classification key (or notation).",
+        "description": "An IfcClassificationReference is a reference into a classification system or source (see IfcClassification) for a specific classification key (or notation). The inherited attributes have the following meaning: - Identification: holds the key provided for a specific references to classification items (or tables). - Name: allows for a human interpretable designation of a classification notation. - Location: optionally holds a direct URI link into the classification system (or source) to hyperlink the classification key. The IfcClassificationReference can either be assigned directly to the IfcClassification, such as if no classification hierarchy has to be included, or it references the parent classification notation, if the fully classification hierarchy is included in the data set. The first is refered to as \"lightweight classification\", and the second as \"full classification\". The attribute ReferencedSource then holds the following information (choice by IfcClassificationReferenceSelect): - being of type IfcClassification: direct reference to the classification system (with meta information provided); - being of type IfcClassificationReference: reference to the parent classification notation within the classification hierarchy.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifcclassificationreference.htm"
     },
     "IfcClosedShell": {
-        "description": "",
+        "description": "Informal Propositions: - Every edge shall be referenced exactly twice by the loops of the face. - Each oriented edge shall be unique. - No edge shall be referenced by more than two faces. - Distinct faces of the shell do not intersect, but may share edges or vertices. - Distinct edges do not intersect but may share vertices. - Each face reference shall be unique. - The loops of the shell shall not be a mixture of poly loop and other loop types. Note: this is given, since only poly loop is defined as face bound definition. - The closed shell shall be an oriented arcwise connected 2-manifold. - The Euler equation shall be satisfied. Note: Please refer to ISO 10303-42 for the equation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcclosedshell.htm"
     },
     "IfcCoil": {
-        "description": "A coil is a device used to provide heat transfer between non-mixing media. A common example is a cooling coil, which utilizes a finned coil in which circulates chilled water, antifreeze, or refrigerant that is used to remove heat from air moving across the surface of the coil. A coil may be used either for heating or cooling purposes by placing a series of tubes (the coil) carrying a heating or cooling fluid into an airstream. The coil may be constructed from tubes bundled in a serpentine form or from finned tubes that give a extended heat transfer surface.",
+        "description": "A coil is a device used to provide heat transfer between non-mixing media. A common example is a cooling coil, which utilizes a finned coil in which circulates chilled water, antifreeze, or refrigerant that is used to remove heat from air moving across the surface of the coil. A coil may be used either for heating or cooling purposes by placing a series of tubes (the coil) carrying a heating or cooling fluid into an airstream. The coil may be constructed from tubes bundled in a serpentine form or from finned tubes that give a extended heat transfer surface. Coils may also be used for non-airflow cases such as embedded in a floor slab.",
         "predefined_types": {
             "DXCOOLINGCOIL": "Cooling coil using a refrigerant to cool the air stream directly.",
             "ELECTRICHEATINGCOIL": "Heating coil using electricity as a heating source.",
@@ -999,7 +999,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifccoil.htm"
     },
     "IfcCoilType": {
-        "description": "The energy conversion device type IfcCoilType defines commonly shared information for occurrences of coils. The set of shared information may include:",
+        "description": "The energy conversion device type IfcCoilType defines commonly shared information for occurrences of coils. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a coil type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCoilType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCoilType are represented by instances of IfcCoil. Refer to the documentation at IfcCoil for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "DXCOOLINGCOIL": "Cooling coil using a refrigerant to cool the air stream directly.",
             "ELECTRICHEATINGCOIL": "Heating coil using electricity as a heating source.",
@@ -1026,7 +1026,7 @@
         "attributes": {
             "ColourList": "List of colours defined by the red, green, blue components. All values are provided as a ratio of 0.0 \u2264 _value_ \u2264 1.0. When using 8bit for each colour channel, a value of 0.0 equals 0, a value of 1.0 equals 255, and values between are interpolated."
         },
-        "description": "The IfcColourRgbList defines an ordered collection of RGB colour values. Each colour value is a fixed list of three colour components (red, green, blue). The attribute ColourList is a two-dimensional list, where:",
+        "description": "The IfcColourRgbList defines an ordered collection of RGB colour values. Each colour value is a fixed list of three colour components (red, green, blue). The attribute ColourList is a two-dimensional list, where: - first dimension is an unbounded list representing each colour value; - second dimension is a fixed list of four list members, where [1] is the red component, [2] the green component, and [3] the blue component.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifccolourrgblist.htm"
     },
     "IfcColourSpecification": {
@@ -1037,7 +1037,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifccolourspecification.htm"
     },
     "IfcColumn": {
-        "description": "<An IfcColumn is a vertical structural member which often is aligned with a structural grid intersection. It represents a vertical, or nearly vertical, structural member that transmits, through compression, the weight of the structure above to other structural elements below. It represents such a member from an architectural point of view. It is not required to be load bearing.",
+        "description": "<An IfcColumn is a vertical structural member which often is aligned with a structural grid intersection. It represents a vertical, or nearly vertical, structural member that transmits, through compression, the weight of the structure above to other structural elements below. It represents such a member from an architectural point of view. It is not required to be load bearing. There are two main representations for column occurrences: - IfcColumn with IfcMaterialProfileSetUsage is used for all occurrences of columns, that have a profile defined that is swept along a directrix. The profile might be changed uniformly by a taper definition along the directrix. The profile parameter and its cardinal point of insertion can be fully described by the IfcMaterialProfileSetUsage. These columns are always represented geometricly by an 'Axis' and a 'SweptSolid' or 'AdvancedSweptSolid' shape representation (or by a 'Clipping' geometry based on the swept solid), if a 3D geometric representation is assigned. NOTE The entity IfcColumnStandardCase has been deprecated, IfcColumn with IfcMaterialProfileSetUsage is used instead. - IfcColumn is used for all other occurrences of columns, particularly for columns with changing profile sizes along the extrusion, or columns defined by non-linear extrusion, or columns having only 'Brep', or 'SurfaceModel' geometry, or if a more parametric representation is not intended.",
         "predefined_types": {
             "COLUMN": "A standard member usually vertical and requiring resistance to vertical forces by compression but also sometimes to lateral forces.",
             "NOTDEFINED": "Undefined linear element.",
@@ -1047,11 +1047,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifccolumn.htm"
     },
     "IfcColumnStandardCase": {
-        "description": "The standard column, IfcColumnStandardCase, defines a column with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcColumnStandardCase handles all cases of columns, that:",
+        "description": "The standard column, IfcColumnStandardCase, defines a column with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcColumnStandardCase handles all cases of columns, that: - have a reference to the IfcMaterialProfileSetUsage defining the material profile association of the column with the cardinal point of its insertion relative to the local placement. - are based on a sweep of a planar profile, or set of profiles, as defined by the IfcMaterialProfileSet - have an 'Axis' shape representation with constraints provided below in the geometry use definition - have a 'Body' shape representation with constraints provided below in the geometry use definition - have a start profile, or set of profiles, that is swept along the directrix and might be changed uniformly by a taper definition - are consistent in using the correct cardinal point offset of the profile as compared to the 'Axis' and 'Body' shape representation - are extruded perpendicular to the profile definition plane - NOTE View definitions and implementer agreements may further constrain the applicable geometry types, e.g. by excluding tapering from an IfcBeamStandardCase implementation. Geometric Representations The geometric representation of IfcColumnStandardCase is defined using the following multiple shape representations for its definition: - Axis: A three-dimensional open curve (subtype of IfcBoundedCurve) defining the axis for the standard column. The cardinal point is determined by the column axis. - Body: A Swept Solid Representation or a CSG representation defining the 3D shape of the standard column.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifccolumnstandardcase.htm"
     },
     "IfcColumnType": {
-        "description": "The element type IfcColumnType defines commonly shared information for occurrences of columns. The set of shared information may include:",
+        "description": "The element type IfcColumnType defines commonly shared information for occurrences of columns. The set of shared information may include: - common properties within shared property sets - common material information - common profile definitions - common shape representations It is used to define a column specification, or column style (i.e. the specific product information that is common to all occurrences of that column type). Column types may be exchanged without being already assigned to occurrences. Occurrences of the IfcColumnType within building models are represented by instances of IfcColumnStandardCase if the IfcColumnType has a single associated IfcMaterialProfileSet; otherwise they are represented by instances of IfcColumn. Occurrences of the IfcColumnType within structural analysis models are represented by instances of IfcStructuralCurveMember, or its applicable subtypes.",
         "predefined_types": {
             "COLUMN": "A standard member usually vertical and requiring resistance to vertical forces by compression but also sometimes to lateral forces.",
             "NOTDEFINED": "Undefined linear element.",
@@ -1061,7 +1061,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifccolumntype.htm"
     },
     "IfcCommunicationsAppliance": {
-        "description": "A communications appliance transmits and receives electronic or digital information as data or sound.",
+        "description": "A communications appliance transmits and receives electronic or digital information as data or sound. Communication appliances may be fixed in place or may be able to be moved from one space to another. Communication appliances require an electrical supply that may be supplied either by an electrical circuit or provided from a local battery source.",
         "predefined_types": {
             "ANTENNA": "A transducer designed to transmit or receive electromagnetic waves.",
             "COMPUTER": "A desktop, laptop, tablet, or other type of computer that can be moved from one place to another and connected to an electrical supply via a plugged outlet.",
@@ -1081,7 +1081,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifccommunicationsappliance.htm"
     },
     "IfcCommunicationsApplianceType": {
-        "description": "The flow terminal type IfcCommunicationsApplianceType defines commonly shared information for occurrences of communications appliances. The set of shared information may include:",
+        "description": "The flow terminal type IfcCommunicationsApplianceType defines commonly shared information for occurrences of communications appliances. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a communications appliance type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCommunicationsApplianceType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCommunicationsApplianceType are represented by instances of IfcCommunicationsAppliance. Refer to the documentation at IfcCommunicationsAppliance for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "ANTENNA": "A transducer designed to transmit or receive electromagnetic waves.",
             "COMPUTER": "A desktop, laptop, tablet, or other type of computer that can be moved from one place to another and connected to an electrical supply via a plugged outlet.",
@@ -1124,7 +1124,7 @@
             "Segments": "The component bounded curves, their transitions and senses. The transition attribute for the last segment defines the transition between the end of the last segment and the start of the first; this transition attribute may take the value discontinuous, which indicates an open curve.",
             "SelfIntersect": "Indication of whether the curve intersects itself or not; this is for information only."
         },
-        "description": "An IfcCompositeCurve is a continuous curve composed of curve segments.",
+        "description": "An IfcCompositeCurve is a continuous curve composed of curve segments. Figure 1 illustrates an example of a composite curve. Consider an IfcCompositeCurve having line segment and an arc segment. The line should be parameterized: - IfcPolyline with start= 0.,0. end= 0.,1., SameSense= TRUE, parametric length = 1. The arch should be parameterized: - IfcTrimmedCurve with start= 180', end= 90', SameSense= FALSE, parametric length = 90. Then the parameterization of the composite curve is: - IfcCompositeCurve with 0. \u2264 T \u2264 1. (line segment) and 1. \u2264 T \u2264 91. (arc segment), parametric length = 91. Informal Propositions: - The SameSense attribute of each segment correctly specifies the senses of the component curves. When traversed in the direction indicated by SameSense, the segments shall join end-to-end.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifccompositecurve.htm"
     },
     "IfcCompositeCurveOnSurface": {
@@ -1150,7 +1150,7 @@
             "Label": "The name by which the composition may be referred to. The actual meaning of the name has to be defined in the context of applications.",
             "Profiles": "The profiles which are used to define the composite profile."
         },
-        "description": "The IfcCompositeProfileDef defines the profile by composition of other profiles. The composition is given by a set of at least two other profile definitions. Any profile definition (except for another composite profile) can be used to construct the composite.",
+        "description": "The IfcCompositeProfileDef defines the profile by composition of other profiles. The composition is given by a set of at least two other profile definitions. Any profile definition (except for another composite profile) can be used to construct the composite. Figure 314 illustrates the composite profile definition. The IfcCompositeProfileDef does not define an own position coordinate system, it is directly defined in the underlying coordinate system. The underlying coordinate system is defined by the swept surface or swept area solid that uses the profile definition. It is the xy plane of either: - IfcSweptSurface.Position - IfcSweptAreaSolid.Position Or in case of sectioned spines it is the xy plane of each list member of IfcSectionedSpine.CrossSectionPositions. The IfcCompositeProfileDef is defined using other profile definitions. Those other profile definitions are directly inserted into the underlying coordinate system. - In case of parameterized profile definitions, the Position attribute of those standard profiles is used to place the profiles relatively to each other. - In case of arbitrary profile definitions, each Cartesian coordinate is given directly within the underlying coordinate system. Twin profiles special case If twin profiles are modeled by profile composition, the base profile should only be specified once. It is then included into the composite profile directly and additionally indirectly via IfcMirroredProfileDef. For example, a double angle made of two L100x10 with 10mm air gap between them, i.e. a | | shape, can be modeled as",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifccompositeprofiledef.htm"
     },
     "IfcCompressor": {
@@ -1177,7 +1177,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifccompressor.htm"
     },
     "IfcCompressorType": {
-        "description": "The flow moving device type IfcCompressorType defines commonly shared information for occurrences of compressors. The set of shared information may include:",
+        "description": "The flow moving device type IfcCompressorType defines commonly shared information for occurrences of compressors. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a compressor type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCompressorType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCompressorType are represented by instances of IfcCompressor. Refer to the documentation at IfcCompressor for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BOOSTER": "Positive-displacement reciprocating compressor where pressure is increased by a booster.",
             "DYNAMIC": "The pressure of refrigerant vapor is increased by a continuous transfer of angular momentum from a rotating member to the vapor followed by conversion of this momentum into static pressure.",
@@ -1215,7 +1215,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifccondenser.htm"
     },
     "IfcCondenserType": {
-        "description": "The energy conversion device type IfcCondenserType defines commonly shared information for occurrences of condensers. The set of shared information may include:",
+        "description": "The energy conversion device type IfcCondenserType defines commonly shared information for occurrences of condensers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a condenser type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCondenserType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCondenserType are represented by instances of IfcCondenser. Refer to the documentation at IfcCondenser for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "AIRCOOLED": "A condenser in which heat is transferred to an air-stream.",
             "EVAPORATIVECOOLED": "A condenser that is cooled evaporatively.",
@@ -1240,7 +1240,7 @@
         "attributes": {
             "CfsFaces": "The set of faces arcwise connected along common edges or vertices."
         },
-        "description": "",
+        "description": "Informal Propositions: - The union of the domains of the faces and their bounding loops shall be arcwise connected.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcconnectedfaceset.htm"
     },
     "IfcConnectionCurveGeometry": {
@@ -1248,11 +1248,11 @@
             "CurveOnRelatedElement": "The bounded curve at which the connected objects are aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.",
             "CurveOnRelatingElement": "The bounded curve at which the connected objects are aligned at the relating element, given in the LCS of the relating element."
         },
-        "description": "IfcConnectionCurveGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a curve or at an edge with curve geometry associated. It is envisioned as a control that applies to the element connection relationships.",
+        "description": "IfcConnectionCurveGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a curve or at an edge with curve geometry associated. It is envisioned as a control that applies to the element connection relationships. The IfcCurve (or the IfcEdgeCurve with an associated IfcCurve) at the CurveOnRelatingElement attribute defines the curve where the basic geometry items of the connected elements connects. The curve geometry and coordinates are provided within the local coordinate system of the RelatingElement, as specified at the IfcRelConnects subtype that utilizes the IfcConnectionCurveGeometry. Optionally, the same curve geometry and coordinates can also be provided within the local coordinate system of the RelatedElement by using the CurveOnRelatedElement attribute. The available geometry for the connection constraint may be further restricted to only allow straight segments by applying IfcPolyline only. Such an usage constraint is provided at the object definition of the IfcElement subtype, utilizing the element connection by referring to the subtype of IfcRelConnects with the associated IfcConnectionCurveGeometry.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcconnectioncurvegeometry.htm"
     },
     "IfcConnectionGeometry": {
-        "description": "IfcConnectionGeometry is used to describe the geometric and topological constraints that facilitate the physical connection of two objects. It is envisioned as a control that applies to the element connection relationships.",
+        "description": "IfcConnectionGeometry is used to describe the geometric and topological constraints that facilitate the physical connection of two objects. It is envisioned as a control that applies to the element connection relationships. The IfcConnectionGeometry allows for the provision of connection constraints between geometric and topological elements, the following connection geometry/topology types are in scope: - point | vertex point, - curve | edge curve, - surface | face surface,",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcconnectiongeometry.htm"
     },
     "IfcConnectionPointEccentricity": {
@@ -1261,7 +1261,7 @@
             "EccentricityInY": "Distance in y direction between the two points (or vertex points) engaged in the point connection.",
             "EccentricityInZ": "Distance in z direction between the two points (or vertex points) engaged in the point connection."
         },
-        "description": "IfcConnectionPointEccentricity is used to describe the geometric constraints that facilitate the physical connection of two objects at a point or vertex point with associated point coordinates. There is a physical distance, or eccentricity, etween the connection points of both object. The eccentricity can be either given by:",
+        "description": "IfcConnectionPointEccentricity is used to describe the geometric constraints that facilitate the physical connection of two objects at a point or vertex point with associated point coordinates. There is a physical distance, or eccentricity, etween the connection points of both object. The eccentricity can be either given by: - providing the PointOnRelatingElement and the PointOnRelatedElement, where both point coordinates are not identical within a common parent coordinate system (latestly within the world coordinate system), - providing the PointOnRelatingElement and the three distance measures, EccentricityInX, EccentricityInY, and EccentricityInZ (or only EccentricityInX, and EccentricityInY if the underlying coordinate system is two-dimensional), or - providing both. The IfcPoint (or the IfcVertexPoint with an associated IfcPoint) at the PointOnRelatingElement attribute defines the point where the basic geometry items of the connected elements connects. The point coordinates are provided within the local coordinate system of the RelatingElement, as specified at the IfcRelConnects subtype that utilizes the IfcConnectionPointGeometry. Optionally, the same point coordinates can also be provided within the local coordinate system of the RelatedElement by using the PointOnRelatedElement attribute, otherwise the distance to the point at the RelatedElement has to be given by the three eccentricity values. The explicit values for EccentricityInX, EccentricityInY, and EccentricityInZ are always measured in the following direction and coordinate system (defining when the value is positive or negative): - from the PointOnRelatedElement to PointOnRelatingElement within the coordinate system of the RelatingElement. - in addition: when used to specify connections in structural analysis models, the IfcStructuralMember is to be used as the RelatingElement of the relationship object utilizing IfcConnectionPointEccentricity, and the IfcStructuralConnection is the RelatedElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcconnectionpointeccentricity.htm"
     },
     "IfcConnectionPointGeometry": {
@@ -1269,7 +1269,7 @@
             "PointOnRelatedElement": "Point at which connected objects are aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.",
             "PointOnRelatingElement": "Point at which the connected object is aligned at the relating element, given in the LCS of the relating element."
         },
-        "description": "IfcConnectionPointGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a point (here IfcCartesianPoint) or at an vertex with point coordinates associated. It is envisioned as a control that applies to the element connection relationships.",
+        "description": "IfcConnectionPointGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a point (here IfcCartesianPoint) or at an vertex with point coordinates associated. It is envisioned as a control that applies to the element connection relationships. The IfcPoint (or the IfcVertexPoint with an associated IfcPoint) at the PointOnRelatingElement attribute defines the point where the basic geometry items of the connected elements connect. The point coordinates are provided within the local coordinate system of the RelatingElement, as specified at the IfcRelConnectsSubtype that utilizes the IfcConnectionPointGeometry. Optionally, the same point coordinates can also be provided within the local coordinate system of the RelatedElement by using the PointOnRelatedElement attribute. If both point coordinates are not identical within a common parent coordinate system (ultimately within the world coordinate system), the subtype IfcConnectionPointEccentricity shall be used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcconnectionpointgeometry.htm"
     },
     "IfcConnectionSurfaceGeometry": {
@@ -1277,7 +1277,7 @@
             "SurfaceOnRelatedElement": "Surface at which the relating element is aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.",
             "SurfaceOnRelatingElement": "Surface at which related object is aligned at the relating element, given in the LCS of the relating element."
         },
-        "description": "IfcConnectionSurfaceGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a surface or at a face with surface geometry associated. It is envisioned as a control that applies to the element connection relationships.",
+        "description": "IfcConnectionSurfaceGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a surface or at a face with surface geometry associated. It is envisioned as a control that applies to the element connection relationships. The IfcSurface (or the IfcFaceSurface with an associated IfcSurface) at the SurfaceOnRelatingElement attribute defines the surface where the basic geometry items of the connected elements connects. The surface geometry and coordinates are provided within the local coordinate system of the RelatingElement, as specified at the IfcRelConnectsSubtype that utilizes the IfcConnectionSurfaceGeometry. Optionally, the same surface geometry and coordinates can also be provided within the local coordinate system of the RelatedElement by using the SurfaceOnRelatedElement attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcconnectionsurfacegeometry.htm"
     },
     "IfcConnectionVolumeGeometry": {
@@ -1285,7 +1285,7 @@
             "VolumeOnRelatedElement": "Volume at which related object overlaps with the relating element, given in the LCS of the related element.",
             "VolumeOnRelatingElement": "Volume at which related object overlaps with the relating element, given in the LCS of the relating element."
         },
-        "description": "IfcConnectionVolumeGeometry is used to describe the geometric constraints that facilitate the physical connection (or overlap) of two objects at a volume defined by a solid or closed shell. It is envisioned as a control that applies to the element connection or interference relationships.",
+        "description": "IfcConnectionVolumeGeometry is used to describe the geometric constraints that facilitate the physical connection (or overlap) of two objects at a volume defined by a solid or closed shell. It is envisioned as a control that applies to the element connection or interference relationships. The IfcSolidModel (or the IfcClosedShell) at the VolumeOnRelatingElement attribute defines the volume where the basic geometry items of the interfering elements overlap. The volume geometry and coordinates are provided within the local coordinate system of the RelatingElement, as specified at the subtypes of the relationship IfcRelConnects that utilizes the IfcConnectionSurfaceGeometry. Optionally, the same volume geometry and coordinates can also be provided within the local coordinate system of the RelatedElement by using the VolumeOnRelatedElement attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcconnectionvolumegeometry.htm"
     },
     "IfcConstraint": {
@@ -1300,11 +1300,11 @@
             "PropertiesForConstraint": "Reference to the properties to which the constraint is applied.",
             "UserDefinedGrade": "Allows for specification of user defined grade of the constraint  beyond the enumeration values (hard, soft, advisory) provided by ConstraintGrade attribute of type _IfcConstraintEnum_.  When a value is provided for attribute UserDefinedGrade in parallel the attribute ConstraintGrade shall have enumeration value USERDEFINED."
         },
-        "description": "An IfcConstraint is used to define a constraint or limiting value or boundary condition that may be applied to an object or to the value of a property.",
+        "description": "An IfcConstraint is used to define a constraint or limiting value or boundary condition that may be applied to an object or to the value of a property. Constraints may be subdivided into user-defined constraints and system-defined constraints. User-defined constraints are applied by a user and are restricted to high-level definitions such as object properties. System-defined constraints may apply to any object attribute, are typically defined by an application to enforce data validation or parametric behavior, and are intended to be enforced by applications but not to be directly editable by an end-user. IfcConstraint may be associated with any subtype of IfcObjectDefinition or IfcPropertyDefinition through the IfcRelAssociatesConstraint relationship to indicate a system-defined constraint, or may be associated with IfcResourceObjectSelect (such as IfcPropertySingleValue) by IfcResourceConstraintRelationship to indicate a user-defined constraint. A constraint must have a name applied through the IfcConstraint.Name attribute and optionally, a description through IfcConstraint.Description. The grade of the constraint (hard, soft, advisory) must be specified through IfcConstraint.ConstraintGrade or IfcConstraint.UserDefinedGrade whilst the source, creating actor and time at which the constraint is created may be optionally asserted through IfcConstraint.ConstraintSource, IfcConstraint.CreatingActor and IfcConstraint.CreationTime. A constraint may also have additional external information (such as classification or document information) associated to it by IfcExternalReferenceRelationship, accessible through inverse attribute IfcConstraint.HasExternalReferences",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstraintresource/lexical/ifcconstraint.htm"
     },
     "IfcConstructionEquipmentResource": {
-        "description": "IfcConstructionEquipmentResource is usage of construction equipment to assist in the performance of construction. Construction Equipment resources are wholly or partially consumed or occupied in the performance of construction.",
+        "description": "IfcConstructionEquipmentResource is usage of construction equipment to assist in the performance of construction. Construction Equipment resources are wholly or partially consumed or occupied in the performance of construction. Occurrences of IfcConstructionEquipmentResource are products that are used as resources to assist the process of construction. More specifically, they are products that are standalone items brought to a project to fulfil a particular purpose. Examples might be a tower crane or other mobile crane, a screwing machine, or a lifting hoist. Instances of any subtype of IfcProduct may be assigned to the equipment resource using IfcRelAssignsToResource in order to characterize the equipment further, as described at the supertype IfcResource. Examples of relevant subtypes of IfcProduct are IfcTransportElement, IfcDiscreteAccessory, or IfcProxy (for particular cases where more precise usage details are not available)",
         "predefined_types": {
             "DEMOLISHING": "Removal or destruction of building elements.",
             "EARTHMOVING": "Excavating, filling, or contouring earth.",
@@ -1320,7 +1320,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifcconstructionequipmentresource.htm"
     },
     "IfcConstructionEquipmentResourceType": {
-        "description": "The resource type IfcConstructionEquipmentType defines commonly shared information for occurrences of construction equipment resources. The set of shared information may include:",
+        "description": "The resource type IfcConstructionEquipmentType defines commonly shared information for occurrences of construction equipment resources. The set of shared information may include: - common productivities - common cost rates - common properties within shared property sets It is used to define a construction equipment resource specification (the specific resource information that is common to all occurrences of that resource). Resource types may be exchanged without being already assigned to occurrences. Occurrences of the IfcConstructionEquipmentResourceType are represented by instances of IfcConstructionEquipmentResource. Assignment use definition In addition to assignments specified at the base class IfcConstructionResourceType, a construction equipment resource type may have assignments of its own using IfcRelAssignsToResource where RelatingResource refers to the IfcConstructionEquipmentResourceType and RelatedObjects contains one or more IfcTypeProduct subtypes. Such relationship indicates the type of equipment to be used as input, which is instantiated as an occurrence assigned for each resource occurrence. There may be multiple chains of production where such product type may have its own task and resource types assigned indicating how to assemble such equipment.",
         "predefined_types": {
             "DEMOLISHING": "Removal or destruction of building elements.",
             "EARTHMOVING": "Excavating, filling, or contouring earth.",
@@ -1336,7 +1336,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifcconstructionequipmentresourcetype.htm"
     },
     "IfcConstructionMaterialResource": {
-        "description": "IfcConstructionMaterialResource identifies a material resource type in a construction project.",
+        "description": "IfcConstructionMaterialResource identifies a material resource type in a construction project. Occurrences of IfcConstructionMaterialResource are consumed (wholly or partially), or occupied during a construction work task (IfcTask). Similar to IfcConstructionProductResource, sometimes things such as 5000kg of gravel are already instantiated as an instance of an IfcProduct subtype because it is a result of a work task (for example, \u2018transporting gravel\u2019). In this case, the instance of IfcConstructionMaterialResource can be associated with the product instance \u20185000kg of gravel\u2019 to provide more information for resource uses. Nevertheless, IfcConstructionMaterialResource should only be used to represent resource usage, but not product substances.",
         "predefined_types": {
             "AGGREGATES": "Construction aggregate including sand, gravel, and crushed stone.",
             "CONCRETE": "Cast-in-place concrete.",
@@ -1353,7 +1353,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifcconstructionmaterialresource.htm"
     },
     "IfcConstructionMaterialResourceType": {
-        "description": "The resource type IfcConstructionMaterialType defines commonly shared information for occurrences of construction material resources. The set of shared information may include:",
+        "description": "The resource type IfcConstructionMaterialType defines commonly shared information for occurrences of construction material resources. The set of shared information may include: - common productivities - common cost rates - common properties within shared property sets It is used to define a construction material resource specification (the specific resource information that is common to all occurrences of that resource). Resource types may be exchanged without being already assigned to occurrences. Occurrences of the IfcConstructionMaterialResourceType are represented by instances of IfcConstructionMaterialResource. Assignment Use Definition In addition to assignments specified at the base class IfcConstructionResourceType, a construction material resource type may have assignments of its own using IfcRelAssignsToResource where RelatingResource refers to the IfcConstructionMaterialResourceType and RelatedObjects contains one or more IfcTypeProduct subtypes. Such relationship indicates material specifications to be used as input, which is instantiated as an occurrence assigned for each resource occurrence. The IfcGeographicElementType product type may be used to hold the material representation (via IfcRelAssociatesMaterial. There may be multiple chains of production where such product type may have its own task and resource types assigned indicating how to transport or extract such material.",
         "predefined_types": {
             "AGGREGATES": "Construction aggregate including sand, gravel, and crushed stone.",
             "CONCRETE": "Cast-in-place concrete.",
@@ -1370,7 +1370,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifcconstructionmaterialresourcetype.htm"
     },
     "IfcConstructionProductResource": {
-        "description": "IfcConstructionProductResource defines the role of a product that is consumed (wholly or partially), or occupied in the performance of construction.",
+        "description": "IfcConstructionProductResource defines the role of a product that is consumed (wholly or partially), or occupied in the performance of construction. Occurrences of IfcConstructionProductResource are usage of products to assist the process of construction. More specifically, they are usage of products that result from some construction processes and that are then used as resources to facilitate further construction. For instance, formworks can be instantiated as products resulting from the process \u2018constructing formwork\u2019. However, they are used as resources in the process \u2018pouring concrete\u2019 in a later stage of the project.",
         "predefined_types": {
             "ASSEMBLY": "Construction of assemblies for use as input to the building model or other assemblies.",
             "FORMWORK": "Construction or placement of forms for placing materials such as concrete.",
@@ -1380,7 +1380,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifcconstructionproductresource.htm"
     },
     "IfcConstructionProductResourceType": {
-        "description": "The resource type IfcConstructionProductType defines commonly shared information for occurrences of construction product resources. The set of shared information may include:",
+        "description": "The resource type IfcConstructionProductType defines commonly shared information for occurrences of construction product resources. The set of shared information may include: - common productivities - common cost rates - common properties within shared property sets It is used to define a construction product resource specification (i.e. the specific resource information that is common to all occurrences of that resource). Resource types may be exchanged without being already assigned to occurrences. Occurrences of the IfcConstructionProductResourceType are represented by instances of IfcConstructionProductResource. Assignment use definition In addition to assignments specified at the base class IfcConstructionResourceType, a construction product resource type may have assignments of its own using IfcRelAssignsToResource where RelatingResource refers to the IfcConstructionProductResourceType and RelatedObjects contains one or more IfcTypeProduct subtypes. Such relationship indicates the type of product to be used as input, which is instantiated as an occurrence assigned for each resource occurrence. There may be multiple chains of production where such product type may have its own task and resource types assigned.",
         "predefined_types": {
             "ASSEMBLY": "Construction of assemblies for use as input to the building model or other assemblies.",
             "FORMWORK": "Construction or placement of forms for placing materials such as concrete.",
@@ -1395,7 +1395,7 @@
             "BaseQuantity": "Identifies the base quantity consumed of the resource relative to assignments.    For crew, labour, subcontract, and equipment resources, this refers to _IfcQuantityTime_.  For material resources, this refers to _IfcQuantityVolume_.  For product resources, this refers to _IfcQuantityCount_.",
             "Usage": "Indicates the work, usage, and times scheduled and completed.  Some attributes on this object may have associated constraints or time series; see documentation of _IfcResourceTime_ for specific usage.  If the resource is nested, then certain values may be calculated based on the component resources as indicated at _IfcResourceTime_."
         },
-        "description": "IfcConstructionResource is an abstract generalization of the different resources used in construction projects, mainly labour, material, equipment and product resources, plus subcontracted resources and aggregations such as a crew resource.",
+        "description": "IfcConstructionResource is an abstract generalization of the different resources used in construction projects, mainly labour, material, equipment and product resources, plus subcontracted resources and aggregations such as a crew resource. A resource represents \"use of something\" and does not necessarily correspond to a single item such as a person or vehicle, but represents a pool of items having limited availability such as general labor or an equipment fleet. A resource can represent either a generic resource pool (not having any task assignment) or a task-specific resource allocation (having an IfcTask assignment). Declaration use definition A root-level resource (specifically IfcCrewResource or IfcSubContractResource) is declared within the project by IfcRelDeclares where RelatingContext refers to the single IfcProject and RelatedObjects refers to one or more IfcConstructionResource, and other root-level objects within the project. Assignment use definition A resource may be assigned to an actor by IfcRelAssignsToActor where RelatingActor refers to an IfcActor and RelatedObjects refers to one or more IfcConstructionResource or other objects. Such relationship indicates the actor responsible for allocating the resource such as partitioning into task-specific allocations, delegating to other actors, and/or scheduling over time. Note that this assignment does not indicate the person or organization performing the work; that is indicated by IfcRelAssignsToResource. The actor responsible for the resource may or may not be the same as any actor(s) performing work. A resource may be assigned to a control by IfcRelAssignsToControl where RelatingProduct refers to an IfcControl and RelatedObjects refers to one or more IfcConstructionResource or other objects. Most commonly an IfcWorkCalendar is assigned indicating availability of the resource, where such calendar is nested within a base calendar or an IfcWorkPlan which in turn is assigned to the IfcProject. A resource may be assigned to a group by IfcRelAssignsToGroup where RelatingGroup refers to an IfcGroup and RelatedObjects refers to one or more IfcConstructionResource or other objects. Most commonly an IfcAsset is assigned indicating the asset to be tracked, where such asset is nested within an IfcInventory which in turn is assigned to the IfcProject. A resource may be assigned to a product by IfcRelAssignsToProduct where RelatingProduct refers to an IfcProduct and RelatedObjects refers to one or more IfcConstructionResource or other objects. Most commonly an IfcElement subtype is assigned indicating the product to be constructed, where such product is connected to a spatial structure which in turn is aggregated within the IfcProject. A resource may be assigned to a process by IfcRelAssignsToProcess where RelatingProcess refers to an IfcProcess and RelatedObjects refers to one or more IfcConstructionResource or other objects. Most commonly an IfcTask is assigned indicating the task to be performed by the resource, where such task is nested within a summary task which in turn is assigned to the IfcProject. A resource may have assignments of other objects using IfcRelAssignsToResource where RelatingResource refers to the IfcConstructionResource and RelatedObjects refers to one or more objects such as IfcActor or IfcProduct subtypes. This relationship indicates specific objects assigned to fulfill resource usage. Figure 1 illustrates resource assignment. Baseline use definition A resource may have any number of baselines defined using the relationship IfcRelDefinesByObject where RelatingObject is the \"current\" resource and RelatedObjects consists of multiple \"baseline\" resources, each representing a copy of the resource as it existed at an earlier point in time as shown in Figure 185. Each baseline IfcConstructionResource is identified by its nested IfcRelAssignsToControl relationship to an IfcWorkSchedule having PredefinedType=BASELINE, IfcWorkSchedule.CreationDate indicating the date of the baseline, and IfcWorkSchedule.Name indicating the name of the baseline.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifcconstructionresource.htm"
     },
     "IfcConstructionResourceType": {
@@ -1403,7 +1403,7 @@
             "BaseCosts": "Indicates the unit costs and environmental impacts for which accrued amounts should be calculated.  Such unit costs may be split into _Name_ designations (e.g. 'Standard', 'Overtime'), and may contain a hierarchy of cost values that apply at different dates (using _IfcCostValue.ApplicableDate_ and _IfcCostValue.FixedUntilDate_).",
             "BaseQuantity": "Identifies the quantity for which the _BaseQuantityProduced_ applies.  The _Name_ of the _IfcPhysicalQuantity_ identifies the quantity definition being measured, e.g. \"GrossVolume\".  For production-based resources (e.g. carpentry labor), this value refers to quantities on _IfcProduct_(s) to which the assigned _IfcTask_ is assigned.  For duration-based resources (e.g. safety inspector, fuel for equipment), this value refers to quantities that may be assigned to occurrences of the assigned _IfcTaskType_."
         },
-        "description": "IfcConstructionResourceType is an abstract generalization of the different resource types used in construction projects, mainly labor, material, equipment and product resource types, plus subcontracted resource types and aggregations such as a crew resource type.",
+        "description": "IfcConstructionResourceType is an abstract generalization of the different resource types used in construction projects, mainly labor, material, equipment and product resource types, plus subcontracted resource types and aggregations such as a crew resource type. A resource type represents a model of \"use of something\" and does not necessarily correspond to a specific type of object such as a person or vehicle, but represents possible usages of such objects such as general labor or an equipment fleet. A resource type can either represent usage in general (consumption attributes defined but no task type assignment) or a task-specific resource type (production attributes defined and having an IfcTask assignment). A construction resource type captures common productivities and cost rates for applying resources to particular task types. Composition use definition Resource types may be decomposed into nested resource types indicating productivities when applying the resource to specific task types using the IfcRelNests relationship where IfcRelNests.RelatingObject refers to the general resource type and IfcRelNests.RelatedObjects refers to one or more task-specific productivities. For example, an IfcLaborResourceType may be defined for \"Carpenter\" which may have a nested IfcLaborResourceType for \"Carpenter - Wall Framing\" and another nested IfcLaborResourceType for \"Carpenter - Drywall\", each of which may have productivities based according to specific task types (IfcTaskType). Assignment use definition Resource types may be assigned to process types (IfcTypeProcess subtypes) using the IfcRelAssignsToProcess relationship as shown in Figure 1. Such relationship indicates that the resource type applies to the process type for the use indicated (e.g. IfcTaskType.PredefinedType). Such relationship enables a scenario of placing an IfcProduct of a particular IfcTypeProduct, querying for a set of IfcTypeProcess process types for constructing such product (e.g. IfcTaskTypeEnum.CONSTRUCTION), querying each IfcTypeProcess for a set of IfcTypeResource resource types for carrying out the process, and finally choosing an IfcTypeProcess and IfcTypeResource combination resulting in the shortest time for instantiated IfcTask occurrence(s) and/or lowest-cost for instantiated IfcConstructionResource occurrence(s).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifcconstructionresourcetype.htm"
     },
     "IfcContext": {
@@ -1416,7 +1416,7 @@
             "RepresentationContexts": "Context of the representations used within the context. When the context is a project and it includes shape representations for its components, one or several geometric representation contexts need to be included that define e.g. the world coordinate system, the coordinate space dimensions, and/or the precision factor.",
             "UnitsInContext": "Units globally assigned to measure types used within the context."
         },
-        "description": "IfcContext is the generalization of a project context in which objects, type objects, property sets, and properties are defined. The IfcProject as subtype of IfcContext provides the context for all information on a construction project, it may include one or several IfcProjectLibrary's as subtype of IfcContext to register the included libraries for the project. A library of products that is referenced is declared within the IfcProjectLibrary as the context of that library.",
+        "description": "IfcContext is the generalization of a project context in which objects, type objects, property sets, and properties are defined. The IfcProject as subtype of IfcContext provides the context for all information on a construction project, it may include one or several IfcProjectLibrary's as subtype of IfcContext to register the included libraries for the project. A library of products that is referenced is declared within the IfcProjectLibrary as the context of that library. Context definitions can be named, using the inherited Name attribute, which should be a user recognizable key or number for the context. The LongName can add a full name. Further explanations to the context can be given using the inherited Description attribute. A Context is declared by the relationship object IfcRelDeclares that refers to the corresponding objects within the context. More specific relationships are introduced at the level of subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifccontext.htm"
     },
     "IfcContextDependentUnit": {
@@ -1436,7 +1436,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifccontrol.htm"
     },
     "IfcController": {
-        "description": "A controller is a device that monitors inputs and controls outputs within a building automation system.",
+        "description": "A controller is a device that monitors inputs and controls outputs within a building automation system. A controller may be physical (having placement within a spatial structure) or logical (a software interface or aggregated within a programmable physical controller).",
         "predefined_types": {
             "FLOATING": "Output increases or decreases at a constant or accelerating rate.",
             "MULTIPOSITION": "Output is discrete value, can be one of three or more values.",
@@ -1449,7 +1449,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcbuildingcontrolsdomain/lexical/ifccontroller.htm"
     },
     "IfcControllerType": {
-        "description": "The distribution control element type IfcControllerType defines commonly shared information for occurrences of controllers. The set of shared information may include:",
+        "description": "The distribution control element type IfcControllerType defines commonly shared information for occurrences of controllers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a controller type specification indicating the specific product information that is common to all occurrences of that product type. The IfcControllerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcControllerType are represented by instances of IfcController. Refer to the documentation at IfcController for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "FLOATING": "Output increases or decreases at a constant or accelerating rate.",
             "MULTIPOSITION": "Output is discrete value, can be one of three or more values.",
@@ -1474,7 +1474,7 @@
         "attributes": {
             "ConversionOffset": "A positive or negative offset to add after the inherited _ConversionFactor_ was applied."
         },
-        "description": "IfcConversionBasedUnitWithOffset is a unit which is converted from another unit by applying a conversion factor and an offset.",
+        "description": "IfcConversionBasedUnitWithOffset is a unit which is converted from another unit by applying a conversion factor and an offset. Example: The temperature unit Fahrenheit is based on the temperature unit Kelvin as follows: wherein k is an absolute temperature expressed in Kelvin and f is the same temperature in Fahrenheit. The following entity instances provide Fahrenheit as a unit:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcconversionbasedunitwithoffset.htm"
     },
     "IfcCooledBeam": {
@@ -1488,7 +1488,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifccooledbeam.htm"
     },
     "IfcCooledBeamType": {
-        "description": "The energy conversion device type IfcCooledBeamType defines commonly shared information for occurrences of cooled beams. The set of shared information may include:",
+        "description": "The energy conversion device type IfcCooledBeamType defines commonly shared information for occurrences of cooled beams. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a cooled beam type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCooledBeamType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCooledBeamType are represented by instances of IfcCooledBeam. Refer to the documentation at IfcCooledBeam for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "ACTIVE": "An active or ventilated cooled beam provides cooling (and heating) but can also function as an air terminal in a ventilation system.",
             "NOTDEFINED": "Undefined cooled beam type.",
@@ -1509,7 +1509,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifccoolingtower.htm"
     },
     "IfcCoolingTowerType": {
-        "description": "The energy conversion device type IfcCoolingTowerType defines commonly shared information for occurrences of cooling towers. The set of shared information may include:",
+        "description": "The energy conversion device type IfcCoolingTowerType defines commonly shared information for occurrences of cooling towers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a cooling tower type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCoolingTowerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCoolingTowerType are represented by instances of IfcCoolingTower. Refer to the documentation at IfcCoolingTower for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "MECHANICALFORCEDDRAFT": "Air flow is produced by a mechanical device, typically one or more fans, located on the inlet air side of the cooling tower.",
             "MECHANICALINDUCEDDRAFT": "Air flow is produced by a mechanical device, typically one or more fans, located on the air outlet side of the cooling tower.",
@@ -1524,7 +1524,7 @@
             "SourceCRS": "Source coordinate reference system for the operation.",
             "TargetCRS": "Target coordinate reference system for the operation."
         },
-        "description": "The coordinate operation is an abstract supertype to handle any operation (transformation or conversion) between two coordinate reference systems. It is meant to provide expandability for future versions, since currently only the conversion of a local engineering coordinate system into a map coordinate reference system is dealt with by the subtype IfcMapConversion.",
+        "description": "The coordinate operation is an abstract supertype to handle any operation (transformation or conversion) between two coordinate reference systems. It is meant to provide expandability for future versions, since currently only the conversion of a local engineering coordinate system into a map coordinate reference system is dealt with by the subtype IfcMapConversion. By convention, a coordinate operation is given between the SourceCRS being the more local, or child coordinate reference system, and the TargetCRS being the more remote or parent coordinate reference system, in the special case the coordinate operation between the local engineering coordinate system of the construction project and any map or other coordinate reference system.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifccoordinateoperation.htm"
     },
     "IfcCoordinateReferenceSystem": {
@@ -1535,7 +1535,7 @@
             "Name": "Name by which the coordinate reference system is identified. > NOTE  The name shall be taken from the list recognized by the European Petroleum Survey Group EPSG. It should then be qualified by the EPSG name space, for example as 'EPSG:5555'.",
             "VerticalDatum": "Name by which the vertical datum is identified. The vertical datum is associated with the height axis of the coordinate reference system and indicates the reference plane and fundamental point defining the origin of a height system. It needs to be provided, if the _Name_ identifier does not unambiguously define the vertical datum as well and if the coordinate reference system is a 3D reference system."
         },
-        "description": "The IfcCoordinateReferenceSystem is a definition of a coordinate reference system by means of qualified identifiers only. The interpretation of the identifier is expected to be well-known to the receiving software.",
+        "description": "The IfcCoordinateReferenceSystem is a definition of a coordinate reference system by means of qualified identifiers only. The interpretation of the identifier is expected to be well-known to the receiving software. The unambiguous identifier by which the coordinate reference system is know, is stored in the Name attribute. Well defined identifiers include the geodetic and often also the vertical datum. In these cases the GeodeticDatum and the VerticalDatum can be omitted.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifccoordinatereferencesystem.htm"
     },
     "IfcCostItem": {
@@ -1543,7 +1543,7 @@
             "CostQuantities": "Component quantities of the same type for which the total quantity for the cost item is calculated as the sum.",
             "CostValues": "Component costs for which the total cost for the cost item is calculated, and then multiplied by the total _CostQuantities_ if provided.    If _CostQuantities_ is provided then values indicate unit costs, otherwise values indicate total costs.  For calculation purposes, the cost values may be directly added unless they have qualifications.  Cost values with qualifications (e.g. _IfcCostValue.ApplicableDate_, _IfcCostValue.FixedUntilDate_) should be excluded from such calculation if they do not apply."
         },
-        "description": "An IfcCostItem describes a cost or financial value together with descriptive information that describes its context in a form that enables it to be used within a cost schedule. An IfcCostItem can be used to represent the cost of goods and services, the execution of works by a process, lifecycle cost and more.",
+        "description": "An IfcCostItem describes a cost or financial value together with descriptive information that describes its context in a form that enables it to be used within a cost schedule. An IfcCostItem can be used to represent the cost of goods and services, the execution of works by a process, lifecycle cost and more. Each instance of IfcCostItem may have a name and a description. Depending on the use for which the cost is intended, these values should be asserted on the basis of agreement. For instance, the Name attribute could be used to provide a common value that enables distinct instances to be brought together in a nesting arrangement (see below) while the Description attribute may be used to provide text used for item description in a costing schedule. An IfcCostItem can link one or many IfcCostValue's representing a unit cost, total cost, or a unit cost with one or many quantities used to generate the total cost. The quantities can be given as individual quantities, or those quantities are provided as element quantities by one or many building elements. The IfcCostValue.CostType attribute indicates the category of cost, which may be used to present the value in a particular column. For nested cost items (having IfcRelNests relationship), IfcCostValue.CostType is significant such that IfcCostValue.AppliedValue is calculated as the sum of all nested costs having the same IfcCostValue.CostType or if set to an asterisk ('*'), then the sum of all nested costs of all cost types. An IfcCostValue may represent an original value or a value derived from formulas using IfcAppliedValueRelationship. For example, taxes may be calculated as a percentage of a subtotal.",
         "predefined_types": {
             "NOTDEFINED": "Undefined type.",
             "USERDEFINED": "User-defined type."
@@ -1571,7 +1571,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedmgmtelements/lexical/ifccostschedule.htm"
     },
     "IfcCostValue": {
-        "description": "IfcCostValue is an amount of money or a value that affects an amount of money.",
+        "description": "IfcCostValue is an amount of money or a value that affects an amount of money. Each instance of IfcCostValue may also have a category. There are many possible types of cost value that may be identified. While there is a broad understanding of the meaning of names that may be assigned to different types of costs, there is no general standard for naming cost types nor are there any broadly defined classifications. The following defines some cost categories that might be applied to the Category attribute: - Annual rate of return - Bonus - Bulk purchase rebate - Contract - Consultancy - Delivery - Estimated cost - Hire - Installation - Interest rate - Labor - Lease - List price - Maintenance - Material - Overhead - Postage and packing - Profit - Purchase - Rental - Repair - Replacement - Sale - Small quantity surcharge - Spares - Storage - Sub-Contract - Trade discount - Transportation - Waste allowance - Whole life",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifccostresource/lexical/ifccostvalue.htm"
     },
     "IfcCovering": {
@@ -1579,7 +1579,7 @@
             "CoversElements": "Reference to the objectified relationship that handles the relationship of the covering to the covered element.",
             "CoversSpaces": "Reference to the objectified relationship that handles the relationship of the covering to the covered space."
         },
-        "description": "A covering is an element which covers some part of another element and is fully dependent on that other element. The IfcCovering defines the occurrence of a covering type, that (if given) is expressed by the IfcCoveringType.",
+        "description": "A covering is an element which covers some part of another element and is fully dependent on that other element. The IfcCovering defines the occurrence of a covering type, that (if given) is expressed by the IfcCoveringType. Coverings are elements with relationships to the covered element and the space on the other side, they may contain openings, assigned by IfcRelVoidsElement, material information, assigned by IfcRelAssociatesMaterial, and others. Coverings can be assigned to - a space represented by IfcSpace using the inverse relationship CoversSpaces pointing to IfcRelCoversSpaces. The space is then accessible via IfcRelCoversSpaces.RelatedSpace. It defines to which space a covering is facing towards. - a space boundary represented by IfcRelSpaceBoundary using the inverse relationship ProvidesBoundaries pointing to IfcRelSpaceBoundary. The space is then accessible via IfcRelSpaceBoundary.RelatingSpace. - a building element represented by IfcBuildingElement using the inverse relationship Covers pointing to IfcRelCoversBldgElements. The building element is then accessible via IfcRelCoversBldgElements.RelatingBuildingElement. The following guideline shall apply: - (default) if the space has coverings that may not have their own shape representation and no defined relationships to the building elements they cover, then the IfcCovering shall be assigned to IfcSpace using the IfcRelCoversSpaces relationship, - if the space has coverings that have an own shape representation and the space has defined space boundaries, then the covering, which relates to that space, shall be contained in the space using IfcRelContainedInSpatialStructure. It may be assigned to the space boundaries using the IfcRelSpaceBoundary. - if the covering does not relate to a space, then the covering should be assigned to the building element or a distribution element using the IfcRelCoversBldgElements relationship.",
         "predefined_types": {
             "CEILING": "The covering is used torepresent a ceiling.",
             "CLADDING": "The covering is used to represent a cladding.",
@@ -1597,7 +1597,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifccovering.htm"
     },
     "IfcCoveringType": {
-        "description": "The element type IfcCoveringType defines commonly shared information for occurrences of coverings. The set of shared information may include:",
+        "description": "The element type IfcCoveringType defines commonly shared information for occurrences of coverings. The set of shared information may include: - common properties within shared property sets - common material (layer set) information - common shape representations It is used to define an covering specification or covering style (i.e. the specific product information, that is common to all occurrences of that product type). Covering types may be exchanged without being already assigned to occurrences. The occurrences of the IfcCoveringType are represented by instances of IfcCovering Informal Propositions: - The material assignment, if provided using the IfcRelAssociatesMaterial relationship, shall not reference IfcMaterialLayerSetUsage or IfcMaterialProfileSetUsage.",
         "predefined_types": {
             "CEILING": "The covering is used torepresent a ceiling.",
             "CLADDING": "The covering is used to represent a cladding.",
@@ -1615,7 +1615,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifccoveringtype.htm"
     },
     "IfcCrewResource": {
-        "description": "IfcCrewResource represents a collection of internal resources used in construction processes.",
+        "description": "IfcCrewResource represents a collection of internal resources used in construction processes. Identification of people and equipment of a crew is achieved through their specification at the level of the component. Therefore, knowing which persons are within a crew is achieved through identifying the persons assigned to each IfcLaborResource within the IfcCrewResource. Similarly, identifying that a screwing machine for pipe fitting forms part of the crew is achieved by relating an appropriate instance of IfcElementComponent to the IfcConstructionEquipmentResource forming an element of the IfcCrewResource.",
         "predefined_types": {
             "NOTDEFINED": "Undefined resource.",
             "OFFICE": "A composition of resources performing administration work in an office.",
@@ -1625,7 +1625,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifccrewresource.htm"
     },
     "IfcCrewResourceType": {
-        "description": "The resource type IfcCrewResourceType defines commonly shared information for occurrences of crew resources. The set of shared information may include:",
+        "description": "The resource type IfcCrewResourceType defines commonly shared information for occurrences of crew resources. The set of shared information may include: - common productivities - common cost rates - common properties within shared property sets It is used to define a crew resource specification (the specific resource information that is common to all occurrences of that resource). Resource types may be exchanged without being already assigned to occurrences. Occurrences of the IfcCrewResourceType are represented by instances of IfcCrewResource.",
         "predefined_types": {
             "NOTDEFINED": "Undefined resource.",
             "OFFICE": "A composition of resources performing administration work in an office.",
@@ -1646,7 +1646,7 @@
         "attributes": {
             "TreeRootExpression": "Boolean expression of primitives and regularized operators describing the solid. The root of the tree of Boolean expressions is given explicitly as an _IfcBooleanResult_ entitiy or as a primitive (subtypes of _IfcCsgPrimitive3D_)."
         },
-        "description": "An IfcCsgSolid is the representation of a 3D shape using constructive solid geometry model. It is represented by a single 3D CSG primitive, or as a result of a Boolean operation. The operants of a Boolean operation can be Boolean operations themselves forming a CSG tree. The following volumes can be parts of the CSG tree:",
+        "description": "An IfcCsgSolid is the representation of a 3D shape using constructive solid geometry model. It is represented by a single 3D CSG primitive, or as a result of a Boolean operation. The operants of a Boolean operation can be Boolean operations themselves forming a CSG tree. The following volumes can be parts of the CSG tree: - Boundary representation models, such as IfcFacetedBrep, IfcFacetedBrepWithVoids, - Closed tesselated representation modles, such as IfcPolygonalFaceSet, IfcTriangulatedFaceSet, - Swept area solids, such as IfcExtrudedAreaSolid, IfcRevolvedAreaSolid, and their subtypes for tapering, - Advanced swept area solids, such as IfcSurfaceCurveSweptAreaSolid), IfcFixedReferenceSweptAreaSolid, IfcSweptDiskSolid - Half space solids, such as IfcHalfSpaceSolid and its subtypes), and - CSG primitives, the subtypes of IfcCsgPrimitive3D.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifccsgsolid.htm"
     },
     "IfcCurrencyRelationship": {
@@ -1657,11 +1657,11 @@
             "RelatedMonetaryUnit": "The monetary unit to which an exchange results. For instance, in the case of a conversion from GBP to USD, the related monetary unit is USD.",
             "RelatingMonetaryUnit": "The monetary unit from which an exchange is derived. For instance, in the case of a conversion from GBP to USD, the relating monetary unit is GBP."
         },
-        "description": "IfcCurrencyRelationship defines the rate of exchange that applies between two designated currencies at a particular time and as published by a particular source.",
+        "description": "IfcCurrencyRelationship defines the rate of exchange that applies between two designated currencies at a particular time and as published by a particular source. An IfcCurrencyRelationship is used where there may be a need to reference an IfcCostValue in one currency to an IfcCostValue in another currency. It takes account of fact that currency exchange rates may vary by requiring the recording the date and time of the currency exchange rate used and the source that publishes the rate. There may be many sources and there are different strategies for currency conversion (spot rate, forward buying of currency at a fixed rate). The source for the currency exchange is defined as an instance of IfcLibraryInformation that includes a name and a URL.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifccostresource/lexical/ifccurrencyrelationship.htm"
     },
     "IfcCurtainWall": {
-        "description": "A curtain wall is an exterior wall of a building which is an assembly of components, hung from the edge of the floor/roof structure rather than bearing on a floor. Curtain wall is represented as a building element assembly and implemented as a subtype of IfcBuildingElement that uses an IfcRelAggregates relationship.",
+        "description": "A curtain wall is an exterior wall of a building which is an assembly of components, hung from the edge of the floor/roof structure rather than bearing on a floor. Curtain wall is represented as a building element assembly and implemented as a subtype of IfcBuildingElement that uses an IfcRelAggregates relationship. The geometric representation of IfcCurtainWall is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Independent 'Body' geometric representation, as described below, should only be used when the IfcCurtainWall is not defined as an aggregate. If defined as an aggregate, the geometric representation is the sum of the representations of the components within the aggregate. The geometric representation of IfcCurtainWall is defined using the following multiple shape representations for its definition: - Axis: A two-dimensional open curve (for restrictions see below) defining the axis for the curtain wall. This is an optional representation for curtain walls. - Body: A surface model or boundary representation model representation defining the 3D shape of the curtain wall. If the IfcCurtainWall has components (referenced by SELF\\IfcObject.IsDecomposedBy) then no independent shape representation with RepresentationType = 'Body' shall be defined. The body of IfcCurtainWall is then geometrically represented by the shape representation of its components. The components are accessed via SELF\\IfcObject.IsDecomposedBy[1].RelatedObjects. If the IfcCurtainWall has no components defined (empty set of SELF\\IfcObject.IsDecomposedBy) then the IfcCurtainWall may be represented by an shape representation with the RepresentationIdentifier ='Body'.",
         "predefined_types": {
             "NOTDEFINED": "",
             "USERDEFINED": ""
@@ -1669,7 +1669,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifccurtainwall.htm"
     },
     "IfcCurtainWallType": {
-        "description": "The building element type IfcCurtainWallType defines commonly shared information for occurrences of curtain walls. The set of shared information may include:",
+        "description": "The building element type IfcCurtainWallType defines commonly shared information for occurrences of curtain walls. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a curtain wall type specification indicating the specific product information that is common to all occurrences of that product type. The IfcCurtainWallType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcCurtainWallType are represented by instances of IfcCurtainWall. Refer to the documentation at IfcCurtainWall for supported property sets, materials, and composition.",
         "predefined_types": {
             "NOTDEFINED": "",
             "USERDEFINED": ""
@@ -1680,7 +1680,7 @@
         "attributes": {
             "Dim": "The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve. IfcCurveDim(SELF)"
         },
-        "description": "An IfcCurve is a curve in two-dimensional or three-dimensional space. It includes definitions for bounded and unbounded curves.",
+        "description": "An IfcCurve is a curve in two-dimensional or three-dimensional space. It includes definitions for bounded and unbounded curves. Informal Propositions: - A curve shall be arcwise connected - A curve shall have an arc length greater than zero.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifccurve.htm"
     },
     "IfcCurveBoundedPlane": {
@@ -1689,7 +1689,7 @@
             "InnerBoundaries": "An optional set of inner boundaries. They shall not intersect each other or the outer boundary.",
             "OuterBoundary": "The outer boundary of the surface."
         },
-        "description": "The IfcCurveBoundedPlane is a parametric planar surface with curved boundaries defined by one or more boundary curves. The bounded plane is defined to be the portion of the basis surface in the direction of N x T from any point on the boundary, where N is the surface normal and T the boundary curve tangent vector at this point. The region so defined shall be arcwise connected.",
+        "description": "The IfcCurveBoundedPlane is a parametric planar surface with curved boundaries defined by one or more boundary curves. The bounded plane is defined to be the portion of the basis surface in the direction of N x T from any point on the boundary, where N is the surface normal and T the boundary curve tangent vector at this point. The region so defined shall be arcwise connected. The BasisSurface is an IfcPlane that establishes the position coordinate system by SELF\\IfcElementarySurface.Position. The OuterBoundary and the InnerBoundaries (if provided) shall lie on the surface of IfcPlane. The outer and inner boundary curves shall be defined using the u, and v values provided by parameterization of the BasisSurface as their x, and y coordinate values.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifccurveboundedplane.htm"
     },
     "IfcCurveBoundedSurface": {
@@ -1698,7 +1698,7 @@
             "Boundaries": "The outer boundary of the surface.",
             "ImplicitOuter": ""
         },
-        "description": "The IfcCurveBoundedSurface is a parametric surface with boundaries defined by p-curves, that is, a curve which lies on the basis of a surface and is defined in the parameter space of that surface. The p-curve is a special type of a composite curve segment and shall only be used to bound a surface.",
+        "description": "The IfcCurveBoundedSurface is a parametric surface with boundaries defined by p-curves, that is, a curve which lies on the basis of a surface and is defined in the parameter space of that surface. The p-curve is a special type of a composite curve segment and shall only be used to bound a surface. The outer boundary shall be either defined by: - an IfcOuterBoundaryCurve a closed composite curve on surface for the definition of an outer boundary, in this case the attribute ImplicitOuter has to be set to FALSE, or - an implicit boundary of the bounded surface, e.g. the u1, u2, v1, v2 of IfcRectangularTrimmedSurface, in this case the attribute ImplicitOuter has to be set to TRUE. Informal Propositions: - Each curve in the set of Boundaries shall be closed. - No two curves in the set of Boundaries shall intersect. - At most one of the boundary curves may enclose any other boundary curve. If an IfcOuterBoundaryCurve is designated, only that curve may enclose any other boundary curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifccurveboundedsurface.htm"
     },
     "IfcCurveStyle": {
@@ -1708,7 +1708,7 @@
             "CurveWidth": "A positive length measure in units of the presentation area for the width of a presented curve. If not given, then the style should be taken from the layer assignment with style, if that is not given either, then the default style applies.",
             "ModelOrDraughting": "Indication whether the length measures provided for the presentation style are model based, or draughting based."
         },
-        "description": "An IfcCurveStyle provides the style table for presentation information assigned to geometric curves. The style is defined by a color, a font and a width. The IfcCurveStyle defines curve patterns as model patterns, that is, the distance between visible and invisible segments of curve patterns are given in model space dimensions (that have to be scaled using the target plot scale).",
+        "description": "An IfcCurveStyle provides the style table for presentation information assigned to geometric curves. The style is defined by a color, a font and a width. The IfcCurveStyle defines curve patterns as model patterns, that is, the distance between visible and invisible segments of curve patterns are given in model space dimensions (that have to be scaled using the target plot scale). Styles are intended to be shared by multiple IfcStyledItem's, assigning the style to occurrences of (subtypes of) IfcGeometricRepresentationItem's. Measures given to a font pattern or a curve width are given in global drawing length units. The measure values for font pattern and curve width apply to the model space with a target plot scale provided for the correct appearance in the default plot scale.. For different scale and projection dependent curve styles a different instance of IfcCurveStyle needs to be used by IfcPresentationStyleAssignment for different IfcGeometricRepresentationSubContext dependent representations. An IfcCurveStyle can be assigned to IfcGeometricRepresentationItem's via the IfcPresentationStyleAssignment through an intermediate IfcStyledItem or IfcAnnotationCurveOccurrence.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifccurvestyle.htm"
     },
     "IfcCurveStyleFont": {
@@ -1725,7 +1725,7 @@
             "CurveFontScaling": "The scale factor.",
             "Name": "Name that may be assigned with the scaling of a curve font."
         },
-        "description": "The IfcCurveStyleFontAndScaling allows for the reuse of the same curve style definition in several sizes. The definition of the CurveFontScale is the scaling of a base curve style pattern to be used as a new or derived curve style pattern.",
+        "description": "The IfcCurveStyleFontAndScaling allows for the reuse of the same curve style definition in several sizes. The definition of the CurveFontScale is the scaling of a base curve style pattern to be used as a new or derived curve style pattern. An example for IfcCurveStyleFontAndScaling is the sizing of a basic curve style dash pattern 'dash' (visible 0.01m, invisible 0.005m) into 'dash large' with CurveFontScale = 2 (resulting in visible 0.02m, invisible 0.01m), and into 'dash small' with CurveFontScale = 0.5 (resulting in visible 0.005m, invisible 0.0025m).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifccurvestylefontandscaling.htm"
     },
     "IfcCurveStyleFontPattern": {
@@ -1740,7 +1740,7 @@
         "attributes": {
             "Radius": "The radius of the cylindrical surface."
         },
-        "description": "The cylindrical surface is a surface unbounded in the direction of z. Bounded cylindrical surfaces are defined by using a subtype of IfcBoundedSurface with BasisSurface being a cylindrical surface.",
+        "description": "The cylindrical surface is a surface unbounded in the direction of z. Bounded cylindrical surfaces are defined by using a subtype of IfcBoundedSurface with BasisSurface being a cylindrical surface. The inherited attributes are interpreted as - SELF\\IfcElementarySurface.Position defines the location and orientation of the cylindrical surface. - SELF\\IfcElementarySurface.Position.Location definesd a point on the axis of the cylindrical surface. - SELF\\IfcElementarySurface.Position.P[3] defines the direction of the axis of the cylindrical surface.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifccylindricalsurface.htm"
     },
     "IfcDamper": {
@@ -1763,7 +1763,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcdamper.htm"
     },
     "IfcDamperType": {
-        "description": "The flow controller type IfcDamperType defines commonly shared information for occurrences of dampers. The set of shared information may include:",
+        "description": "The flow controller type IfcDamperType defines commonly shared information for occurrences of dampers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a damper type specification indicating the specific product information that is common to all occurrences of that product type. The IfcDamperType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcDamperType are represented by instances of IfcDamper. Refer to the documentation at IfcDamper for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BACKDRAFTDAMPER": "Damper used for purposes of manually balancing pressure differences.  Commonly operated by mechanical adjustment.",
             "BALANCINGDAMPER": "Backdraft damper used to restrict the movement of air in one direction.  Commonly operated by mechanical spring.",
@@ -1787,7 +1787,7 @@
             "Operator": "Transformation operator applied to the parent profile.",
             "ParentProfile": "The parent profile provides the origin of the transformation."
         },
-        "description": "IfcDerivedProfileDef defines the profile by transformation from the parent profile. The transformation is given by a two dimensional transformation operator. Transformation includes translation, rotation, mirror and scaling. The latter can be uniform or non uniform. The derived profiles may be used to define swept surfaces, swept area solids or sectioned spines.",
+        "description": "IfcDerivedProfileDef defines the profile by transformation from the parent profile. The transformation is given by a two dimensional transformation operator. Transformation includes translation, rotation, mirror and scaling. The latter can be uniform or non uniform. The derived profiles may be used to define swept surfaces, swept area solids or sectioned spines. The transformation effects the position, rotation, mirroring or scale of the profile at the underlying coordinate system, i.e. the coordinate system defined by the swept surface or swept area solid that uses the profile definition. It is the xy plane of either: - IfcSweptSurface.Position - IfcSweptAreaSolid.Position or in case of sectioned spines the xy plane of each list member of IfcSectionedSpine.CrossSectionPositions. The position and potential rotation of the ParentProfile within the underlying coordinate system is taken into consideration before applying the Cartesian transformation operator. Note, if only mirroring is required, IfcMirroredProfileDef should be used instead. Figure 1 illustrates examples of derived profiles.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcderivedprofiledef.htm"
     },
     "IfcDerivedUnit": {
@@ -1841,7 +1841,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedcomponentelements/lexical/ifcdiscreteaccessory.htm"
     },
     "IfcDiscreteAccessoryType": {
-        "description": "The element component type IfcDiscreteAccessoryType defines commonly shared information for occurrences of discrete accessorys. The set of shared information may include:",
+        "description": "The element component type IfcDiscreteAccessoryType defines commonly shared information for occurrences of discrete accessorys. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a discrete accessory type specification indicating the specific product information that is common to all occurrences of that product type. The IfcDiscreteAccessoryType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcDiscreteAccessoryType are represented by instances of IfcDiscreteAccessory. Type Use Definition The exact type information of the IfcDiscreteAccessoryType is given in the PredefinedType attribute, possibly in combination with the ElementType attribute inherited from IfcElementType. Standard ElementType designations are provided for guideline below. The list is not exhaustive and the list of definitions may be extended based on local agreements. Corbels as separate components: - 'Hidden steel corbel': Corbel system made from steel components embedded into the master element. - 'Visible steel corbel': Corbel system made from steel components protruding from the master element. - 'Visible concrete corbel': Corbel system made as a separate precast concrete component added to the master element. Connecting accessories, for example for sandwich wall panels: - 'Diagonal truss connector': A fixing device in truss form with diagonal cross bars holding two precast conrete panels together in a sandwich wall panel. - 'Ladder truss connector': A fixing device in truss form with straight cross bars in ladder form holding two precast conrete panels together in a sandwich wall panel. - 'Panel suspender': A straight fixing device holding two precast conrete panels together in a sandwich wall panel. Electrical accessories for precast concrete elements: - 'Protective plug': Protective plug used in element for protecting electrical accessories during manufacturing, transportation and assembly. Fixing parts: - 'Standard fixing plate': Standard fixing plate. - 'Edge fixing plate': Fixing plate attached to the edge of an element. - 'Corner fixing plate': Fixing plate attached to the corner of an element. - 'Slab fixing plate': Fixing plate for slabs. - 'Channel fixing': Fixing channels, often realized as cast-in channels. - 'Balcony hinge': Accessory supporting and fixing balconies. - 'Frame shoe': Fixing shoe for frames. - 'Thermo frame': Thermo frame. - 'Column shoe': Fixing shoe for columns. - 'Wall shoe': Fixing shoe for walls. - 'Fixing socket': Fixing socket. Joint accessories: - 'Neoprene bearing plate': Rubber plate used as a bearing in, for example, joints between column corbels and beams. - 'Working joint reinforcement': Reinforcement accessory used in working joints. - 'Expansion joint reinforcement': Reinforcement accessory used in expansion joints. - 'Ribbed steel bar extension': Extension accessory made of a ribbed (reinforcement) bar used in joints. - 'Steel pin bolt': Pin bolt used to join together, for example, columns and beams. - 'Concrete dowel': Dowel pin used in joints. - 'Concrete groove': A groove made in a joint. - 'Steel plate': A steel plate used as an accessory in a joint. - 'Wire loop': A joint connector accessory made from a wire loop. - 'Steel loop': A joint connector accessory made from a steel bar loop. - 'Sealing strip': A strip sealing the joint. - 'Sealing compound': Sealing compound protecting and sealing the joint. Lifting accessories: - 'Wire lifting hook': A lifting aid in the form of a wire loop. - 'Steel lifting hook': A lifting aid in the form of a steel bar loop. - 'Lifting socket': A lifting aid in the form of a socket. - 'Steel lifting anchor': A lifting aid in the form of a steel lifting anchor. - 'Lifting hole': A lifting aid in the form of a hole. Accessories mainly used in the building services domain: - 'Antivibration' : An isolating device to prevent other elements to be effected by vibrations. - 'Drop rod' : A length of material providing a hanging support to a bracket. Note that a drop rod is considered to include nuts and washers required for securing. - 'Duct foot' : A base support used to receive a vertical pipe . - 'Framing' : A frame placed around a penetration to prevent scraping against the building surface or structure. - 'Grommet' : An element placed within a penetration that seals the penetration for a particular reason. - 'Rack' : A set of shelving for the purposes of storage that may be freestanding or bolted to a structure. - 'Safety part' : A part, typically installed in vertical shafts at each level, to ensure safety from falling when entering the shaft. - 'Sleeve' : A thin barrier placed between a penetration and a penetrating element. - 'Support section' : A section of material that is used as an intermediate support upon which multiple brackets can be mounted.",
         "predefined_types": {
             "ANCHORPLATE": "An accessory consisting of a steel plate, shear stud connectors or welded-on rebar which is embedded into the surface of a concrete element so that other elements can be welded or bolted onto it later.",
             "BRACKET": "An L-shaped or similarly shaped accessory attached in a corner between elements to hold them together or to carry a secondary element.",
@@ -1852,7 +1852,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedcomponentelements/lexical/ifcdiscreteaccessorytype.htm"
     },
     "IfcDistributionChamberElement": {
-        "description": "A distribution chamber element defines a place at which distribution systems and their constituent elements may be inspected or through which they may travel.",
+        "description": "A distribution chamber element defines a place at which distribution systems and their constituent elements may be inspected or through which they may travel. An IfcDistributionChamberElement is a formed volume used in a distribution system, such as a sump, trench or manhole. Instances of IfcDistributionSystem or IfcDistributionFlowElement may be related to the IfcDistributionChamberElement enabling their location in or at the chamber to be determined.",
         "predefined_types": {
             "FORMEDDUCT": "Space formed in the ground for the passage of pipes, cables, ducts.",
             "INSPECTIONCHAMBER": "Chamber constructed on a drain, sewer or pipeline with a removable cover that permits visble inspection.",
@@ -1868,7 +1868,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcdistributionchamberelement.htm"
     },
     "IfcDistributionChamberElementType": {
-        "description": "The distribution flow element type IfcDistributionChamberElementType defines commonly shared information for occurrences of distribution chamber elements. The set of shared information may include:",
+        "description": "The distribution flow element type IfcDistributionChamberElementType defines commonly shared information for occurrences of distribution chamber elements. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a distribution chamber element type specification indicating the specific product information that is common to all occurrences of that product type. The IfcDistributionChamberElementType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcDistributionChamberElementType are represented by instances of IfcDistributionChamberElement. Refer to the documentation at IfcDistributionChamberElement for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "FORMEDDUCT": "Space formed in the ground for the passage of pipes, cables, ducts.",
             "INSPECTIONCHAMBER": "Chamber constructed on a drain, sewer or pipeline with a removable cover that permits visble inspection.",
@@ -1884,29 +1884,29 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcdistributionchamberelementtype.htm"
     },
     "IfcDistributionCircuit": {
-        "description": "A distribution circuit is a partition of a distribution system that is conditionally switched such as an electrical circuit.",
+        "description": "A distribution circuit is a partition of a distribution system that is conditionally switched such as an electrical circuit. *Composition Use Definition* An IfcDistributionCircuit may aggregate an IfcDistributionSystem using the IfcRelAggregates relationship where RelatingObject refers to the IfcDistributionSystem and RelatedObjects includes one or more IfcDistributionCircuit groups. An IfcDistributionCircuit may be aggregated into sub-circuits using the IfcRelAggregates relationship where RelatingObject refers to the parent IfcDistributionCircuit and RelatedObjects refers to one or more IfcDistributionCircuit sub-circuits. *Assignment Use Definition* An IfcDistributionCircuit should be assigned to an IfcDistributionPort on an IfcFlowController element indicating the host or origination of the system using the IfcRelAssignsToProduct relationship. Each device whose operation is conditional based upon the state of the circuit is assigned to the IfcDistributionCircuit via the IfcRelAssignsToGroup relationship. An IfcDistributionElement may belong to multiple systems or circuits, however only one IfcDistributionSystem or IfcDistributionCircuit of a particular PredefinedType.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcdistributioncircuit.htm"
     },
     "IfcDistributionControlElement": {
         "attributes": {
             "AssignedToFlowElement": "Reference through the relationship object to related distribution flow elements."
         },
-        "description": "The distribution element IfcDistributionControlElement defines occurrence elements of a building automation control system that are used to impart control over elements of a distribution system.",
+        "description": "The distribution element IfcDistributionControlElement defines occurrence elements of a building automation control system that are used to impart control over elements of a distribution system. IfcDistributionControlElement defines elements of a building automation control system. These are typically used to control distribution system elements to maintain variables such as temperature, humidity, pressure, flow, power, or lighting levels, through the modulation, staging or sequencing of mechanical or electrical devices. The three general functional categories of control elements are as follows: - Impart control over flow control elements (IfcFlowController) in a distribution system such as dampers, valves, or relays, typically through the use of actuation (IfcActuator). - Sensing elements (IfcSensor) that measure changes in the controlled variable such as temperature, humidity, pressure, or flow. - Controllers (IfcController) typically classified according to the control action they seek to perform and generally responsible for making decisions about the elements under control. Since IfcDistributionControlElement and its subtypes typically relate to many different distribution flow elements (IfcDistributionFlowElement), the objectified relationship IfcRelFlowControlElements has been provided to relate control and flow elements as required. The key distinction between IfcDistributionFlowElement and IfcDistributionControlElement is whether it is internal or external to the flow system, respectively. For example, the distinction between IfcFlowMeter (subtype of IfcDistributionFlowElement measuring a flow quantity) and IfcFlowInstrument (subtype of IfcDistributionControlElement measuring a flow quality), is based on this principal. A physical device that connects within the flow system in which it measures (having inlet/outlet pipes for the measured substance) follows the IfcDistributionFlowElement hierarchy (and therefore IfcFlowMeter which measures the flow internally). Otherwise, if it monitors/controls but does not connect inline within the flow system (it is external or is a component of another device), then it follows the IfcDistributionControlElement hierarchy (and therefore IfcFlowInstrument which may display various attributes through connected sensors).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcdistributioncontrolelement.htm"
     },
     "IfcDistributionControlElementType": {
-        "description": "The element type IfcDistributionControlElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (the specific product information that is common to all occurrences of that product type).",
+        "description": "The element type IfcDistributionControlElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (the specific product information that is common to all occurrences of that product type). Distribution control element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDistributionControlElementType are represented by instances of IfcDistributionControlElement or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcdistributioncontrolelementtype.htm"
     },
     "IfcDistributionElement": {
         "attributes": {
             "HasPorts": "Reference to the element to port connection relationship. The relationship then refers to the port which is contained in this element."
         },
-        "description": "This IfcDistributionElement is a generalization of all elements that participate in a distribution system. Typical examples of IfcDistributionElement's are (among others):",
+        "description": "This IfcDistributionElement is a generalization of all elements that participate in a distribution system. Typical examples of IfcDistributionElement's are (among others): - building service elements within a heating systems - building service elements within a cooling system - building service elements within a ventilation system - building service elements within a plumbing system - electrical elements - elements within a communication network The IfcDistributionElement is further specialized in the IFC specification. Direct instantiation of IfcDistributionElement without an assigned subtype of IfcDistributionElementType provides the meaning of an distribution element proxy.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcdistributionelement.htm"
     },
     "IfcDistributionElementType": {
-        "description": "The IfcDistributionElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The IfcDistributionElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). A distribution element type is used to define the common properties of a certain type of a distribution element that may be applied to many instances of that feature type to assign a specific style. Distribution element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDistributionElementType are represented by instances of IfcDistributionElement (or its subtypes).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcdistributionelementtype.htm"
     },
     "IfcDistributionFlowElement": {
@@ -1917,7 +1917,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcdistributionflowelement.htm"
     },
     "IfcDistributionFlowElementType": {
-        "description": "The element type IfcDistributionFlowElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (the specific product information that is common to all occurrences of that product type).",
+        "description": "The element type IfcDistributionFlowElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (the specific product information that is common to all occurrences of that product type). Distribution flow element types (orthe instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcDistributionFlowElementType are represented by instances of IfcDistributionFlowElement or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcdistributionflowelementtype.htm"
     },
     "IfcDistributionPort": {
@@ -1925,7 +1925,7 @@
             "FlowDirection": "Enumeration that identifies if this port is a Sink (inlet), a Source (outlet) or both a SinkAndSource.",
             "SystemType": "Enumeration that identifies the system type.  If a system type is defined, the port may only be connected to other ports having the same system type."
         },
-        "description": "A distribution port is an inlet or outlet of a product through which a particular substance may flow.",
+        "description": "A distribution port is an inlet or outlet of a product through which a particular substance may flow. Distribution ports are used for passage of solid, liquid, or gas substances, as well as electricity for power or communications. Flow segments (pipes, ducts, cables) may be used to connect ports across products. Distribution ports are defined by system type and flow direction such that for two ports to be connected, they must share the same system type and have opposite flow directions (one side being a SOURCE and the other being a SINK). Ports are similar to openings in that they do not have any visible geometry; such geometry is captured at the shape representation of the enclosing element or element type. Ports may have placement that indicates the position and orientation of the connection. Ports are assigned the distribution systems in order to indicate its role in a particular system, e.g. cold water inlet.",
         "predefined_types": {
             "CABLE": "Connection to cable segment or fitting for distribution of electricity.",
             "CABLECARRIER": "Connection to cable carrier segment or fitting for enclosing cables.",
@@ -1940,7 +1940,7 @@
         "attributes": {
             "LongName": "Long name for a distribution system, used for informal purposes. It should be used, if available, in conjunction with the inherited _Name_ attribute. > NOTE  In many scenarios the _Name_ attribute refers to the short name or number of a distribution system or branch circuit, and the _LongName_ refers to a descriptive name."
         },
-        "description": "A distribution system is a network designed to receive, store, maintain, distribute, or control the flow of a distribution media. A common example is a heating hot water system that consists of a pump, a tank, and an interconnected piping system for distributing hot water to terminals.",
+        "description": "A distribution system is a network designed to receive, store, maintain, distribute, or control the flow of a distribution media. A common example is a heating hot water system that consists of a pump, a tank, and an interconnected piping system for distributing hot water to terminals. The group IfcDistributionSystem defines the occurrence of a specialized system for use within the context of building services. Important functionalities for the description of a distribution system are derived from existing IFC entities: - From IfcSystem it inherits the ability to couple the distribution system via IfcRelServicesBuildings to one or more IfcSpatialElement subtypes as necessary. - From IfcGroup it inherits the inverse attribute IsGroupedBy, pointing to the relationship entity IfcRelAssignsToGroup. This allows to group distribution elements (instances of IfcDistributionElement subtypes), and in special cases ports directly (instances of IfcDistributionPort). - From IfcObject it inherits the inverse attribute IsDecomposedBy pointing to the relationship entity IfcRelAggregates. It provides the hierarchy between the separate (partial) distribution systems. For example, an electrical main circuit may be aggregated into branch circuits.",
         "predefined_types": {
             "AIRCONDITIONING": "Conditioned air distribution system for purposes of maintaining a temperature range within one or more spaces.",
             "AUDIOVISUAL": "A transport of a single media source, having audio and/or video streams.",
@@ -2013,7 +2013,7 @@
             "ValidFrom": "Date when the document becomes valid.",
             "ValidUntil": "Date until which the document remains valid."
         },
-        "description": "IfcDocumentInformation captures \"metadata\" of an external document. The actual content of the document is not defined in this specification; instead, it can be found following the Location attribute.",
+        "description": "IfcDocumentInformation captures \"metadata\" of an external document. The actual content of the document is not defined in this specification; instead, it can be found following the Location attribute. The same IfcDocumentInformation can be referenced from the exchange structure in total or in parts (e.g. by refering to particular chapters or paragraphs) using the IfcDocumentReference. All IfcDocumentReference's that utilize the IfcDocumentInformation are accessible by the inverse relationship HasDocumentReferences.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifcdocumentinformation.htm"
     },
     "IfcDocumentInformationRelationship": {
@@ -2041,7 +2041,7 @@
             "OverallWidth": "Overall measure of the width, it reflects the X Dimension of a bounding box, enclosing the ~~body of the~~ door opening. If omitted, the _OverallWidth_ should be taken from the geometric representation of the _IfcOpening_ in which the door is inserted.     > NOTE  The body of the door might be wider then the door opening (e.g. in cases where the door lining includes a casing). In these cases the _OverallWidth_ shall still be given as the door opening width, and not as the total width of the door lining.",
             "UserDefinedOperationType": "Designator for the user defined operation type, shall only be provided, if the value of _OperationType_ is set to USERDEFINED."
         },
-        "description": "The door is a building element that is predominately used to provide controlled access for people and goods. It includes constructions with hinged, pivoted, sliding, and additionally revolving and folding operations. A door consists of a lining and one or several panels.",
+        "description": "The door is a building element that is predominately used to provide controlled access for people and goods. It includes constructions with hinged, pivoted, sliding, and additionally revolving and folding operations. A door consists of a lining and one or several panels. The IfcDoor defines a particular occurrence of a door inserted in the spatial context of a project. A door can: - be inserted as a filler in an opening using the IfcRelFillsElement relationship, then the IfcDoor has an inverse attribute FillsVoids provided; NOTE Model View Definitions may restrict the relationship to only include one door into one opening - be part of an element assembly, in general an IfcCurtainWall, using the IfcRelAggregates relationship, then the IfcDoor has an inverse attribute Decomposes is provided; - be a \"free standing\" door, then the IfcDoor has no inverse attributes FillsVoids or Decomposes provided. There are two main representations for door occurrences: - IfcDoor with a shape representation having RepresentationIdenfifier='Profile' is used for all occurrences of doors, that have a 'Profile' shape representation defined to which a set of shape parameters for lining and framing properties apply. Additionally it requires the provision of an IfcDoorType that references one IfcDoorLiningProperties and one to many IfcDoorPanelProperties; NOTE The entity IfcDoorStandardCase has been deprecated. - IfcDoor with other shape representations an no assiged IfcDoorLiningProperties and IfcDoorPanelProperties is used for all other occurrences of doors, particularly for doors having only 'Brep', or 'SurfaceModel' geometry without applying shape parameters. The actual parameters of the door and/or its shape are defined by the IfcDoor as the object occurrence definition, or by the IfcDoorType as the object type definition. The following parameters are provided: - at the IfcDoor for occurrence specific parameters. The IfcDoor specifies: - the door width and height the door opening direction (by the y-axis of the ObjectPlacement)* at the IfcDoorType, to which the IfcDoor is related by the inverse relationship IsTypedBy pointing to IfcRelDefinesByType, for type parameters common to all occurrences of the same type. - the operation type (single swing, double swing, revolving, etc.) the door hinge side (by using two different styles for right and left opening doors) the construction material type the particular attributes for the lining by the IfcDoorLiningProperties the particular attributes for the panels by the IfcDoorPanelProperties The geometric representation of IfcDoor is given by the IfcProductDefinitionShape, allowing multiple geometric representations. The IfcDoor may get its parameter and shape from the IfcDoorType. If an IfcRepresentationMap (a block definition) is defined for the IfcDoorType, then the IfcDoor inserts it through the IfcMappedItem. The geometric representation of IfcDoor is defined using the following (potentially multiple) IfcShapeRepresentation's for its IfcProductDefinitionShape: - Profile: A 'Curve3D' consisting of a single losed curve defining the outer boundary of the door (lining). The door parametric representation uses this profile in order to apply the door lining and panel parameter. If not provided, the profile of the IfcOpeningElement is taken. - FootPrint: A 'GeometricCurveSet', or 'Annotation2D' representation defining the 2D shape of the door - Body: A 'SweptSolid', 'SurfaceModel', or 'Brep' representation defining the 3D shape of the door. In addition the parametric representation of a (limited) door shape is available by applying the parameters from IfcDoorType referencing IfcDoorLiningProperties and IfcDoorPanelProperties. The purpose of the parameter is described at those entities and below (door opening operation by door type). The overall size of the IfcDoor to be used to apply the lining or panel parameter provided by the IfcDoorType is determined by the IfcShapeRepresentation with the RepresentationIdentifier = 'Profile'.",
         "predefined_types": {
             "DOOR": "A standard door usually within a wall opening, as a door panel in a curtain wall, or as a \"free standing\" door.",
             "GATE": "A gate is a point of entry to a property usually within an opening in a fence. Or as a \"free standing\" gate.",
@@ -2067,7 +2067,7 @@
             "TransomOffset": "Offset of the transom (if given) which divides the door leaf from a glazing (or window) above. The offset is given from the bottom of the door opening.",
             "TransomThickness": "Thickness (width in plane parallel to door leaf) of the transom (if provided - that is, if the _TransomOffset_ attribute is set), which divides the door leaf from a glazing (or window) above. If the _TransomThickness_ is set to zero (and the _TransomOffset_ set to a positive length), then the door is divided vertically into a leaf and transom window area without a physical frame."
         },
-        "description": "The door lining is the frame which enables the door leaf to be fixed in position. The door lining is used to hang the door leaf. The parameters of the door lining define the geometrically relevant parameter of the lining.",
+        "description": "The door lining is the frame which enables the door leaf to be fixed in position. The door lining is used to hang the door leaf. The parameters of the door lining define the geometrically relevant parameter of the lining. The IfcDoorLiningProperties are included in the list of properties of IfcDoorType.HasPropertySets. More information about the door lining can be included in the same list of the IfcDoorTyype using another IfcPropertySet for dynamic extensions. The IfcDoorLiningProperties does not hold its own geometric representation. However it defines parameters which can be used to create the shape of the door type (which is inserted by the IfcDoor into the spatial context of the project) as shown in Figure 1. The parameters of the IfcDoorLiningProperties define a standard door lining, including (if given) a threshold and a transom. The outer boundary of the lining is determined by the 'Profile' shape representation assigned to the IfcDoor, which inserts the IfcDoorType.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcdoorliningproperties.htm"
     },
     "IfcDoorPanelProperties": {
@@ -2078,11 +2078,11 @@
             "PanelWidth": "Width of this panel, given as ratio relative to the total clear opening width of the door. If omited, it defaults to 1. A value has to be provided for all doors with _OperationType_'s at _IfcDoorStyle_ defining a door with more then one panel.",
             "ShapeAspectStyle": "Pointer to the shape aspect, if given. The shape aspect reflects the part of the door shape, which represents the door panel."
         },
-        "description": "A door panel is normally a door leaf that opens to allow people or goods to pass. The parameters of the door panel define the geometrically relevant parameter of the panel,",
+        "description": "A door panel is normally a door leaf that opens to allow people or goods to pass. The parameters of the door panel define the geometrically relevant parameter of the panel, The IfcDoorPanelProperties are used to parametrically describe the shape and operation of door panels. The parametric definition can be added solely or additionally to the explicit shape representation of the door. The IfcDoorType can define doors consisting of more then one panel. In this case, one instance of IfcDoorPanelProperties has to be included for each door panel. The PanelPosition attribute, in conjunction with the IfcDoorStyle.OperationType attribute, determines to which panel the IfcDoorPanelProperties apply. The IfcDoorPanelProperties are included in the list of properties , given by attribute HasPropertySets of the IfcDoorType. More information about the door panel can be included in the same list of the IfcDoorStyle using the IfcPropertySet for dynamic extensions. The IfcDoorPanelProperties does not hold a geometric representation. However it defines parameters which can be used to create the shape of the door type(which is inserted by the IfcDoor into the spatial context of the project) as shown in Figure 1. The parameters of the IfcDoorPanelProperties define a standard door panel, including (if given) a proportional width to define non-uniform double swing (or sliding, or folding) doors. The outer boundary of the panel is determined by the 'Profile' shape representation assigned to the IfcDoor, which inserts the IfcDoorType. It has to take the lining parameter into account as well.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcdoorpanelproperties.htm"
     },
     "IfcDoorStandardCase": {
-        "description": "The standard door, IfcDoorStandardCase, defines a door with certain constraints for the provision of operation types, opening directions, frame and lining parameters, and with certain constraints for the geometric representation. The IfcDoorStandardCase handles all cases of doors, that:",
+        "description": "The standard door, IfcDoorStandardCase, defines a door with certain constraints for the provision of operation types, opening directions, frame and lining parameters, and with certain constraints for the geometric representation. The IfcDoorStandardCase handles all cases of doors, that: - are inserted into an opening, represented by IfcOpeningElement, using the IfcRelFillsElement relationship; - have a local placement relative to this opening, and with the y-axis of the placement pointing into the opening direction; - have a profile geometry, represented by IfcShapeRepresentation.RepresentationIdentifier=\"Profile\" as a closed curve to which the door parameters apply; - have a reference to an IfcDoorType to define the opening direction and the operation type (swinging, sliding, folding, etc.) of the door. The attribute OperationType shall be provided and not being UNDEFINED, and the attribute ParameterTakesPrecedence shall be \"TRUE\"; - have an IfcDoorLiningProperties and IfcDoorPanelProperties instances included in the set of HasPropertySets at IfcDoorType. Geometric Representations The geometric representation of IfcDoorStandardCase is defined using the following multiple shape representations for its definition: - Profile: a three-dimensional closed curve within a particular shape representation. The profile is used to apply the parameter of the parametric door representation. The profile around the edges of the opening is used to apply the door lining and door panel shape parameter. - MappedRepresentation: A SweptSolid, SurfaceModel, Brep or a CSG representation additionally defining the 3D shape of the standard door in addition to the parametric representation by applying the IfcDoorLiningProperties and an the IfcDoorPanelProperties to the 'Profile' representation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcdoorstandardcase.htm"
     },
     "IfcDoorStyle": {
@@ -2092,7 +2092,7 @@
             "ParameterTakesPrecedence": "The Boolean value reflects, whether the parameter given in the attached lining and panel properties exactly define the geometry (TRUE), or whether the attached style shape take precedence (FALSE). In the last case the parameter have only informative value.",
             "Sizeable": "The Boolean indicates, whether the attached _IfcMappedRepresentation_ (if given) can be sized (using scale factor of transformation), or not (FALSE). If not, the _IfcMappedRepresentation_ should be _IfcShapeRepresentation_ of the _IfcDoor_ (using _IfcMappedItem_ as the _Item_) with the scale factor = 1."
         },
-        "description": "Definition: The door style, IfcDoorStyle, defines a particular style of doors, which may be included into the spatial context of the building model through instances of IfcDoor. A door style defines the overall parameter of the door style and refers to the particular parameter of the lining and one (or several) panels through the IfcDoorLiningProperties and the IfcDoorPanelProperties.",
+        "description": "Definition: The door style, IfcDoorStyle, defines a particular style of doors, which may be included into the spatial context of the building model through instances of IfcDoor. A door style defines the overall parameter of the door style and refers to the particular parameter of the lining and one (or several) panels through the IfcDoorLiningProperties and the IfcDoorPanelProperties. The door entity, IfcDoor, defines a particular occurrence of a door inserted in the spatial context of a project. The actual parameter of the door and/or its shape is defined at the IfcDoorStyle, to which the IfcDoor is related by the inverse relationship IsDefinedBy pointing to IfcRelDefinedByType. The IfcDoorStyle also defines the particular attributes for the lining_, IfcDoorLiningProperties_, and panels, IfcDoorPanelProperties. The IfcDoorStyle defines the baseline geometry, or the representation map, for all occurrences of the door style, given by the IfcDoor, pointing to this style. The representation of the door style may be given by the agreed set of minimal parameters, defined for the door lining and the door panel(s), or it may be given by a geometric representation used by the IfcRepresentationMap. The attribute ParameterTakesPrecedence decides, whether the set of parameters can be used to exactly represent the shape of the door style (TRUE), or whether the attached IfcRepresentationMap holds the exact representation (FALSE). The IfcDoorStyleOperationTypeEnum defines the general layout of the door style. Depending on the enumerator, the appropriate instances of IfcDoorLiningProperties and IfcDoorPanelProperties are attached in the list of HasPropertySets. The IfcDoorStyleOperationTypeEnum mainly determines the hinge side (left hung, or right hung), the operation (swinging, sliding, folding, etc.) and the number of panels. See geometry use definitions at IfcDoorStyleOperationTypeEnum for the correct usage of opening symbols for different operation types.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcdoorstyle.htm"
     },
     "IfcDoorType": {
@@ -2101,7 +2101,7 @@
             "ParameterTakesPrecedence": "The Boolean value reflects, whether the parameter given in the attached lining and panel properties exactly define the geometry (TRUE), or whether the attached style shape take precedence (FALSE). In the last case the parameter have only informative value. If not provided, no such information can be infered.",
             "UserDefinedOperationType": "Designator for the user defined operation type, shall only be provided, if the value of _OperationType_ is set to USERDEFINED."
         },
-        "description": "The element type IfcDoorType defines commonly shared information for occurrences of doors. The set of shared information may include:",
+        "description": "The element type IfcDoorType defines commonly shared information for occurrences of doors. The set of shared information may include: - common properties within shared property sets - common material information - common operation type definitions - common shape representations A door type defines the particular parameter of the lining and one (or several) panels through the IfcDoorLiningProperties and the IfcDoorPanelProperties as predefined property sets applicable to doors only. It is used to define a door specification, or door style (i.e. the specific product information that is common to all occurrences of that door type). Door types may be exchanged without being already assigned to occurrences. Occurrences of the IfcDoorType within building models are represented by instances of IfcDoor or IfcDoorStandardCase.",
         "predefined_types": {
             "DOOR": "A standard door usually within a wall opening, as a door panel in a curtain wall, or as a \"free standing\" door.",
             "GATE": "A gate is a point of entry to a property usually within an opening in a fence. Or as a \"free standing\" gate.",
@@ -2112,11 +2112,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcdoortype.htm"
     },
     "IfcDraughtingPreDefinedColour": {
-        "description": "The draughting pre defined colour is a pre defined colour for the purpose to identify a colour by name. Allowable names are:",
+        "description": "The draughting pre defined colour is a pre defined colour for the purpose to identify a colour by name. Allowable names are: - 'black', - 'red', - 'green', - 'blue', - 'yellow', - 'magenta', - 'cyan', - 'white', - 'by layer' The following table states the RGB values associated with the names given by the IfcDraughtingPreDefinedColour.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcdraughtingpredefinedcolour.htm"
     },
     "IfcDraughtingPreDefinedCurveFont": {
-        "description": "The draughting predefined curve font type defines a selection of widely used curve fonts for draughting purposes by name.",
+        "description": "The draughting predefined curve font type defines a selection of widely used curve fonts for draughting purposes by name. Figure 1 illustrates predefined curve fonts.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcdraughtingpredefinedcurvefont.htm"
     },
     "IfcDuctFitting": {
@@ -2135,7 +2135,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcductfitting.htm"
     },
     "IfcDuctFittingType": {
-        "description": "The flow fitting type IfcDuctFittingType defines commonly shared information for occurrences of duct fittings. The set of shared information may include:",
+        "description": "The flow fitting type IfcDuctFittingType defines commonly shared information for occurrences of duct fittings. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a duct fitting type specification indicating the specific product information that is common to all occurrences of that product type. The IfcDuctFittingType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcDuctFittingType are represented by instances of IfcDuctFitting. Refer to the documentation at IfcDuctFitting for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BEND": "A fitting with typically two ports used to change the direction of flow between connected elements.",
             "CONNECTOR": "Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two duct segments).",
@@ -2160,7 +2160,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcductsegment.htm"
     },
     "IfcDuctSegmentType": {
-        "description": "The flow segment type IfcDuctSegmentType defines commonly shared information for occurrences of duct segments. The set of shared information may include:",
+        "description": "The flow segment type IfcDuctSegmentType defines commonly shared information for occurrences of duct segments. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a duct segment type specification indicating the specific product information that is common to all occurrences of that product type. The IfcDuctSegmentType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcDuctSegmentType are represented by instances of IfcDuctSegment. Refer to the documentation at IfcDuctSegment for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "FLEXIBLESEGMENT": "A flexible segment is a continuous non-linear segment of duct that can be deformed and change the direction of flow.",
             "NOTDEFINED": "Undefined segment.",
@@ -2181,7 +2181,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcductsilencer.htm"
     },
     "IfcDuctSilencerType": {
-        "description": "The flow treatment device type IfcDuctSilencerType defines commonly shared information for occurrences of duct silencers. The set of shared information may include:",
+        "description": "The flow treatment device type IfcDuctSilencerType defines commonly shared information for occurrences of duct silencers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a duct silencer type specification indicating the specific product information that is common to all occurrences of that product type. The IfcDuctSilencerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcDuctSilencerType are represented by instances of IfcDuctSilencer. Refer to the documentation at IfcDuctSilencer for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "FLATOVAL": "Flat-oval shaped duct silencer type.",
             "NOTDEFINED": "Undefined duct silencer type.",
@@ -2196,7 +2196,7 @@
             "EdgeEnd": "End point (vertex) of the edge. The same vertex can be used for both EdgeStart and EdgeEnd.",
             "EdgeStart": "Start point (vertex) of the edge."
         },
-        "description": "An IfcEdge defines two vertices being connected topologically. The geometric representation of the connection between the two vertices defaults to a straight line if no curve geometry is assigned using the subtype IfcEdgeCurve. The IfcEdge can therefore be used to exchange straight edges without an associated geometry provided by IfcLine or IfcPolyline thought IfcEdgeCurve.EdgeGeometry.",
+        "description": "An IfcEdge defines two vertices being connected topologically. The geometric representation of the connection between the two vertices defaults to a straight line if no curve geometry is assigned using the subtype IfcEdgeCurve. The IfcEdge can therefore be used to exchange straight edges without an associated geometry provided by IfcLine or IfcPolyline thought IfcEdgeCurve.EdgeGeometry. Informal Propositions: - The edge has dimensionality 1. - The extent of an edge shall be finite and nonzero.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcedge.htm"
     },
     "IfcEdgeCurve": {
@@ -2204,7 +2204,7 @@
             "EdgeGeometry": "The curve which defines the shape and spatial location of the edge. This curve may be unbounded and is implicitly trimmed by the vertices of the edge; this defines the edge domain. Multiple edges can reference the same curve.",
             "SameSense": "This logical flag indicates whether (TRUE), or not (FALSE) the senses of the edge and the curve defining the edge geometry are the same. The sense of an edge is from the edge start vertex to the edge end vertex; the sense of a curve is in the direction of increasing parameter."
         },
-        "description": "An IfcEdgeCurve defines two vertices being connected topologically including the geometric representation of the connection.",
+        "description": "An IfcEdgeCurve defines two vertices being connected topologically including the geometric representation of the connection. Informal Propositions: - The domain of the edge curve is formally defined to be the domain of its edge geometry as trimmed by the vertices. This domain does not include the vertices. - An edge curve has non-zero finite extent. - An edge curve is a manifold. - An edge curve is arcwise connected. - The edge start is not a part of the edge domain. - The edge end is not a part of the edge domain. - Vertex geometry shall be consistent with edge geometry.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcedgecurve.htm"
     },
     "IfcEdgeLoop": {
@@ -2212,11 +2212,11 @@
             "EdgeList": "A list of oriented edge entities which are concatenated together to form this path.",
             "Ne": "The number of elements in the edge list. SIZEOF(EdgeList)"
         },
-        "description": "",
+        "description": "Informal Propositions: - The genus of the IfcEdgeLoop shall be 1 or greater. - The Euler formula shall be satisfied: (number of vertices) + genus - (number of edges) = 1; - No edge may be referenced more than once by the same IfcEdgeLoop with the same sense. For this purpose, an edge which is not an oriented edge is considered to be referenced with the sense TRUE.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcedgeloop.htm"
     },
     "IfcElectricAppliance": {
-        "description": "An electric appliance is a device intended for consumer usage that is powered by electricity.",
+        "description": "An electric appliance is a device intended for consumer usage that is powered by electricity. Electric appliances may be fixed in place or may be able to be moved from one space to another. Electric appliances require an electrical supply that may be supplied either by an electrical circuit or provided from a local battery source.",
         "predefined_types": {
             "DISHWASHER": "An appliance that has the primary function of washing dishes.",
             "ELECTRICCOOKER": "An electrical appliance that has the primary function of cooking food (including oven, hob, grill).",
@@ -2240,7 +2240,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectricappliance.htm"
     },
     "IfcElectricApplianceType": {
-        "description": "The flow terminal type IfcElectricApplianceType defines commonly shared information for occurrences of electric appliances. The set of shared information may include:",
+        "description": "The flow terminal type IfcElectricApplianceType defines commonly shared information for occurrences of electric appliances. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a electric appliance type specification indicating the specific product information that is common to all occurrences of that product type. The IfcElectricApplianceType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcElectricApplianceType are represented by instances of IfcElectricAppliance. Refer to the documentation at IfcElectricAppliance for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "DISHWASHER": "An appliance that has the primary function of washing dishes.",
             "ELECTRICCOOKER": "An electrical appliance that has the primary function of cooking food (including oven, hob, grill).",
@@ -2264,7 +2264,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectricappliancetype.htm"
     },
     "IfcElectricDistributionBoard": {
-        "description": "A distribution board is a flow controller in which instances of electrical devices are brought together at a single place for a particular purpose.",
+        "description": "A distribution board is a flow controller in which instances of electrical devices are brought together at a single place for a particular purpose. A distribution provides a housing for connected electrical distribution elements so that they can be viewed, operated or acted upon from a single place. Each connected item may have its own geometric representation and location.",
         "predefined_types": {
             "CONSUMERUNIT": "A distribution point on the incoming electrical supply, typically in domestic premises, at which protective devices are located.",
             "DISTRIBUTIONBOARD": "A distribution point at which connections are made for distribution of electrical circuits usually through protective devices.",
@@ -2276,7 +2276,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectricdistributionboard.htm"
     },
     "IfcElectricDistributionBoardType": {
-        "description": "The flow controller type IfcElectricDistributionBoardType defines commonly shared information for occurrences of electric distribution boards. The set of shared information may include:",
+        "description": "The flow controller type IfcElectricDistributionBoardType defines commonly shared information for occurrences of electric distribution boards. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a electric distribution board type specification indicating the specific product information that is common to all occurrences of that product type. The IfcElectricDistributionBoardType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcElectricDistributionBoardType are represented by instances of IfcElectricDistributionBoard. Refer to the documentation at IfcElectricDistributionBoard for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CONSUMERUNIT": "A distribution point on the incoming electrical supply, typically in domestic premises, at which protective devices are located.",
             "DISTRIBUTIONBOARD": "A distribution point at which connections are made for distribution of electrical circuits usually through protective devices.",
@@ -2301,7 +2301,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectricflowstoragedevice.htm"
     },
     "IfcElectricFlowStorageDeviceType": {
-        "description": "The flow storage device type IfcElectricFlowStorageDeviceType defines commonly shared information for occurrences of electric flow storage devices. The set of shared information may include:",
+        "description": "The flow storage device type IfcElectricFlowStorageDeviceType defines commonly shared information for occurrences of electric flow storage devices. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a electric flow storage device type specification indicating the specific product information that is common to all occurrences of that product type. The IfcElectricFlowStorageDeviceType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcElectricFlowStorageDeviceType are represented by instances of IfcElectricFlowStorageDevice. Refer to the documentation at IfcElectricFlowStorageDevice for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BATTERY": "A device for storing energy in chemical form so that it can be released as electrical energy.",
             "CAPACITORBANK": "A device that stores electrical energy when an external power supply is present using the electrical property of capacitance.",
@@ -2325,7 +2325,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectricgenerator.htm"
     },
     "IfcElectricGeneratorType": {
-        "description": "The energy conversion device type IfcElectricGeneratorType defines commonly shared information for occurrences of electric generators. The set of shared information may include:",
+        "description": "The energy conversion device type IfcElectricGeneratorType defines commonly shared information for occurrences of electric generators. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a electric generator type specification indicating the specific product information that is common to all occurrences of that product type. The IfcElectricGeneratorType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcElectricGeneratorType are represented by instances of IfcElectricGenerator. Refer to the documentation at IfcElectricGenerator for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CHP": "Combined heat and power supply, used not only as a source of electric energy but also as a heating source for the building. It may therefore be not only part of an electrical system but also of a heating system.",
             "ENGINEGENERATOR": "Electrical generator with a fuel-driven engine, for example a diesel-driven emergency power supply.",
@@ -2349,7 +2349,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectricmotor.htm"
     },
     "IfcElectricMotorType": {
-        "description": "The energy conversion device type IfcElectricMotorType defines commonly shared information for occurrences of electric motors. The set of shared information may include:",
+        "description": "The energy conversion device type IfcElectricMotorType defines commonly shared information for occurrences of electric motors. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a electric motor type specification indicating the specific product information that is common to all occurrences of that product type. The IfcElectricMotorType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcElectricMotorType are represented by instances of IfcElectricMotor. Refer to the documentation at IfcElectricMotor for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "DC": "A motor using either generated or rectified Direct Current (DC) power.",
             "INDUCTION": "An alternating current motor in which the primary winding on one member (usually the stator) is connected to the power source and a secondary winding or a squirrel-cage secondary winding on the other member (usually the rotor) carries the induced current. There is no physical electrical connection to the secondary winding, its current is induced.",
@@ -2373,7 +2373,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectrictimecontrol.htm"
     },
     "IfcElectricTimeControlType": {
-        "description": "The flow controller type IfcElectricTimeControlType defines commonly shared information for occurrences of electric time controls. The set of shared information may include:",
+        "description": "The flow controller type IfcElectricTimeControlType defines commonly shared information for occurrences of electric time controls. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a electric time control type specification indicating the specific product information that is common to all occurrences of that product type. The IfcElectricTimeControlType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcElectricTimeControlType are represented by instances of IfcElectricTimeControl. Refer to the documentation at IfcElectricTimeControl for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "NOTDEFINED": "Undefined type.",
             "RELAY": "Electromagnetically operated contactor for making or breaking a control circuit.",
@@ -2399,14 +2399,14 @@
             "ReferencedInStructures": "Reference relationship to the spatial structure element, to which the element is additionally associated. This relationship may not be hierarchical, an element may be referenced by zero, one or many spatial structure elements.",
             "Tag": "The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level."
         },
-        "description": "An element is a generalization of all components that make up an AEC product.",
+        "description": "An element is a generalization of all components that make up an AEC product. Elements are physically existent objects, although they might be void elements, such as holes. Elements either remain permanently in the AEC product, or only temporarily, as formwork does. Elements can be either assembled on site or pre-manufactured and built in on site. The elements can be logically contained by a spatial structure element that constitutes a certain level within a project structure hierarchy (site, building, storey or space). This is done by using the IfcRelContainedInSpatialStructure relationship. An element can have material and quantity information assigned through the IfcRelAssociatesMaterial and IfcRelDefinesByProperties relationship. In addition an element can be declared to be a specific occurrence of an element type (and thereby be defined by the element type properties) using the IfcRelDefinesByType relationship. An element can also be defined as an element assembly that is a group of semantically and topologically related elements that form a higher level part of the AEC product. Those element assemblies are defined by virtue of the IfcRelAggregates relationship. Elements that performs the same function may be grouped by an \"Element Group By Function\". It is realized by an instance of IfcGroup with the ObjectType ='ElementGroupByFunction'.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcelement.htm"
     },
     "IfcElementAssembly": {
         "attributes": {
             "AssemblyPlace": "A designation of where the assembly is intended to take place defined by an Enum."
         },
-        "description": "The IfcElementAssembly represents complex element assemblies aggregated from several elements, such as discrete elements, building elements, or other elements.",
+        "description": "The IfcElementAssembly represents complex element assemblies aggregated from several elements, such as discrete elements, building elements, or other elements. The assembly structure can be nested, i.e. an IfcElementAssembly could be an aggregated part within another IfcElementAssembly. The geometry of an IfcElementAssembly is generally formed from its components, in which case it does not need to have an explicit geometric representation. In some cases it may be useful to also expose an own explicit representation of the aggregate. Informal Propositions: - The IfcElementAssembly shall have an aggregation relationship to the contained parts, i.e. the (INV) IsDecomposedBy relationship shall be utilzed.",
         "predefined_types": {
             "ACCESSORY_ASSEMBLY": "Assembled accessories or components.",
             "ARCH": "A curved structure.",
@@ -2423,7 +2423,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcelementassembly.htm"
     },
     "IfcElementAssemblyType": {
-        "description": "The IfcElementAssemblyType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The IfcElementAssemblyType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). An element assembly type is used to define the common properties of a certain type of an element assembly that may be applied to many instances of that type to assign a specific style. An element assembly types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcElementAssemblyType are represented by instances of IfcElementAssembly.",
         "predefined_types": {
             "ACCESSORY_ASSEMBLY": "Assembled accessories or components.",
             "ARCH": "A curved structure.",
@@ -2440,11 +2440,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcelementassemblytype.htm"
     },
     "IfcElementComponent": {
-        "description": "An element component is a representation for minor items included in, added to or connecting to or between elements, which usually are not of interest from the overall building structure viewpoint. However, these small parts may have vital and load carrying functions within the construction. These items do not provide any actual space boundaries. Typical examples of _IfcElementComponent_s include different kinds of fasteners and various accessories.",
+        "description": "An element component is a representation for minor items included in, added to or connecting to or between elements, which usually are not of interest from the overall building structure viewpoint. However, these small parts may have vital and load carrying functions within the construction. These items do not provide any actual space boundaries. Typical examples of _IfcElementComponent_s include different kinds of fasteners and various accessories. One or several instances of subtypes of IfcElementComponent should always be accompanied by a defining instance of a respective subtype of IfcElementComponentType. The type object holds shape and material information. It is often desirable to model a number of same-shaped element components by means of a single occurrence object, e.g. several bolts within a connection or a row of reinforcement elements. In this IFC release, this is possible by means of multiple mapped representation as documented below. To express the multiplicity of element components also on a higher semantic level, a Qto_ElementComponentPatternQuantities should be provided via IfcRelDefinesByProperties and contain the number of pieces which are placed by a single IfcElementComponent instance. Symbolic Representation A symbolic representation is defined for a row of components or several rows of components within a single instance of IfcElementComponent. Such rows or arrays may contain possibly large numbers of individual pieces. The product definition shape consists of an IfcShapeRepresentation with the attribute values - RepresentationIdentifier : 'Row' - RepresentationType : 'GeometricCurveSet' and one or several curves as geometric items. The curves represent where reference points of the pieces are located. For example, such reference points may be at the heads of mechanical fasteners or at the starting point of the extrusion axis of reinforcement bars. In case of straight components (bolts, nails, staples, straight reinforcement bars, or similar), the local placement of the IfcElementComponent shall be located and oriented such that the local z axis is parallel with the axes of the components. A Qto_ElementComponentPatternQuantities should denote the count of pieces in the row or array and their spacing.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedcomponentelements/lexical/ifcelementcomponent.htm"
     },
     "IfcElementComponentType": {
-        "description": "The element type IfcElementComponentType defines commonly shared information for occurrences of element components. The set of shared information may include:",
+        "description": "The element type IfcElementComponentType defines commonly shared information for occurrences of element components. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a element component type specification indicating the specific product information that is common to all occurrences of that product type. The IfcElementComponentType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcElementComponentType are represented by instances of IfcElementComponent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedcomponentelements/lexical/ifcelementcomponenttype.htm"
     },
     "IfcElementQuantity": {
@@ -2452,14 +2452,14 @@
             "MethodOfMeasurement": "Name of the method of measurement used to calculate the element quantity. The method of measurement attribute has to be made recognizable by further agreements.",
             "Quantities": "The individual quantities for the element, can be a set of length, area, volume, weight or count based quantities."
         },
-        "description": "An IfcElementQuantity defines a set of derived measures of an element's physical property. Elements could be spatial structure elements (like buildings, storeys, or spaces) or building elements (like walls, slabs, finishes). The IfcElementQuantity gets assigned to the element by using the IfcRelDefinesByProperties relationship.",
+        "description": "An IfcElementQuantity defines a set of derived measures of an element's physical property. Elements could be spatial structure elements (like buildings, storeys, or spaces) or building elements (like walls, slabs, finishes). The IfcElementQuantity gets assigned to the element by using the IfcRelDefinesByProperties relationship. The optional MethodOfMeasurement attribute defines the code, e.g. from a standard method of measurement, which had been used to calculate the element quantity. The name attribute, given at the individual Quantities provides a recognizable semantic meaning of the element quantity. Both information is needed to establish a precise meaning for the measure value. An optional description may be assigned to each of the Quantities. All quantities assigned by a single instance of IfcElementQuantity are deemed to have been generated according to the same method of measurement. However several instances of IfcElementQuantity are assignable to an element, thus allowing for an element having quantities generated according to several methods of measurement. The IfcElementQuantity can have the following subtypes of IfcPhysicalQuantity within its SET of Quantities, which count for the basis measure types used: - count measure - weight measure - length measure - area measure - volume measure - time measure Base quantities are quantity definitions that are independent of a particular method of measurement and therefore internationally applicable. Base quantities are defined as gross and net values and provided by measurement of the correct geometric shape representation of the element. This specification includes a set of base quantity definition. See each subtype of IfcElement for applicable base quantities. The following general agreements apply for each base quantity set - IfcElementQuantity.Name = <name of the qto definition template> - IfcElementQuantity.MethodOfMeasurement = 'BaseQuantities' - IfcElementQuantity.Quantities = SET of subtypes of IfcPhysicalSimpleQuantity with values for the Name attribute as published as part of this specifciation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcelementquantity.htm"
     },
     "IfcElementType": {
         "attributes": {
             "ElementType": "The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute 'PredefinedType' is set to USERDEFINED."
         },
-        "description": "IfcElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "IfcElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type). An element type is used to define the common properties of a certain type or style of an element that may be applied to instances of that element type to assign a specific style. Element types (the instantiable subtypes) may be exchanged without being already assigned to occurrences.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcelementtype.htm"
     },
     "IfcElementarySurface": {
@@ -2474,7 +2474,7 @@
             "SemiAxis1": "The first radius of the ellipse which shall be positive. Placement.Axes[1] gives the direction of the SemiAxis1.",
             "SemiAxis2": "The second radius of the ellipse which shall be positive."
         },
-        "description": "An IfcEllipse is a curve consisting of a set of points whose distances to two fixed points add to the same constant.",
+        "description": "An IfcEllipse is a curve consisting of a set of points whose distances to two fixed points add to the same constant. The inherited SELF\\IfcConic.Position.Location is the center of the IfcEllipse, and the inherited S_ELF\\IfcConic.Position.Position.P[1] is the direction of the _SemiAxis1.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcellipse.htm"
     },
     "IfcEllipseProfileDef": {
@@ -2482,7 +2482,7 @@
             "SemiAxis1": "The first radius of the ellipse. It is measured along the direction of Position.P[1].",
             "SemiAxis2": "The second radius of the ellipse. It is measured along the direction of Position.P[2]."
         },
-        "description": "IfcEllipseProfileDef defines an ellipse as the profile definition used by the swept surface geometry or the swept area solid. It is given by its semi axis attributes and placed within the 2D position coordinate system, established by the Position attribute.",
+        "description": "IfcEllipseProfileDef defines an ellipse as the profile definition used by the swept surface geometry or the swept area solid. It is given by its semi axis attributes and placed within the 2D position coordinate system, established by the Position attribute. Figure 1 illustrates parameters for the ellipse profile definition. The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept surface or swept area solid that uses the profile definition. It is the xy plane of either: - IfcSweptSurface.Position - IfcSweptAreaSolid.Position Or in case of sectioned spines it is the xy plane of each list member of IfcSectionedSpine.CrossSectionPositions. By using offsets of the position location, the parameterized profile can be positioned centric (using x,y offsets = 0.), or at any position relative to the profile. Explicit coordinate offsets are used to define cardinal points (for example, upper-left bound). The location of the position coordinate system defines the center of the ellipse. The SemiAxis1 attribute defines the first radius of the ellipse in the direction of the X axis, the SemiAxis2 attribute defines the second radius of the ellipse in the direction of the Y axis.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcellipseprofiledef.htm"
     },
     "IfcEnergyConversionDevice": {
@@ -2490,7 +2490,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcenergyconversiondevice.htm"
     },
     "IfcEnergyConversionDeviceType": {
-        "description": "The element type IfcEnergyConversionType defines a list of commonly shared property set definitions of an energy conversion device and an optional set of product representations. It is used to define an energy conversion device specification (the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcEnergyConversionType defines a list of commonly shared property set definitions of an energy conversion device and an optional set of product representations. It is used to define an energy conversion device specification (the specific product information, that is common to all occurrences of that product type). A energy conversion type is used to define the common properties of a energy conversion device that may be applied to many occurrences of that type. An energy conversion device is a building systems device that converts energy from one form into another such as a boiler (combusting gas to heat water), chiller (using a refrigeration cycle to cool a liquid), or a cooling coil (using the phase-change characteristics of a refrigerant to cool air). Energy conversion types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. Occurrences of the IfcEnergyConversionType are represented by instances of IfcEnergyConversionDevice or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcenergyconversiondevicetype.htm"
     },
     "IfcEngine": {
@@ -2504,7 +2504,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcengine.htm"
     },
     "IfcEngineType": {
-        "description": "The energy conversion device type IfcEngineType defines commonly shared information for occurrences of engines. The set of shared information may include:",
+        "description": "The energy conversion device type IfcEngineType defines commonly shared information for occurrences of engines. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a engine type specification indicating the specific product information that is common to all occurrences of that product type. The IfcEngineType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcEngineType are represented by instances of IfcEngine. Refer to the documentation at IfcEngine for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "EXTERNALCOMBUSTION": "Combustion is external.",
             "INTERNALCOMBUSTION": "Combustion is internal.",
@@ -2531,7 +2531,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcevaporativecooler.htm"
     },
     "IfcEvaporativeCoolerType": {
-        "description": "The energy conversion device type IfcEvaporativeCoolerType defines commonly shared information for occurrences of evaporative coolers. The set of shared information may include:",
+        "description": "The energy conversion device type IfcEvaporativeCoolerType defines commonly shared information for occurrences of evaporative coolers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a evaporative cooler type specification indicating the specific product information that is common to all occurrences of that product type. The IfcEvaporativeCoolerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcEvaporativeCoolerType are represented by instances of IfcEvaporativeCooler. Refer to the documentation at IfcEvaporativeCooler for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "DIRECTEVAPORATIVEAIRWASHER": "Direct evaporative air washer: Cools the air stream by evaporating water dircectly into the air stream using coolers with spray-type air washer consist of a chamber or casing containing spray nozzles, and tank for collecting spray water, and an eliminator section for removing entrained drops of water from the air.",
             "DIRECTEVAPORATIVEPACKAGEDROTARYAIRCOOLER": "Direct evaporative packaged rotary air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers that wet and wash the evaporative pad by rotating it through a water bath.",
@@ -2562,7 +2562,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcevaporator.htm"
     },
     "IfcEvaporatorType": {
-        "description": "The energy conversion device type IfcEvaporatorType defines commonly shared information for occurrences of evaporators. The set of shared information may include:",
+        "description": "The energy conversion device type IfcEvaporatorType defines commonly shared information for occurrences of evaporators. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a evaporator type specification indicating the specific product information that is common to all occurrences of that product type. The IfcEvaporatorType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcEvaporatorType are represented by instances of IfcEvaporator. Refer to the documentation at IfcEvaporator for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "DIRECTEXPANSION": "Direct-expansion evaporator.",
             "DIRECTEXPANSIONBRAZEDPLATE": "Direct-expansion evaporator where a refrigerant evaporates inside plates brazed or welded together to make up an assembly of separate channels.",
@@ -2581,7 +2581,7 @@
             "EventTriggerType": "Identifies the predefined types of event trigger from which      the type required may be set.",
             "UserDefinedEventTriggerType": "A user defined event trigger type, the value of which is      asserted when the value of an event trigger type is declared      as USERDEFINED."
         },
-        "description": "An IfcEvent is something that happens that triggers an action or response.",
+        "description": "An IfcEvent is something that happens that triggers an action or response. Use definitions IfcEvent is used to capture information about particular things that happen or that may happen. Particularly used in work plans (or process maps) they identify e.g. a point at which a message containing information may be issued or at which a rule or constraint is invoked.",
         "predefined_types": {
             "ENDEVENT": "A terminating event of a process.",
             "INTERMEDIATEEVENT": "An event that occurs at an intermediate stage of a process.",
@@ -2598,7 +2598,7 @@
             "LateDate": "The latest date on which an event can occur. It is a calculated value.",
             "ScheduleDate": "The date on which an event is scheduled to occur.      The value might be measured or somehow calculated, which is defined by     _ScheduleDataOrigin_."
         },
-        "description": "IfcEventTime captures the time-related information about an event including the different types of event dates (i.e. actual, scheduled, early, and late).",
+        "description": "IfcEventTime captures the time-related information about an event including the different types of event dates (i.e. actual, scheduled, early, and late). All given values should be provided by the application, that is, the IFC schema does not deal with dependencies between process time values. At this stage there is also no consistency check through where rules that guarantee a meaningful population of date values. Thus, an application is responsible to provide reasonable values and, if an application receives event dates, has to make consistency checks by their own. IfcEventTime furthermore provides a generic mechanism to differentiate between user given time values and time values derived from user given time values and other constraints such as work calendars and assigned resources (derived from the process graph). The data origin flag is provided as a single attribute applying to all date time related attributes of IfcEventTime.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifceventtime.htm"
     },
     "IfcEventType": {
@@ -2606,7 +2606,7 @@
             "EventTriggerType": "Identifies the predefined types of event trigger from which      the type required may be set.",
             "UserDefinedEventTriggerType": "A user defined event trigger type, the value of which      is asserted when the value of an event trigger type is      declared as USERDEFINED."
         },
-        "description": "An IfcEventType defines a particular type of event that may be specified.",
+        "description": "An IfcEventType defines a particular type of event that may be specified. An IfcEventType provides for all forms of types of event that may be specified. Usage of IfcEventType defines the parameters for one or more occurrences of IfcEvent. Parameters may be specified through property sets that may be enumerated in the IfcEventTypeEnum data type or through explicit attributes of IfcEvent. Event occurrences (IfcEvent entities) are linked to the event type through the IfcRelDefinesByType relationship.",
         "predefined_types": {
             "ENDEVENT": "A terminating event of a process.",
             "INTERMEDIATEEVENT": "An event that occurs at an intermediate stage of a process.",
@@ -2622,11 +2622,11 @@
             "Name": "The name given to the set of properties.",
             "Properties": "The set of properties provided for this extended property collection."
         },
-        "description": "The IfcExtendedProperties is an abstract supertype of all extensible property collections that are applicable to certain characterized entities. Instantiable subtypes of IfcExtendedProperties assign the property collection to a particular characterized entity.",
+        "description": "The IfcExtendedProperties is an abstract supertype of all extensible property collections that are applicable to certain characterized entities. Instantiable subtypes of IfcExtendedProperties assign the property collection to a particular characterized entity. Instantiable subtypes have a set of Properties, each providing property name, value and unit and other instance information, depending on the subtype of IfcProperty referenced.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpropertyresource/lexical/ifcextendedproperties.htm"
     },
     "IfcExternalInformation": {
-        "description": "An IfcExternalInformation is the identification of an information source that is not explicitly represented in the current model or in the project database (as an implementation of the current model). The IfcExternalInformation identifies the external source (classification, document, or library), but not the particular items such as a dictionary entry, a classification notation, or a document reference within the external source",
+        "description": "An IfcExternalInformation is the identification of an information source that is not explicitly represented in the current model or in the project database (as an implementation of the current model). The IfcExternalInformation identifies the external source (classification, document, or library), but not the particular items such as a dictionary entry, a classification notation, or a document reference within the external source The IfcExternalInformation is an abstract supertype of all external information entities.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifcexternalinformation.htm"
     },
     "IfcExternalReference": {
@@ -2636,7 +2636,7 @@
             "Location": "Location, where the external source (classification, document or library) can be accessed by electronic means. The electronic location is provided as an URI, and would normally be given as an URL location string.",
             "Name": "Optional name to further specify the reference. It can provide a human readable identifier (which does not necessarily need to have a counterpart in the internal structure of the document)."
         },
-        "description": "An IfcExternalReference is the identification of information that is not explicitly represented in the current model or in the project database (as an implementation of the current model). Such information may be contained in classifications, documents or libraries. The IfcExternalReference identifies a particular item, such as a dictionary entry, a classification notation, or a document reference within the external source.",
+        "description": "An IfcExternalReference is the identification of information that is not explicitly represented in the current model or in the project database (as an implementation of the current model). Such information may be contained in classifications, documents or libraries. The IfcExternalReference identifies a particular item, such as a dictionary entry, a classification notation, or a document reference within the external source. Only the Location (as a URL) is given to describe the place where the information can be found. Also an optional Identification as a key to allow more specific references (as to sections or tables) is provided. The Identification defines a system interpretable method to identify the relevant part of information at the source. In addition a human interpretable Name can be assigned to identify the information subject, such as a classification code. IfcExternalReference is an abstract supertype of all external reference entities.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifcexternalreference.htm"
     },
     "IfcExternalReferenceRelationship": {
@@ -2651,7 +2651,7 @@
         "attributes": {
             "BoundedBy": "Reference to a set of _IfcRelSpaceBoundary_'s that defines the physical or virtual delimitation of that external spacial element against physical or virtual boundaries."
         },
-        "description": "The external spatial element defines external regions at the building site. Those regions can be defined:",
+        "description": "The external spatial element defines external regions at the building site. Those regions can be defined: - logically - for example, an instance of IfcExternalSpatialElement could represent the air space around the building without having an own shape representation, or - physically - for example, an instance of IfcExternalSpatialElement could represent the sloping ground around the building to identify the part of the external building envelop that is below ground.",
         "predefined_types": {
             "EXTERNAL": "External air space around the building.",
             "EXTERNAL_EARTH": "External volume covered by earth around the building.",
@@ -2683,14 +2683,14 @@
             "Depth": "The distance the surface is to be swept along the _ExtrudedDirection_.",
             "ExtrudedDirection": "The direction in which the surface, provided by _SweptArea_ is to be swept."
         },
-        "description": "The IfcExtrudedAreaSolid is defined by sweeping a cross section provided by a profile definition. The direction of the extrusion is given by the ExtrudedDirection attribute and the length of the extrusion is given by the Depth attribute. If the planar area has inner boundaries (holes defined), then those holes shall be swept into holes of the solid.",
+        "description": "The IfcExtrudedAreaSolid is defined by sweeping a cross section provided by a profile definition. The direction of the extrusion is given by the ExtrudedDirection attribute and the length of the extrusion is given by the Depth attribute. If the planar area has inner boundaries (holes defined), then those holes shall be swept into holes of the solid. The resulting solid is positioned by the IfcSweptAreaSolid.Position relative to the object coordinate system. If provided, it allows to reposition the extruded solid. If not provided, it defaults to the current object coordinate system. The ExtrudedDirection is given within the position coordinate system as defined by IfcSweptAreaSolid.Position. The extruded direction can be any direction which is not perpendicular to the z axis of the position coordinate system. Texture use definition For side faces, textures are aligned facing upright continuously along the sides with origin at the first point of an arbitrary profile, and following the outer bound of the profile counter-clockwise (as seen from above). For parameterized profiles, the origin is defined at the +Y extent for rounded profiles (having no sharp edge) and the first sharp edge counter-clockwise from the +Y extent for all other profiles. Textures are stretched or repeated on each side along the outer boundary of the profile according to RepeatS. Textures are stretched or repeated on each side along the extrusion axis according to RepeatT. For top and bottom caps, textures are aligned facing front-to-back, with the origin at the minimum X and Y extent. Textures are stretched or repeated on the top and bottom to the extent of each face according to RepeatS and RepeatT. For profiles with voids, textures are aligned facing upright along the inner side with origin at the first point of an arbitrary profile, and following the inner bound of the profile clockwise (as seen from above). For parameterized profiles, the origin of inner sides is defined at the +Y extent for rounded profiles (having no sharp edge such as hollow ellipses or rounded rectangles) and the first sharp edge clockwise from the +Y extent for all other profiles.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcextrudedareasolid.htm"
     },
     "IfcExtrudedAreaSolidTapered": {
         "attributes": {
             "EndSweptArea": "The surface defining the end of the swept area. It is given as a profile definition. The position coordinate system of the _EndSwptArea_ is generated by translating the _SELF\\IfcSweptAreaSolid.Position_ along the _SELF\\IfcExtrudedAreaSolid.ExtrudedDirection_ by the distance of _SELF\\IfcExtrudedAreaSolid.Depth_."
         },
-        "description": "IfcExtrudedAreaSolidTapered is defined by sweeping a cross section along a linear spine. The cross section may change along the sweep from the shape of the start cross section into the shape of the end cross section. The resulting solid is bounded by three or more faces: A start face, an end face (each defined by start and end planes and sections), and one or more lateral faces. Each lateral face is a ruled surface defined by a pair of corresponding edges of the start and end section.",
+        "description": "IfcExtrudedAreaSolidTapered is defined by sweeping a cross section along a linear spine. The cross section may change along the sweep from the shape of the start cross section into the shape of the end cross section. The resulting solid is bounded by three or more faces: A start face, an end face (each defined by start and end planes and sections), and one or more lateral faces. Each lateral face is a ruled surface defined by a pair of corresponding edges of the start and end section. The linear spine is defined by: - Start point: SELF\\IfcSweptAreaSolid.Position.Location - Direction: SELF\\IfcExtrudedAreaSolid.ExtrudedDirection - Distance: SELF\\IfcExtrudedAreaSolid.Depth The start cross section is defined by SELF\\IfcSweptAreaSolid.SweptArea: - A bounded planar surface lying in the XY plane of the position coordinate system defined by SELF\\IfcSweptAreaSolid.Position.P[1] and SELF\\IfcSweptAreaSolid.Position.P[2] - The linear spine starts at the plane of the start cross section. The spine is not necessarily perpendicular to the plane. The end cross section is defined by EndSweptArea: - A bounded planar surface lying in the XY plane of the position coordinate system defined by translating the start position coordinates provided by SELF\\IfcSweptAreaSolid.Position along the spine direction by the spine distance. The plane of the end cross section is coplanar to the plane of the start cross section. - The end cross section is topologically similar to the start cross section (i.e. having the same number of vertices and edges). The end cross section can either be defined by the same paramteric profile using different parameter values, or by a 2D Cartesian transformation of the start profile within the end cross section plane. In case of two parameterized profiles the shape is constructed as follows: - The end profile, defined by a cross section based on the same profile paramterization as the start profile, is translated by the spine distance along the spine direction. - It may be shifted within the XY plane of the end postion coordinate system and may be twisted using the rotation parameter. - The shift and rotation parameter are provided by the end cross section being of type IfcParameterizedProfileDef, where Shift is EndSweptArea\\IfcParameterizedProfileDef.Position.Location Rotation is EndSweptArea\\IfcParameterizedProfileDef.Position.RefDirection - Corresponding vertices of the start and end cross section are connected. Lateral faces are constructed as ruled surfaces between corresponding edges of start and end cross section. In case of Cartesian transformation of the start cross section the shape is constructed as follows: - The cross section curve, which starts as a curve in the XY plane of the position coordinate system, is first scaled about the origin by the scale parameter. It is then translated by the spine distance along the spine direction. It maybe twisted by using the rotation parameter. - The scale and rotation parameter are provided by the end cross section being of type IfcDerivedProfileDef, where Scale is EndSweptArea\\IfcDerivedProfileDef.Operator.Scale Rotation is EndSweptArea\\IfcDerivedProfileDef.Operator.Axis1 - Corresponding vertices of the start and end cross section are connected. Lateral faces are constructed as ruled surfaces between corresponding edges of start and end cross section. Informal Propositions: - Mirroring within IfcDerivedProfileDef.Operator shall not be used",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcextrudedareasolidtapered.htm"
     },
     "IfcFace": {
@@ -2698,7 +2698,7 @@
             "Bounds": "Boundaries of the face.",
             "HasTextureMaps": ""
         },
-        "description": "An IfcFace is topological entity used to define surface, bounded by loops, of a shell.",
+        "description": "An IfcFace is topological entity used to define surface, bounded by loops, of a shell. Informal Propositions: - No edge shall be referenced by the face more than twice. - Distinct face bounds of the face shall have no common vertices. - If geometry is present, distinct loops of the same face shall not intersect. - The face shall satisfy the Euler Equation: (number of vertices) - (number of edges) - (number of loops) + (sum of genus for loops) = 0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcface.htm"
     },
     "IfcFaceBasedSurfaceModel": {
@@ -2706,7 +2706,7 @@
             "Dim": "The space dimensionality of this class, it is always 3. 3",
             "FbsmFaces": "The set of connected face sets comprising the face based surface model."
         },
-        "description": "The IfcFaceBasedSurfaceModel represents the a shape by connected face sets. The connected faces have a dimensionality 2 and are placed in a coordinate space of dimensionality 3.",
+        "description": "The IfcFaceBasedSurfaceModel represents the a shape by connected face sets. The connected faces have a dimensionality 2 and are placed in a coordinate space of dimensionality 3. Informal Propositions: - The connected face sets shall not overlap or intersect except at common faces, edges or vertices. - The fbsm faces have dimensionality 2.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcfacebasedsurfacemodel.htm"
     },
     "IfcFaceBound": {
@@ -2726,18 +2726,18 @@
             "FaceSurface": "The surface which defines the internal shape of the face. This surface may be unbounded. The domain of the face is defined by this surface and the bounding loops in the inherited attribute SELF\\FaceBounds.",
             "SameSense": "This flag indicates whether the sense of the surface normal agrees with (TRUE), or opposes (FALSE), the sense of the topological normal to the face."
         },
-        "description": "The IfcFaceSurface defines the underlying geometry of the associated surface to the face.",
+        "description": "The IfcFaceSurface defines the underlying geometry of the associated surface to the face. Informal Propositions: - The domain of the face surface is formally defined to be the domain of its face geometry as trimmed by the loops, this domain does not include the bounding loops. - A face surface has non zero finite extent. - A face surface is a manifold. - A face surface is arcwise connected. - A face surface has surface genus 0. - The loops are not part of the face domain. - Loop geometry shall be consistent with face geometry. This implies that any edge - curves or vertex points used in defining the loops bounding the face surface shall lie on the face geometry. - The loops of the face shall not intersect.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcfacesurface.htm"
     },
     "IfcFacetedBrep": {
-        "description": "The IfcFacetedBrep is a manifold solid brep with the restriction that all faces are planar and bounded polygons.",
+        "description": "The IfcFacetedBrep is a manifold solid brep with the restriction that all faces are planar and bounded polygons. Informal Propositions: - All the bounding loops of all the faces of all the shells in the IfcFacetedBrep shall be of type IfcPolyLoop. - All vertices shall be referenced by all polyloops, sharing the vertex. I.e., each Cartesian point shall be references by at least three polyloops.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcfacetedbrep.htm"
     },
     "IfcFacetedBrepWithVoids": {
         "attributes": {
             "Voids": "Set of closed shells defining voids within the solid."
         },
-        "description": "The IfcFacetedBrepWithVoids is a specialization of a faceted B-rep which contains one or more voids in its interior. The voids are represented as closed shells which are defined so that the shell normal point into the void.",
+        "description": "The IfcFacetedBrepWithVoids is a specialization of a faceted B-rep which contains one or more voids in its interior. The voids are represented as closed shells which are defined so that the shell normal point into the void. Informal Propositions: - Each void shell shall be disjoint from the outer shell and from every other void shell - Each void shell shall be enclosed within the outer shell but not within any other void shell. In particular the outer shell is not in the set of void shells - Each shell in the IfcManifoldSolidBrep shall be referenced only once. - All the bounding loops of all the faces of all the shells in the IfcFacetedBrep shall be of type IfcPolyLoop.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcfacetedbrepwithvoids.htm"
     },
     "IfcFailureConnectionCondition": {
@@ -2749,7 +2749,7 @@
             "TensionFailureY": "Tension force in y-direction leading to failure of the connection.",
             "TensionFailureZ": "Tension force in z-direction leading to failure of the connection."
         },
-        "description": "Defines forces at which a support or connection fails.",
+        "description": "Defines forces at which a support or connection fails. Applicability: - Point supports and connections.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcfailureconnectioncondition.htm"
     },
     "IfcFan": {
@@ -2768,7 +2768,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcfan.htm"
     },
     "IfcFanType": {
-        "description": "The flow moving device type IfcFanType defines commonly shared information for occurrences of fans. The set of shared information may include:",
+        "description": "The flow moving device type IfcFanType defines commonly shared information for occurrences of fans. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a fan type specification indicating the specific product information that is common to all occurrences of that product type. The IfcFanType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcFanType are represented by instances of IfcFan. Refer to the documentation at IfcFan for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CENTRIFUGALAIRFOIL": "Air flows through the impeller radially using blades that are airfoil shaped.",
             "CENTRIFUGALBACKWARDINCLINEDCURVED": "Air flows through the impeller radially using blades that are backward curved.",
@@ -2794,7 +2794,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedcomponentelements/lexical/ifcfastener.htm"
     },
     "IfcFastenerType": {
-        "description": "The element component type IfcFastenerType defines commonly shared information for occurrences of fasteners. The set of shared information may include:",
+        "description": "The element component type IfcFastenerType defines commonly shared information for occurrences of fasteners. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a fastener type specification indicating the specific product information that is common to all occurrences of that product type. The IfcFastenerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcFastenerType are represented by instances of IfcFastener.",
         "predefined_types": {
             "GLUE": "A fastening connection where glue is used to join together elements.",
             "MORTAR": "A composition of mineralic or other materials used to fill jointing gaps and possibly fulfilling a load carrying role.",
@@ -2805,21 +2805,21 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedcomponentelements/lexical/ifcfastenertype.htm"
     },
     "IfcFeatureElement": {
-        "description": "A feature element is a generalization of all existence dependent elements which modify the shape and appearance of the associated master element. The IfcFeatureElement offers the ability to handle shape modifiers as semantic objects within the IFC object model.",
+        "description": "A feature element is a generalization of all existence dependent elements which modify the shape and appearance of the associated master element. The IfcFeatureElement offers the ability to handle shape modifiers as semantic objects within the IFC object model. In contrary to the aggregation, as used in IfcElementAssembly, that defines the aggregate as a container element, that has equally treated parts, the feature concept introduced by IfcFeatureElement defines the master element with subordinate parts as additions, or with voids or cut-outs as subtractions.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcfeatureelement.htm"
     },
     "IfcFeatureElementAddition": {
         "attributes": {
             "ProjectsElements": "Reference to the _IfcRelProjectsElement_ relationship that uses this _IfcFeatureElementAddition_ to create a volume addition at an element. The _IfcFeatureElementAddition_ can only be used to create a single addition at a single element using Boolean addition operation."
         },
-        "description": "A feature element addition is a specialization of the general feature element, that represents an existence dependent element which modifies the shape and appearance of the associated master element. The IfcFeatureElementAddition offers the ability to handle shape modifiers as semantic objects within the IFC object model that add to the shape of the master element.",
+        "description": "A feature element addition is a specialization of the general feature element, that represents an existence dependent element which modifies the shape and appearance of the associated master element. The IfcFeatureElementAddition offers the ability to handle shape modifiers as semantic objects within the IFC object model that add to the shape of the master element. The IfcFeatureElementAddition is associated to its master element by virtue of the objectified relationship IfcRelProjectsElement. This relationship implies a Boolean 'union' operation between the shape of the master element and the shape of the addition feature. The local placement for IfcFeatureElementAddition is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. The local placement is always defined in relation to the local placement of the element to which the feature element is added: - The PlacementRelTo relationship of IfcLocalPlacement shall point to the local placement of the same IfcElement, which is used in the HasAdditionFeature.RelatingElement inverse attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcfeatureelementaddition.htm"
     },
     "IfcFeatureElementSubtraction": {
         "attributes": {
             "VoidsElements": "Reference to the Voids Relationship that uses this Opening Element to create a void within an Element. The Opening Element can only be used to create a single void within a single Element."
         },
-        "description": "The IfcFeatureElementSubtraction is specialization of the general feature element, that represents an existence dependent elements which modifies the shape and appearance of the associated master element. The IfcFeatureElementSubtraction offers the ability to handle shape modifiers as semantic objects within the IFC object model that subtract from the shape of the master element.",
+        "description": "The IfcFeatureElementSubtraction is specialization of the general feature element, that represents an existence dependent elements which modifies the shape and appearance of the associated master element. The IfcFeatureElementSubtraction offers the ability to handle shape modifiers as semantic objects within the IFC object model that subtract from the shape of the master element. The voiding relationship between a master element and a subtraction feature is geometrically resolved by a Boolean difference operation. The local placement for IfcFeatureElementSubtraction is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. The local placement is always defined in relation to the local placement of the building element from which the feature element substration is substracted: - The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcElement, which is used in the VoidsElements.RelatingElement inverse attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcfeatureelementsubtraction.htm"
     },
     "IfcFillAreaStyle": {
@@ -2827,7 +2827,7 @@
             "FillStyles": "The set of fill area styles to use in presenting visible curve segments, annotation fill areas or surfaces.",
             "ModelorDraughting": "Indication whether the length measures provided for the presentation style are model based, or draughting based."
         },
-        "description": "An IfcFillAreaStyle provides the style table for presentation information assigned to annotation fill areas or surfaces for hatching and tiling. The IfcFillAreaStyle_defines hatches as model hatches, that is, the distance between hatch lines, or the curve patterns of hatch lines are given in model space dimensions (that have to be scaled using the target plot scale). The _IfcFillAreaStyle allows for the following combinations of defining the style of hatching and tiling:",
+        "description": "An IfcFillAreaStyle provides the style table for presentation information assigned to annotation fill areas or surfaces for hatching and tiling. The IfcFillAreaStyle_defines hatches as model hatches, that is, the distance between hatch lines, or the curve patterns of hatch lines are given in model space dimensions (that have to be scaled using the target plot scale). The _IfcFillAreaStyle allows for the following combinations of defining the style of hatching and tiling: - Solid fill for areas and surfaces by only assigning IfcColour to the set of FillStyles. It then provides the background colour for the filled area or surface. - Vector based hatching for areas and surfaces based on a single row of hatch lines by assigning a single instance of IfcFillAreaStyleHatching to the set of FillStyles. If an instance of IfcColour is assigned in addition to the set of FillStyles, it provides the background colour for the hatching. - Vector based hatching for areas and surfaces based on two (potentially crossing) rows of hatch lines by assigning two instances of IfcFillAreaStyleHatching to the set of FillStyles. If an instance of IfcColour is assigned in addition to the set of FillStyles, it provides the background colour for the hatching. - Externally defined hatch style by assigning a single instance of IfcExternallyDefinedHatchStyle to the set of FillStyles. If an instance of IfcColour is assigned in addition to the set of FillStyles, it provides the background colour for the hatching. Measures given to a hatch or tile pattern are given in global drawing length units. The measure values for hatch or tile pattern apply to the model space with a target plot scale provided for the correct appearance in the default plot scale. For different scale and projection dependent fill area styles a different instance of IfcFillAreaStyle needs to be used by IfcPresentationStyleAssignment for different IfcGeometricRepresentationSubContext dependent representations. An IfcFillAreaStyle can be assigned to IfcFillArea via the IfcPresentationStyleAssignment through an intermediate IfcStyledItem or subtype IfcAnnotationFillAreaOccurrence.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcfillareastyle.htm"
     },
     "IfcFillAreaStyleHatching": {
@@ -2838,7 +2838,7 @@
             "PointOfReferenceHatchLine": "A Cartesian point which defines the offset of the reference hatch line from the origin of the (virtual) hatching coordinate system. The origin is used for mapping the fill area style hatching onto an annotation fill area or surface. The reference hatch line would then appear with this offset from the fill style target point.   If not given the reference hatch lines goes through the origin of the (virtual) hatching coordinate system.",
             "StartOfNextHatchLine": "A repetition factor that determines the distance between adjacent hatch lines. The factor can either be defined by a parallel offset, or by a repeat factor provided by _IfcVector_."
         },
-        "description": "The IfcFillAreaStyleHatching is used to define simple, vector-based hatching patterns, based on styled straight lines. The curve font, color and thickness is given by the HatchLineAppearance, the angle by the HatchLineAngle and the distance to the next hatch line by StartOfNextHatchLine, being either an offset distance or a vector.",
+        "description": "The IfcFillAreaStyleHatching is used to define simple, vector-based hatching patterns, based on styled straight lines. The curve font, color and thickness is given by the HatchLineAppearance, the angle by the HatchLineAngle and the distance to the next hatch line by StartOfNextHatchLine, being either an offset distance or a vector. For better control of the hatching appearance, when using hatch lines with other fonts then continuous, the PatternStart allows to offset the start of the curve font pattern along the reference hatch line (if not given, the PatternStart is at zero distance from the virtual point of origin). If the reference hatch line does not go through the origin (of the virtual hatching coordinate system), it can be offset by using the PatternStart . Figure 1 illustrates hatch attributes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcfillareastylehatching.htm"
     },
     "IfcFillAreaStyleTiles": {
@@ -2847,7 +2847,7 @@
             "TilingPattern": "A two direction repeat factor defining the shape and relative positioning of the tiles.",
             "TilingScale": "The scale factor applied to each tile as it is placed in the annotation fill area."
         },
-        "description": "The IfcFillAreaStyleTiles defines the filling of an IfcAnnotationFillArea by recurring patterns of styled two dimensional geometry, called a tile. The recurrence pattern is determined by two vectors, that multiply the tile in regular form.",
+        "description": "The IfcFillAreaStyleTiles defines the filling of an IfcAnnotationFillArea by recurring patterns of styled two dimensional geometry, called a tile. The recurrence pattern is determined by two vectors, that multiply the tile in regular form. The two vectors act as a two dimensional repeat factor that determins eight new positions for the tiles.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcfillareastyletiles.htm"
     },
     "IfcFilter": {
@@ -2865,7 +2865,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcfilter.htm"
     },
     "IfcFilterType": {
-        "description": "The flow treatment device type IfcFilterType defines commonly shared information for occurrences of filters. The set of shared information may include:",
+        "description": "The flow treatment device type IfcFilterType defines commonly shared information for occurrences of filters. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a filter type specification indicating the specific product information that is common to all occurrences of that product type. The IfcFilterType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcFilterType are represented by instances of IfcFilter. Refer to the documentation at IfcFilter for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "AIRPARTICLEFILTER": "A filter used to remove particulates from air.",
             "COMPRESSEDAIRFILTER": "A filter used to remove particulates from compressed air.",
@@ -2879,7 +2879,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcfiltertype.htm"
     },
     "IfcFireSuppressionTerminal": {
-        "description": "A fire suppression terminal has the purpose of delivering a fluid (gas or liquid) that will suppress a fire.",
+        "description": "A fire suppression terminal has the purpose of delivering a fluid (gas or liquid) that will suppress a fire. A fire suppression terminal provides for all forms of sprinkler, spreader and other form of terminal that is connected to a pipework system and intended to act in the role of suppressing a fire.",
         "predefined_types": {
             "BREECHINGINLET": "Symmetrical pipe fitting that unites two or more inlets into a single pipe. A breeching inlet may be used on either a wet or dry riser. Used by fire services personnel for fast connection of fire appliance hose reels. May also be used for foam.",
             "FIREHYDRANT": "Device, fitted to a pipe, through which a temporary supply of water may be provided.  May also be termed a stand pipe.",
@@ -2892,7 +2892,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcplumbingfireprotectiondomain/lexical/ifcfiresuppressionterminal.htm"
     },
     "IfcFireSuppressionTerminalType": {
-        "description": "The flow terminal type IfcFireSuppressionTerminalType defines commonly shared information for occurrences of fire suppression terminals. The set of shared information may include:",
+        "description": "The flow terminal type IfcFireSuppressionTerminalType defines commonly shared information for occurrences of fire suppression terminals. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a fire suppression terminal type specification indicating the specific product information that is common to all occurrences of that product type. The IfcFireSuppressionTerminalType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcFireSuppressionTerminalType are represented by instances of IfcFireSuppressionTerminal. Refer to the documentation at IfcFireSuppressionTerminal for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BREECHINGINLET": "Symmetrical pipe fitting that unites two or more inlets into a single pipe. A breeching inlet may be used on either a wet or dry riser. Used by fire services personnel for fast connection of fire appliance hose reels. May also be used for foam.",
             "FIREHYDRANT": "Device, fitted to a pipe, through which a temporary supply of water may be provided.  May also be termed a stand pipe.",
@@ -2911,7 +2911,7 @@
             "FixedReference": "The direction providing the fixed axis1 (x-axis) direction for orienting the swept area during the sweeping operation along the _Directrix_.",
             "StartParam": "The parameter value on the _Directrix_ at which the sweeping operation commences. If no value is provided the start of the sweeping operation is at the start of the Directrix."
         },
-        "description": "An IfcFixedReferenceSweptAreaSolid is a type of swept area solid which is the result of sweeping an area along a Directrix. The swept area is provided by a subtype of IfcProfileDef. The profile is placed by an implicit cartesian transformation operator at the start point of the sweep, where the profile normal agrees to the tangent of the directrix at this point, and the profile's x-axis agrees to the FixedReference direction. The orientation of the curve during the sweeping operation is controlled by the FixedReference direction.",
+        "description": "An IfcFixedReferenceSweptAreaSolid is a type of swept area solid which is the result of sweeping an area along a Directrix. The swept area is provided by a subtype of IfcProfileDef. The profile is placed by an implicit cartesian transformation operator at the start point of the sweep, where the profile normal agrees to the tangent of the directrix at this point, and the profile's x-axis agrees to the FixedReference direction. The orientation of the curve during the sweeping operation is controlled by the FixedReference direction. The SweptArea is swept along the Directrix in such a way that the origin of the local coordinate system used to define the SweptArea is on the Directrix and the local X axis is in the direction of the projection of FixedReference onto the normal plane to the directrix at this point. The resulting solid has the property that the cross section of the surface by the normal plane to the Directrix at any point is a copy of the SweptArea. The resulting swept solid is placed by the Position coordinate system. The Directrix and the ReferenceSurface are positioned within the object coordinate system. The start of the sweeping operation is at the StartParam, the parameter value is provided based on the curve parameterization. If no StartParam is provided the start defaults to the begin of the directrix. The end of the sweeping operation is at the EndParam, the parameter value is provided based on the curve parameterization. If no EndParam is provided the end defaults to the end of the directrix. The orientation of the SweptArea as it sweeps along the Directrix is precisely defined by a CartesianTransformationOperator3d with attributes: - LocalOrigin as point (0; 0; 0), - Axis1 as the FixedReference. - Axis3 as the direction of the tangent vector t at the point of the Directrix with parameter u. The remaining attributes are defaulted to define a corresponding transformation matrix T(u), which varies with the Directrix parameter u. Informal Propositions: - The SweptArea shall lie in the plane z = 0. - The FixedReference shall not be parallel to a tangent vector to the directrix at any point along this curve. - The Directrix curve shall be tangent continuous.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcfixedreferencesweptareasolid.htm"
     },
     "IfcFlowController": {
@@ -2919,7 +2919,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowcontroller.htm"
     },
     "IfcFlowControllerType": {
-        "description": "The element type IfcFlowControllerType defines a list of commonly shared property set definitions of a flow controller and an optional set of product representations. It is used to define a flow controller specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowControllerType defines a list of commonly shared property set definitions of a flow controller and an optional set of product representations. It is used to define a flow controller specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow controller type is used to define the common properties of a flow controller that may be applied to many occurrences of that type. A flow controller is a device that regulates flow within a distribution system, such as a valve in a piping system, modulating damper in an air distribution system, or electrical switch in an electrical distribution system. Flow controller types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. Occurrences of the IfcFlowControllerType are represented by instances of IfcFlowController or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowcontrollertype.htm"
     },
     "IfcFlowFitting": {
@@ -2927,11 +2927,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowfitting.htm"
     },
     "IfcFlowFittingType": {
-        "description": "The element type IfcFlowFittingType defines a list of commonly shared property set definitions of a flow fitting and an optional set of product representations. It is used to define a flow fitting specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowFittingType defines a list of commonly shared property set definitions of a flow fitting and an optional set of product representations. It is used to define a flow fitting specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow fitting type is used to define the common properties of a flow fitting that may be applied to many occurrences of that type. A flow fitting is a device that is used to interconnect flow segments or other fittings within a distribution system, such as a tee in a ducted system that branches flow into two directions, or a junction box in an electrical distribution system. Flow fitting types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. Occurrences of the IfcFlowFittingType are represented by instances of IfcFlowFitting or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowfittingtype.htm"
     },
     "IfcFlowInstrument": {
-        "description": "A flow instrument reads and displays the value of a particular property of a system at a point, or displays the difference in the value of a property between two points.",
+        "description": "A flow instrument reads and displays the value of a particular property of a system at a point, or displays the difference in the value of a property between two points. Instrumentation is typically for the purpose of determining the value of the property at a point in time. It is not the purpose of an instrument to record or integrate the values over time (although they may be connected to recording devices that do perform such a function). This entity provides for all forms of mechanical flow instrument (thermometers, pressure gauges etc.) and electrical flow instruments (ammeters, voltmeters etc.)",
         "predefined_types": {
             "AMMETER": "A device that reads and displays the current flow in a circuit.",
             "FREQUENCYMETER": "A device that reads and displays the electrical frequency of an alternating current circuit.",
@@ -2947,7 +2947,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcbuildingcontrolsdomain/lexical/ifcflowinstrument.htm"
     },
     "IfcFlowInstrumentType": {
-        "description": "The distribution control element type IfcFlowInstrumentType defines commonly shared information for occurrences of flow instruments. The set of shared information may include:",
+        "description": "The distribution control element type IfcFlowInstrumentType defines commonly shared information for occurrences of flow instruments. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a flow instrument type specification indicating the specific product information that is common to all occurrences of that product type. The IfcFlowInstrumentType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcFlowInstrumentType are represented by instances of IfcFlowInstrument. Refer to the documentation at IfcFlowInstrument for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "AMMETER": "A device that reads and displays the current flow in a circuit.",
             "FREQUENCYMETER": "A device that reads and displays the electrical frequency of an alternating current circuit.",
@@ -2975,7 +2975,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcflowmeter.htm"
     },
     "IfcFlowMeterType": {
-        "description": "The flow controller type IfcFlowMeterType defines commonly shared information for occurrences of flow meters. The set of shared information may include:",
+        "description": "The flow controller type IfcFlowMeterType defines commonly shared information for occurrences of flow meters. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a flow meter type specification indicating the specific product information that is common to all occurrences of that product type. The IfcFlowMeterType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcFlowMeterType are represented by instances of IfcFlowMeter. Refer to the documentation at IfcFlowMeter for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "ENERGYMETER": "An electric meter or energy meter is a device that measures the amount of electrical energy supplied to or produced by a residence, business or machine.",
             "GASMETER": "A device that measures the quantity of a gas or fuel.",
@@ -2991,15 +2991,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowmovingdevice.htm"
     },
     "IfcFlowMovingDeviceType": {
-        "description": "The element type IfcFlowMovingDeviceType defines a list of commonly shared property set definitions of a flow moving device and an optional set of product representations. It is used to define a flow moving device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowMovingDeviceType defines a list of commonly shared property set definitions of a flow moving device and an optional set of product representations. It is used to define a flow moving device specification (i.e. the specific product information, that is common to all occurrences of that product type). A flow moving type is used to define the common properties of a flow moving device that may be applied to many occurrences of that type. A flow moving device is a device that is used to produce a pressure differential in a distribution system, such as a pump, fan, or compressor. Flow moving types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowMovingDeviceType are represented by instances of IfcFlowMovingDevice or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowmovingdevicetype.htm"
     },
     "IfcFlowSegment": {
-        "description": "The distribution flow element IfcFlowSegment defines the occurrence of a segment of a flow distribution system.",
+        "description": "The distribution flow element IfcFlowSegment defines the occurrence of a segment of a flow distribution system. The IfcFlowSegment defines a particular occurrence of a segment inserted in the spatial context of a project. The parameters defining the type of the segment and/or its shape are defined by the IfcFlowSegmentType, which is related by the inverse relationship IsDefinedBy pointing to IfcRelDefinesByType.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowsegment.htm"
     },
     "IfcFlowSegmentType": {
-        "description": "The element type IfcFlowSegmentType defines a list of commonly shared property set definitions of a flow segment and an optional set of product representations. It is used to define a flow segment specification (the specific product information, that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowSegmentType defines a list of commonly shared property set definitions of a flow segment and an optional set of product representations. It is used to define a flow segment specification (the specific product information, that is common to all occurrences of that product type). A flow segment type is used to define the common properties of a flow segment that may be applied to many occurrences of that type. A flow segment is a section of a distribution system, such as a duct, pipe, or conduit, that typically has only two ports. Flow segment types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. Occurrences of the IfcFlowSegmentType are represented by instances of IfcFlowSegment or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowsegmenttype.htm"
     },
     "IfcFlowStorageDevice": {
@@ -3007,7 +3007,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowstoragedevice.htm"
     },
     "IfcFlowStorageDeviceType": {
-        "description": "The element type IfcFlowStorageDeviceType defines a list of commonly shared property set definitions of a flow storage device and an optional set of product representations. It is used to define a flow storage device specification (the specific product information that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowStorageDeviceType defines a list of commonly shared property set definitions of a flow storage device and an optional set of product representations. It is used to define a flow storage device specification (the specific product information that is common to all occurrences of that product type). A flow storage device is a device used for the temporary storage of a fluid (such as a tank) or the voltage potential induced by the induced electron flow (such as a battery). Flow storage types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowStorageDeviceType are represented by instances of IfcFlowStorageDevice or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowstoragedevicetype.htm"
     },
     "IfcFlowTerminal": {
@@ -3015,7 +3015,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowterminal.htm"
     },
     "IfcFlowTerminalType": {
-        "description": "The element type IfcFlowTerminalType defines a list of commonly shared property set definitions of a flow terminal and an optional set of product representations. It is used to define a flow terminal specification (the specific product information that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowTerminalType defines a list of commonly shared property set definitions of a flow terminal and an optional set of product representations. It is used to define a flow terminal specification (the specific product information that is common to all occurrences of that product type). A flow terminal type is used to define the common properties of a flow terminal that may be applied to many occurrences of that type. A flow terminal acts as a terminus or beginning element in a distribution system such as a ceiling register in a ducted air distribution system, a sink in a waste-water system, or a light fixture in an electrical lighting system. Flow terminal types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowTerminalType are represented by instances of IfcFlowTerminal or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowterminaltype.htm"
     },
     "IfcFlowTreatmentDevice": {
@@ -3023,7 +3023,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowtreatmentdevice.htm"
     },
     "IfcFlowTreatmentDeviceType": {
-        "description": "The element type IfcFlowTreatmentDeviceType defines a list of commonly shared property set definitions of a flow treatment device and an optional set of product representations. It is used to define a flow treatment device specification (the specific product information that is common to all occurrences of that product type).",
+        "description": "The element type IfcFlowTreatmentDeviceType defines a list of commonly shared property set definitions of a flow treatment device and an optional set of product representations. It is used to define a flow treatment device specification (the specific product information that is common to all occurrences of that product type). A flow treatment device is a device used to change the physical properties of the medium, such as an air, oil or water filter (used to remove particulates from the fluid), or a duct silencer (used to attenuate noise). Flow treatment types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFlowTreatmentDeviceType are represented by instances of IfcFlowTreatmentDevice or its subtypes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowtreatmentdevicetype.htm"
     },
     "IfcFooting": {
@@ -3040,7 +3040,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcfooting.htm"
     },
     "IfcFootingType": {
-        "description": "The building element type IfcFootingType defines commonly shared information for occurrences of footings. The set of shared information may include:",
+        "description": "The building element type IfcFootingType defines commonly shared information for occurrences of footings. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a footing type specification indicating the specific product information that is common to all occurrences of that product type. The IfcFootingType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcFootingType are represented by instances of IfcFooting. Refer to the documentation at IfcFooting for supported property sets, materials, and composition.",
         "predefined_types": {
             "CAISSON_FOUNDATION": "A foundation construction type used in underwater construction.",
             "FOOTING_BEAM": "Footing elements that are in bending and are supported clear of the ground. They will normally span between piers, piles or pile caps. They are distinguished from beams in the building superstructure since they will normally require a lower grade of finish. They are distinguished from _STRIP_FOOTING_ since they are clear of the ground surface and hence require support to the lower face while the concrete is curing.",
@@ -3053,15 +3053,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcfootingtype.htm"
     },
     "IfcFurnishingElement": {
-        "description": "A furnishing element is a generalization of all furniture related objects. Furnishing objects are characterized as being",
+        "description": "A furnishing element is a generalization of all furniture related objects. Furnishing objects are characterized as being - pre-manufactured and assembled on-site, or - manufactured on-site (built-in) Thus furnishing elements can either be movable, or not (as the built-ins).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcfurnishingelement.htm"
     },
     "IfcFurnishingElementType": {
-        "description": "IfcFurnishingElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (the specific product information, that is common to all occurrences of that product type).",
+        "description": "IfcFurnishingElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (the specific product information, that is common to all occurrences of that product type). A furnishing element type is used to define the common properties of a certain type of a furnishing element that may be applied to many instances of that feature type to assign a specific style. Furnishing element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcFurnishingElementType are represented by instances of IfcFurnishingElement (or its subtypes).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcfurnishingelementtype.htm"
     },
     "IfcFurniture": {
-        "description": "Furniture defines complete furnishings such as a table, desk, chair, or cabinet, which may or may not be permanently attached to a building structure.",
+        "description": "Furniture defines complete furnishings such as a table, desk, chair, or cabinet, which may or may not be permanently attached to a building structure. Occurrences of furniture that are built in (where the property Pset_FurnitureTypeCommon.IsBuiltIn is asserted to be TRUE) should have their connection relationship with a building element occurrence defined through the IfcRelConnectsElements relationship.",
         "predefined_types": {
             "BED": "Furniture for sleeping.",
             "CHAIR": "Furniture for seating a single person.",
@@ -3079,7 +3079,7 @@
         "attributes": {
             "AssemblyPlace": "A designation of where the assembly is intended to take place. A selection of alternatives s provided in an enumerated list."
         },
-        "description": "The furnishing element type IfcFurnitureType defines commonly shared information for occurrences of furnitures. The set of shared information may include:",
+        "description": "The furnishing element type IfcFurnitureType defines commonly shared information for occurrences of furnitures. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a furniture type specification indicating the specific product information that is common to all occurrences of that product type. The IfcFurnitureType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcFurnitureType are represented by instances of IfcFurniture. Refer to the documentation at IfcFurniture for supported property sets, materials, and composition.",
         "predefined_types": {
             "BED": "Furniture for sleeping.",
             "CHAIR": "Furniture for seating a single person.",
@@ -3103,7 +3103,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcgeographicelement.htm"
     },
     "IfcGeographicElementType": {
-        "description": "An IfcGeographicElementType is used to define an element specification of a geographic element (i.e. the specific product information, that is common to all occurrences of that product type). Geographic element types include for different types of element that may be used to represent information within a geographical landscape external to a building. Within the world of geographic information they are referred to generally as 'features'. IfcGeographicElementType's include:",
+        "description": "An IfcGeographicElementType is used to define an element specification of a geographic element (i.e. the specific product information, that is common to all occurrences of that product type). Geographic element types include for different types of element that may be used to represent information within a geographical landscape external to a building. Within the world of geographic information they are referred to generally as 'features'. IfcGeographicElementType's include: - point features such as seating, bus shelters, signage, trees; - linear features such as layby's; - area features such as ponds, lakes, woods and forests; - drainage such as catchment, reserver or outfall. The specification of the specific types are given by the inherited attribute IfcElementType.ElementType given as an IfcLabel. Geographic element types are frequently identified in feature catalogs that are produced for particular purposes. The IfcGeographicElementType entity enables the continued use of existing feature catalogs through capture of their identity and attributes. Information from feature catalogs might be captured in various ways: - via property sets, some of which will be specifically defined within the IFC property set catalog whilst others will be created for local use; this is the form of capture that is expected to be most widely used - through use of the IFC classification model whereby features might be identified through an IfcClassificationReference with additional description; in which case, any further attributes required would still need to be captured in property sets.",
         "predefined_types": {
             "NOTDEFINED": "",
             "TERRAIN": "",
@@ -3124,11 +3124,11 @@
             "TrueNorth": "Direction of the true north, or geographic northing direction, relative to the underlying project coordinate system. It is given by a 2 dimensional direction within the xy-plane of the project coordinate system. If not present, it defaults to 0. 1., meaning that the positive Y axis of the project coordinate system equals the geographic northing direction.  > NOTE  If a geographic placement is provided using _IfcMapConversion_ then the true north is for information only. In case of inconsistency, the value provided with _IfcMapConversion_ shall take precedence.",
             "WorldCoordinateSystem": "Establishment of the engineering coordinate system (often referred to as the world coordinate system in CAD) for all representation contexts used by the project.   > NOTE  It can be used to provide better numeric stability if the placement of the building(s) is far away from the origin. In most cases however it would be set to origin: (0.,0.,0.) and directions x(1.,0.,0.), y(0.,1.,0.), z(0.,0.,1.).    If an geographic placement is provided using _IfcMapConversion_ then the _WorldCoordinateSystem_ atttibute is used to define the offset between the zero point of the local engineering coordinate system and the geographic reference point to which the _IfcMapConversion_ offset relates. In preferred practise both points (also called \"project base point\" and \"survey point\") should be coincidental. However it is possible to offset the geographic reference point from the local zero point."
         },
-        "description": "The IfcGeometricRepresentationContext defines the context that applies to several shape representations of products within a project. It defines the type of the context in which the shape representation is defined, and the numeric precision applicable to the geometric representation items defined in this context. In addition it can be used to offset the project coordinate system from a global point of origin, using the WorldCoordinateSystem attribute. The main representation context may also provide the true north direction, see Figure 1.",
+        "description": "The IfcGeometricRepresentationContext defines the context that applies to several shape representations of products within a project. It defines the type of the context in which the shape representation is defined, and the numeric precision applicable to the geometric representation items defined in this context. In addition it can be used to offset the project coordinate system from a global point of origin, using the WorldCoordinateSystem attribute. The main representation context may also provide the true north direction, see Figure 1. The use of one instance of IfcGeometricRepresentationContext to represent the model (3D) view is mandatory, the use of a second instance of IfcGeometricRepresentationContext to represent the plan (2D) view is optional (but needs to be given, if there are scale dependent plan views), the additional scale or view dependent contexts need to be handled by using the subtype IfcGeometricRepresentationSubContext pointing to the model view (or the plan view) as the ParentContext. See Figure 2 for an example using geometric representation contexts for 3D and 2D with assigned sub contexts.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcgeometricrepresentationcontext.htm"
     },
     "IfcGeometricRepresentationItem": {
-        "description": "An IfcGeometricRepresentationItem is the common supertype of all geometric items used within a representation. It is positioned within a geometric coordinate system, directly or indirectly through intervening items.",
+        "description": "An IfcGeometricRepresentationItem is the common supertype of all geometric items used within a representation. It is positioned within a geometric coordinate system, directly or indirectly through intervening items. An indirect reference to a Cartesian point or direction means that a given geometric item references the Cartesian point or direction through one or more intervening geometry or topology items.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcgeometricrepresentationitem.htm"
     },
     "IfcGeometricRepresentationSubContext": {
@@ -3142,7 +3142,7 @@
             "UserDefinedTargetView": "User defined target view, this attribute value shall be given, if the TargetView attribute is set to USERDEFINED.",
             "WorldCoordinateSystem": "ParentContext.WorldCoordinateSystem"
         },
-        "description": "IfcGeometricRepresentationSubContext defines the context that applies to several shape representations of a product being a sub context, sharing the WorldCoordinateSystem, CoordinateSpaceDimension, Precision and TrueNorth attributes with the parent IfcGeometricRepresentationContext.",
+        "description": "IfcGeometricRepresentationSubContext defines the context that applies to several shape representations of a product being a sub context, sharing the WorldCoordinateSystem, CoordinateSpaceDimension, Precision and TrueNorth attributes with the parent IfcGeometricRepresentationContext. The IfcGeometricRepresentationSubContext is used to define semantically distinguished representation types for different information content, dependent on the representation view and the target scale. It can be used to control the level of detail of the shape representation that is most applicable to this geometric representation context. In addition the sub context is used to control the later appearance of the IfcShapeRepresentation within a plot view. Each IfcProduct can then have several instances of subtypes of IfcRepresentation, each being assigned to a different IfcGeometricRepresentationSubContext). The applicable values for the inherited ContextIdentifier attribute shall be identical to the RepresentationIdentifier attrubute defined at IfcShapeRepresentation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcgeometricrepresentationsubcontext.htm"
     },
     "IfcGeometricSet": {
@@ -3160,7 +3160,7 @@
             "VAxes": "List of grid axes defining the second row of grid lines.",
             "WAxes": "List of grid axes defining the third row of grid lines. It may be given in the case of a triangular grid."
         },
-        "description": "IfcGrid ia a planar design grid defined in 3D space used as an aid in locating structural and design elements. The position of the grid (ObjectPlacement) is defined by a 3D coordinate system (and thereby the design grid can be used in plan, section or in any position relative to the world coordinate system). The position can be relative to the object placement of other products or grids. The XY plane of the 3D coordinate system is used to place the grid axes, which are 2D curves (for example, line, circle, arc, polyline).",
+        "description": "IfcGrid ia a planar design grid defined in 3D space used as an aid in locating structural and design elements. The position of the grid (ObjectPlacement) is defined by a 3D coordinate system (and thereby the design grid can be used in plan, section or in any position relative to the world coordinate system). The position can be relative to the object placement of other products or grids. The XY plane of the 3D coordinate system is used to place the grid axes, which are 2D curves (for example, line, circle, arc, polyline). The inherited attributes Name and Description can be used to define a descriptive name of the grid and to indicate the grid's purpose. A grid is defined by (normally) two, or (in case of a triangular grid) three lists of grid axes. The following figures shows some examples. A grid may support a rectangular layout as shown in Figure 1, a radial layout as shown in Figure 2, or a triangular layout as shown in Figure 3. Informal Propositions:",
         "predefined_types": {
             "IRREGULAR": "An _IfcGrid_ with u-axes, v-axes, and optionally w-axes that cannot be described by the patterns.",
             "NOTDEFINED": "Not known whether grid conforms to any standard type.",
@@ -3181,7 +3181,7 @@
             "PartOfW": "If provided, the _IfcGridAxis_ is part of the _WAxes_ of _IfcGrid_.",
             "SameSense": "Defines whether the original sense of curve is used or whether it is reversed in the context of the grid axis."
         },
-        "description": "An individual axis, IfcGridAxis, is defined in the context of a design grid. The axis definition is based on a curve of dimensionality 2. The grid axis is positioned within the XY plane of the position coordinate system defined by the IfcGrid.",
+        "description": "An individual axis, IfcGridAxis, is defined in the context of a design grid. The axis definition is based on a curve of dimensionality 2. The grid axis is positioned within the XY plane of the position coordinate system defined by the IfcGrid. The standard geometric representation of IfcGridAxis is defined using a 2D curve entity. Grid axes are normally defined by an offset to another axis. The IfcOffsetCurve2D supports this concept. Each grid axis has a sense given by the parameterization of the curve. The attribute SameSense is an indicator of whether or not the sense of the grid axis agrees with, or opposes, that of the underlying curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcgridaxis.htm"
     },
     "IfcGridPlacement": {
@@ -3189,14 +3189,14 @@
             "PlacementLocation": "Placement of the object coordinate system defined by the intersection of two grid axes.",
             "PlacementRefDirection": "Reference to either an explicit direction, or a second grid axis intersection, which defines the orientation of the grid placement."
         },
-        "description": "IfcGridPlacement provides a specialization of IfcObjectPlacement in which the placement and axis direction of the object coordinate system is defined by a reference to the design grid as defined in IfcGrid.",
+        "description": "IfcGridPlacement provides a specialization of IfcObjectPlacement in which the placement and axis direction of the object coordinate system is defined by a reference to the design grid as defined in IfcGrid. The location of the object coordinate system is given by the attribute PlacementLocation. It is defined as an IfcVirtualGridIntersection, that is, an intersection between two grid axes with optional offsets. The axis direction of the x-axis of the object coordinate system is given either: - PlacementRefDirection = NIL: by the tangent of the first grid axis (PlacementLocation.IntersectingAxes[1]) at the virtual intersection (maybe using the offset curve, if PlacementLocation.OffsetDistances is given); - PlacementRefDirection = IfcDirection: by the explicitly provided direction information; - PlacementRefDirection = IfcVirtualGridIntersection: by the tangent between the virtual grid intersection of PlacementLocation and the virtual grid intersection of PlacementRefDirection. Offsets as potentially provided in the IfcVirtualGridIntersection's of PlacementLocation and PlacementRefDirection have to be taken into account. The direction of the y-axis of the IfcGridPlacement is the orthogonal complement to the x-axis. The plane defined by the x and y axis shall be co-planar to the xy plane of the local placement of the IfcGrid. The direction of the z-axis is the orientation of the cross product of the x-axis and the y-axis, i.e. the z-axis of the IfcGridPlacement shall be co-linear to the z-axis of the local placement of the IfcGrid. The following figures show the usage of placement location and direction for an IfcGridPlacement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcgridplacement.htm"
     },
     "IfcGroup": {
         "attributes": {
             "IsGroupedBy": "Reference to the relationship _IfcRelAssignsToGroup_ that assigns the one to many group members to the _IfcGroup_ object."
         },
-        "description": "IfcGroup is an generalization of any arbitrary group. A group is a logical collection of objects. It does not have its own position, nor can it hold its own shape representation. Therefore a group is an aggregation under some non-geometrical / topological grouping aspects.",
+        "description": "IfcGroup is an generalization of any arbitrary group. A group is a logical collection of objects. It does not have its own position, nor can it hold its own shape representation. Therefore a group is an aggregation under some non-geometrical / topological grouping aspects. A group can hold any collection of objects, the relationship IfcRelAssignsToGroup is used to establish the group collection. Objects within a group are products, processes, controls, resources, actors or other groups, thus groups can be nested. An object can be part of zero, one, or many groups. Grouping relationships are not required to be hierarchical nor do they imply a dependency. Groups are assigned to other objects (such as a process or a resource) by the relationship object that refers to the corresponding object: - Process: assigned using IfcRelAssignsToProcess - Resource: assigned using IfcRelAssignsToResource - Controls: affecting the group using IfcRelAssignsToControl A group can be exchanged without having already objects within the group collection. IfcGroup does not define an own object coordinate system, nor does it have an independent shape representation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcgroup.htm"
     },
     "IfcHalfSpaceSolid": {
@@ -3205,11 +3205,11 @@
             "BaseSurface": "Surface defining side of half space.",
             "Dim": "The space dimensionality of this class, it is always 3 3"
         },
-        "description": "A half space solid divides the domain into two by a base surface. Normally, the base surface is a plane and devides the infinitive space into two and indicates the side of the half-space by agreeing or disagreeing to the normal of the plane.",
+        "description": "A half space solid divides the domain into two by a base surface. Normally, the base surface is a plane and devides the infinitive space into two and indicates the side of the half-space by agreeing or disagreeing to the normal of the plane. Figure 1 illustrates the definition of the IfcHalfSpaceSolid within a given coordinate system. The base surface is given by an unbounded plane, the red boundary is shown for visualization purposes only. Informal Propositions: - The base surface shall divide the domain into exactly two subsets. If the half space solid is of subtype boxed half space (IfcBoxedHalfSpace), the domain in question is that of the attribute enclosure. In all other cases the domain is all of space and the base surface shall be unbounded. - The base surface shall be an unbounded surface (subtype of IfcElementarySurface).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifchalfspacesolid.htm"
     },
     "IfcHeatExchanger": {
-        "description": "A heat exchanger is a device used to provide heat transfer between non-mixing media such as plate and shell and tube heat exchangers.",
+        "description": "A heat exchanger is a device used to provide heat transfer between non-mixing media such as plate and shell and tube heat exchangers. IfcHeatExchanger is commonly used on water-side distribution systems to recover energy from a liquid to another liquid (typically water-based), whereas IfcAirToAirHeatRecovery is commonly used on air-side distribution systems to recover energy from a gas to a gas (usually air).",
         "predefined_types": {
             "NOTDEFINED": "Undefined heat exchanger type.",
             "PLATE": "Plate heat exchanger.",
@@ -3219,7 +3219,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcheatexchanger.htm"
     },
     "IfcHeatExchangerType": {
-        "description": "The energy conversion device type IfcHeatExchangerType defines commonly shared information for occurrences of heat exchangers. The set of shared information may include:",
+        "description": "The energy conversion device type IfcHeatExchangerType defines commonly shared information for occurrences of heat exchangers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a heat exchanger type specification indicating the specific product information that is common to all occurrences of that product type. The IfcHeatExchangerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcHeatExchangerType are represented by instances of IfcHeatExchanger. Refer to the documentation at IfcHeatExchanger for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "NOTDEFINED": "Undefined heat exchanger type.",
             "PLATE": "Plate heat exchanger.",
@@ -3250,7 +3250,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifchumidifier.htm"
     },
     "IfcHumidifierType": {
-        "description": "The energy conversion device type IfcHumidifierType defines commonly shared information for occurrences of humidifiers. The set of shared information may include:",
+        "description": "The energy conversion device type IfcHumidifierType defines commonly shared information for occurrences of humidifiers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a humidifier type specification indicating the specific product information that is common to all occurrences of that product type. The IfcHumidifierType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcHumidifierType are represented by instances of IfcHumidifier. Refer to the documentation at IfcHumidifier for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "ADIABATICAIRWASHER": "Water vapor is added into the airstream through adiabatic evaporation using an air washing element.",
             "ADIABATICATOMIZING": "Water vapor is added into the airstream through adiabatic evaporation using an atomizing element.",
@@ -3280,14 +3280,14 @@
             "OverallWidth": "Total extent of the width, defined parallel to the x axis of the position coordinate system.",
             "WebThickness": "Thickness of the web of the I-shape. The web is centred on the x-axis and the y-axis of the position coordinate system."
         },
-        "description": "IfcIShapeProfileDef defines a section profile that provides the defining parameters of an 'I' or 'H' section. The I-shape profile has values for its overall depth, width and its web and flange thicknesses. Additionally a fillet radius, flange edge radius, and flange slope may be given. This profile definition represents an I-section which is symmetrical about its major and minor axes; top and bottom flanges are equal and centred on the web.",
+        "description": "IfcIShapeProfileDef defines a section profile that provides the defining parameters of an 'I' or 'H' section. The I-shape profile has values for its overall depth, width and its web and flange thicknesses. Additionally a fillet radius, flange edge radius, and flange slope may be given. This profile definition represents an I-section which is symmetrical about its major and minor axes; top and bottom flanges are equal and centred on the web. Figure 1 illustrates parameters of the I-shape profile definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcishapeprofiledef.htm"
     },
     "IfcImageTexture": {
         "attributes": {
             "URLReference": "Location, provided as an URI, at which the image texture is electronically published."
         },
-        "description": "An IfcImageTexture provides a 2-dimensional texture that can be applied to a surface of an geometric item and that provides lighting parameters of a surface onto which it is mapped. The texture is provided as an image file at an external location for which an URL is provided.",
+        "description": "An IfcImageTexture provides a 2-dimensional texture that can be applied to a surface of an geometric item and that provides lighting parameters of a surface onto which it is mapped. The texture is provided as an image file at an external location for which an URL is provided. The following definitions from ISO/IEC 19775-1 X3D Architecture and base components (X3D Specification) apply: - Greyscale pixels without alpha or simple transparency are treated as intensity textures. - Greyscale pixels with alpha or simple transparency are treated as intensity plus alpha textures. - RGB pixels without alpha channel or simple transparency are treated as full RGB textures. - RGB pixels with alpha channel or simple transparency are treated as full RGB plus alpha textures. - If the image specifies colours as indexed-colour (that is, palettes or colourmaps), the following semantics should be used (note that `greyscale' refers to a palette entry with equal red, green, and blue values): If all the colours in the palette are greyscale and there is no transparency chunk, it is treated as an intensity texture. If all the colours in the palette are greyscale and there is a transparency chunk, it is treated as an intensity plus opacity texture. >If any colour in the palette is not grey and there is no transparency chunk, it is treated as a full RGB texture. If any colour in the palette is not grey and there is a transparency chunk, it is treated as a full RGB plus alpha texture. - Texture nodes that require support for JPEG files shall interpret JPEG files as follows: Greyscale files (number of components equals 1) are treated as intensity textures. YCbCr files are treated as full RGB textures. No other JPEG file types are required. It is recommended that other JPEG files are treated as a full RGB textures. - Texture nodes that recommend support for GIF files shall follow the applicable semantics described above for the PNG format. The Uniform Resource Locator (URL) is a form of an URI and specified in RFC1738 by IETF. It supports resources located on a particular server being accessed by a particular protocol (usually http), and resources located at a local machine.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcimagetexture.htm"
     },
     "IfcIndexedColourMap": {
@@ -3297,7 +3297,7 @@
             "MappedTo": "Reference to the _IfcTessellatedFaceSet_ to which it applies the colours and alpha channel.",
             "Opacity": "The the opacity value, that applies equaly to all faces of the tessellated face set. 1.0 means opaque, and 0.0 completely transparent. If not provided, 1.0 is assumed (all colours are opque).  > NOTE  The definition of the alpha channel component for opacity follows the new definitions in image processing, where 0.0 means full transparency and 1.0 (or 2^bit depths^ -1) means fully opaque. This is contrary to the definition of transparency in _IfcSurfaceStyleShading_."
         },
-        "description": "The IfcIndexedColourMap provides the assignment of colour information to individual faces. It is used for colouring faces of tessellated face sets. The IfcIndexedColourMap defines an index into an indexed list of colour information. The Colours are a two-dimensional list of colours provided by three RGB values. The ColourIndex attribute corresponds to the CoordIndex of the IfcTessellatedFaceSet defining the corresponding index list of faces. The Opacity attribute provides the alpha channel for all faces of the tessellated face set.",
+        "description": "The IfcIndexedColourMap provides the assignment of colour information to individual faces. It is used for colouring faces of tessellated face sets. The IfcIndexedColourMap defines an index into an indexed list of colour information. The Colours are a two-dimensional list of colours provided by three RGB values. The ColourIndex attribute corresponds to the CoordIndex of the IfcTessellatedFaceSet defining the corresponding index list of faces. The Opacity attribute provides the alpha channel for all faces of the tessellated face set. Figure 1 shows the use of IfcTriangulatedFaceSet with colours per face.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcindexedcolourmap.htm"
     },
     "IfcIndexedPolyCurve": {
@@ -3306,7 +3306,7 @@
             "Segments": "List of straight line and circular arc segments, each providing a list of indices into the Cartesian point list. Indices should preserve consecutive connectivity between the segments, the start index of the next segment shall be identical with the end index of the previous segment.",
             "SelfIntersect": "Indication of whether the curve intersects itself or not; this is for information only."
         },
-        "description": "The IfcIndexedPolyCurve is a bounded curve with only linear and circular arc segments defined by a Cartesian point list and an optional list of segments, providing indices into the Cartesian point list. In the case that the list of Segments is not provided, all points in the IfcCartesianPointList are connected by straight line segments in the order they appear in the IfcCartesianPointList.",
+        "description": "The IfcIndexedPolyCurve is a bounded curve with only linear and circular arc segments defined by a Cartesian point list and an optional list of segments, providing indices into the Cartesian point list. In the case that the list of Segments is not provided, all points in the IfcCartesianPointList are connected by straight line segments in the order they appear in the IfcCartesianPointList. In the case that the list of Segments is provided, it is interpreted as such: - Segment of type IfcLineIndex: The first index is the start point of the poly line segment, the last index is the end point of the poly line segment. If more than two indices are included, then all intermediate indices define intermediate points of the polyline connected in the order of appearance of the indices; - Segment of type IfcArcIndex: The first index is the start point of the circular arc, the second index is a point on arc, the third index is the end point of the circular arc. The three points shall not be co-linear. In case that this informal proposition is not maintained, the arc segment shall be treated as a polyline segment. The IfcIndexedPolyCurve represents an open or a closed curve depending on the following condition: - In the case that the list of Segments is provided: If the last index of the last Segment and the first index of the first Segment are identical, then the poly curve is a closed curve, otherwise it is an open curve. - In the case that the list of Segments is not provided: If the first and the last Cartesian point in the Cartesian point list are identical, then the poly curve is a closed curve, otherwise it is an open curve. Informal Propositions: - Any two consecutive points of the IfcIndexedPolyCurve shall not be coincident after taking the Precision factor into account, given by the applicable IfcGeometricRepresentationContext. - The three points of any IfcArcIndex segment of the IfcIndexedPolyCurve shall not be colinear after taking the Precision factor into account, given by the applicable IfcGeometricRepresentationContext.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcindexedpolycurve.htm"
     },
     "IfcIndexedPolygonalFace": {
@@ -3314,7 +3314,7 @@
             "CoordIndex": "One-dimensional list with the indices for the three or more points, that define the vertices of the outer loop. If the tessellated face set is closed, indicated by _SELF\\IfcTessellatedFaceSet.Closed_, then the points, defining the outer loop, shall connect counter clockwise, as seen from the outside of the body, so that the resulting normal will point outwards. > NOTE  The coordinates of the vertices are provided by the indexed list of _SELF\\IfcTessellatedFaceSet.Coordinates.CoordList_. If the _SELF\\IfcTessellatedFaceSet.PnIndex_ is provided, the indices point into it, otherwise directly into the _IfcCartesianPointList3D_.",
             "ToFaceSet": "Reference to the _IfcPolygonalFaceSet_ for which this face is associated."
         },
-        "description": "The IfcIndexedPolygonalFace is a compact representation of a planar face being part of a face set. The vertices of the polygonal planar face are provided by 3 or more Cartesian points, defined by indices that point into an IfcCartesianPointList3D, either direcly, or via the PnIndex, if provided at IfcPolygonalFaceSet.",
+        "description": "The IfcIndexedPolygonalFace is a compact representation of a planar face being part of a face set. The vertices of the polygonal planar face are provided by 3 or more Cartesian points, defined by indices that point into an IfcCartesianPointList3D, either direcly, or via the PnIndex, if provided at IfcPolygonalFaceSet. Figure 1 shows an IfcIndexedPolygonalFace at an IfcPolygonalFaceSet not using PnIndex (the default). Figure 2 shows an IfcIndexedPolygonalFace at an IfcPolygonalFaceSet using PnIndex.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcindexedpolygonalface.htm"
     },
     "IfcIndexedPolygonalFaceWithVoids": {
@@ -3329,14 +3329,14 @@
             "MappedTo": "Reference to the _IfcTessellatedFaceSet_ to which it applies the texture map.",
             "TexCoords": "Indexable list of texture vertices."
         },
-        "description": "The IfcIndexedTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to faces of tessellated face sets.",
+        "description": "The IfcIndexedTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to faces of tessellated face sets. The IfcIndexedTextureMap defines an index into an indexed list of texture coordinates. The TexCoords are a two-dimensional list of texture coordinates provided by two parameter values. Subtypes of IfcIndexedTextureMap establish the index attribute corresponding to subtypes of IfcTessellatedFaceSet defining the corresponding index lists of vertices.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcindexedtexturemap.htm"
     },
     "IfcIndexedTriangleTextureMap": {
         "attributes": {
             "TexCoordIndex": "Index into the _IfcTextureVertexList_ for each vertex of the triangles representing the _IfcTriangulatedFaceSet_."
         },
-        "description": "The IfcIndexedTriangleTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to triangles of the IfcTriangulatedFaceSet.",
+        "description": "The IfcIndexedTriangleTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to triangles of the IfcTriangulatedFaceSet. The IfcIndexedTriangleTextureMap defines an index into an indexed list of texture coordinates. The TexCoordIndex is a two-dimensional list, where - first dimension is the unbounded list of faces corresponding to the list of triangles defined by CoordIndex at IfcTriangulatedFaceSet; - second dimension is the fixed list of three indices to texture vertices cooresponding to the fixed list of indices to vertices at IfcTriangulatedFaceSet The TexCoords defined at supertype IfcIndexedTextureMap are a two-dimensional list of texture coordinates provided by two parameter values. Each index of the second dimension list of TexCoordIndex points to a texture vertex in TexCoords. Figure 1 shows the use of IfcTriangulatedFaceSet with textures. Figure 2 illustrates an IfcTriangulatedFaceSet represented by IfcTriangulatedFaceSet.CoordIndex: ((1,6,5), (1,2,6), (6,2,7), (7,2,3), (7,8,6), (6,8,5), (5,8,1), (1,8,4), (4,2,1), (2,4,3), (4,8,7), (7,3,4)) IfcCartesianPointList.CoordList: ((0.,0.,0.), (1.,0.,0.), (1.,1.,0.), (0.,1.,0.), (0.,0.,2.), (1.,0.,2.), (1.,1.,2.), (0.,1.,2.)) IfcIndexedTriangleTextureMap.TexCoordsIndex: ((1 4 3), (1 2 4), (3 1 4), (4 1 2), (8 7 6), (6 7 5), (4 3 2), (2 3 1), (5 8 7), (8 5 6), (2 4 3), (3 1 2)) IfcTextureVertexList.TexCoordsList: ((0. -0.5), (1. -0.5), (0. 1.5), (1. 1.5), (0. 0.), (0. 1.), (1. 0.), (1. 1.))",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcindexedtriangletexturemap.htm"
     },
     "IfcInterceptor": {
@@ -3352,7 +3352,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcplumbingfireprotectiondomain/lexical/ifcinterceptor.htm"
     },
     "IfcInterceptorType": {
-        "description": "The flow treatment device type IfcInterceptorType defines commonly shared information for occurrences of interceptors. The set of shared information may include:",
+        "description": "The flow treatment device type IfcInterceptorType defines commonly shared information for occurrences of interceptors. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a interceptor type specification indicating the specific product information that is common to all occurrences of that product type. The IfcInterceptorType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcInterceptorType are represented by instances of IfcInterceptor. Refer to the documentation at IfcInterceptor for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CYCLONIC": "Removes larger liquid drops or larger solid particles.",
             "GREASE": "Chamber, on the line of a drain or discharge pipe, that prevents grease passing into a drainage system.",
@@ -3375,7 +3375,7 @@
             "OriginalValue": "An estimate of the original cost value of the inventory.",
             "ResponsiblePersons": "Persons who are responsible for the inventory."
         },
-        "description": "An inventory is a list of items within an enterprise.",
+        "description": "An inventory is a list of items within an enterprise. Various types of inventory can be included. These are identified by the range of values within the inventory type enumeration which includes space, asset, and furniture. User defined inventories can also be defined for lists of particular types of element such as may be required in operating and maintenance instructions. Such inventories should be constrained to contain a list of elements of a restricted type. There are a number of actors that can be associated with an inventory, each actor having a role. Actors within the scope of the project are indicated using the IfcRelAssignsToActor relationship in which case roles should be defined through the IfcActorRole class; otherwise principal actors are identified as attributes of the class. In the existence of both, direct attributes take precedence. There are a number of costs that can be associated with an inventory, each cost having a role. These are specified through the CurrentValue and OriginalValue attributes.",
         "predefined_types": {
             "ASSETINVENTORY": "A collection of asset instances of type IfcAsset.",
             "FURNITUREINVENTORY": "A collection of furniture instances of type IfcFurnishingElement.",
@@ -3401,7 +3401,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcirregulartimeseriesvalue.htm"
     },
     "IfcJunctionBox": {
-        "description": "A junction box is an enclosure within which cables are connected.",
+        "description": "A junction box is an enclosure within which cables are connected. Cables may be members of an electrical circuit (for electrical power systems) or be information carriers (in a telecommunications system). A junction box is typically intended to conceal a cable junction from sight, eliminate tampering or provide a safe place for electrical connection.",
         "predefined_types": {
             "DATA": "Contains cables, outlets, and/or switches for communications use.",
             "NOTDEFINED": "Undefined type.",
@@ -3411,7 +3411,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcjunctionbox.htm"
     },
     "IfcJunctionBoxType": {
-        "description": "The flow fitting type IfcJunctionBoxType defines commonly shared information for occurrences of junction boxs. The set of shared information may include:",
+        "description": "The flow fitting type IfcJunctionBoxType defines commonly shared information for occurrences of junction boxs. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a junction box type specification indicating the specific product information that is common to all occurrences of that product type. The IfcJunctionBoxType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcJunctionBoxType are represented by instances of IfcJunctionBox. Refer to the documentation at IfcJunctionBox for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "DATA": "Contains cables, outlets, and/or switches for communications use.",
             "NOTDEFINED": "Undefined type.",
@@ -3429,11 +3429,11 @@
             "Thickness": "Constant wall thickness of profile, see illustration above (= ts).",
             "Width": "Leg length, see illustration above (= b). Same as the overall width. This attribute is formally optional for historic reasons only. Whenever the width is known, it shall be provided by value."
         },
-        "description": "IfcLShapeProfileDef defines a section profile that provides the defining parameters of an L-shaped section (equilateral L profiles are also covered by this entity) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The shorter leg has the same direction as the positive Position.P[1]-axis, the longer or equal leg the same as the positive Position.P[2]-axis. The centre of the position coordinate system is in the profiles centre of the bounding box.",
+        "description": "IfcLShapeProfileDef defines a section profile that provides the defining parameters of an L-shaped section (equilateral L profiles are also covered by this entity) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The shorter leg has the same direction as the positive Position.P[1]-axis, the longer or equal leg the same as the positive Position.P[2]-axis. The centre of the position coordinate system is in the profiles centre of the bounding box. Figure 1 illustrates parameters of equal-sided and non-equal sided L-shaped section definitions.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifclshapeprofiledef.htm"
     },
     "IfcLaborResource": {
-        "description": "An IfcLaborResource is used in construction with particular skills or crafts required to perform certain types of construction or management related work.",
+        "description": "An IfcLaborResource is used in construction with particular skills or crafts required to perform certain types of construction or management related work. The purpose of an IfcLaborResource is to identify a skillset that may be required or used. The skillset identified may be (for instance) charge-hand, foreman, labourer, plumbers mate etc. and provides a designation of a particular level of skill. It can be used to identify the generic type of labour resource that is required for a purpose without having to be specific about the actor (person or organization) providing the resource occurrence. It may be particularly useful when creating an overall plan for a process or processes. For instance, within maintenance or work planning there may be a known task that needs to be done which is planned to require a 'chargehand pipe fitter'. There may be several such labour resources available and so the need to identify which will be used is not necessary at the planning stage. At a later stage, individual actors can be determined for the labour resources. This is achieved through specifying the actor through IfcActor. The actor is then identified as the labour resource occurrence through the IfcRelAssignsToResource.RelatedResource attribute. The IfcLaborResource provides the IfcRelAssignsToResource.RelatingResource attribute.",
         "predefined_types": {
             "ADMINISTRATION": "Coordination of work.",
             "CARPENTRY": "Rough carpentry including framing.",
@@ -3460,7 +3460,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifclaborresource.htm"
     },
     "IfcLaborResourceType": {
-        "description": "The resource type IfcLaborResourceType defines commonly shared information for occurrences of labour resources. The set of shared information may include:",
+        "description": "The resource type IfcLaborResourceType defines commonly shared information for occurrences of labour resources. The set of shared information may include: - common productivities - common cost rates - common properties within shared property sets It is used to define a labour resource specification (the specific resource information that is common to all occurrences of that resource). Resource types may be exchanged without being already assigned to occurrences. Occurrences of the IfcLaborResourceType are represented by instances of IfcLaborResource.",
         "predefined_types": {
             "ADMINISTRATION": "Coordination of work.",
             "CARPENTRY": "Rough carpentry including framing.",
@@ -3491,7 +3491,7 @@
             "DurationType": "The allowed types of task duration that specify the lag time     measurement (work time or elapsed time).",
             "LagValue": "Value of the time lag selected as being either a ratio or a     time measure."
         },
-        "description": "IfcLagTime describes the time parameters that may exist within a sequence relationship between two processes.",
+        "description": "IfcLagTime describes the time parameters that may exist within a sequence relationship between two processes. An IfcLagTime provides information about the time lag that exists between the predecessor and successor process in a sequence. The assertion of the time lag is optional for a sequence but for work schedules that specifically deal with processes occurring at particular times, it should be asserted. A lag time has a duration type. This allows the identification of whether elapsed time or work time is being measured (where work time is the estimate of the time required to complete the process and elapsed time being the amount of time actually allocated to the process) The form of measurement of the duration can be captured. Allowed values for this are MEASURED, PREDICTED or SIMULATED. The selection of this value depends on the use of the schedule. A NOTDEFINED value is also allowed. The value of the time lag may be selected as being either a percentage ratio or an actual time measure. If selected as a ratio, the percentage should apply to the duration of the predecessor process (relating process) such that e.g. a value of 0.5 (50%) would indicate that the successor task should start when the predecessor task is 50% complete (if a START-START sequence type is used) or should wait for 50% of the duration of the predecessor process to have elapsed after the finish of the predecessor process in case of a FINISH-START sequence type. The time unit for the task duration may also be set and this may be set to any allowed unit of time measure.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifclagtime.htm"
     },
     "IfcLamp": {
@@ -3512,7 +3512,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifclamp.htm"
     },
     "IfcLampType": {
-        "description": "The flow terminal type IfcLampType defines commonly shared information for occurrences of lamps. The set of shared information may include:",
+        "description": "The flow terminal type IfcLampType defines commonly shared information for occurrences of lamps. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a lamp type specification indicating the specific product information that is common to all occurrences of that product type. The IfcLampType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcLampType are represented by instances of IfcLamp. Refer to the documentation at IfcLamp for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "COMPACTFLUORESCENT": "A fluorescent lamp having a compact form factor produced by shaping the tube.",
             "FLUORESCENT": "A typically tubular discharge lamp in which most of the light is emitted by one or several layers of phosphors excited by ultraviolet radiation from the discharge.",
@@ -3539,7 +3539,7 @@
             "Version": "Identifier for the library version used for reference.",
             "VersionDate": "Date of the referenced version of the library."
         },
-        "description": "An IfcLibraryInformation describes a library where a library is a structured store of information, normally organized in a manner which allows information lookup through an index or reference value. IfcLibraryInformation provides the library Name and optional Description, Version, VersionDate and Publisher attributes. A Location may be added for electronic access to the library.",
+        "description": "An IfcLibraryInformation describes a library where a library is a structured store of information, normally organized in a manner which allows information lookup through an index or reference value. IfcLibraryInformation provides the library Name and optional Description, Version, VersionDate and Publisher attributes. A Location may be added for electronic access to the library. In a broder sense, IfcLibraryInformation includes the meta data for capture the revision information when checking in library and other data into a revision control system.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifclibraryinformation.htm"
     },
     "IfcLibraryReference": {
@@ -3549,7 +3549,7 @@
             "LibraryRefForObjects": "The library reference with which objects are associated.",
             "ReferencedLibrary": "The library information that is being referenced."
         },
-        "description": "An IfcLibraryReference is a reference into a library of information by Location (provided as a URI). It also provides an optional inherited Identification key to allow more specific references to library sections or tables. The inherited Name attribute allows for a human interpretable identification of the library item. Also, general information on the library from which the reference is taken, is given by the ReferencedLibrary relation which identifies the relevant occurrence of IfcLibraryInformation.",
+        "description": "An IfcLibraryReference is a reference into a library of information by Location (provided as a URI). It also provides an optional inherited Identification key to allow more specific references to library sections or tables. The inherited Name attribute allows for a human interpretable identification of the library item. Also, general information on the library from which the reference is taken, is given by the ReferencedLibrary relation which identifies the relevant occurrence of IfcLibraryInformation. The ifcLibraryReference additionally provides the capability to handle multilingual library entries. The Language attribute then holds the language tag for the language used by the strings kept in the Name and the Description attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifclibraryreference.htm"
     },
     "IfcLightDistributionData": {
@@ -3558,7 +3558,7 @@
             "MainPlaneAngle": "The main plane angle (A, B or C angles, according to the light distribution curve chosen).",
             "SecondaryPlaneAngle": "The list of secondary plane angles (the \u03b1, \u03b2 or \u03b3 angles) according to the light distribution curve chosen.  > NOTE  The _SecondaryPlaneAngle_ and _LuminousIntensity_ lists are corresponding lists."
         },
-        "description": "IfcLightDistributionData defines the luminous intensity of a light source given at a particular main plane angle. It is based on some standardized light distribution curves; the MainPlaneAngle is either the",
+        "description": "IfcLightDistributionData defines the luminous intensity of a light source given at a particular main plane angle. It is based on some standardized light distribution curves; the MainPlaneAngle is either the - A angle; if the IfcLightDistributionCurveEnum is set to TYPE_A - B angle; if the IfcLightDistributionCurveEnum is set to TYPE_B - C angle; if the IfcLightDistributionCurveEnum is set to TYPE_C For each MainPlaneAngle (considered as being the row of a table) a list of _SecondaryPlaneAngle'_s are given (considered to be the columns of a table). They are either the: - \u03b1 angle; if the IfcLightDistributionCurveEnum is set to TYPE_A - \u03b2 angle; if the IfcLightDistributionCurveEnum is set to TYPE_B - \u03b3 angle; if the IfcLightDistributionCurveEnum is set to TYPE_C For each pair of MainPlaneAngle and SecondaryPlaneAngle the LuminousIntensity is provided (the unit is given by the IfcUnitAssignment referring to the LuminousIntensityDistributionUnit, normally cd/klm).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationorganizationresource/lexical/ifclightdistributiondata.htm"
     },
     "IfcLightFixture": {
@@ -3573,7 +3573,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifclightfixture.htm"
     },
     "IfcLightFixtureType": {
-        "description": "The flow terminal type IfcLightFixtureType defines commonly shared information for occurrences of light fixtures. The set of shared information may include:",
+        "description": "The flow terminal type IfcLightFixtureType defines commonly shared information for occurrences of light fixtures. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a light fixture type specification indicating the specific product information that is common to all occurrences of that product type. The IfcLightFixtureType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcLightFixtureType are represented by instances of IfcLightFixture. Refer to the documentation at IfcLightFixture for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "DIRECTIONSOURCE": "A light fixture that is considered to have a length or surface area from which it emits light in a direction. A light fixture containing one or more fluorescent lamps is an example of a direction source.",
             "NOTDEFINED": "Undefined type.",
@@ -3621,7 +3621,7 @@
             "LuminousFlux": "Luminous flux is a photometric measure of radiant flux, i.e. the volume of light emitted from a light source. Luminous flux is measured either for the interior as a whole or for a part of the interior (partial luminous flux for a solid angle). All other photometric parameters are derivatives of luminous flux. Luminous flux is measured in lumens (lm). The luminous flux is given as a nominal value for each lamp.",
             "Position": "The position of the light source. It is used to orientate the light distribution curves."
         },
-        "description": "IfcLightSourceGoniometric defines a light source for which exact lighting data is available. It specifies the type of a light emitter, defines the position and orientation of a light distribution curve and the data concerning lamp and photometric information.",
+        "description": "IfcLightSourceGoniometric defines a light source for which exact lighting data is available. It specifies the type of a light emitter, defines the position and orientation of a light distribution curve and the data concerning lamp and photometric information. Figure 1 shows an example of a light emitter having two light sources (of type IfcLightSourceGoniometric).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationorganizationresource/lexical/ifclightsourcegoniometric.htm"
     },
     "IfcLightSourcePositional": {
@@ -3658,18 +3658,18 @@
             "PlacementRelTo": "Reference to Object that provides the relative placement by its local coordinate system. If it is omitted, then the local placement is given to the WCS, established by the geometric representation context.",
             "RelativePlacement": "Geometric placement that defines the transformation from the related coordinate system into the relating. The placement can be either 2D or 3D, depending on the dimension count of the coordinate system."
         },
-        "description": "An IfcLocalPlacement defines the relative placement of a product in relation to the placement of another product or the absolute placement of a product within the geometric representation context of the project.",
+        "description": "An IfcLocalPlacement defines the relative placement of a product in relation to the placement of another product or the absolute placement of a product within the geometric representation context of the project. The IfcLocalPlacement allows that an IfcProduct can be placed by this IfcLocalPlacement (through the attribute_ObjectPlacement_) within the local coordinate system of the object placement of another IfcProduct, which is referenced by the PlacementRelTo. Rules to prevent cyclic relative placements have to be introduced on the application level. If the PlacementRelTo is not given, then the IfcProduct is placed absolutely within the world coordinate system. The following conventions shall apply as default relative positions if the relative placement is used. The conventions are given for all five direct subtypes of IfcProduct, the IfcSpatialStructureElement, IfcElement, IfcAnnotation, IfcGrid, IfcPort. More detailed placement information is given at the level of subtypes of those five types mentioned. - For the subtypes of IfcSpatialStructureElement the following conventions apply IfcSite shall be placed absolutely within the world coordinate system established by the geometric representation context of the IfcProject IfcBuilding shall be placed relative to the local placement of IfcSite IfcBuildingStorey shall be placed relative to the local placement of IfcBuilding - For IfcGrid and IfcAnnotation the convention applies that it shall be placed relative to the local placement of its container, either IfcSite, IfcBuilding, or IfcBuildingStorey it should be the same container element that is referenced by the IfcRelContainedInSpatialStructure containment relationship, - For IfcPort the convention applies that it shall be placed relative to the local placement of the IfcElement it belongs to it should be the same element that is referenced by the IfcRelConnectsPortToElement connection relationship, - For IfcElement the convention applies that it shall be placed relative: to the local placement of its container, either IfcSite, IfcBuilding, or IfcBuildingStorey it should be the same container element that is referenced by the IfcRelContainedInSpatialStructure containment relationship, to the local placement of the IfcElement to which it is tied by an element composition relationship for features that are located relative to the main component (such as openings), as expressed by IfcRelVoidsElement and IfcRelProjectsElement; for elements that fill an opening (such as doors or windows), as expressed by IfcRelFillsElement; for coverings that cover the element, as expressed by IfcRelCoversBldgElements; for sub components that are aggregated to the main component, as expressed by IfcRelAggregates and IfcRelNests.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifclocalplacement.htm"
     },
     "IfcLoop": {
-        "description": "",
+        "description": "Informal Propositions: - A loop has a finite extent. - A loop describes a closed (topological) curve with coincident start and end vertices.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcloop.htm"
     },
     "IfcManifoldSolidBrep": {
         "attributes": {
             "Outer": "A closed shell defining the exterior boundary of the solid. The shell normal shall point away from the interior of the solid."
         },
-        "description": "The IfcManifoldSolidBrep is a solid represented as a collection of connected surfaces that delimit the solid from the surrounding non-solid.",
+        "description": "The IfcManifoldSolidBrep is a solid represented as a collection of connected surfaces that delimit the solid from the surrounding non-solid. Instances of type IfcManifoldSolidBrep shall be of type IfcFacetedBrep, using only IfcPolyLoop for the bounds of IfcFaceBound, or of type IfcAdvancedBrep, using only IfcAdvancedFace for the face geometry, and IfcEdgeCurve for the edges. Informal proposition: - The dimensionality of a manifold solid brep shall be 3. - The extent of the manifold solid brep shall be finite and non-zero. - All elements of the manifold solid brep shall have defined associated geometry. - The shell normals shall agree with the B-rep normal and point away from the solid represented by the B-rep. - Each face shall be referenced only once by the shells of the manifold solid brep. - The Euler equation shall be satisfied for the boundary representation, where the genus term \"shell term\" us the sum of the genus values for the shells of the brep.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcmanifoldsolidbrep.htm"
     },
     "IfcMapConversion": {
@@ -3681,7 +3681,7 @@
             "XAxisAbscissa": "Specifies the value along the easing axis of the end point of a vector indicating the position of the local x axis of the engineering coordinate reference system. > NOTE 1 for right-handed Cartesian coordinate systems this would establish the location along the x axis  > NOTE 2 together with the _XAxisOrdinate_ it provides the direction of the local x axis within the horizontal plane of the map coordinate system",
             "XAxisOrdinate": "Specifies the value along the northing axis of the end point of a vector indicating the position of the local x axis of the engineering coordinate reference system. > NOTE 1 for right-handed Cartesian coordinate systems this would establish the location along the y axis"
         },
-        "description": "The map conversion deals with transforming the local engineering coordinate system, often called world coordinate system, into the coordinate reference system of the underlying map.",
+        "description": "The map conversion deals with transforming the local engineering coordinate system, often called world coordinate system, into the coordinate reference system of the underlying map. The map conversion allows to convert the local origin of the local engineering coordinate system to its place within a map (easting, northing, orthogonal height) and to rotate the x-axis of the local engineering coordinate system within the horizontal (easting/westing) plane of the map. The scale factor can be used when the length unit for the 3 axes of the map coordinate system are not identical with the length unit established for this project (see IfcProject.UnitsInContext), if omitted, the scale factor 1.0 is assumed.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcmapconversion.htm"
     },
     "IfcMappedItem": {
@@ -3689,7 +3689,7 @@
             "MappingSource": "A representation map that is the source of the mapped item. It can be seen as a block (or cell or marco) definition.",
             "MappingTarget": "A representation item that is the target onto which the mapping source is mapped. It is constraint to be a Cartesian transformation operator."
         },
-        "description": "The IfcMappedItem is the inserted instance of a source definition (to be compared with a block / shared cell / macro definition). The instance is inserted by applying a Cartesian transformation operator as the MappingTarget.",
+        "description": "The IfcMappedItem is the inserted instance of a source definition (to be compared with a block / shared cell / macro definition). The instance is inserted by applying a Cartesian transformation operator as the MappingTarget. Informal Propositions: - A mapped item shall not be self-defining by participating in the definition of the representation being mapped. - The dimensionality of the mapping source and the mapping target has to be the same, if the mapping source is a geometric representation item.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcmappeditem.htm"
     },
     "IfcMaterial": {
@@ -3701,7 +3701,7 @@
             "Name": "Name of the material.  > EXAMPLE A view definition may require _Material.Name_ to uniquely specify e.g. concrete or steel grade, in which case the attribute Material.Category could take the value 'Concrete' or 'Steel'.  > NOTE  Material grade may have different meaning in different view definitions, e.g. strength grade for structural design and analysis, or visible appearance grade in architectural application. Also, more elaborate material grade definition may be associated as classification via inverse attribute _HasExternalReferences_.",
             "RelatesTo": "Reference to a material relationship indicating that this material composite has parts (or constituents)."
         },
-        "description": "IfcMaterial is a homogeneous or inhomogeneous substance that can be used to form elements (physical products or their components).",
+        "description": "IfcMaterial is a homogeneous or inhomogeneous substance that can be used to form elements (physical products or their components). IfcMaterial is the basic entity for material designation and definition; this includes identification by name and classification (via reference to an external classification), as well as association of material properties (isotropic or anisotropic) defined by (subtypes of) IfcMaterialProperties. An instance of IfcMaterial may be associated to an element or element type using the IfcRelAssociatesMaterial relationship. The assignment might either be direct as a single material information, or via - a material layer set - a material profile set - a material constituent set An IfcMaterial may also have presentation information associated. Such presentation information is provided by IfcMaterialDefinitionRepresentation, associating curve styles, hatching definitions or surface colouring/rendering information to a material.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmaterial.htm"
     },
     "IfcMaterialClassificationRelationship": {
@@ -3739,14 +3739,14 @@
             "HasExternalReferences": "Reference to external references, e.g. library, classification, or document information, that are associated to the material.",
             "HasProperties": "Material properties assigned to instances of subtypes of _IfcMaterialDefinition_."
         },
-        "description": "IfcMaterialDefinition is a general supertype for all material related information items in IFC that have common material related properties that may include association of material with some shape parameters or assignments to identified parts of a component.",
+        "description": "IfcMaterialDefinition is a general supertype for all material related information items in IFC that have common material related properties that may include association of material with some shape parameters or assignments to identified parts of a component. There are three ways of assigning materials to a single component or multiple components; they are characterized as: - by layer - assigning a material to a layer with constant thickness - by profile - assigning a material to a profile with a constant of varying shape along an extrusion - by constituents - assigning a material to an identified part of a component shape; the identification is by a keyword rather than by a shape parameter Each instantiable subtype of IfcMaterialDefinition may have material properties assigned, or have an external classification of its definition. It can be assigned to either a subtype of IfcElement, or a subtype of IfcElementType by using the objectified relationship IfcRelAssociatesMaterial.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmaterialdefinition.htm"
     },
     "IfcMaterialDefinitionRepresentation": {
         "attributes": {
             "RepresentedMaterial": "Reference to the material to which the representation applies."
         },
-        "description": "IfcMaterialDefinitionRepresentation defines presentation information relating to IfcMaterial. It allows for multiple presentations of the same material for different geometric representation contexts.",
+        "description": "IfcMaterialDefinitionRepresentation defines presentation information relating to IfcMaterial. It allows for multiple presentations of the same material for different geometric representation contexts. The IfcMaterialDefinitionRepresentation can apply - different presentation styles for different representation contexts, for example, a different style for sketch view, model view or plan view, or for different target scales, - for each representation context is can apply curve style, fill area style (hatching), symbol, text and surface style. Use definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcmaterialdefinitionrepresentation.htm"
     },
     "IfcMaterialLayer": {
@@ -3760,7 +3760,7 @@
             "Priority": "The relative priority of the layer, expressed as normalised integer range [0..100]. Controls how layers intersect in connections and corners of building elements: a layer from one element protrudes into (i.e. displaces) a layer from another element in a joint of these elements if the former element's layer has higher priority than the latter. The priority value for a material layer in an element has to be set and maintained by software applications in relation to the material layers in connected elements.  > NOTE  The layer priority at a connection may be overridden by the priority attributes of _IfcRelConnectsPathElements_ if that relationship is used to establish a logical connection between two building elements having a layer structure.",
             "ToMaterialLayerSet": "Reference to the _IfcMaterialLayerSet_ in which the material layer is included."
         },
-        "description": "IfcMaterialLayer is a single and identifiable part of an element which is constructed of a number of layers (one or more). Each IfcMaterialLayer has a constant thickness and is located relative to the referencing IfcMaterialLayerSet along the material layer set base (MlsBase).",
+        "description": "IfcMaterialLayer is a single and identifiable part of an element which is constructed of a number of layers (one or more). Each IfcMaterialLayer has a constant thickness and is located relative to the referencing IfcMaterialLayerSet along the material layer set base (MlsBase). Air gaps within a material layer set are represented as an IfcMaterialLayer with the attribute IsVentilated having the value TRUE or UNKNOWN. Such air gaps shall be interpreted as voids (not having a material). The IfcMaterialLayer may have a material layer name which may differ from the IfcMaterial name referenced.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmateriallayer.htm"
     },
     "IfcMaterialLayerSet": {
@@ -3770,7 +3770,7 @@
             "MaterialLayers": "Identification of the _IfcMaterialLayer_\u2019s from which the _IfcMaterialLayerSet_ is composed.",
             "TotalThickness": "Total thickness of the material layer set is derived from the function _IfcMlsTotalThickness._ IfcMlsTotalThickness(SELF)"
         },
-        "description": "The IfcMaterialLayerSet is a designation by which materials of an element constructed of a number of material layers is known and through which the relative positioning of individual layers can be expressed.",
+        "description": "The IfcMaterialLayerSet is a designation by which materials of an element constructed of a number of material layers is known and through which the relative positioning of individual layers can be expressed. The Material Layer Set Base (MlsBase) describes the imaginary axis along which the material layers are positioned. - In case of assigning the IfcMaterialLayerSet directly to an element or element type, the individual layers are stacked according to their position within the list of MaterialLayers without providing information on how to spatially relate the material layer information to the shape representation of the element or element type. - In case of assigning the IfcMaterialLayerSet through an IfcMaterialLayerSetUsage to an element, the MlsBase is positioned along the reference axis or reference plane of the element. An offset from the reference axis or plane to MlsBase is supported by IfcMaterialLayerSetUsage which combines layers and an offset. Offsets from element edges are supported by the subtype IfcMaterialLayerWithOffsets. The positive LayerSetDirection (MlsDirection) describes the direction by which the individual material layers are stacked. The IfcMaterialLayer's are stacked with no gap. Gaps within a material layer set are expressed as layers by themselves. Attribute use definition As shown in Figure 1, each IfcMaterialLayerSet implicitly defines a material layer set base line (MlsBase), to which the start of the first IfcMaterialLayer is aligned. The total thickness of a layer set is calculated from the individual layer thicknesses, the first layer starting from the MlsBase and following layers being placed on top of the previous (no gaps or overlaps).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmateriallayerset.htm"
     },
     "IfcMaterialLayerSetUsage": {
@@ -3781,7 +3781,7 @@
             "OffsetFromReferenceLine": "Offset of the material layer set base line (MlsBase) from reference geometry (line or plane) of element. The offset can be positive or negative, unless restricted for a particular building element type in its use definition or by implementer agreement. A positive value means, that the MlsBase is placed on the positive side of the reference line or plane, on the axis established by LayerSetDirection (in case of AXIS2 into the direction of +y, or in case of AXIS2 into the direction of +z). A negative value means that the MlsBase is placed on the negative side, as established by LayerSetDirection (in case of AXIS2 into the direction of -y).  > NOTE  the positive or negative sign in the offset only affects the MlsBase placement, it does not have any effect on the application of DirectionSense for orientation of the material layers; also DirectionSense does not change the MlsBase placement.",
             "ReferenceExtent": "Extent of the extrusion of the elements body shape representation to which the _IfcMaterialLayerSetUsage_ applies. It is used as the reference value for the upper _OffsetValues[2]_ provided by the _IfcMaterialLayerSetWithOffsets_ subtype for included material layers."
         },
-        "description": "The IfcMaterialLayerSetUsage determines the usage of IfcMaterialLayerSet in terms of its location and orientation relative to the associated element geometry. The location of material layer set shall be compatible with the building element geometry (that is, material layers shall fit inside the element geometry). The rules to ensure the compatibility depend on the type of the building element.",
+        "description": "The IfcMaterialLayerSetUsage determines the usage of IfcMaterialLayerSet in terms of its location and orientation relative to the associated element geometry. The location of material layer set shall be compatible with the building element geometry (that is, material layers shall fit inside the element geometry). The rules to ensure the compatibility depend on the type of the building element. The IfcMaterialLayerSetUsage is always assigned to an individual occurrence object (and only to relevant subtypes of IfcElement). The IfcMaterialLayerSet, referenced by ForLayerSet, can however be shared among several occurrence objects. If the element type is available (in other words, an instance of the relevant subtype of IfcElementType exists), then the IfcMaterialLayerSet can be assigned to the element type. The assignment between a subtype of IfcElement and the IfcMaterialLayerSetUsage is handled by IfcRelAssociatesMaterial. Attribute use definition The IfcMaterialLayerSetUsage is primarily intended to be associated with planar building elements having a constant thickness. With further agreements on the interpretation of LayerSetDirection, the usage can be extended also to other cases, for example to curved building elements, provided that the material layer thicknesses are constant. Generally, an element may be layered in any of its primary directions, denoted by its x, y or z axis. The geometry use definitions at each specific type of building element will determine the applicable LayerSetDirection. The following examples illustrate how the IfcMaterialLayerSetUsage attributes (LayerSetDirection, DirectionSense, OffsetFromReferenceLine) can be used in different cases. Normative material use definitions are documented at each element (how these shall be used). Figure 1 shows an example of the use of IfcMaterialLayerSetUsage aligned to the axis of a wall. Figure 2 shows an example of the use of IfcMaterialLayerSetUsage aligned to a slab. Figure 3 shows an example of the use of IfcMaterialLayerSetUsage aligned to a roof slab with non-perpendicular extrusion.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmateriallayersetusage.htm"
     },
     "IfcMaterialLayerWithOffsets": {
@@ -3789,7 +3789,7 @@
             "OffsetDirection": "Orientation of the offset; shall be perpendicular to the parent layer set direction.",
             "OffsetValues": "The numerical value of layer offset, in the direction of the axis assigned by the attribute _OffsetDirection_. The _OffsetValues[1]_ identifies the offset from the lower position along the axis direction (normally the start of the standard extrusion), the _OffsetValues[2]_ identifies the offset from the upper position along the axis direction (normally the end of the standard extrusion)."
         },
-        "description": "IfcMaterialLayerWithOffsets is a specialization of IfcMaterialLayer enabling definition of offset values along edges (within the material layer set usage in parent layer set).",
+        "description": "IfcMaterialLayerWithOffsets is a specialization of IfcMaterialLayer enabling definition of offset values along edges (within the material layer set usage in parent layer set). It defines the assignment of two offset values for a material layer in its intended use within a material layer set. Offsets are applied to the edges of layered elements (that is, in directions perpendicular to the layer set direction). Offsets shall not be used in layer set direction, that is, for modelling gaps (or overlaps) between layers; gaps shall be modeled as layers with appropriate material assignment for the void. Attribute use definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmateriallayerwithoffsets.htm"
     },
     "IfcMaterialList": {
@@ -3836,14 +3836,14 @@
             "CardinalEndPoint": "Index reference to a significant point in the second section profile. Describes how this section is aligned relative to the axis of the member it is associated with. This parametric specification of profile alignment can be provided redundantly to the explicit alignment defined by ForProfileSet.MaterialProfiles[\\*].Profile.",
             "ForProfileEndSet": "The second _IfcMaterialProfileSet_ set to which the usage is applied."
         },
-        "description": "IfcMaterialProfileSetUsageTapering specifies dual material profile sets in association with tapered prismatic (beam- or column-like) elements.",
+        "description": "IfcMaterialProfileSetUsageTapering specifies dual material profile sets in association with tapered prismatic (beam- or column-like) elements. Usage with tapered building elements The inherited attribute ForProfileSet specifies the profile and material at the start of the member, ForProfileEndSet at its end. Start and end correspond to the extrusion direction in the shape model of the shape representation of the element or element type. Both material profile sets should refer to the same material, that is, only differ with respect to their profiles. Usage with structural analysis curve members IfcMaterialProfileSetUsageTapering may be used with the structural analysis idealization (IfcStructuralCurveMember) of uniform members as well as of tapered members. In case of uniform members, ForProfileSet and ForProfileEndSet refer to the same material profile set. In case of tapered members, ForProfileSet specifies the profile and material at the start of the member, ForProfileEndSet at its end. Start and end correspond to the edge direction in the topological representation of the curve member.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmaterialprofilesetusagetapering.htm"
     },
     "IfcMaterialProfileWithOffsets": {
         "attributes": {
             "OffsetValues": "The numerical value of profile offset, in the direction of the axis direction - always AXIS1 that is, the axis along the extrusion path. The _OffsetValues[1]_ identifies the offset from the lower position along the axis direction (normally the start of the standard extrusion), the _OffsetValues[2]_ identifies the offset from the upper position along the axis direction (normally the end of the standard extrusion)."
         },
-        "description": "IfcMaterialProfileWithOffsets is a specialization of IfcMaterialProfile with additional longitudinal offsets .",
+        "description": "IfcMaterialProfileWithOffsets is a specialization of IfcMaterialProfile with additional longitudinal offsets . Relative positions of IfcMaterialProfileWithOffsets in the longitudinal direction of an element can be defined giving offsets at the start at the end, or at start and end. This shall not be used for relative positions of individual profiles in the plane of profile definition, which is given in composite profile definition itself. Also, care should be taken especially when used with IfcMaterialProfileSetUsageTapering for correct start and end offset assignment.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmaterialprofilewithoffsets.htm"
     },
     "IfcMaterialProperties": {
@@ -3866,7 +3866,7 @@
         "attributes": {
             "AssociatedTo": "Use of the _IfcMaterialUsageDefinition_ subtypes within the material association of an element occurrence. The association is established by the _IfcRelAssociatesMaterial_ relationship."
         },
-        "description": "IfcMaterialUsageDefinition is a general supertype for all material related information items in IFC that have occurrence specific assignment parameters to assign a set of materials with shape parameters to a reference geometry item of that component.",
+        "description": "IfcMaterialUsageDefinition is a general supertype for all material related information items in IFC that have occurrence specific assignment parameters to assign a set of materials with shape parameters to a reference geometry item of that component. There are two ways of assigning a set of materials with shape parameters: - a layer set to a reference curve - assigning a material layer set with material layers having a sequence and thickness parameter to a reference curve of an element - represented by the 'Axis' shape representation of that element - a profile set to a cardinal point - assigning a material profile set with assigned profile geometry and insertion points to a reference curve by an offset, called \"cardinal point\" - the reference curve is represented by the 'Axis' shape representation of that element Each instantiable subtype of IfcMaterialUsageDefinition has to be assigned to a subtype of IfcElement by using the objectified relationship IfcRelAssociatesMaterial; it is only valid in conjunction with an element occurrence. Informal Propositions: - It is illegal to assign a subtype of IfcMaterialUsageDefinition to a subtype of IfcElementType, it shall only be assigned to an element occurrence.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmaterialusagedefinition.htm"
     },
     "IfcMeasureWithUnit": {
@@ -3874,7 +3874,7 @@
             "UnitComponent": "The unit in which the physical quantity is expressed.",
             "ValueComponent": "The value of the physical quantity when expressed in the specified units."
         },
-        "description": "",
+        "description": "IfcMeasureWithUnit has two usages: 1. For representing measure value together with its unit on the entity type attribute level; thus overriding the IFC model global unit assignments. 2. For conversion based unit to give the conversion rate and its base.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmeasurewithunit.htm"
     },
     "IfcMechanicalFastener": {
@@ -3904,7 +3904,7 @@
             "NominalDiameter": "The nominal diameter describing the cross-section size of the fastener type.",
             "NominalLength": "The nominal length describing the longitudinal dimensions of the fastener type."
         },
-        "description": "The element component type IfcMechanicalFastenerType defines commonly shared information for occurrences of mechanical fasteners. The set of shared information may include:",
+        "description": "The element component type IfcMechanicalFastenerType defines commonly shared information for occurrences of mechanical fasteners. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a mechanical fastener type specification indicating the specific product information that is common to all occurrences of that product type. The IfcMechanicalFastenerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcMechanicalFastenerType are represented by instances of IfcMechanicalFastener. Classification Use Definition Mechanical fasteners, especially bolts, are often standardized. To refer to a formal fastener designation according to a standard (a product norm), IfcRelAssociatesClassification together with IfcClassificationReference should be used. - IfcClassificationReference.Identification contains a machine-readable form of the formal fastener designation from the norm. Example: 'M16X80-10.9-HV' for a high-strength structural bolting assembly for preloading with hexagon bolt and nut. (On the other hand, IfcMechanicalFastenerType.Name contains a displayable name which may not necessarily be the same as the formal designation.) - IfcClassificationReference.Name carries the short name of the fastener norm. Example: 'EN 14399-4' as the respective European standard for high-strength hexagon bolts. - Optionally, the norm can be further described by IfcClassificationReference.ReferencedSource, including information like publisher and date of issue of the norm. Furthermore, IfcRelAssociatesLibrary together with IfcLibraryReference may be used to refer to a library which contains fastener definitions.",
         "predefined_types": {
             "ANCHORBOLT": "A special bolt which is anchored into conrete, stone, or brickwork.",
             "BOLT": "A threaded cylindrical rod that engages with a similarly threaded hole in a nut or any other part to form a fastener. The mechanical fastener often also includes one or more washers and one or more nuts.",
@@ -3922,7 +3922,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedcomponentelements/lexical/ifcmechanicalfastenertype.htm"
     },
     "IfcMedicalDevice": {
-        "description": "A medical device is attached to a medical piping system and operates upon medical gases to perform a specific function. Medical gases include medical air, medical vacuum, oxygen, carbon dioxide, nitrogen, and nitrous oxide.",
+        "description": "A medical device is attached to a medical piping system and operates upon medical gases to perform a specific function. Medical gases include medical air, medical vacuum, oxygen, carbon dioxide, nitrogen, and nitrous oxide. Outlets for medical gasses should use IfcValve with PredefinedType equal to GASTAP, containing an IfcDistributionPort with FlowDirection=SINK and PredefinedType equal to COMPRESSEDAIR, VACUUM, or CHEMICAL, and having property sets on the port further indicating the gas type and pressure. Tanks for medical gasses should use IfcTank with PredefinedType equal to PRESSUREVESSEL, containing an IfcDistributionPort with FlowDirection=SOURCE and PredefinedType=CHEMICAL, and having property sets on the port further indicating the gas type and pressure range.",
         "predefined_types": {
             "AIRSTATION": "Device that provides purified medical air, composed of an air compressor and air treatment line.",
             "FEEDAIRUNIT": "Device that feeds air to an oxygen generator, composed of an air compressor, air treatment line, and an air receiver.",
@@ -3935,7 +3935,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcmedicaldevice.htm"
     },
     "IfcMedicalDeviceType": {
-        "description": "The flow terminal type IfcMedicalDeviceType defines commonly shared information for occurrences of medical devices. The set of shared information may include:",
+        "description": "The flow terminal type IfcMedicalDeviceType defines commonly shared information for occurrences of medical devices. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a medical device type specification indicating the specific product information that is common to all occurrences of that product type. The IfcMedicalDeviceType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcMedicalDeviceType are represented by instances of IfcMedicalDevice. Refer to the documentation at IfcMedicalDevice for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "AIRSTATION": "Device that provides purified medical air, composed of an air compressor and air treatment line.",
             "FEEDAIRUNIT": "Device that feeds air to an oxygen generator, composed of an air compressor, air treatment line, and an air receiver.",
@@ -3948,7 +3948,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcmedicaldevicetype.htm"
     },
     "IfcMember": {
-        "description": "An IfcMember is a structural member designed to carry loads between or beyond points of support. It is not required to be load bearing. The orientation of the member (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcBeam and IfcColumn). An IfcMember represents a linear structural element from an architectural or structural modeling point of view and shall be used if it cannot be expressed more specifically as either an IfcBeam or an IfcColumn.",
+        "description": "An IfcMember is a structural member designed to carry loads between or beyond points of support. It is not required to be load bearing. The orientation of the member (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcBeam and IfcColumn). An IfcMember represents a linear structural element from an architectural or structural modeling point of view and shall be used if it cannot be expressed more specifically as either an IfcBeam or an IfcColumn. There are two main representations for member occurrences: - IfcMember with IfcMaterialProfileSetUsage is used for all occurrences of members, that have a profile defined that is swept along a directrix. The profile might be changed uniformly by a taper definition along the directrix. The profile parameter and its cardinal point of insertion can be fully described by the IfcMaterialProfileSetUsage. These beams are always represented geometricly by an 'Axis' and a 'SweptSolid' or 'AdvancedSweptSolid' shape representation (or by a 'Clipping' geometry based on the swept solid), if a 3D geometric representation is assigned. In addition they have to have a corresponding IfcMaterialProfileSetUsage assigned. NOTE The entity IfcMemberStandardCase has been deprecated, IfcMember with IfcMaterialProfileSetUsage is used instead. - IfcMember without IfcMaterialProfileSetUsage is used for all other occurrences of members, particularly for members with changing profile sizes along the extrusion, or members defined by non-linear extrusion, or members having only 'Brep', or 'SurfaceModel' geometry, or if a more parametric representation is not intended.",
         "predefined_types": {
             "BRACE": "A linear element (usually sloped) often used for bracing of a girder or truss.",
             "CHORD": "Upper or lower longitudinal member of a truss, used horizontally or sloped.",
@@ -3968,11 +3968,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcmember.htm"
     },
     "IfcMemberStandardCase": {
-        "description": "The standard member, IfcMemberStandardCase, defines a member with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcMemberStandardCase handles all cases of members, that:",
+        "description": "The standard member, IfcMemberStandardCase, defines a member with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcMemberStandardCase handles all cases of members, that: - have a reference to the IfcMaterialProfileSetUsage defining the material profile association of the member with the cardinal point of its insertion relative to the local placement. - are based on a sweep of a planar profile, or set of profiles, as defined by the IfcMaterialProfileSet - have an 'Axis' shape representation with constraints provided below in the geometry use definition - have a 'Body' shape representation with constraints provided below in the geometry use definition - have a start profile, or set of profiles, that is swept along the directrix and might be changed uniformly by a taper definition - are consistent in using the correct cardinal point offset of the profile as compared to the 'Axis' and 'Body' shape representation - are extruded perpendicular to the profile definition plane",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcmemberstandardcase.htm"
     },
     "IfcMemberType": {
-        "description": "The element type IfcMemberType defines commonly shared information for occurrences of members. Members are predominately linear building elements, often forming part of a structural system. The orientation of the member (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to beam and column). The set of shared information may include:",
+        "description": "The element type IfcMemberType defines commonly shared information for occurrences of members. Members are predominately linear building elements, often forming part of a structural system. The orientation of the member (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to beam and column). The set of shared information may include: - common properties within shared property sets - common material information - common profile definitions - common shape representations It is used to define a member specification, or member style (the specific product information that is common to all occurrences of that member type). Member types may be exchanged without being already assigned to occurrences. Occurrences of the IfcMemberType within building models are represented by instances of IfcMemberStandardCase if the IfcMemberType has a single associated IfcMaterialProfileSet; otherwise they are represented by instances of IfcMember. Occurrences of the IfcMemberType within structural analysis models are represented by instances of IfcStructuralCurveMember, or its applicable subtypes.",
         "predefined_types": {
             "BRACE": "A linear element (usually sloped) often used for bracing of a girder or truss.",
             "CHORD": "Upper or lower longitudinal member of a truss, used horizontally or sloped.",
@@ -3998,14 +3998,14 @@
             "ReferencePath": "Optional path to an attribute to be constrained on associated objects. If provided, the metric may be validated by resolving the path to the current value on associated object(s), and comparing such value with _DataValue_ according to the _Benchmark_.",
             "ValueSource": "Reference source for data values.   If _DataValue_ refers to an _IfcTable_, this attribute identifies the relevent column identified by _IfcTableColumn_._Identifier_."
         },
-        "description": "An IfcMetric is used to capture quantitative resultant metrics that can be applied to objectives.",
+        "description": "An IfcMetric is used to capture quantitative resultant metrics that can be applied to objectives. IfcMetric is a subtype of IfcConstraint and may be associated with any subtype of IfcRoot through the IfcRelAssociatesConstraint relationship in the IfcControlExtension schema, or may be associated with IfcProperty by IfcResourceConstraintRelationship. The aim of IfcMetric is to capture the quantitative aspects of a constraint.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstraintresource/lexical/ifcmetric.htm"
     },
     "IfcMirroredProfileDef": {
         "attributes": {
             "Operator": "IfcRepresentationItem() || IfcGeometricRepresentationItem() || IfcCartesianTransformationOperator(     -- Axis1     IfcRepresentationItem() || IfcGeometricRepresentationItem() ||     IfcDirection([-1., 0.]),     -- Axis2     IfcRepresentationItem() || IfcGeometricRepresentationItem() ||     IfcDirection([ 0., 1.]),     -- LocalOrigin     IfcRepresentationItem() || IfcGeometricRepresentationItem() ||     IfcPoint() || IfcCartesianPoint([0., 0.]),     -- Scale     1.) || IfcCartesianTransformationOperator2D()"
         },
-        "description": "The IfcMirroredProfileDef defines the profile by mirroring the parent profile about the y axis of the parent profile coordinate system. That is, left and right of the parent profile are swapped.",
+        "description": "The IfcMirroredProfileDef defines the profile by mirroring the parent profile about the y axis of the parent profile coordinate system. That is, left and right of the parent profile are swapped. Notes: IfcMirroredProfileDef is primarily useful together with IfcCShapeProfileDef, IfcLShapeProfileDef, IfcUShapeProfileDef, or IfcZShapeProfileDef as parent profile but can be used with other parent profile types as well. Mirroring of an IfcParameterizedProfileDef is performed after translation and rotation according to its Position attribute. For example, if the parent profile's Position offsets it by half of its width to the right, then the mirrored profile will be offset by half of its width to the left. Mirroring about the x axis, i.e. swapping top and bottom, can be achieved by mirroring about the y axis coupled with 180 degree rotation about the z axis. In general, rotation happens in a containing object such as IfcSweptAreaSolid, i.e. after mirroring by IfcMirroredProfileDef was performed. If the parent profile is an IfcParameterizedProfileDef, rotation can alternatively happen already in the parent profile by means of its Position attribute, i.e. before mirroring by IfcMirroredProfileDef was performed.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcmirroredprofiledef.htm"
     },
     "IfcMonetaryUnit": {
@@ -4027,7 +4027,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcmotorconnection.htm"
     },
     "IfcMotorConnectionType": {
-        "description": "The energy conversion device type IfcMotorConnectionType defines commonly shared information for occurrences of motor connections. The set of shared information may include:",
+        "description": "The energy conversion device type IfcMotorConnectionType defines commonly shared information for occurrences of motor connections. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a motor connection type specification indicating the specific product information that is common to all occurrences of that product type. The IfcMotorConnectionType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcMotorConnectionType are represented by instances of IfcMotorConnection. Refer to the documentation at IfcMotorConnection for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BELTDRIVE": "An indirect connection made through the medium of a shaped, flexible continuous loop.",
             "COUPLING": "An indirect connection made through the medium of the viscosity of a fluid.",
@@ -4053,7 +4053,7 @@
             "IsTypedBy": "Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated _IfcTypeObject_, or its subtypes, contains the specific information (or type, or style), that is common to all instances of _IfcObject_, or its subtypes, referring to the same type.",
             "ObjectType": "The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute _PredefinedType_ is set to USERDEFINED."
         },
-        "description": "An IfcObject is the generalization of any semantically treated thing or process. Objects are things as they appear - i.e. occurrences.",
+        "description": "An IfcObject is the generalization of any semantically treated thing or process. Objects are things as they appear - i.e. occurrences. Objects can be named, using the inherited Name attribute, which should be a user recognizable label for the object occurrance. Further explanations to the object can be given using the inherited Description attribute. The ObjectType attribute is used: - to store the user defined value for all subtypes of IfcObject, where a PredefinedType attribute is given, and its value is set to USERDEFINED. - to provide a type information (could be seen as a very lightweight classifier) of the subtype of IfcObject, if no PredefinedType attribute is given. This is often the case, if no comprehensive list of predefined types is available. Objects are independent pieces of information that might contain or reference other pieces of information. There are several relationships in which objects can be involved: - Association to external/internal resource information - an association relationship that refers to external/internal sources of information. See supertype IfcObjectDefinition for more information. - Assignment of other objects - an assignment relationship that refers to other types of objects. See supertype IfcObjectDefinition for more information. - Aggregation of other objects - an aggregation relationship that establishes a whole/part relation. Objects can either be a whole, or a part, or both. See supertype IfcObjectDefinition for more information. - Assignment of a type : IsTypedBy - a definition relationship IfcRelDefinesByType that uses a type definition to define the common characteristics of this occurrences, potentially including the common shape representation and common properties of all object occurrences assigned to this type. It is a specific - occurrence relationship with implied dependencies (as the occurrence properties depend on the properties of the type, but may override them). - Assignment of a partial type : IsDeclaredBy, Declares - a definition relationship IfcRelDefinesByObject that uses a component of a type definition (a part of a type, called the \"declaring part\") to define a component of an occurence (part of occurrence, called the \"reflected part\"). This is also refered to as a \"deep copy\". The common characteristics of all parts in the occurrence are defined by parts in the type. It is a specific - occurrence relationship with implied dependencies (as the occurrence properties depend on the properties of the type, but may override them). - Assignment of property sets : IsDefinedBy - a definition relationship IfcRelDefinesByProperties that assignes property set definitions to the object occurrence. Informal Propositions: - A partial type assignment, i.e. the inverse attribute IsDeclaredBy, or Declares shall only be used, if the object is part of a decomposition, i.e. if either IsDecomposedBy, or Decomposes is exerted.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcobject.htm"
     },
     "IfcObjectDefinition": {
@@ -4066,7 +4066,7 @@
             "IsNestedBy": "References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).",
             "Nests": "References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only)."
         },
-        "description": "An IfcObjectDefinition is the generalization of any semantically treated thing or process, either being a type or an occurrences. Object defintions can be named, using the inherited Name attribute, which should be a user recognizable label for the object occurrance. Further explanations to the object can be given using the inherited Description attribute. A context is a specific kind of object definition as it provides the project or library context in which object types and object occurrences are defined.",
+        "description": "An IfcObjectDefinition is the generalization of any semantically treated thing or process, either being a type or an occurrences. Object defintions can be named, using the inherited Name attribute, which should be a user recognizable label for the object occurrance. Further explanations to the object can be given using the inherited Description attribute. A context is a specific kind of object definition as it provides the project or library context in which object types and object occurrences are defined. Objects are independent pieces of information that might contain or reference other pieces of information. There are four essential kinds of relationships in which object definitons (by their instantiable subtypes) can be involved: - Assignment of other objects - an assignment relationship (IfcRelAssigns) that refers to other types of objects and creates a bi-directional association. The semantic of the assignment is established at the level of the subtypes of the general IfcRelAssigns relationship. There is no dependency implied a priori by the assignment. - Association to external resources - an association relationship (IfcRelAssociates) that refers to external sources of information (most notably a classification or document) and creates a uni-directional association. There is no dependency implied by the association. - Aggregation of other objects - an aggregation relationship (IfcRelAggregates) that establishes an unordered, spatial whole/part relation and creates a bi-directional relation. There is an implied dependency established. - Nesting of other objects - a nesting relationship (IfcRelNests) that establishes an ordered, non-spatial whole/part relation and creates a bi-directional relation. There is an implied dependency established. - Declaration within a context - a relationship (IfcRelDeclares) of the uppermost object definition within the object definition tree (e.g. the summary object within an object nesting tree) to the context (a project or project library). It applies the units, representation context and other context information to this object definition and all dependent ones.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcobjectdefinition.htm"
     },
     "IfcObjectPlacement": {
@@ -4074,7 +4074,7 @@
             "PlacesObject": "The _IfcObjectPlacement_ shall be used to provide a placement and  an object coordinate system for instances of _IfcProduct_.",
             "ReferencedByPlacements": "Placements that are given relative to this placement of an object."
         },
-        "description": "IfcObjectPlacement is an abstract supertype for the special types defining the object coordinate system. The IfcObjectPlacement has to be provided for each product that has a shape representation.",
+        "description": "IfcObjectPlacement is an abstract supertype for the special types defining the object coordinate system. The IfcObjectPlacement has to be provided for each product that has a shape representation. The object placement can be given: - absolute: by an axis2 placement, relative to the world coordinate system, - relative: by an axis2 placement, relative to the object placement of another product, - by grid reference: by the virtual intersection and reference direction given by two axes of a design grid. In any case the object placement has to unambiguously define the object coordinate system as either two-dimensional axis placement (IfcAxis2Placement2D) or three-dimensional axis placement (IfcAxis2Placement3D). The axis placement may have to be calculated.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcobjectplacement.htm"
     },
     "IfcObjective": {
@@ -4084,11 +4084,11 @@
             "ObjectiveQualifier": "Enumeration that qualifies the type of objective constraint.",
             "UserDefinedQualifier": "A user defined value that qualifies the type of objective constraint when ObjectiveQualifier attribute of type _IfcObjectiveEnum_ has value USERDEFINED."
         },
-        "description": "An IfcObjective captures qualitative information for an objective-based constraint.",
+        "description": "An IfcObjective captures qualitative information for an objective-based constraint. IfcObjective is a subtype of IfcConstraint and may be associated with any subtype of IfcRoot through the IfcRelAssociatesConstraint relationship in the IfcControlExtension schema, or may be associated with IfcProperty by IfcResourceConstraintRelationship. The aim of IfcObjective is to specify the purpose for which the constraint is applied and to capture the benchmark metrics of the constraint.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstraintresource/lexical/ifcobjective.htm"
     },
     "IfcOccupant": {
-        "description": "An occupant is a type of actor that defines the form of occupancy of a property.",
+        "description": "An occupant is a type of actor that defines the form of occupancy of a property. The principal purpose of IfcOccupant is to determine the nature of occupancy of a property for a particular actor. All characteristics relating to the actor (name and organization details) are inherited from the IfcActor entity.",
         "predefined_types": {
             "ASSIGNEE": "Actor receiving the assignment of a property agreement from an assignor.",
             "ASSIGNOR": "Actor assigning a property agreement to an assignor.",
@@ -4118,18 +4118,18 @@
             "RefDirection": "The direction used to define the direction of the offset curve 3d from the basis curve.",
             "SelfIntersect": "An indication of whether the offset curve self-intersects, this is for information only."
         },
-        "description": "An IfcOffsetCurve3D is a curve defined by an offset in 3D space from its BasisCurve.",
+        "description": "An IfcOffsetCurve3D is a curve defined by an offset in 3D space from its BasisCurve. Informal Propositions: - At no point on the curve shall ref direction be parallel, or opposite to, the direction of the tangent vector.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcoffsetcurve3d.htm"
     },
     "IfcOpenShell": {
-        "description": "",
+        "description": "Informal Propositions: - Every edge shall be referenced exactly twice by the face bounds of the face. - Each oriented edge shall be unique. - No edge shall be referenced by more than two faces. - Distinct faces of the shell do not intersect, but may share edges or vertices. - Distinct edges do not intersect but may share vertices. - Each face reference shall be unique. - The loops of the shell shall not be a mixture of poly loop and other loop types. Note: this is given, since only poly loop is defined as face bound definition. - The closed shell shall be an oriented arcwise connected 2-manifold. - The Euler equation shall be satisfied.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcopenshell.htm"
     },
     "IfcOpeningElement": {
         "attributes": {
             "HasFillings": "Reference to the Filling Relationship that is used to assign Elements as Fillings for this Opening Element. The Opening Element can be filled with zero-to-many Elements."
         },
-        "description": "The opening element stands for opening, recess or chase, all reflecting voids. It represents a void within any element that has physical manifestation. Openings can be inserted into walls, slabs, beams, columns, or other elements.",
+        "description": "The opening element stands for opening, recess or chase, all reflecting voids. It represents a void within any element that has physical manifestation. Openings can be inserted into walls, slabs, beams, columns, or other elements. There are two main representations for opening elements: - Openings that have a constant profile along a linear extrusion. They are placed relative to the voided elements and the extrusion direction is perpendicular to the plane of the element (horizontally for walls, vertically for slabs). Only a single extrusion body is allowed. It cuts through the whole thickness of the voided element, i.e. it reflects a true opening. NOTE The entity IfcOpeningStandardCase has been deprecated. - IfcOpeningElement is used for all other occurrences of openings and in particular also for niches or recesses. There are two different types of opening elements: - an opening, where the thickness of the opening is greater or equal to the thickness of the element; - a recess or niche, where the thickness of the recess is smaller than the thickness of the element. The attribute PredefinedType should be used to capture the differences, - the attribute is set to OPENING for an opening or - the attribute is set to RECESS for a recess or niche. - If the value for PredefinedType is omitted, or the value is set to NOTDEFINED, no specific information of whether it is an opening or recess shall be assumed. An IfcOpeningElement has to be inserted into an IfcElement by using the IfcRelVoidsElement relationship. It may be filled by an IfcDoor, IfcWindow, or another filling element by using the relationship IfcRelFillsElements. Depending on the type of the IfcShapeRepresentation of the IfcOpeningElement the voiding relationship implies: - if the IfcShapeRepresentation.<emRepresentationIdentifier = 'Body', then the Body shape represntation of the opening has to be subtracted from the body shape representation of the voided element - implicit Boolean difference operation. - if the IfcShapeRepresentation.<emRepresentationIdentifier = 'Reference', then the Reference shape representation of the opening is not subtracted, it is provided in addition to the hole in the Body shape representation of the voided element. The IfcOpeningElement shall not participate in the containment relationship, i.e. it is not linked directly to the spatial structure of the project. It has a mandatory VoidsElements inverse relationship pointing to the IfcElement that is contained in the spatial structure. - The inverse relationship ContainedInStructure shall be NIL.",
         "predefined_types": {
             "NOTDEFINED": "Undefined opening element.",
             "OPENING": "An opening as subtraction feature that cuts through the element it voids. It thereby creates a hole. An opening in addiion have a particular meaning for either providing a void for doors or windows, or an opening to permit flow of air and passing of light.",
@@ -4139,7 +4139,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcopeningelement.htm"
     },
     "IfcOpeningStandardCase": {
-        "description": "The standard opening, IfcOpeningStandardCase, defines an opening with certain constraints for the dimension parameters, position within the voided element, and with certain constraints for the geometric representation. The IfcOpeningStandardCase handles all cases of openings, that:",
+        "description": "The standard opening, IfcOpeningStandardCase, defines an opening with certain constraints for the dimension parameters, position within the voided element, and with certain constraints for the geometric representation. The IfcOpeningStandardCase handles all cases of openings, that: - are true openings where the opening depth is greather than or equal to the thickness of the element, and the Predefinedtype is set correctly to .OPENING. - are true recesses where the opening depth is lower than the thickness of the element, and the Predefinedtype is set correctly to .RECESS. - are extruded perpendicular to the wall plane in case of openings in a wall - are extruded perpendicular to the slab plane in case of openings in a slab - have a local placement relative to the local placement of the voided element - have a 'Body' shape representation with 'SweptSolid' representation type - have only a single extrusion body within the 'Body' shape representation",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcopeningstandardcase.htm"
     },
     "IfcOrganization": {
@@ -4171,7 +4171,7 @@
             "EdgeStart": "The start vertex of the oriented edge. It derives from the vertices of the edge element after taking account of the orientation. IfcBooleanChoose  (Orientation, EdgeElement.EdgeStart, EdgeElement.EdgeEnd)",
             "Orientation": "BOOLEAN, If TRUE the topological orientation as used coincides with the orientation from start vertex to end vertex of the edge element. If FALSE otherwise."
         },
-        "description": "The IfcOrientedEdge represents an IfcEdge with an Orientation flag applied. It allows to reuse the same IfcEdge when traversed exactly twice, once forwards and once backwards.",
+        "description": "The IfcOrientedEdge represents an IfcEdge with an Orientation flag applied. It allows to reuse the same IfcEdge when traversed exactly twice, once forwards and once backwards. The reused edge with a geometric representation as IfcEdgeCurve defines the edge in 3D coordinate space. In some cases, particularly when using elementary or swept surfaces, there is the risk of imprecise mapping of the 3D (x, y, z) IfcEdgeCurve onto the adjacent surfaces to determine the boundaries of these surfaces. The optional CurveOnSurface defines the 2D (u, v) edge within the parametric space of the surface. It could be used to determine the correctness of the mapping of the 3D IfcEdgeCurve onto this surface.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcorientededge.htm"
     },
     "IfcOuterBoundaryCurve": {
@@ -4179,7 +4179,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcouterboundarycurve.htm"
     },
     "IfcOutlet": {
-        "description": "An outlet is a device installed at a point to receive one or more inserted plugs for electrical power or communications.",
+        "description": "An outlet is a device installed at a point to receive one or more inserted plugs for electrical power or communications. Power outlets are commonly connected within a junction box; data outlets may be directly connected to a wall. For power outlets sharing the same circuit within a junction box, the ports should indicate the logical wiring relationship to the enclosing junction box, even though they may be physically connected to a cable going to another outlet, switch, or fixture.",
         "predefined_types": {
             "AUDIOVISUALOUTLET": "An outlet used for an audio or visual device.",
             "COMMUNICATIONSOUTLET": "An outlet used for connecting communications equipment.",
@@ -4192,7 +4192,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcoutlet.htm"
     },
     "IfcOutletType": {
-        "description": "The flow terminal type IfcOutletType defines commonly shared information for occurrences of outlets. The set of shared information may include:",
+        "description": "The flow terminal type IfcOutletType defines commonly shared information for occurrences of outlets. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a outlet type specification indicating the specific product information that is common to all occurrences of that product type. The IfcOutletType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcOutletType are represented by instances of IfcOutlet. Refer to the documentation at IfcOutlet for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "AUDIOVISUALOUTLET": "An outlet used for an audio or visual device.",
             "COMMUNICATIONSOUTLET": "An outlet used for connecting communications equipment.",
@@ -4215,21 +4215,21 @@
             "OwningUser": "Direct reference to the end user who currently \"owns\" this object. Note that IFC includes the concept of ownership transfer from one user to another and therefore distinguishes between the Owning User and Creating User.",
             "State": "Enumeration that defines the current access state of the object."
         },
-        "description": "IfcOwnerHistory defines all history and identification related information. In order to provide fast access it is directly attached to all independent objects, relationships and properties.",
+        "description": "IfcOwnerHistory defines all history and identification related information. In order to provide fast access it is directly attached to all independent objects, relationships and properties. IfcOwnerHistory is used to identify the creating and owning application and user for the associated object, as well as capture the last modifying application and user. Informal Propositions: - If LastModifiedDate is defined but ChangeAction is not asserted, then the state of ChangeAction is assumed to be UNDEFINED. - If both LastModifiedDate and ChangeAction are asserted, then the state of ChangeAction applies to the value asserted in LastModifiedDate.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcutilityresource/lexical/ifcownerhistory.htm"
     },
     "IfcParameterizedProfileDef": {
         "attributes": {
             "Position": "Position coordinate system of the parameterized profile definition. If unspecified, no translation and no rotation is applied."
         },
-        "description": "The parameterized profile definition defines a 2D position coordinate system to which the parameters of the different profiles relate to. All profiles are defined centric to the origin of the position coordinate system, or more specific, the origin [0.,0.] shall be in the center of the bounding box of the profile.",
+        "description": "The parameterized profile definition defines a 2D position coordinate system to which the parameters of the different profiles relate to. All profiles are defined centric to the origin of the position coordinate system, or more specific, the origin [0.,0.] shall be in the center of the bounding box of the profile. The Position attribute of IfcParameterizedProfileDef is used to position the profile within the XY plane of the underlying coordinate system of the swept surface geometry, the swept area solid or the sectioned spine. It can be used to position the profile at any point which becomes the origin [0.,0.,0.] of the extruded or rotated surface or solid. The Position attribute should not be used if the transformation can be specified in a containing object instead. In particular, this applies if the IfcParameterizedProfileDef is referenced as SweptArea in subtypes of IfcSweptAreaSolid or as CrossSections in IfcSectionedSpine. Several subtypes of IfcParameterizedProfileDef provide shape parameters which are optional. Sending systems should always provide values for these parameters if possible. If these parameters are left unspecified, receiving systems may retrieve values for them by external reference (if a reference to an external document or library is given; see guidance at IfcProfileDef), or estimate them, or simply assume zero values.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcparameterizedprofiledef.htm"
     },
     "IfcPath": {
         "attributes": {
             "EdgeList": "The list of oriented edges which are concatenated together to form this path."
         },
-        "description": "",
+        "description": "Informal Propositions: - A path has dimensionality 1. - A path is arcwise connected. - The edges of the path do not intersect except at common vertices. - A path has a finite, non-zero extent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcpath.htm"
     },
     "IfcPcurve": {
@@ -4244,7 +4244,7 @@
         "attributes": {
             "LifeCyclePhase": "Describes the applicable building life-cycle phase. Typical values should be DESIGNDEVELOPMENT, SCHEMATICDEVELOPMENT, CONSTRUCTIONDOCUMENT, CONSTRUCTION, ASBUILT, COMMISSIONING, OPERATION, etc."
         },
-        "description": "IfcPerformanceHistory is used to document the actual performance of an occurrence instance over time. It includes machine-measured data from building automation systems and human-specified data such as task and resource usage. The data may represent actual conditions, predictions, or simulations.",
+        "description": "IfcPerformanceHistory is used to document the actual performance of an occurrence instance over time. It includes machine-measured data from building automation systems and human-specified data such as task and resource usage. The data may represent actual conditions, predictions, or simulations. The realtime data tracked by performance history takes the form of property sets where all properties are based on time series. Unlike design-based data at occurrences and types, performance-driven data is time-sensitive and may change in realtime by some measurement device. Data may be captured at irregular intervals such as when values change beyond established thresholds, or at regular intervals of specified duration. IfcPerformanceHistory may be declared within a project using IfcRelDeclares where RelatingContext refers to the IfcProject and RelatedDefinitions includes the IfcPerformanceHistory. Default units (used for property sets) are indicated by the declaring project. Only top-level objects are declared; nested performance history objects (through IfcRelNests) do not participate in such relationship.",
         "predefined_types": {
             "NOTDEFINED": "",
             "USERDEFINED": ""
@@ -4259,7 +4259,7 @@
             "PanelPosition": "Position of this permeable covering panel within the overall window or door type.",
             "ShapeAspectStyle": "Optional link to a shape aspect definition, which points to the part of the geometric representation of the window style, which is used to represent the permeable covering."
         },
-        "description": "This entity is a description of a panel within a door or window (as fillers for opening) which allows for air flow. It is given by its properties (IfcPermeableCoveringProperties). A permeable covering is a casement, such as a component, fixed or opening, consisting essentially of a frame and the infilling. The infilling is normally a grill, a louver or a screen. The way of operation is defined in the operation type.",
+        "description": "This entity is a description of a panel within a door or window (as fillers for opening) which allows for air flow. It is given by its properties (IfcPermeableCoveringProperties). A permeable covering is a casement, such as a component, fixed or opening, consisting essentially of a frame and the infilling. The infilling is normally a grill, a louver or a screen. The way of operation is defined in the operation type. The IfcPermeableCoveringProperties are included in the list of properties (HasPropertySets) of the IfcWindowStyle or the IfcDoorStyle. More information about the permeable covering can be included in the same list of the window or door style using the IfcPropertySet for dynamic extensions. This particularly applies for additional properties for the various operation types The IfcPermeableCoveringProperties does not hold a geometric representation. However it defines parameters which can be used to create the shape of the IfcWindowStyle (which is inserted by the IfcWindow into the spatial context of the project), or of the IfcDoorStyle (which is inserted by the IfcDoor). The parameters at the IfcPermeableCoveringProperties define a standard permeable covering. The outer boundary of the panel is determined by the occurrence parameter assigned to the IfcWindow or IfcDoor. It has to take the lining parameter into account as well. The position of the permeable covering within the overall window or door is determined by the PanelPosition attribute. Figure 1 illustrates the panel applied to the position within the lining, as defined by the panel position attribute. The following parameters apply to that panel: FrameDepth, FrameThickness.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcpermeablecoveringproperties.htm"
     },
     "IfcPermit": {
@@ -4308,7 +4308,7 @@
             "Quality": "Additional indication of a quality of the quantities that are grouped under this physical complex quantity.",
             "Usage": "Additional indication of a usage type of the quantities that are grouped under this physical complex quantity."
         },
-        "description": "The complex physical quantity, IfcPhysicalComplexQuantity, is an entity that holds a set of single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity), that all apply to a given component or aspect of the element.",
+        "description": "The complex physical quantity, IfcPhysicalComplexQuantity, is an entity that holds a set of single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity), that all apply to a given component or aspect of the element. A section \"Quantity Use Definition\" at individual entities as subtypes of IfcBuildingElement gives guidance to the usage of the Name and Discrimination attribute to characterize the complex quantities.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcquantityresource/lexical/ifcphysicalcomplexquantity.htm"
     },
     "IfcPhysicalQuantity": {
@@ -4318,14 +4318,14 @@
             "Name": "Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements.",
             "PartOfComplex": "Reference to a physical complex quantity in which the physical quantity may be contained."
         },
-        "description": "The physical quantity, IfcPhysicalQuantity, is an abstract entity that holds a complex or simple quantity measure together with a semantic definition of the usage for the single or several measure value.",
+        "description": "The physical quantity, IfcPhysicalQuantity, is an abstract entity that holds a complex or simple quantity measure together with a semantic definition of the usage for the single or several measure value. The Name attribute defines the actual usage or kind of measure. The interpretation of the name label has to be established within the actual exchange context. In addition an informative text may be associated to each quantity by the Description attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcquantityresource/lexical/ifcphysicalquantity.htm"
     },
     "IfcPhysicalSimpleQuantity": {
         "attributes": {
             "Unit": "Optional assignment of a unit. If no unit is given, then the global unit assignment, as established at the IfcProject, applies to the quantity measures."
         },
-        "description": "The physical quantity, IfcPhysicalSimpleQuantity, is an entity that holds a single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity) together with a semantic definition of the usage for the measure value.",
+        "description": "The physical quantity, IfcPhysicalSimpleQuantity, is an entity that holds a single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity) together with a semantic definition of the usage for the measure value. A section \"Quantity Use Definition\" at individual entities as subtypes of IfcBuildingElement gives guidance to the usage of the Name attribute to characterize the individual quantities. If the Unit attribute is given, the value attribute (introduced at the level of subtypes of IfcPhysicalSimpleQuantity) are given as quantities of this unit, otherwise the global unit definitions (given by IfcUnitAssignment) are used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcquantityresource/lexical/ifcphysicalsimplequantity.htm"
     },
     "IfcPile": {
@@ -4346,7 +4346,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcpile.htm"
     },
     "IfcPileType": {
-        "description": "The building element type IfcPileType defines commonly shared information for occurrences of piles. The set of shared information may include:",
+        "description": "The building element type IfcPileType defines commonly shared information for occurrences of piles. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a pile type specification indicating the specific product information that is common to all occurrences of that product type. The IfcPileType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcPileType are represented by instances of IfcPile. Refer to the documentation at IfcPile for supported property sets, materials, and composition.",
         "predefined_types": {
             "BORED": "A bore pile.",
             "COHESION": "A cohesion pile.",
@@ -4360,7 +4360,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcpiletype.htm"
     },
     "IfcPipeFitting": {
-        "description": "A pipe fitting is a junction or transition in a piping flow distribution system used to connect pipe segments, resulting in changes in flow characteristics to the fluid such as direction or flow rate.",
+        "description": "A pipe fitting is a junction or transition in a piping flow distribution system used to connect pipe segments, resulting in changes in flow characteristics to the fluid such as direction or flow rate. Pipe fittings include elbows, junctions, manifolds, and plumbing boxes.",
         "predefined_types": {
             "BEND": "A fitting with typically two ports used to change the direction of flow between connected elements.",
             "CONNECTOR": "Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two pipe segments).",
@@ -4375,7 +4375,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcpipefitting.htm"
     },
     "IfcPipeFittingType": {
-        "description": "The flow fitting type IfcPipeFittingType defines commonly shared information for occurrences of pipe fittings. The set of shared information may include:",
+        "description": "The flow fitting type IfcPipeFittingType defines commonly shared information for occurrences of pipe fittings. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a pipe fitting type specification indicating the specific product information that is common to all occurrences of that product type. The IfcPipeFittingType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcPipeFittingType are represented by instances of IfcPipeFitting. Refer to the documentation at IfcPipeFitting for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BEND": "A fitting with typically two ports used to change the direction of flow between connected elements.",
             "CONNECTOR": "Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two pipe segments).",
@@ -4403,7 +4403,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcpipesegment.htm"
     },
     "IfcPipeSegmentType": {
-        "description": "The flow segment type IfcPipeSegmentType defines commonly shared information for occurrences of pipe segments. The set of shared information may include:",
+        "description": "The flow segment type IfcPipeSegmentType defines commonly shared information for occurrences of pipe segments. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a pipe segment type specification indicating the specific product information that is common to all occurrences of that product type. The IfcPipeSegmentType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcPipeSegmentType are represented by instances of IfcPipeSegment. Refer to the documentation at IfcPipeSegment for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CULVERT": "A covered channel or large pipe that forms a watercourse below ground level, usually under a road or railway.",
             "FLEXIBLESEGMENT": "A flexible segment is a continuous non-linear segment of pipe that can be deformed and change the direction of flow.",
@@ -4422,7 +4422,7 @@
             "Pixel": "Flat list of hexadecimal values, each describing one pixel by 1, 2, 3, or 4 components.",
             "Width": "The number of pixels in width (S) direction."
         },
-        "description": "An IfcPixelTexture provides a 2D image-based texture map as an explicit array of pixel values (list of Pixel binary attributes). In contrary to the IfcImageTexture the IfcPixelTexture holds a 2 dimensional list of pixel color (and opacity) directly, instead of referencing to an URL.",
+        "description": "An IfcPixelTexture provides a 2D image-based texture map as an explicit array of pixel values (list of Pixel binary attributes). In contrary to the IfcImageTexture the IfcPixelTexture holds a 2 dimensional list of pixel color (and opacity) directly, instead of referencing to an URL. The following definitions from ISO/IEC 19775-1 X3D Architecture and base components (X3D Specification) apply: - The PixelTexture node defines a 2D image-based texture map as an explicit array of pixel values (image field) and parameters controlling tiling repetition of the texture onto geometry. - Texture maps are defined in a 2D coordinate system (s, t) that ranges from 0.0 to 1.0 in both directions. The bottom edge of the pixel image corresponds to the S-axis of the texture map, and left edge of the pixel image corresponds to the T-axis of the texture map. The lower-left pixel of the pixel image corresponds to s=0.0, t=0.0, and the top-right pixel of the image corresponds to s = 1.0, t = 1.0. - The Image field specifies a single uncompressed 2-dimensional pixel image. Image fields contain three integers representing the width, height and number of components in the image, followed by width\u00d7height hexadecimal values representing the pixels in the image. Pixel values are limited to 256 levels of intensity (that is, 0x00-0xFF hexadecimal). A one-component image specifies one-byte hexadecimal value representing the intensity of the image. For example, 0xFF is full intensity in hexadecimal (255 in decimal), 0x00 is no intensity (0 in decimal). A two-component image specifies the intensity in the first (high) byte and the alpha opacity in the second (low) byte. Pixels in a three-component image specify the red component in the first (high) byte, followed by the green and blue components (for example, 0xFF0000 is red, 0x00FF00 is green, 0x0000FF is blue). Four-component images specify the alpha opacity byte after red/green/blue (e.g., 0x0000FF80 is semi-transparent blue). A value of 00 is completely transparent, FF is completely opaque, 80 is semi-transparent. - Note that alpha equals (1.0 -transparency), if alpha and transparency each range from 0.0 to 1.0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcpixeltexture.htm"
     },
     "IfcPlacement": {
@@ -4449,11 +4449,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationdefinitionresource/lexical/ifcplanarextent.htm"
     },
     "IfcPlane": {
-        "description": "The planar surface is an unbounded surface in the direction of x and y. Bounded planar surfaces are defined by using a subtype of IfcBoundedSurface with BasisSurface being a plane.",
+        "description": "The planar surface is an unbounded surface in the direction of x and y. Bounded planar surfaces are defined by using a subtype of IfcBoundedSurface with BasisSurface being a plane. The inherited attributes are interpreted as - SELF\\IfcElementarySurface.Position defines the location and orientation of the planar surface. - SELF\\IfcElementarySurface.Position.Location defines a point on the planar surface. - SELF\\IfcElementarySurface.Position.P[3] defines the normal of the planar surface.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcplane.htm"
     },
     "IfcPlate": {
-        "description": "An IfcPlate is a planar and often flat part with constant thickness. A plate may carry loads between or beyond points of support, or provide stiffening. The location of the plate (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcWall and IfcSlab (as floor slab)).",
+        "description": "An IfcPlate is a planar and often flat part with constant thickness. A plate may carry loads between or beyond points of support, or provide stiffening. The location of the plate (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcWall and IfcSlab (as floor slab)). Plates are normally made of steel, other metallic material, or by glass panels. However the definition of IfcPlate is material independent and specific material information shall be handled by using IfcAssociatesMaterial to assign a material specification to the IfcPlate. An instance IfcPlate should preferably get its geometric representation and material assignment through the type definition by IfcPlateType assigned using the IfcRelDefinesByType relationship. This allows identical plates in a construction to be represented by the same instance of IfcPlateType. The position number of a plate as often used in steel construction is assigned through the attribute IfcElement.Tag There are two main representations for plate occurrences: - IfcPlate with IfcMaterialLayerSetUsage is used for all occurrences of plates, that are prismatic and where the thickness parameter can be fully described by the IfcMaterialLayerSetUsage. These plates are always represented geometrically by a 'SweptSolid' geometry (or by a 'Clipping' geometry based on 'SweptSolid'), if a 3D geometric representation is assigned. NOTE The entity IfcPlateStandardCase has been deprecated, IfcPlate with IfcMaterialLayerSetUsage is used instead. - IfcPlate without IfcMaterialLayerSetUsage is used for all other occurrences of plates, particularly for plates with changing thickness, or plates with non planar surfaces, and plates having only 'SurfaceModel' or 'Brep' geometry or if a more parametric representation is not intended.",
         "predefined_types": {
             "CURTAIN_PANEL": "A planar element within a curtain wall, often consisting of a frame with fixed glazing.",
             "NOTDEFINED": "Undefined linear element.",
@@ -4463,11 +4463,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcplate.htm"
     },
     "IfcPlateStandardCase": {
-        "description": "The standard plate, IfcPlateStandardCase, defines a plate with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcPlateStandardCase handles all cases of plates, that:",
+        "description": "The standard plate, IfcPlateStandardCase, defines a plate with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcPlateStandardCase handles all cases of plates, that: - have a reference to the IfcMaterialLayerSetUsage defining the material layers of the plate with thicknesses - are based on an extrusion of a planar surface as defined by the plate profile - have a constant thickness along the extrusion direction - are consistent in using the correct material layer set offset to the base planar surface in regard to the shape representation - are extruded perpendicular to the plane surface The definitions of plate openings and niches are the same as given at the supertype IfcPlate. The same agreements to the special types of plates, as defined in the PredefinedType attribute apply as well.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcplatestandardcase.htm"
     },
     "IfcPlateType": {
-        "description": "The element type IfcPlateType defines commonly shared information for occurrences of plates. The set of shared information may include:",
+        "description": "The element type IfcPlateType defines commonly shared information for occurrences of plates. The set of shared information may include: - common properties within shared property sets - common material information - common material layer definitions - common shape representations It is used to define a plate specification (i.e. the specific product information, that is common to all occurrences of that product type). Plate types may be exchanged without being already assigned to occurrences. The occurrences of the IfcPlateType within building models are represented by instances of IfcPlateStandardCase if the IfcPlateType has a single associated IfcMaterialLayerSet; otherwise they are represented by instances of IfcPlate. Informal Propositions: - The material assignment, if provided using the IfcRelAssociatesMaterial relationship, shall not reference the IfcMaterialLayerSetUsage.",
         "predefined_types": {
             "CURTAIN_PANEL": "A planar element within a curtain wall, often consisting of a frame with fixed glazing.",
             "NOTDEFINED": "Undefined linear element.",
@@ -4486,7 +4486,7 @@
             "Dim": "The space dimensionality of this class, determined by the space dimensionality of the basis curve. BasisCurve.Dim",
             "PointParameter": "The parameter value of the point location."
         },
-        "description": "The IfcPointOnCurve is a point defined by a parameter value of its defining curve.",
+        "description": "The IfcPointOnCurve is a point defined by a parameter value of its defining curve. Informal Propositions: - The value of the point parameter shall not be outside the parametric range of the curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcpointoncurve.htm"
     },
     "IfcPointOnSurface": {
@@ -4496,14 +4496,14 @@
             "PointParameterU": "The first parameter value of the point location.",
             "PointParameterV": "The second parameter value of the point location."
         },
-        "description": "The IfcPointOnSurface is a point defined by two parameter value of its defining surface.",
+        "description": "The IfcPointOnSurface is a point defined by two parameter value of its defining surface. Informal Propositions: - The parametric values specified for u and v shall not be outside the parametric range of the basis surface.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcpointonsurface.htm"
     },
     "IfcPolyLoop": {
         "attributes": {
             "Polygon": "List of points defining the loop. There are no repeated points in the list."
         },
-        "description": "",
+        "description": "The IfcPolyLoop is always closed and the last segment is from the last IfcCartesianPoint in the list of Polygon's to the first IfcCartesianPoint. Therefore the first point shall not be repeated at the end of the list, neither by referencing the same instance, nor by using an additional instance of IfcCartesianPoint having the coordinates as the first point. Informal Propositions: - All the points in the polygon defining the poly loop shall be coplanar. - The first and the last Polygon shall be different by value.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcpolyloop.htm"
     },
     "IfcPolygonalBoundedHalfSpace": {
@@ -4511,7 +4511,7 @@
             "PolygonalBoundary": "Two-dimensional ~~polyline~~ bounded curve, defined in the xy plane of the position coordinate system.",
             "Position": "Definition of the position coordinate system for the bounding polyline ~~and the base surface~~."
         },
-        "description": "The polygonal bounded half space is a special subtype of a half space solid, where the material of the half space used in Boolean expressions is bounded by a polygonal boundary. The base surface of the half space is positioned by its normal relative to the object coordinate system (as defined at the supertype IfcHalfSpaceSolid), and its polygonal (with or without arc segments) boundary is defined in the XY plane of the position coordinate system established by the Position attribute, the subtraction body is extruded perpendicular to the XY plane of the position coordinate system, that is, into the direction of the positive Z axis defined by the Position attribute.",
+        "description": "The polygonal bounded half space is a special subtype of a half space solid, where the material of the half space used in Boolean expressions is bounded by a polygonal boundary. The base surface of the half space is positioned by its normal relative to the object coordinate system (as defined at the supertype IfcHalfSpaceSolid), and its polygonal (with or without arc segments) boundary is defined in the XY plane of the position coordinate system established by the Position attribute, the subtraction body is extruded perpendicular to the XY plane of the position coordinate system, that is, into the direction of the positive Z axis defined by the Position attribute. The boundary is defined by a 2 dimensional polyline (or 2 dimensional composite curve, consisting of straight segments and circular arc segments) within the XY plane of the position coordinate system. The side of the surface which is in the half space is determined by the surface normal and the agreement flag. If the agreement flag is TRUE, then the subset is the one the normal points away from. If the agreement flag is FALSE, then the subset is the one the normal points into. Figure 1 illustrates a polygonal bounded half space. The polygonal bounded half space is used to limit the volume of the half space in Boolean difference expressions. Only the part that is defined by a theoretical intersection between the half space solid and an extruded area solid, defined by extruding the polygonal boundary, is used for Boolean expressions. The PolygonalBoundary defines the 2D polyline which bounds the effectiveness of the half space in Boolean expressions. The BaseSurface is defined by a plane, and the normal of the plane together with the AgreementFlag defines the side of the material of the half space. Informal Propositions: - The IfcPolyline or the IfcCompositeCurve providing the PolygonalBoundary shall be closed. - If the PolygonalBoundary is given by an IfcCompositeCurve, it shall only have IfcCompositeCurveSegment's of type IfcPolyline, or IfcTrimmedCurve (having a BasisCurve of type IfcLine, or IfcCircle) - The BaseSurface defined at supertype IfcHalfSpaceSolid shall be of type IfcPlane - The normal of the plane, being the BaseSurface, shall not be perpendicular to the z-axis of the position coordinate system",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcpolygonalboundedhalfspace.htm"
     },
     "IfcPolygonalFaceSet": {
@@ -4520,7 +4520,7 @@
             "Faces": "The list of polygonal faces, with or without inner loops, that bound the faceted face set.",
             "PnIndex": "The list of integers defining the locations in the _IfcCartesianPointList3D_ to obtain the point coordinates for the indices at the indexed polygonal faces. If the _PnIndex_ is not provided the indices at the indexed polygonal faces point directly into the  _IfcCartesianPointList3D_."
         },
-        "description": "The IfcPolygonalFaceSet is a tessellated face set with all faces being bound by polygons. The planar faces are constructed by implicit polylines defined by three or more Cartesian points. Each planar face is defined by an instance of IfcIndexedPolygonalFace, or in case of faces with inner loops by IfcIndexedPolygonalFaceWithVoids.",
+        "description": "The IfcPolygonalFaceSet is a tessellated face set with all faces being bound by polygons. The planar faces are constructed by implicit polylines defined by three or more Cartesian points. Each planar face is defined by an instance of IfcIndexedPolygonalFace, or in case of faces with inner loops by IfcIndexedPolygonalFaceWithVoids. Depending on the value of the attribute Closed the instance of IfcPolygonalFaceSet represents: - if TRUE, a boundary represention (or B-rep); - if FALSE, a face based surface representation. The attribute Faces refers to a list of IfcIndexedPolygonalFace's having an one-based CoordIndex that provides three or more indices. If the face has inner loops, the IfcIndexedPolygonalFaceWithVoids has a two-dimensional, one-based list, where:* the first dimension of the two-dimensional list addresses the list of inner loops; * the second dimension of the two-dimensional list provides three or more indices each being a vertex of the planar polygon representing the inner loop. Depending on the provision of PnIndex the indices point either directly into the IfcCartesianPointList3D referenced by Coordinates defined at the supertype IfcTessellatedFaceSet, or they point into the PnIndex where the integer values at that position provides the location of the coordinate values within the IfcCartesianPointList3D. See Figure 1 for the handling of point index. Informal Propositions: - If Closed = TRUE, the same topological constraints as imposed by an faceted boundary representation shall be safisfied. In particular: each face shall be unique; each edge shall be used by exactly two outer or inner boundaries of faces; the topological normal at each point on the boundary of the polygonal face set shall point away from the material of the solid.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcpolygonalfaceset.htm"
     },
     "IfcPolyline": {
@@ -4536,7 +4536,7 @@
             "ConnectedTo": "Reference to the port connection relationship. The relationship then refers to the other port to which this port is connected.",
             "ContainedIn": "Reference to the element to port connection relationship. The relationship then refers to the element in which this port is contained."
         },
-        "description": "A port provides the means for an element to connect to other elements.",
+        "description": "A port provides the means for an element to connect to other elements. An IfcPort is associated with an IfcElement, it belongs to through the objectified relationship IfcRelNests if such port is fixed, or IfcRelConnectsPortToElement if such port is dynamically attached. Exactly two ports, belonging to two different elements, are connected with each other through the objectified relationship IfcRelConnectsPorts. An instance of IfcElement may have one or more points at which it connects to other instances of IfcElement. An instance of em>IfcPort is located at a point where a connection can occur. The location of the port is determined in the context of the local coordinate system of the element to which it belongs. As a subordinate part being fully dependent on the master element the IfcPort shall have no independent containment relationship to the spatial structure. The local placement for IfcPort is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. The PlacementRelTo relationship of IfcLocalPlacement shall point to the local placement of the master IfcElement or IfcElementType (relevant subtypes), which is related to the IfcPort by the relationship object IfcRelNests for fixed ports, or IfcRelConnectsPortToElement for dynamic ports.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcport.htm"
     },
     "IfcPostalAddress": {
@@ -4572,11 +4572,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpropertyresource/lexical/ifcpredefinedproperties.htm"
     },
     "IfcPreDefinedPropertySet": {
-        "description": "IfcPreDefinedPropertySet is a generalization of all statically defined property sets that are assigned to an object or type object. The statically or pre-defined property sets are entities with a fixed list of attributes having particular defined data types.",
+        "description": "IfcPreDefinedPropertySet is a generalization of all statically defined property sets that are assigned to an object or type object. The statically or pre-defined property sets are entities with a fixed list of attributes having particular defined data types. Property sets are related to other objects by using the relationship object that refers to the corresponding object: - Occurrence Object: IfcRelDefinesByProperties using the inverse attribute DefinesOccurrence. - Type Object: using a direct link by inverse attribute DefinesType. IfcPreDefinedPropertySet's can be assigned to objects and object types but do not have a defining property set template.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcpredefinedpropertyset.htm"
     },
     "IfcPreDefinedTextFont": {
-        "description": "The pre defined text font determines those qualified names which can be used for fonts that are in scope of the current data exchange specification (in contrary to externally defined text fonts). There are two choices:",
+        "description": "The pre defined text font determines those qualified names which can be used for fonts that are in scope of the current data exchange specification (in contrary to externally defined text fonts). There are two choices: - IfcDraughtingPreDefinedTextFont for definitions from ISO/IS 10303-46:1994 for (old) vector based and monospace text. - IfcTextStyleFontModel for definitions from Cascading Style Sheets, level 1, W3C Recommendation 17 Dec 1996, revised 11 Jan 1999, CSS1, for all true type text. The use of the CSS1 definitions is the preferred way to represent text fonts.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcpredefinedtextfont.htm"
     },
     "IfcPresentationItem": {
@@ -4590,7 +4590,7 @@
             "Identifier": "An (internal) identifier assigned to the layer.",
             "Name": "Name of the layer."
         },
-        "description": "The presentation layer assignment provides the layer name (and optionally a description and an identifier) for a collection of geometric representation items. The IfcPresentationLayerAssignment corresponds to the term \"CAD Layer\" and is used mainly for grouping and visibility control.",
+        "description": "The presentation layer assignment provides the layer name (and optionally a description and an identifier) for a collection of geometric representation items. The IfcPresentationLayerAssignment corresponds to the term \"CAD Layer\" and is used mainly for grouping and visibility control. Visibility and access control and layer style assignment (colour, line style, line width) is handled by the subtype IfcPresentationLayerAssignmentWithStyle. Attribute use definition Figure 1 illustrates assignment of items by shape representation or representation item. The set of AssignedItems can either include a whole shape representation, or individual geometric representation items. If both, the IfcShapeRepresentation has a layer assignment, and an individual geometric representation item in the set of IfcShapeRepresentation.Items, then the layer assignment of the IfcGeometricRepresentationItem overides the layer assignment of the IfcShapeRepresentation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationorganizationresource/lexical/ifcpresentationlayerassignment.htm"
     },
     "IfcPresentationLayerWithStyle": {
@@ -4600,14 +4600,14 @@
             "LayerOn": "A logical setting, TRUE indicates that the layer is set to 'On', FALSE that the layer is set to 'Off', UNKNOWN that such information is not available.",
             "LayerStyles": "Assignment of presentation styles to the layer to provide a default style for representation items. > NOTE  In most cases the assignment of styles to a layer is restricted to an _IfcCurveStyle_ representing the layer curve colour, layer curve thickness, and layer curve type."
         },
-        "description": "An IfcPresentationLayerAssignmentWithStyle extends the presentation layer assignment with capabilities to define visibility control, access control and common style information.",
+        "description": "An IfcPresentationLayerAssignmentWithStyle extends the presentation layer assignment with capabilities to define visibility control, access control and common style information. The visibility control allows to define a layer to be either 'on' or 'off', and/or 'frozen' or 'not frozen'. The access control allows to block graphical entities from manipulations by setting a layer to be either 'blocked' or 'not blocked'. Common style information can be given to the layer.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationorganizationresource/lexical/ifcpresentationlayerwithstyle.htm"
     },
     "IfcPresentationStyle": {
         "attributes": {
             "Name": "Name of the presentation style."
         },
-        "description": "The IfcPresentationStyle is an abstract generalization of style table for presentation information assigned to geometric representation items. It includes styles for curves, areas, surfaces, and text. Style information may include colour, hatching, rendering, and text fonts.",
+        "description": "The IfcPresentationStyle is an abstract generalization of style table for presentation information assigned to geometric representation items. It includes styles for curves, areas, surfaces, and text. Style information may include colour, hatching, rendering, and text fonts. The different styles may include length measures (directly as a length measure with infered unit, or indirectly as a ratio in relation to another length measure). They may apply to curve pattern, hatch line distances, text spacing and font sizes. The attribute ModelOrDraughting determines whether those length measures are provided as model or draughting measures. - Model measures, also called scale dependent measures, define the distance, size or other length measures as being always the same in model space and the distance size or other length measures on paper depend on the plotting scale. - Draughting measures, also called scale independent measures, define the distance , size or other length measures as being always the same, when plotted on paper, independent of the plot scale. Each subtype of IfcPresentationStyle is assigned to the IfcGeometricRepresentationItem's through an intermediate IfcStyledItem.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcpresentationstyle.htm"
     },
     "IfcPresentationStyleAssignment": {
@@ -4618,7 +4618,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcpresentationstyleassignment.htm"
     },
     "IfcProcedure": {
-        "description": "An IfcProcedure is a logical set of actions to be taken in response to an event or to cause an event to occur.",
+        "description": "An IfcProcedure is a logical set of actions to be taken in response to an event or to cause an event to occur. Use definitions IfcProcedure is used to capture information about stepped processes such as calibration, start/stop procedures for equipment items, designated actions to take in the event of an emergency etc. A procedure is not a task, but may describe a set of tasks and their order of occurrence in response to or to cause an event. As shown in Figure 11, IfcProcedure does not restrict anything but describes specific steps of how something should happen. While a procedure does control/restrict in the sense of indicating \"this is how the task should be performed\" by nature of describing inner detail, this is not different than parts of a product indicating \"this is how the parts should be assembled\". Consequently, it doesn't restrict the outer item as a whole but provides inner detail of the item.",
         "predefined_types": {
             "ADVICE_CAUTION": "A caution that should be taken note of as a procedure or when carrying out a procedure.",
             "ADVICE_NOTE": "Additional information or advice that should be taken note of as a procedure or when carrying out a procedure.",
@@ -4633,7 +4633,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprocessextension/lexical/ifcprocedure.htm"
     },
     "IfcProcedureType": {
-        "description": "An IfcProcedureType defines a particular type of procedure that may be specified.",
+        "description": "An IfcProcedureType defines a particular type of procedure that may be specified. An IfcProcedureType provides for all forms of types of procedure that may be specified. Usage of IfcProcedureType defines the parameters for one or more occurrences of IfcProcedure. Parameters may be specified through property sets that may be enumerated in the IfcProcedureTypeEnum data type or through explict attributes of IfcProcedure. Procedure occurrences (IfcProcedure entities) are linked to the procedure type through the IfcRelDefinesByType relationship.",
         "predefined_types": {
             "ADVICE_CAUTION": "A caution that should be taken note of as a procedure or when carrying out a procedure.",
             "ADVICE_NOTE": "Additional information or advice that should be taken note of as a procedure or when carrying out a procedure.",
@@ -4655,7 +4655,7 @@
             "LongDescription": "An extended description or narrative that may be provided.",
             "OperatesOn": "Set of relationships to other objects, e.g. products, processes, controls, resources or actors, that are operated on by the process."
         },
-        "description": "IfcProcess is defined as one individual activity or event, that is ordered in time, that has sequence relationships with other processes, which transforms input in output, and may connect to other other processes through input output relationships. An IfcProcess can be an activity (or task), or an event. It takes usually place in building construction with the intent of designing, costing, acquiring, constructing, or maintaining products or other and similar tasks or procedures. Figure 1 illustrates process relationships.",
+        "description": "IfcProcess is defined as one individual activity or event, that is ordered in time, that has sequence relationships with other processes, which transforms input in output, and may connect to other other processes through input output relationships. An IfcProcess can be an activity (or task), or an event. It takes usually place in building construction with the intent of designing, costing, acquiring, constructing, or maintaining products or other and similar tasks or procedures. Figure 1 illustrates process relationships. Process information relates to other objects by establishing the following relationships: - Nesting of processes : IfcRelNests - A process can contain sub processes and thereby be nested. - Sequencing of processes : IfcRelSequence - Processes can be placed in sequence (including overlapping for parallel tasks), and have predecessors and successors. - Assigning process to schedules : IfcRelAssignsToControl - Activities such as tasks, and predominately summary tasks, are assigned to a work schedule. - Having a product assigned to the process as input : IfcRelAssignsToProcess - Products can be assigned as input to a process, such as for construction process planning. - Having a product assigned to the process as output : IfcRelAssignsToProduct - Products can be assigned as output to a process, such as for construction process planning. - Having a control assigned to the process as process control : IfcRelAssignsToProcess - Items that act as a control onto the process can be assigned to a process, such as for cost management (a cost item assigned to a work task). - Having a resource assigned to the process as consumed by the process : IfcRelAssignsToProcess - Items that act as a mechanism to a process, such as labor, material and equipment in cost calculations.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcprocess.htm"
     },
     "IfcProduct": {
@@ -4664,7 +4664,7 @@
             "ReferencedBy": "Reference to the _IfcRelAssignsToProduct_ relationship, by which other products, processes, controls, resources or actors (as subtypes of _IfcObjectDefinition_) can be related to this product.",
             "Representation": "Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement."
         },
-        "description": "The IfcProduct is an abstract representation of any object that relates to a geometric or spatial context. An IfcProduct occurs at a specific location in space if it has a geometric representation assigned. It can be placed relatively to other products, but ultimately relative to the project coordinate system. The ObjectPlacement attribute establishes the coordinate system in which all points and directions used by the geometric representation items under Representation are founded. The Representation is provided by an IfcProductDefinitionShape being either a geometric shape representation, or a topology representation (with or without underlying geometry of the topological items).",
+        "description": "The IfcProduct is an abstract representation of any object that relates to a geometric or spatial context. An IfcProduct occurs at a specific location in space if it has a geometric representation assigned. It can be placed relatively to other products, but ultimately relative to the project coordinate system. The ObjectPlacement attribute establishes the coordinate system in which all points and directions used by the geometric representation items under Representation are founded. The Representation is provided by an IfcProductDefinitionShape being either a geometric shape representation, or a topology representation (with or without underlying geometry of the topological items). Products include manufactured, supplied or created objects (referred to as elements) for incorporation into an AEC/FM project. This also includes objects that are created indirectly by other products, as spaces are defined by bounding elements. Products can be designated for permanent use or temporary use, an example for the latter is formwork. Products are defined by their properties and representations. In addition to physical products (covered by the subtype IfcElement) and spatial items (covered by the subtype IfcSpatialElement) the IfcProduct also includes non-physical items, that relate to a geometric or spatial contexts, such as grid, port, annotation, structural actions, etc. Any instance of IfcProduct defines a particular occurrence of a product, the common type information, that relates to many similar (or identical) occurrences of IfcProduct, is handled by the IfcTypeProduct (and its subtypes), assigned to one or many occurrences of IfcProduct by using the objectified relationship IfcRelDefinesByType. The IfcTypeProduct may provide, in addition to common properties, also a common geometric representation for all occurrences. On a generic level products can be assigned to processes, controls, resources, project by using the relationship objects that refer to the corresponding object: - Having a control applied: assigned using IfcRelAssignsToControl linking the IfcProduct to an IfcControl - Being assigned to a process: assigned using IfcRelAssignsToProcess linking the IfcProduct to an IfcProcess - Being assigned to a resource: assigned using IfcRelAssignsToResource linking the IfcProduct to an IfcResource",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcproduct.htm"
     },
     "IfcProductDefinitionShape": {
@@ -4672,7 +4672,7 @@
             "HasShapeAspects": "Reference to the shape aspect that represents part of the shape or its feature distinctively.",
             "ShapeOfProduct": "The _IfcProductDefinitionShape_ shall be used to provide a representation for a single instance of _IfcProduct_."
         },
-        "description": "The IfcProductDefinitionShape defines all shape relevant information about an IfcProduct. It allows for multiple geometric shape representations of the same product. The shape relevant information includes:",
+        "description": "The IfcProductDefinitionShape defines all shape relevant information about an IfcProduct. It allows for multiple geometric shape representations of the same product. The shape relevant information includes: - the shape representation including geometric representation items (for 3D solids, 2D annotations, etc.) and: associated presentation information (line color, line type, surface rendering properties) assignment to presentation layers (CAD layers for visibility control) - or the topological representation items for connectivity systems (vertex, edge, face representations) that may include geometric representation items (vertex points, edge curves, face surfaces)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcproductdefinitionshape.htm"
     },
     "IfcProductRepresentation": {
@@ -4691,7 +4691,7 @@
             "ProfileName": "Human-readable name of the profile, for example according to a standard profile table. As noted above, machine-readable standardized profile designations should be provided in _IfcExternalReference.ItemReference_.",
             "ProfileType": "Defines the type of geometry into which this profile definition shall be resolved, either a curve or a surface area. In case of curve the profile should be referenced by a swept surface, in case of area the profile should be referenced by a swept area solid."
         },
-        "description": "IfcProfileDef is the supertype of all definitions of standard and arbitrary profiles within IFC. It is used to define a standard set of commonly used section profiles by their parameters or by their explicit curve geometry.",
+        "description": "IfcProfileDef is the supertype of all definitions of standard and arbitrary profiles within IFC. It is used to define a standard set of commonly used section profiles by their parameters or by their explicit curve geometry. - Parameterized profiles are 2D primitives, which are used within the industry to describe cross sections by a description of its parameters. - Arbitrary profiles are cross sections defined by an outer boundary as bounded curve, which may also include holes, defined by inner boundaries. - Derived profiles, based on a transformation of a parent profile, are also part of the profile definitions available. - In addition composite profiles can be defined, which include two or more profile definitions to define the resulting profile. Use in material association Beams, columns, and similarly shaped building elements and their type objects may be associated with a section profile definition, combined with material definition, by means of IfcRelAssociatesMaterial together with IfcMaterialProfileSet and IfcMaterialProfileSetUsage. This way, building elements and element types with same section and material can share a common section profile definition and association. The profile definition in material association is required to be consistent with shape representations of the respective building elements. A higher-level description of spatial aligment of the section profile of a member (such as centered, bottom-left, in the geometric centroid, and more) can be provided within IfcMaterialProfileSetUsage by means of a cardinal point reference. This can be used redundant to geometric data in order to convey design intent. Use in shape models Profile definitions are used within the geometry and geometric model resource to create either swept surfaces, swept area solids, or sectioned spines. The purpose of the profile definition within the swept surfaces or swept area solids is to define a uniform cross section being swept: - along a line (extrusion) using IfcSurfaceOfLinearExtrusion or IfcExtrudedAreaSolid - along a circular arc (revolution) using IfcSurfaceOfRevolution or IfcRevolvedAreaSolid - along a directrix lying on a reference surface using IfcSurfaceCurveSweptAreaSolid The purpose of the profile definition within the sectioned spine is to define a varying cross sections at several positions along a spine curve. The subtype IfcDerivedProfileDef is particularly suited to provide the consecutive profiles to be based on transformations of the start profile and thus maintaining the identity of vertices and edges. An IfcProfileDef is treated as bounded area if it is used within swept area solids. In this case, the inside of the profile is part of the profile. The attribute ProfileType is set to AREA. An IfcProfileDef is treated as a curve if it is used within swept surfaces. In this case, the inside of the profile (if the curve is closed) is not part of the profile. The attribute ProfileType is set to CURVE. Figure 1 illustrates use of parameterized profiles within a swept area solid. Profile types Results of the different usage of the ProfileType attribute are demonstrated here. The ProfileType defines whether the inside (the bounded area) is part of the profile definition (Area) or not (Curve). Figure 2 illustrates the resulting area or curve depending on ProfileType. Profile specification by external reference If the profile is standardized by a norm or a catalogue, a reference to this norm or catalogue should be provided by means of HasExternalReference. This inverse relationship is used to associate an IfcExternalReference (notably IfcClassificationReference or IfcLibraryReference) with the profile. IfcClassificationReference is used to refer to a profile norm (a common standard or manufacturer's standard). In this case, - IfcClassificationReference.ItemReference contains the formal profile designation from the norm. (On the other hand, IfcProfileDef.ProfileName contains a displayable name which may not necessarily be the same as the formal designation.) - IfcClassificationReference.Name carries the short name of the profile norm. - Optionally, the norm can be further described by IfcClassificationReference.ReferencedSource. IfcLibraryReference is used to refer to a library which contains profile definitions. In this case, - IfcLibraryReference.ItemReference contains the identifier of the profile within the library and is meant to be machine-readable (in contrast to IfcProfileDef.ProfileName which should be human-readable). - IfcLibraryReference.Location and .Name or .ReferencedLibrary further describe the library. If an external reference is provided, sending systems shall ensure that the shape of the profile definition object agrees with the definitions in the referenced classification or library. Direct instances of IfcProfileDef Usually, only subtypes of IfcProfileDef should be instantiated. In some special cases, e.g. if the profile object is used for purposes other than geometric models (e.g. for structural analysis models), it may be possible to directly instantiate IfcProfileDef and further specify the profile only by external reference or by profile properties. The latter are tracked by the inverse attribute HasProperties.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcprofiledef.htm"
     },
     "IfcProfileProperties": {
@@ -4702,11 +4702,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcprofileproperties.htm"
     },
     "IfcProject": {
-        "description": "IfcProject indicates the undertaking of some design, engineering, construction, or maintenance activities leading towards a product. The project establishes the context for information to be exchanged or shared, and it may represent a construction project but does not have to. The IfcProject's main purpose in an exchange structure is to provide the root instance and the context for all other information items included.",
+        "description": "IfcProject indicates the undertaking of some design, engineering, construction, or maintenance activities leading towards a product. The project establishes the context for information to be exchanged or shared, and it may represent a construction project but does not have to. The IfcProject's main purpose in an exchange structure is to provide the root instance and the context for all other information items included. The context provided by the IfcProject includes: - the default units - the geometric representation context for exchange structures including shape representations the project coordinate system the coordinate space dimension the precision used within the geometric representations optionally the indication of the true north optionally the map conversion between the project coordinate system and the geospatial coordinate reference system. Informal Propositions: - There shall only be one project within the exchange context. This is enforced by the global rule IfcSingleProjectInstance.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcproject.htm"
     },
     "IfcProjectLibrary": {
-        "description": "An IfcProjectLibrary collects all library elements that are included within a referenced project data set.",
+        "description": "An IfcProjectLibrary collects all library elements that are included within a referenced project data set. Examples for project libraries include: - type libraries (also called style or family libraries): a collection of subtypes of IfcTypeObject - property definition libraries: a collections of IfcPropertySetTemplate or IfcPropertyTemplates The inherited attributes RepresentationContext and UnitsInContext have the following meaning: - Context of the representations used within the project library. When the project library includes shape representations for its library type objects, one or several geometric representation contexts need to be included that define the coordinate system, the coordinate space dimensions, and/or the precision factor, - Units locally assigned to measure types used within the context of this project library. Instances of IfcProjectLibrary are assigned to the project context using the IfcRelDeclares relationship and accessible through the inverse attribute HasContext. Individual object types and property (set) templates are assigned to the IfcProjectLibrary using the IfcRelDeclares relationship and are accessible through the inverse attribute Declares. An IfcProjectLibrary may be decomposed into sub libraries using the relationship IfcRelNests. Sub libraries are accessed by the IfcProjectLibrary through the inverse attribute IsNestedBy.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcprojectlibrary.htm"
     },
     "IfcProjectOrder": {
@@ -4714,7 +4714,7 @@
             "LongDescription": "A detailed description of the project order describing the work to be completed.",
             "Status": "The current status of a project order.Examples of status values that might be used for a project order status include: * PLANNED * REQUESTED * APPROVED * ISSUED * STARTED * DELAYED * DONE"
         },
-        "description": "A project order is a directive to purchase products and/or perform work, such as for construction or facilities management.",
+        "description": "A project order is a directive to purchase products and/or perform work, such as for construction or facilities management. Project orders are typically formal contracts between two organizations, where cost and time information may be rigid or flexible according to contained schedule types and constraints.",
         "predefined_types": {
             "CHANGEORDER": "An instruction to make a change to a product or work being undertaken and a description of the work that is to be performed.",
             "MAINTENANCEWORKORDER": "An instruction to carry out maintenance work and a description of the work that is to be performed.",
@@ -4732,11 +4732,11 @@
             "MapUnit": "Unit of the coordinate axes composing the map coordinate system. > NOTE  Only length measures are in scope and all two or three axes of the map coordinate system shall have the same length unit.",
             "MapZone": "Name by which the map zone, relating to the _MapProjection_, is identified."
         },
-        "description": "IfcProjectedCRS is a coordinate reference system of the map to which the map translation of the local engineering coordinate system of the construction or facility engineering project relates. The MapProjection and MapZone attributes uniquely identify the projection to the underlying geographic coordinate reference system, provided that they are well-known in the receiving application. The projected coordinate reference system is assumed to be a 2D or 3D right-handed Cartesian coordinate system, the optional MapUnit attribute can be used determine the length unit used by the map.",
+        "description": "IfcProjectedCRS is a coordinate reference system of the map to which the map translation of the local engineering coordinate system of the construction or facility engineering project relates. The MapProjection and MapZone attributes uniquely identify the projection to the underlying geographic coordinate reference system, provided that they are well-known in the receiving application. The projected coordinate reference system is assumed to be a 2D or 3D right-handed Cartesian coordinate system, the optional MapUnit attribute can be used determine the length unit used by the map. The unambiguous identifier by which the coordinate reference system is know, is stored in the inherited Name attribute. Well defined identifiers include the map projection and also the map zone information. In these cases the MapProjection and the MapZone attributes can be omitted.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcprojectedcrs.htm"
     },
     "IfcProjectionElement": {
-        "description": "The projection element is a specialization of the general feature element to represent projections applied to building elements. It represents a solid attached to any element that has physical manifestation.",
+        "description": "The projection element is a specialization of the general feature element to represent projections applied to building elements. It represents a solid attached to any element that has physical manifestation. An IfcProjectionElement has to be linked to a element (all subtypes of IfcElement) by using the IfcRelProjectsElement relationship. Its existence depends on the existence of the master element. The relationship implies a Boolean union operation between the volume of the projection element and the volume of the element. The IfcProjectionElement shall not participate in the containment relationship, i.e. it is not linked directly to the spatial structure of the project. It has a mandatory ProjectsElements inverse relationship pointing to the IfcElement that is contained in the spatial structure. - The inverse relationship ContainedInStructure shall be NIL.",
         "predefined_types": {
             "NOTDEFINED": "Undefined projection element.",
             "USERDEFINED": "User-defined projection element."
@@ -4771,7 +4771,7 @@
             "Unit": "Unit for the upper and lower bound values, if not given, the default value for the measure type is used as defined by the global unit assignment at _IfcProject.UnitInContext_. The applicable unit is then selected by the underlying TYPE of the _UpperBoundValue_, _LowerBoundValue_, and _SetPointValue_)",
             "UpperBoundValue": "Upper bound value for the interval defining the property value. If the value is not given, it indicates an open bound (all values to be greater than or equal to _LowerBoundValue_)."
         },
-        "description": "A property with a bounded value, IfcPropertyBoundedValue, defines a property object which has a maximum of two (numeric or descriptive) values assigned, the first value specifying the upper bound and the second value specifying the lower bound. It defines a property - value bound (min-max) combination for which the property Name, an optional Description, the optional UpperBoundValue with measure type, the optional LowerBoundValue with measure type, and the optional Unit is given. A set point value can be provided in addition to the upper and lower bound values for operational value setting.",
+        "description": "A property with a bounded value, IfcPropertyBoundedValue, defines a property object which has a maximum of two (numeric or descriptive) values assigned, the first value specifying the upper bound and the second value specifying the lower bound. It defines a property - value bound (min-max) combination for which the property Name, an optional Description, the optional UpperBoundValue with measure type, the optional LowerBoundValue with measure type, and the optional Unit is given. A set point value can be provided in addition to the upper and lower bound values for operational value setting. The unit is handled by the Unit attribute, see Table 1 for an example of a bounded property: - If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, then the unit assigned by the Unit attribute overrides the globally assigned unit. The IfcPropertyBoundedValue allows for the specification of an interval for the value component of the property description. If either the LowerBoundValue or the UpperBoundValue is not given, then it indicates an open bound (either a minimum value or a maximum value). The interval is by definition inclusive, that is, the value given for the LowerBoundValue or the UpperBoundValue is included in the interval.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpropertyresource/lexical/ifcpropertyboundedvalue.htm"
     },
     "IfcPropertyDefinition": {
@@ -4779,7 +4779,7 @@
             "HasAssociations": "Reference to the relationship IfcRelAssociates and thus to those externally defined concepts, like classifications, documents, or library information, which are associated to the property definition.",
             "HasContext": ""
         },
-        "description": "IfcPropertyDefinition defines the generalization of all characteristics (i.e. a grouping of individual properties), that may be assigned to objects. Currently, subtypes of IfcPropertyDefinition include property set occurrences, property set templates, and property templates.",
+        "description": "IfcPropertyDefinition defines the generalization of all characteristics (i.e. a grouping of individual properties), that may be assigned to objects. Currently, subtypes of IfcPropertyDefinition include property set occurrences, property set templates, and property templates. - Property set template - IfcPropertySetTemplate, a collection of property templates that determine the definition of properties used within a project context. - Property template - IfcPropertyTemplate, a single template that determines the definition of a particular property used in the same project context. The template may determine the name, description, data type, the unit, or a standard expression for each property that is based on that template. - Property set occurrence - IfcPropertySet, a set of individual properties (that may or may not be determined by a property template) holding individual values, measure types and units, and are associated to an object occurrence or object type. Property definitions define information that is shared among multiple instances of objects, either object occurrences or object types. IfcPropertyDefinition's (by their instantiable subtypes) can participate within the following relationships: - Assignment to a project context - an HasContext relationship to IfcRelDeclares that establishes the project context in which this property definition is declared. This relationship is predominately applicable to subtypes of IfcPropertyTemplateDefinition. - Association to external resources - an HasAssociation relationship to IfcRelAssociates that refers to external sources of information (most notably a classification or document) and creates a uni-directional association. There is no dependency implied by the association. Subtypes are included in more specific relationships, see IfcPropertySetDefinition and IfcPropertyTemplateDefinition for details.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcpropertydefinition.htm"
     },
     "IfcPropertyDependencyRelationship": {
@@ -4788,7 +4788,7 @@
             "DependingProperty": "The property on which the relationship depends.",
             "Expression": "Expression that further describes the nature of the dependency relation."
         },
-        "description": "An IfcPropertyDependencyRelationship describes an identified dependency between the value of one property and that of another.",
+        "description": "An IfcPropertyDependencyRelationship describes an identified dependency between the value of one property and that of another. Use Definition Whilst the IfcPropertyDependencyRelationship may be used to describe the dependency, and it may do so in terms of the expression of how the dependency operates, it is not possible through the current IFC model for the value of the related property to be actually derived from the value of the relating property. The determination of value according to the dependency is required to be performed by an application that can then use the Expression attribute to flag the form of the dependency.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpropertyresource/lexical/ifcpropertydependencyrelationship.htm"
     },
     "IfcPropertyEnumeratedValue": {
@@ -4796,7 +4796,7 @@
             "EnumerationReference": "Enumeration from which a enumeration value has been selected. The referenced enumeration also establishes the unit of the enumeration value.",
             "EnumerationValues": "Enumeration values, which shall be listed in the referenced _IfcPropertyEnumeration_, if such a reference is provided."
         },
-        "description": "A property with an enumerated value, IfcPropertyEnumeratedValue, defines a property object which has a value assigned that is chosen from an enumeration. It defines a property - value combination for which the property Name, an optional Description, the optional EnumerationValues with measure type and optionally an Unit is given.",
+        "description": "A property with an enumerated value, IfcPropertyEnumeratedValue, defines a property object which has a value assigned that is chosen from an enumeration. It defines a property - value combination for which the property Name, an optional Description, the optional EnumerationValues with measure type and optionally an Unit is given. The unit is handled by the Unit attribute, see Table 1 for an example of a enumerated property: - If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, then the unit assigned by the unit attribute overrides the globally assigned unit. More precisely: The IfcPropertyEnumeratedValue defines a property, which value is selected from a defined list of enumerators. The enumerators are stored in a dynamic enumeration of values including the type information from IfcValue (see IfcPropertyEnumeration). This enables applications to use an enumeration value as a property within a property set (IfcPropertySet) including the allowed list of values. The IfcPropertyEnumeratedValue refers to an IfcPropertyEnumeration, see Table 2 for an example: It is not mandatory to use an instance of IfcPropertyEnumeration to hold the applicable values for IfcPropertyEnumeratedValue, however this is the preferred way. A single instance of IfcPropertyEnumeration can be referenced by multiple instances of IfcPropertyEnumeratedValue.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpropertyresource/lexical/ifcpropertyenumeratedvalue.htm"
     },
     "IfcPropertyEnumeration": {
@@ -4805,7 +4805,7 @@
             "Name": "Name of this enumeration.",
             "Unit": "Unit for the enumerator values, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject."
         },
-        "description": "IfcPropertyEnumeration is a collection of simple or measure values that define a prescribed set of alternatives from which 'enumeration values' are selected. This enables inclusion of enumeration values in property sets. IfcPropertyEnumeration provides a name for the enumeration as well as a list of unique (numeric or descriptive) values (that may have a measure type assigned). The entity defines the list of potential enumerators to be exchanged together (or separately) with properties of type IfcPropertyEnumeratedValue that selects their actual property values from this enumeration.",
+        "description": "IfcPropertyEnumeration is a collection of simple or measure values that define a prescribed set of alternatives from which 'enumeration values' are selected. This enables inclusion of enumeration values in property sets. IfcPropertyEnumeration provides a name for the enumeration as well as a list of unique (numeric or descriptive) values (that may have a measure type assigned). The entity defines the list of potential enumerators to be exchanged together (or separately) with properties of type IfcPropertyEnumeratedValue that selects their actual property values from this enumeration. The unit is handled by the Unit attribute, see Table 1 for an example of a unitless property enumeration: - If the Unit attribute is not given, than the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, the unit assigned by the unit attribute overrides the globally assigned unit.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpropertyresource/lexical/ifcpropertyenumeration.htm"
     },
     "IfcPropertyListValue": {
@@ -4813,7 +4813,7 @@
             "ListValues": "List of property values.",
             "Unit": "Unit for the list values, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject."
         },
-        "description": "An IfcPropertyListValue defines a property that has several (numeric or descriptive) values assigned, these values are given by an ordered list. It defines a property - list value combination for which the property Name, an optional Description, the optional ListValues with measure type and optionally an Unit is given. An IfcPropertyListValue is a list of values. The order in which values appear is significant. All list members shall be of the same type.",
+        "description": "An IfcPropertyListValue defines a property that has several (numeric or descriptive) values assigned, these values are given by an ordered list. It defines a property - list value combination for which the property Name, an optional Description, the optional ListValues with measure type and optionally an Unit is given. An IfcPropertyListValue is a list of values. The order in which values appear is significant. All list members shall be of the same type. The unit is handled by the Unit attribute, see Table 1 for an example of a list property: - If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, then the unit assigned by the Unit attribute overrides the globally assigned unit.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpropertyresource/lexical/ifcpropertylistvalue.htm"
     },
     "IfcPropertyReferenceValue": {
@@ -4828,7 +4828,7 @@
         "attributes": {
             "HasProperties": "Contained set of properties. For property sets defined as part of the IFC Object model, the property objects within a property set are defined as part of the standard. If a property is not contained within the set of predefined properties, its value has not been set at this time."
         },
-        "description": "The IfcPropertySet is a container that holds properties within a property tree. These properties are interpreted according to their name attribute. Each individual property has a significant name string. Some property sets are included in the specification of this standard and have a predefined set of properties indicated by assigning a significant name. These property sets are listed under \"property sets\" within this specification. Property sets applicable to certain objects are listed in the object specification. The naming convention \"Pset_Xxx\" applies to all those property sets that are defined as part of this specification and it shall be used as the value of the Name attribute.",
+        "description": "The IfcPropertySet is a container that holds properties within a property tree. These properties are interpreted according to their name attribute. Each individual property has a significant name string. Some property sets are included in the specification of this standard and have a predefined set of properties indicated by assigning a significant name. These property sets are listed under \"property sets\" within this specification. Property sets applicable to certain objects are listed in the object specification. The naming convention \"Pset_Xxx\" applies to all those property sets that are defined as part of this specification and it shall be used as the value of the Name attribute. In addition any user defined property set can be captured. Property sets that are not declared as part of the IFC specification shall have a Name value not including the \"Pset_\" prefix. IfcPropertySet can be assigned to object occurrences and object types. An IfcPropertySet assigned to an object type is shared among all occurrences of the same object type. An IfcPropertySetTemplate may define the underlying structure, i.e. the required name, the applicable object or object types to which the property set can be attached, and the individual properties that can be included. Property sets are related to other objects by using the relationship object that refers to the corresponding object: - Occurrence Object: IfcRelDefinesByProperties using the inverse attribute DefinesOccurrence. - Type Object: using a direct link by inverse attribute DefinesType. - Underlying template: IfcRelDefinesByTemplate using the inverse attribute IsDefinedBy. - External reference: subtypes of IfcRelAssociates are used to provide a link to a classification system, or external library providing further reference to the property set. Accessible by inverse attribute HasAssociations.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcpropertyset.htm"
     },
     "IfcPropertySetDefinition": {
@@ -4837,7 +4837,7 @@
             "DefinesType": "The type object to which the property set is assigned. The property set acts as a shared property set to all occurrences of the type object. > NOTE  The relationship between the _IfcPropertySetDefinition_ and the _IfcTypeObject_ is a direct relationship, not utilizing _IfcRelDefinesByProperties_, for maintaining compatibility with earlier releases of this standard.",
             "IsDefinedBy": "Relation to the property set template, via the objectified relationship _IfcRelDefinesByTemplate_, that, if given, provides the definition template for the property set or quantity set and its properties."
         },
-        "description": "IfcPropertySetDefinition is a generalization of all individual property sets that can be assigned to an object or type object. The property set definition can be either:",
+        "description": "IfcPropertySetDefinition is a generalization of all individual property sets that can be assigned to an object or type object. The property set definition can be either: - Dynamically extendable property sets - IfcPropertySet, a set of properties for which the IFC specification only provides a kind of \"meta model\", to be further declared by agreement. This means no entity definition of the properties exists within the IFC specification. The declaration is done by assigning a significant string value to the Name attribute of the entity as defined in the entity IfcPropertySet and at each subtype of IfcProperty, referenced by the property set. Dynamically defined property sets may have an underlying template provided by IfcPropertySetTemplate. - Statically defined property sets - IfcPreDefinedPropertySet, a property set entity that exists within the IFC specification. The semantic meaning of each statically defined property set is declared by its entity type and the meaning of the properties is defined by the name and data type of the explicit attribute representing it. Property set definitions define information that is shared among multiple instances of objects, either object occurrences or object types. IfcPropertySetDefinition's (by their instantiable subtypes) can participate within the following relationships: - Assignment to object types - an DefinesType direct relationship to IfcTypeObject that applies the property set, with all included properties, to the object type. Those properties apply to all object occurrences having the same object type. - Assignment to object occurrences - an DefinesOccurrence relationship to IfcRelDefinesByProperties that applies the property set, with all included properties, to the object occurrence.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcpropertysetdefinition.htm"
     },
     "IfcPropertySetTemplate": {
@@ -4847,7 +4847,7 @@
             "HasPropertyTemplates": "Set of _IfcPropertyTemplate_'s that are defined within the scope of the _IfcPropertySetTemplate_.",
             "TemplateType": "Property set type defining whether the property set is applicable to a type (subtypes of _IfcTypeObject_), to an occurrence (subtypes of _IfcObject_), or as a special case to a performance history.      The attribute _ApplicableEntity_ may further refine the applicability to a single or multiple entity type(s)."
         },
-        "description": "IfcPropertySetTemplate defines the template for all dynamically extensible property sets represented by IfcPropertySet. The property set template is a container of property templates within a property tree. The individual property templates are interpreted according to their Name attribute and shall have no values assigned.",
+        "description": "IfcPropertySetTemplate defines the template for all dynamically extensible property sets represented by IfcPropertySet. The property set template is a container of property templates within a property tree. The individual property templates are interpreted according to their Name attribute and shall have no values assigned. Property set templates can form part of a property library used and declared within a project. Depending on the TemplateType the IfcPropertySetTemplate defines a template for: - \"Pset_\" - occurrences of IfcPropertySet - \"QTO_\" - occurrences of IfcElementQuantity The inherited HasContext inverse relation to IfcRelDeclares is used to declare the IfcPropertySetTemplate within a project library. If included in an exchange data set it can then be traversed through the IfcProjectLibrary. The Defines inverse relation to IfcRelDefinesByTemplate is provided to keep the definition relationship between the IfcPropertySetTemplate and the one to many IfcPropertySet's, for which it provides the template. Figure 1 illustrates relationships used for property set templates. Between IfcProperty's within the HasProperties set of IfcPropertySet having the same Name attribute value as the IfcPropertyTemplate's within the HasPropertyTemplates set of IfcPropertySetTemplate an implicit definition relationship is established that assigns the template to the individual properties.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcpropertysettemplate.htm"
     },
     "IfcPropertySingleValue": {
@@ -4855,7 +4855,7 @@
             "NominalValue": "Value and measure type of this property.  > NOTE  By virtue of the defined data type, that is selected from the SELECT _IfcValue_, the appropriate unit can be found within the _IfcUnitAssignment_, defined for the project if no value for the unit attribute is given.",
             "Unit": "Unit for the nominal value, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject."
         },
-        "description": "The property with a single value IfcPropertySingleValue defines a property object which has a single (numeric or descriptive) value assigned. It defines a property - single value combination for which the property Name, an optional Description, and an optional NominalValue with measure type is provided. In addition, the default unit as specified within the project unit context can be overriden by assigning an Unit.",
+        "description": "The property with a single value IfcPropertySingleValue defines a property object which has a single (numeric or descriptive) value assigned. It defines a property - single value combination for which the property Name, an optional Description, and an optional NominalValue with measure type is provided. In addition, the default unit as specified within the project unit context can be overriden by assigning an Unit. The unit is handled by the Unit attribute, see Table 1 for an example of various single value properties: - If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the Unit attribute is given, then the unit assigned by the Unit attribute overrides the globally assigned unit.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpropertyresource/lexical/ifcpropertysinglevalue.htm"
     },
     "IfcPropertyTableValue": {
@@ -4867,7 +4867,7 @@
             "DefiningValues": "List of defining values, which determine the defined values. This list shall have unique values only.",
             "Expression": "Expression for the derivation of defined values from the defining values, the expression is given for information only, i.e. no automatic processing can be expected from the expression."
         },
-        "description": "IfcPropertyTableValue is a property with a value range defined by a property object which has two lists of (numeric or descriptive) values assigned. The values specify a table with two columns. The defining values provide the first column and establish the scope for the defined values (the second column). An optional Expression attribute may give the equation used for deriving the range value, which is for information purposes only.",
+        "description": "IfcPropertyTableValue is a property with a value range defined by a property object which has two lists of (numeric or descriptive) values assigned. The values specify a table with two columns. The defining values provide the first column and establish the scope for the defined values (the second column). An optional Expression attribute may give the equation used for deriving the range value, which is for information purposes only. The IfcPropertyTableValue defines a defining/defined property value combination for which the property name, the table with defining and defined values with measure type (and optional the units for defining and defined values) are given. The units are handled by the DefiningUnit and DefinedUnit attributes, see Table 1 for an example of a table value property: - If the DefiningUnit or DefinedUnit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext). - If the DefiningUnit or DefinedUnit attribute is given, then the unit assigned by the unit attribute overrides the globally assigned unit. The IfcPropertyTableValue allows for the specification of a table of defining/defined value pairs of the property description. The optional attribute CurveInterpolation allows to determine the interval between two given values. Informal Propositions: - The list of DefinedValues and the list of DefiningValues are corresponding lists.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpropertyresource/lexical/ifcpropertytablevalue.htm"
     },
     "IfcPropertyTemplate": {
@@ -4875,15 +4875,15 @@
             "PartOfComplexTemplate": "Reference to a complex property templates. It should only be provided, if the _PropertyType_ of the referenced complex property template is set to COMPLEX.",
             "PartOfPsetTemplate": "Reference to the _IfcPropertySetTemplate_ that defines the scope for the _IfcPropertyTemplate_. A single _IfcPropertyTemplate_ can be defined within the scope of zero, one or many _IfcPropertySetTemplate_'."
         },
-        "description": "The IfcPropertyTemplate is an abstract supertype comprising the templates for all dynamically extensible properties, either as an IfcComplexPropertyTemplate, or an IfcSimplePropertyTemplate. These templates determine the structure of:",
+        "description": "The IfcPropertyTemplate is an abstract supertype comprising the templates for all dynamically extensible properties, either as an IfcComplexPropertyTemplate, or an IfcSimplePropertyTemplate. These templates determine the structure of: - in case of IfcComplexPropertyTemplate an IfcComplexProperty an IfcPhysicalComplexQuantity - in case of IfcSimplePropertyTemplate a subtype of IfcSimpleProperty a subtype of IfcPhysicalSimpleQuantity The individual property templates are interpreted according to their Name attribute and may have a predefined property type, property unit, and property data type. A template however shall not have measure values, or quantity values assigned.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcpropertytemplate.htm"
     },
     "IfcPropertyTemplateDefinition": {
-        "description": "IfcPropertyTemplateDefinition is a generalization of all property and property set templates. Templates define the collection, types, names, applicable measure types and units of individual properties used in a project. The property template definition can be either:",
+        "description": "IfcPropertyTemplateDefinition is a generalization of all property and property set templates. Templates define the collection, types, names, applicable measure types and units of individual properties used in a project. The property template definition can be either: - Property set template - IfcPropertySetTemplate, a collection of property templates that determine the definition of properties used within a project context. - Property template - IfcPropertyTemplate, a single template that determines the definition of a particular property used in the same project context. The template may determine the name, description, data type, the unit, or a standard expression for each property that is based on that template. The subtypes of IfcPropertyTemplateDefinition are declared within a project context. The uppermost template definition (e.g. the IfcPropertySetTemplate including several IfcPropertyTemplate's) should be related to the context, either IfcProject, or IfcProjectLibrary, using the inherited HasContext inverse attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcpropertytemplatedefinition.htm"
     },
     "IfcProtectiveDevice": {
-        "description": "A protective device breaks an electrical circuit when a stated electric current that passes through it is exceeded.",
+        "description": "A protective device breaks an electrical circuit when a stated electric current that passes through it is exceeded. A protective device provides protection against electrical current only (not as a general protective device). It may be used to represent the complete set of elements including both the tripping unit and the breaking unit that provide the protection. This may be particularly useful at earlier stages of design where the approach to breaking the electrical supply may be determined but the method of tripping may not. Alternatively, this entity may be used to specifically represent the breaking unit alone (in which case the tripping unit will also be specifically identified). This entity is specific to dedicated protective devices and excludes electrical outlets that may have circuit protection.",
         "predefined_types": {
             "CIRCUITBREAKER": "A mechanical switching device capable of making, carrying, and breaking currents under normal circuit conditions and also making, carrying for a specified time and breaking, current under specified abnormal circuit conditions such as those of short circuit.",
             "EARTHINGSWITCH": "A safety device used to open or close a circuit when there is no current. Used to isolate a part of a circuit, a machine, a part of an overhead line or an underground line so that maintenance can be safely conducted.",
@@ -4910,7 +4910,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcprotectivedevicetrippingunit.htm"
     },
     "IfcProtectiveDeviceTrippingUnitType": {
-        "description": "The distribution control element type IfcProtectiveDeviceTrippingUnitType defines commonly shared information for occurrences of protective device tripping units. The set of shared information may include:",
+        "description": "The distribution control element type IfcProtectiveDeviceTrippingUnitType defines commonly shared information for occurrences of protective device tripping units. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a protective device tripping unit type specification indicating the specific product information that is common to all occurrences of that product type. The IfcProtectiveDeviceTrippingUnitType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcProtectiveDeviceTrippingUnitType are represented by instances of IfcProtectiveDeviceTrippingUnit. Refer to the documentation at IfcProtectiveDeviceTrippingUnit for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "ELECTROMAGNETIC": "A tripping unit activated by electromagnetic action.",
             "ELECTRONIC": "A tripping unit activated by electronic action.",
@@ -4922,7 +4922,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcprotectivedevicetrippingunittype.htm"
     },
     "IfcProtectiveDeviceType": {
-        "description": "The flow controller type IfcProtectiveDeviceType defines commonly shared information for occurrences of protective devices. The set of shared information may include:",
+        "description": "The flow controller type IfcProtectiveDeviceType defines commonly shared information for occurrences of protective devices. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a protective device type specification indicating the specific product information that is common to all occurrences of that product type. The IfcProtectiveDeviceType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcProtectiveDeviceType are represented by instances of IfcProtectiveDevice. Refer to the documentation at IfcProtectiveDevice for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CIRCUITBREAKER": "A mechanical switching device capable of making, carrying, and breaking currents under normal circuit conditions and also making, carrying for a specified time and breaking, current under specified abnormal circuit conditions such as those of short circuit.",
             "EARTHINGSWITCH": "A safety device used to open or close a circuit when there is no current. Used to isolate a part of a circuit, a machine, a part of an overhead line or an underground line so that maintenance can be safely conducted.",
@@ -4941,7 +4941,7 @@
             "ProxyType": "High level (and only) semantic meaning attached to the IfcProxy, defining the basic construct type behind the Proxy, e.g. Product or Process.",
             "Tag": "The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level."
         },
-        "description": "IfcProxy is intended to be a kind of a container for wrapping objects which are defined by associated properties, which may or may not have a geometric representation and placement in space. A proxy may have a semantic meaning, defined by the Name attribute, and property definitions, attached through the property assignment relationship, which definition may be outside of the definitions given by the current release of IFC.",
+        "description": "IfcProxy is intended to be a kind of a container for wrapping objects which are defined by associated properties, which may or may not have a geometric representation and placement in space. A proxy may have a semantic meaning, defined by the Name attribute, and property definitions, attached through the property assignment relationship, which definition may be outside of the definitions given by the current release of IFC. The ProxyType may give an indication to which high level semantic breakdown of object the semantic definition of the proxy relates to. the Tag attribute may be used to assign a human or system interpretable identifier (such as a serial number or bar code).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcproxy.htm"
     },
     "IfcPump": {
@@ -4960,7 +4960,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcpump.htm"
     },
     "IfcPumpType": {
-        "description": "The flow moving device type IfcPumpType defines commonly shared information for occurrences of pumps. The set of shared information may include:",
+        "description": "The flow moving device type IfcPumpType defines commonly shared information for occurrences of pumps. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a pump type specification indicating the specific product information that is common to all occurrences of that product type. The IfcPumpType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcPumpType are represented by instances of IfcPump. Refer to the documentation at IfcPump for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CIRCULATOR": "A Circulator pump is a generic low-pressure, low-capacity pump. It may have a wet rotor and may be driven by a flexible-coupled motor.",
             "ENDSUCTION": "An End Suction pump, when mounted horizontally, has a single horizontal inlet on the impeller suction side and a vertical discharge. It may have a direct or close-coupled motor.",
@@ -4999,7 +4999,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcquantityresource/lexical/ifcquantitylength.htm"
     },
     "IfcQuantitySet": {
-        "description": "IfcQuantitySet is the the abstract supertype for all quantity sets attached to objects. The quantity set is a container class that holds the individual quantities within a quantity tree. These quantities are interpreted according to their name attribute and classified according to their measure type. Some quantity sets are included in the IFC specification and have a predefined set of quantities indicated by assigning a significant name. These quantity sets are listed as \"quantity sets\" within this specification. Quantity sets applicable to certain objects are listed in the object specification.",
+        "description": "IfcQuantitySet is the the abstract supertype for all quantity sets attached to objects. The quantity set is a container class that holds the individual quantities within a quantity tree. These quantities are interpreted according to their name attribute and classified according to their measure type. Some quantity sets are included in the IFC specification and have a predefined set of quantities indicated by assigning a significant name. These quantity sets are listed as \"quantity sets\" within this specification. Quantity sets applicable to certain objects are listed in the object specification. An IfcPropertySetTemplate may define the underlying structure, i.e. the required name, the applicable object or object types to which the quantity set can be attached, and the individual quantities that maybe included. Quantity sets are related to other objects by using the relationship object that refers to the corresponding object: - Occurrence Object: IfcRelDefinesByProperties using the inverse attribute DefinesOccurrence. - Type Object: using a direct link by inverse attribute DefinesType. - Underlying template: IfcRelDefinesByTemplate using the inverse attribute IsDefinedBy. - External reference: subtypes of IfcRelAssociates are used to provide a link to a classification system, or external library providing further reference to the quantity set. Accessible by inverse attribute HasAssociations.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcquantityset.htm"
     },
     "IfcQuantityTime": {
@@ -5038,7 +5038,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcrailing.htm"
     },
     "IfcRailingType": {
-        "description": "The building element type IfcRailingType defines commonly shared information for occurrences of railings. The set of shared information may include:",
+        "description": "The building element type IfcRailingType defines commonly shared information for occurrences of railings. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a railing type specification indicating the specific product information that is common to all occurrences of that product type. The IfcRailingType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcRailingType are represented by instances of IfcRailing. Refer to the documentation at IfcRailing for supported property sets, materials, and composition.",
         "predefined_types": {
             "BALUSTRADE": "Similar to the definitions of a guardrail except the location is at the edge of a floor, rather then a stair or ramp. Examples are balustrates at roof-tops or balconies.",
             "GUARDRAIL": "A type of railing designed to guard human occupants from falling off a stair, ramp or landing where there is a vertical drop at the edge of such floors/landings.",
@@ -5049,7 +5049,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcrailingtype.htm"
     },
     "IfcRamp": {
-        "description": "A ramp is a vertical passageway which provides a human circulation link between one floor level and another floor level at a different elevation. It may include a landing as an intermediate floor slab. A ramp normally does not include steps.",
+        "description": "A ramp is a vertical passageway which provides a human circulation link between one floor level and another floor level at a different elevation. It may include a landing as an intermediate floor slab. A ramp normally does not include steps. The IfcRamp shall either be represented: - as a ramp assembly that aggregates all parts(ramp flight, landing, etc.) with own shape representations, or - as a single ramp without decomposition including all shape representations directly at the ramp entity.",
         "predefined_types": {
             "HALF_TURN_RAMP": "A ramp making a 180&deg; turn, consisting of two straight flights connected\nby a halfspace landing. The orientation of the turn is determined by the walking line.",
             "NOTDEFINED": "",
@@ -5063,7 +5063,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcramp.htm"
     },
     "IfcRampFlight": {
-        "description": "A ramp comprises a single inclined segment, or several inclined segments that are connected by a horizontal segment, refered to as a landing. A ramp flight is the single inclined segment and part of the ramp construction. In case of single flight ramps, the ramp flight and the ramp are identical.",
+        "description": "A ramp comprises a single inclined segment, or several inclined segments that are connected by a horizontal segment, refered to as a landing. A ramp flight is the single inclined segment and part of the ramp construction. In case of single flight ramps, the ramp flight and the ramp are identical. An IfcRampFlight is an aggregated part of an IfcRamp realized through the IfcRelAggregates relationship, the ramp flight is therefore included in the set of IfcRelAggregates.RelatedObjects. An IfcRampFlight connects the floor slab of zero to two different storeys (or partial storeys or landings) within a building. The connection relationship between the IfcRampFlight and the IfcSlab can be expressed using the IfcRelConnectsElements relationship.",
         "predefined_types": {
             "NOTDEFINED": "Undefined ramp flight.",
             "SPIRAL": "A ramp flight with a circular or elliptic walking line.",
@@ -5073,7 +5073,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcrampflight.htm"
     },
     "IfcRampFlightType": {
-        "description": "The building element type IfcRampFlightType defines commonly shared information for occurrences of ramp flights. The set of shared information may include:",
+        "description": "The building element type IfcRampFlightType defines commonly shared information for occurrences of ramp flights. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a ramp flight type specification indicating the specific product information that is common to all occurrences of that product type. The IfcRampFlightType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcRampFlightType are represented by instances of IfcRampFlight. Refer to the documentation at IfcRampFlight for supported property sets, materials, and composition.",
         "predefined_types": {
             "NOTDEFINED": "Undefined ramp flight.",
             "SPIRAL": "A ramp flight with a circular or elliptic walking line.",
@@ -5083,7 +5083,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcrampflighttype.htm"
     },
     "IfcRampType": {
-        "description": "The building element type IfcRampType defines commonly shared information for occurrences of ramps. The set of shared information may include:",
+        "description": "The building element type IfcRampType defines commonly shared information for occurrences of ramps. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a ramp type specification indicating the specific product information that is common to all occurrences of that product type. The IfcRampType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcRampType are represented by instances of IfcRamp. Refer to the documentation at IfcRamp for supported property sets, materials, and composition.",
         "predefined_types": {
             "HALF_TURN_RAMP": "A ramp making a 180&deg; turn, consisting of two straight flights connected\nby a halfspace landing. The orientation of the turn is determined by the walking line.",
             "NOTDEFINED": "",
@@ -5101,7 +5101,7 @@
             "Weights": "The array of weights associated with the control points. This is derived from the weights data. IfcListToArray(WeightsData,0,SELF\\IfcBSplineCurve.UpperIndexOnControlPoints)",
             "WeightsData": "The supplied values of the weights."
         },
-        "description": "A rational B-spline curve with knots is a B-spline curve described in terms of control points and basic functions. It describes weights in addition to the control points defined at the supertype IfcBSplineCurve.",
+        "description": "A rational B-spline curve with knots is a B-spline curve described in terms of control points and basic functions. It describes weights in addition to the control points defined at the supertype IfcBSplineCurve. All weights shall be positive and the curve is given by: where",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcrationalbsplinecurvewithknots.htm"
     },
     "IfcRationalBSplineSurfaceWithKnots": {
@@ -5109,7 +5109,7 @@
             "Weights": "Array (two-dimensional) of weight values constructed from the _WeightsData_. IfcMakeArrayOfArray(WeightsData,0,UUpper,0,VUpper)",
             "WeightsData": "The weights associated with the control points in the rational case."
         },
-        "description": "A rational B-spline surface with knots is a piecewise parametric rational surface described in terms of control points, and associated weight values.",
+        "description": "A rational B-spline surface with knots is a piecewise parametric rational surface described in terms of control points, and associated weight values. The surface is to be interpreted as follows:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcrationalbsplinesurfacewithknots.htm"
     },
     "IfcRectangleHollowProfileDef": {
@@ -5118,7 +5118,7 @@
             "OuterFilletRadius": "Outer corner radius.",
             "WallThickness": "Thickness of the material."
         },
-        "description": "IfcRectangleHollowProfileDef defines a section profile that provides the defining parameters of a rectangular (or square) hollow section to be used by the swept surface geometry or the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. A square hollow section can be defined by equal values for h and b. The centre of the position coordinate system is in the profiles centre of the bounding box (for symmetric profiles identical with the centre of gravity). Normally, the longer sides are parallel to the y-axis, the shorter sides parallel to the x-axis.",
+        "description": "IfcRectangleHollowProfileDef defines a section profile that provides the defining parameters of a rectangular (or square) hollow section to be used by the swept surface geometry or the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. A square hollow section can be defined by equal values for h and b. The centre of the position coordinate system is in the profiles centre of the bounding box (for symmetric profiles identical with the centre of gravity). Normally, the longer sides are parallel to the y-axis, the shorter sides parallel to the x-axis. Figure 1 illustrates parameters of a rectangular or square hollow profile definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcrectanglehollowprofiledef.htm"
     },
     "IfcRectangleProfileDef": {
@@ -5126,7 +5126,7 @@
             "XDim": "The extent of the rectangle in the direction of the x-axis.",
             "YDim": "The extent of the rectangle in the direction of the y-axis."
         },
-        "description": "IfcRectangleProfileDef defines a rectangle as the profile definition used by the swept surface geometry or the swept area solid. It is given by its X extent and its Y extent, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system.",
+        "description": "IfcRectangleProfileDef defines a rectangle as the profile definition used by the swept surface geometry or the swept area solid. It is given by its X extent and its Y extent, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system. Figure 1 illustrates parameters of the rectangle profile definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcrectangleprofiledef.htm"
     },
     "IfcRectangularPyramid": {
@@ -5135,7 +5135,7 @@
             "XLength": "The length of the base measured along the placement X axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[1]_.",
             "YLength": "The length of the base measured along the placement Y axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[2]_."
         },
-        "description": "The IfcRectangularPyramid is a Construction Solid Geometry (CSG) 3D primitive. It is a solid with a rectangular base and a point called apex as the top. The tapers from the base to the top. The axis from the center of the base to the apex is perpendicular to the base. The inherited Position attribute defines the IfcAxisPlacement3D and provides the location and orientation of the pyramid:",
+        "description": "The IfcRectangularPyramid is a Construction Solid Geometry (CSG) 3D primitive. It is a solid with a rectangular base and a point called apex as the top. The tapers from the base to the top. The axis from the center of the base to the apex is perpendicular to the base. The inherited Position attribute defines the IfcAxisPlacement3D and provides the location and orientation of the pyramid: - SELF\\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcCsgPrimitive3D.Position.Location: The center of the circular area being the bottom face of the cone. - SELF\\IfcCsgPrimitive3D.Position.Position[3]: The z-axis of the inherited placement coordinate system provides the center axis of the IfcRightCircularCone, and the apex is at the Height value applied to the positive direction of the z-axis. The BottomRadius defines the circular base at the xy-plane of the placement coordinate system. As shown in Figure 1, the pyramid is positioned within its own placement coordinate system. The origin is the center of the bottom rectangle, that lies in the XY plane. The apex lies on the positive z axis at [0, 0, Height]. Texture use definition On each triangular side face, textures are aligned facing upright. Textures are stretched or repeated to the extent of the base of each face according to RepeatS. Textures are stretched or repeated towards the top point according to Repeat T, where the top point has coordinates of (0.5,1.0) if RepeatT is False. On the bottom face, textures are aligned facing front-to-back. Figure 2 illustrates default texture mapping with a clamped texture (RepeatS=False and RepeatT=False). The image on the left shows the texture where the S axis points to the right and the T axis points up. The image on the right shows the texture applied to the geometry where the X axis points back to the right, the Y axis points back to the left, and the Z axis points up.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcrectangularpyramid.htm"
     },
     "IfcRectangularTrimmedSurface": {
@@ -5148,7 +5148,7 @@
             "V2": "Second v parametric value.",
             "Vsense": "Flag to indicate whether the direction of the second parameter of the trimmed surface agrees with or opposes the sense of v in the basis surface."
         },
-        "description": "The IfcRectangularTrimmedSurface is a surface created by bounding its BasisSurface along two pairs of parallel curves defined within the parametric space of the referenced surface.",
+        "description": "The IfcRectangularTrimmedSurface is a surface created by bounding its BasisSurface along two pairs of parallel curves defined within the parametric space of the referenced surface. Informal Propositions: - The domain of the trimmed surface shall be within the domain of the surface being trimmed.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcrectangulartrimmedsurface.htm"
     },
     "IfcRecurrencePattern": {
@@ -5162,7 +5162,7 @@
             "TimePeriods": "List of time periods that are defined by a start and end time     of the recurring element (day). The order of the list should     reflect the sequence of the time periods.",
             "WeekdayComponent": "The weekday name of the specified day in a week."
         },
-        "description": "IfcRecurrencePattern defines repetitive time periods on the basis of regular recurrences such as each Monday in a week, or every third Tuesday in a month. The population of the remaining attributes such as DayComponent, Position, and Interval depend on the specified recurrence type.",
+        "description": "IfcRecurrencePattern defines repetitive time periods on the basis of regular recurrences such as each Monday in a week, or every third Tuesday in a month. The population of the remaining attributes such as DayComponent, Position, and Interval depend on the specified recurrence type. IfcRecurrencePattern supports various recurrence patterns that are differentiated by a type definition (IfcRecurrencePattern.RecurrenceType), which is required to provide the meaning of the given values. It can be further constrained by applicable times through specified IfcTimePeriod instances, thus enabling time periods such as between 7:00 and 12:00 and between 13:00 and 17:00 for each of the applicable days, weeks or months.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcrecurrencepattern.htm"
     },
     "IfcReference": {
@@ -5193,7 +5193,7 @@
             "SteelGrade": "The nominal steel grade defined according to local standards.",
             "TotalCrossSectionArea": "The total effective cross-section area of the reinforcement of a specific steel grade."
         },
-        "description": "IfcReinforcementProperties defines the set of properties for a specific combination of reinforcement bar steel grade, bar type and effective depth.",
+        "description": "IfcReinforcementProperties defines the set of properties for a specific combination of reinforcement bar steel grade, bar type and effective depth. The total cross section area for the specific steel grade is always provided. Additionally also general reinforcing bar configurations as a count of bars may be provided as defined in attribute BarCount. In this case the nominal bar diameter should be identical for all given bars as defined in attribute NominalBarDiameter.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcreinforcementbarproperties.htm"
     },
     "IfcReinforcementDefinitionProperties": {
@@ -5201,7 +5201,7 @@
             "DefinitionType": "Descriptive type name applied to reinforcement definition properties.",
             "ReinforcementSectionDefinitions": "The list of section reinforcement properties attached to the reinforcement definition properties."
         },
-        "description": "IfcReinforcementDefinitionProperties defines the cross section properties of reinforcement included in reinforced concrete building elements. The property set definition may be used both in conjunction with insitu and precast structures.",
+        "description": "IfcReinforcementDefinitionProperties defines the cross section properties of reinforcement included in reinforced concrete building elements. The property set definition may be used both in conjunction with insitu and precast structures. This subtype of IfcPropertySetDefinition is used to define the reinforcement properties in early design stages, such as in requirement definition or scheme design. In later design stages explicit instances of subtypes of IfcReinforcingElement are used. The intended usage may be indicated using the DefinitionType attribute value as a designator: recommended values are 'Reinforcement area requirement' or 'Reinforcement configuration requirement'. Other values may be used according to local standards. Only one property set definition of this kind is used for each concrete building element in each intended usage indicated by the DefinitionType attribute value. This set then defines a list of cross section properties in a discrete number of longitudinal sections as instances of IfcSectionReinforcementProperties (one for each structural reinforcement bar role), which in turn have a section cross section property defined as a profile and a number of reinforcement properties, one for each steel grade / bar type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcreinforcementdefinitionproperties.htm"
     },
     "IfcReinforcingBar": {
@@ -5211,7 +5211,7 @@
             "CrossSectionArea": "The effective cross-section area of the reinforcing bar or group of bars.",
             "NominalDiameter": "Deprecated."
         },
-        "description": "A reinforcing bar is usually made of steel with manufactured deformations in the surface, and used in concrete and masonry construction to provide additional strength. A single instance of this class may represent one or many of actual rebars, for example a row of rebars.",
+        "description": "A reinforcing bar is usually made of steel with manufactured deformations in the surface, and used in concrete and masonry construction to provide additional strength. A single instance of this class may represent one or many of actual rebars, for example a row of rebars. Geometry Use Definition Placement and representation are defined at the supertype IfcElementComponent. The representation map of a mapped 'Body' representation should contain a representation of type 'AdvancedSweptSolid' which holds an IfcSweptDiskSolid (including subtype IfcSweptDiskSolidPolygonal).",
         "predefined_types": {
             "ANCHORING": "Anchoring reinforcement.",
             "EDGE": "Edge reinforcement.",
@@ -5235,7 +5235,7 @@
             "CrossSectionArea": "The effective cross-section area of the reinforcing bar.",
             "NominalDiameter": "The nominal diameter defining the cross-section size of the reinforcing bar."
         },
-        "description": "The reinforcing element type IfcReinforcingBarType defines commonly shared information for occurrences of reinforcing bars. The set of shared information may include:",
+        "description": "The reinforcing element type IfcReinforcingBarType defines commonly shared information for occurrences of reinforcing bars. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a reinforcing bar type specification indicating the specific product information that is common to all occurrences of that product type. The IfcReinforcingBarType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcReinforcingBarType are represented by instances of IfcReinforcingBar.",
         "predefined_types": {
             "ANCHORING": "Anchoring reinforcement.",
             "EDGE": "Edge reinforcement.",
@@ -5254,11 +5254,11 @@
         "attributes": {
             "SteelGrade": ""
         },
-        "description": "A reinforcing element represents bars, wires, strands, meshes, tendons, and other components embedded in concrete in such a manner that the reinforcement and the concrete act together in resisting forces.",
+        "description": "A reinforcing element represents bars, wires, strands, meshes, tendons, and other components embedded in concrete in such a manner that the reinforcement and the concrete act together in resisting forces. One or several instances of subtypes of IfcReinforcingElement should always be accompanied by a defining instance of a respective subtype of IfcReinforcingElementType. The type object holds shape and material information.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcreinforcingelement.htm"
     },
     "IfcReinforcingElementType": {
-        "description": "The element component type IfcReinforcingElementType defines commonly shared information for occurrences of reinforcing elements. The set of shared information may include:",
+        "description": "The element component type IfcReinforcingElementType defines commonly shared information for occurrences of reinforcing elements. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a reinforcing element type specification indicating the specific product information that is common to all occurrences of that product type. The IfcReinforcingElementType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcReinforcingElementType are represented by instances of IfcReinforcingElement. Material Use Definition An associated material denotes the steel grade, preferrably using material classification.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcreinforcingelementtype.htm"
     },
     "IfcReinforcingMesh": {
@@ -5272,7 +5272,7 @@
             "TransverseBarNominalDiameter": "Deprecated.",
             "TransverseBarSpacing": "Deprecated."
         },
-        "description": "A reinforcing mesh is a series of longitudinal and transverse wires or bars of various gauges, arranged at right angles to each other and welded at all points of intersection; usually used for concrete slab reinforcement. It is also known as welded wire fabric. In scope are plane meshes as well as bent meshes.",
+        "description": "A reinforcing mesh is a series of longitudinal and transverse wires or bars of various gauges, arranged at right angles to each other and welded at all points of intersection; usually used for concrete slab reinforcement. It is also known as welded wire fabric. In scope are plane meshes as well as bent meshes. Geometry Use Definition Placement and representation are defined at the supertype IfcElementComponent. The representation map of a mapped 'Outline' representation should contain a representation of type 'Curve3D' which holds an IfcPolyline. The representation map of a mapped 'Body' representation should contain a representation of type 'AdvancedSweptSolid' which holds multiple IfcSweptDiskSolid (including subtype IfcSweptDiskSolidPolygonal).",
         "predefined_types": {
             "NOTDEFINED": "The type of mesh is not defined.",
             "USERDEFINED": "The type of mesh is user defined."
@@ -5292,7 +5292,7 @@
             "TransverseBarNominalDiameter": "The nominal diameter denoting the cross-section size of the transverse bars.",
             "TransverseBarSpacing": "The spacing between the transverse bars.  Note: an even distribution of bars is presumed; other cases are handled by classification or property sets."
         },
-        "description": "The reinforcing element type IfcReinforcingMeshType defines commonly shared information for occurrences of reinforcing meshs. The set of shared information may include:",
+        "description": "The reinforcing element type IfcReinforcingMeshType defines commonly shared information for occurrences of reinforcing meshs. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a reinforcing mesh type specification indicating the specific product information that is common to all occurrences of that product type. The IfcReinforcingMeshType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcReinforcingMeshType are represented by instances of IfcReinforcingMesh. Geometry Use Definition The IfcReinforcingMeshType may define the shared geometric representation for many mesh occurrences. The RepresentationMaps attribute refers to a list of IfcRepresentationMap's, that allow for multiple geometric representations.",
         "predefined_types": {
             "NOTDEFINED": "The type of mesh is not defined.",
             "USERDEFINED": "The type of mesh is user defined."
@@ -5304,7 +5304,7 @@
             "RelatedObjects": "The object definitions, either object occurrences or object types, that are being aggregated. They are defined as the parts in the whole/part relationship. No order is implied between the parts.",
             "RelatingObject": "The object definition, either an object type or an object occurrence, that represents the aggregation. It is the whole within the whole/part relationship."
         },
-        "description": "The aggregation relationship IfcRelAggregates is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The aggregation relationship can be applied to all subtypes of IfcObjectDefinition.",
+        "description": "The aggregation relationship IfcRelAggregates is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The aggregation relationship can be applied to all subtypes of IfcObjectDefinition. In cases of aggregation of physical elements into a physical aggregate the shape representation of the whole (within the same representation identifier) can be taken from the sum of the shape representations of the parts. Decompositions imply a dependency, implying that the whole depends on the definition of the parts and the parts depend on the existence of the whole. The behaviour that is implied from the dependency relationship has to be established inside the applications.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelaggregates.htm"
     },
     "IfcRelAssigns": {
@@ -5312,7 +5312,7 @@
             "RelatedObjects": "Related objects, which are assigned to a single object. The type of the single (or relating) object is defined in the subtypes of IfcRelAssigns.",
             "RelatedObjectsType": "Particular type of the assignment relationship. It can constrain the applicable object types, used within the role of _RelatedObjects_."
         },
-        "description": "The assignment relationship, IfcRelAssigns, is a generalization of \"link\" relationships among instances of IfcObject and its various 1^st^ level subtypes. A link denotes the specific association through which one object (the client) applies the services of other objects (the suppliers), or through which one object may navigate to other objects.",
+        "description": "The assignment relationship, IfcRelAssigns, is a generalization of \"link\" relationships among instances of IfcObject and its various 1^st^ level subtypes. A link denotes the specific association through which one object (the client) applies the services of other objects (the suppliers), or through which one object may navigate to other objects. The client is denoted as the relating object and is established at the level of the specific, instantiable subtypes of IfcRelAssigns. The suppliers are denoted as the related objects and they are established by the RelatedObjects attribute. The assignment relationship establishs a bi-directional relationship among the participating objects and does not imply any dependency. The subtypes of IfcRelAssigns establishes the particular semantic meaning of the assignment relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassigns.htm"
     },
     "IfcRelAssignsToActor": {
@@ -5320,7 +5320,7 @@
             "ActingRole": "Role of the actor played within the context of the assignment to the object(s).",
             "RelatingActor": "Reference to the information about the actor. It comprises the information about the person or organization and its addresses."
         },
-        "description": "The objectified relationship IfcRelAssignsToActor handles the assignment of objects (subtypes of IfcObject) to an actor (subtypes of IfcActor).",
+        "description": "The objectified relationship IfcRelAssignsToActor handles the assignment of objects (subtypes of IfcObject) to an actor (subtypes of IfcActor). The IfcRelAssignsToActor objectified relationship defines a relationship between an IfcActor and one or many objects. A particular role of the actor played in that relationship can be associated. If specified, it takes priority over the role that may be directly assigned to the person or organization. Reference to the objects (or single object) on which the actor acts upon in a certain role (if given) is specified in the inherited RelatedObjects attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassignstoactor.htm"
     },
     "IfcRelAssignsToControl": {
@@ -5334,14 +5334,14 @@
         "attributes": {
             "RelatingGroup": "Reference to group that contains all assigned group members."
         },
-        "description": "The objectified relationship IfcRelAssignsToGroup handles the assignment of object definitions (individual object occurrences as subtypes of IfcObject, and object types as subtypes of IfcTypeObject) to a group (subtypes of IfcGroup).",
+        "description": "The objectified relationship IfcRelAssignsToGroup handles the assignment of object definitions (individual object occurrences as subtypes of IfcObject, and object types as subtypes of IfcTypeObject) to a group (subtypes of IfcGroup). The relationship handles the assignment of group members to the group object. It allows for grouping arbitrary objects within a group, including other groups. The grouping relationship can be applied in a recursive manner. The resulting group is of type IfcGroup. The inherited attribute RelatedObjects gives the references to the objects, which are the elements within the group. The RelatingGroup is the group that comprises all elements. The same object or object type can be included in zero, one or many groups. Grouping relationships are not hierarchical. Informal Propositions: - The group assignment relationship shall be acyclic, that is, a group shall not participate in its own grouping relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassignstogroup.htm"
     },
     "IfcRelAssignsToGroupByFactor": {
         "attributes": {
             "Factor": "Factor provided as a ratio measure that identifies the fraction or weighted factor that applies to the group assignment."
         },
-        "description": "The objectified relationship IfcRelAssignsToGroupByFactor is a specialization of the general grouping mechanism. It allows to add a factor to define the ratio that applies to the assignment of object definitions (individual object occurrences as subtypes of IfcObject and object types as subtypes of IfcTypeObject) to a group (subtypes of IfcGroup).",
+        "description": "The objectified relationship IfcRelAssignsToGroupByFactor is a specialization of the general grouping mechanism. It allows to add a factor to define the ratio that applies to the assignment of object definitions (individual object occurrences as subtypes of IfcObject and object types as subtypes of IfcTypeObject) to a group (subtypes of IfcGroup). The ratio can be used to define a percentage assignment. For example, a Factor of 0.8 would indicate that the object is assigned by 80% to the group, or a Factor of 2.5 would indicate the object is assigned with a weight factor of 2.5 to the group. The same object or object type may be included with the same or different Factor values to many groups. Grouping relationships are not hierarchical.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassignstogroupbyfactor.htm"
     },
     "IfcRelAssignsToProcess": {
@@ -5349,14 +5349,14 @@
             "QuantityInProcess": "Quantity of the object specific for the operation by this process.",
             "RelatingProcess": "Reference to the process to which the objects are assigned to."
         },
-        "description": "The objectified relationship IfcRelAssignsToProcess handles the assignment of one or many objects to a process or activity. An object can be a product that is the item the process operates on. Processes and activities can operate on things other than products, and can operate in ways other than input and output.",
+        "description": "The objectified relationship IfcRelAssignsToProcess handles the assignment of one or many objects to a process or activity. An object can be a product that is the item the process operates on. Processes and activities can operate on things other than products, and can operate in ways other than input and output. The inherited attribute RelatedObjects gives the references to the objects, or object type, which the process operates on. The RelatingProcess is the process or process type, that operates on the object. The operation types are captured in the inherited attribute Name.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassignstoprocess.htm"
     },
     "IfcRelAssignsToProduct": {
         "attributes": {
             "RelatingProduct": "Reference to the product or product type to which the objects are assigned to."
         },
-        "description": "The objectified relationship IfcRelAssignsToProduct handles the assignment of objects (subtypes of IfcObject) to a product (subtypes of IfcProduct). The Name attribute should be used to classify the usage of the IfcRelAssignsToProduct objectified relationship. The following Name values are proposed:",
+        "description": "The objectified relationship IfcRelAssignsToProduct handles the assignment of objects (subtypes of IfcObject) to a product (subtypes of IfcProduct). The Name attribute should be used to classify the usage of the IfcRelAssignsToProduct objectified relationship. The following Name values are proposed: - 'Context' : Assignment of a context specific representation, such as of structural members to a different context representation (with potentially different decomposition breakdown) such as of building elements for a specific context specific representation. - 'View' : Assignment of a product (via RelatingProduct) that is decomposed according to a discipline view, to another product (via RelatedObjects) that is decomposed according to a different discipline view. An example is the assignment of the architectural slab to a different decomposition of the pre manufactured sections of a slab (under a precast concrete discipline view).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassignstoproduct.htm"
     },
     "IfcRelAssignsToResource": {
@@ -5370,7 +5370,7 @@
         "attributes": {
             "RelatedObjects": "Set of object or property definitions to which the external references or information is associated. It includes object and type objects, property set templates, property templates and property sets and contexts."
         },
-        "description": "The association relationship IfcRelAssociates refers to sources of information (most notably a classification, library, document, approval, contraint, or material). The information associated may reside internally or externally of the project data. There is no dependency implied by the association.",
+        "description": "The association relationship IfcRelAssociates refers to sources of information (most notably a classification, library, document, approval, contraint, or material). The information associated may reside internally or externally of the project data. There is no dependency implied by the association. Association relationships can be established to objects (occurrences as subtypes of IfcObject) or to types (as subtypes of IfcTypeObject). Some associations (such as approval, or document) may also be applied to property templates (as subtypes of IfcPropertyDefinition). The association relationship establishs an association between one to many objects or property templates and the associated information. The subtypes of IfcRelAssociates establish the particular semantic meaning of the association relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassociates.htm"
     },
     "IfcRelAssociatesApproval": {
@@ -5384,7 +5384,7 @@
         "attributes": {
             "RelatingClassification": "Classification applied to the objects."
         },
-        "description": "The objectified relationship IfcRelAssociatesClassification handles the assignment of a classification item (items of the select IfcClassificationSelect) to objects occurrences (subtypes of IfcObject) or object types (subtypes of IfcTypeObject).",
+        "description": "The objectified relationship IfcRelAssociatesClassification handles the assignment of a classification item (items of the select IfcClassificationSelect) to objects occurrences (subtypes of IfcObject) or object types (subtypes of IfcTypeObject). The relationship is used to assign a classification item, or a classification system itself to objects. Depending on the type of the RelatingClassification it is either: - a reference to an classification item within an external classification system, or - a reference to the classification system itself The inherited attribute RelatedObjects define the objects or object types to which the classification is applied. The attribute RelatingClassification is the reference to a classification, applied to the object(s). A single RelatingClassification can thereby be applied to one or multiple objects.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassociatesclassification.htm"
     },
     "IfcRelAssociatesConstraint": {
@@ -5399,21 +5399,21 @@
         "attributes": {
             "RelatingDocument": "Document information or reference which is applied to the objects."
         },
-        "description": "The objectified relationship (IfcRelAssociatesDocument) handles the assignment of a document information (items of the select IfcDocumentSelect) to objects occurrences (subtypes of IfcObject) or object types (subtypes of IfcTypeObject).",
+        "description": "The objectified relationship (IfcRelAssociatesDocument) handles the assignment of a document information (items of the select IfcDocumentSelect) to objects occurrences (subtypes of IfcObject) or object types (subtypes of IfcTypeObject). The relationship is used to assign a document reference or a more detailed document information to objects. A single document reference can be applied to multiple objects. The inherited attribute RelatedObjects define the objects to which the document association is applied. The attribute RelatingDocument is the reference to a document reference, applied to the object(s).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassociatesdocument.htm"
     },
     "IfcRelAssociatesLibrary": {
         "attributes": {
             "RelatingLibrary": "Reference to a library, from which the definition of the property set is taken."
         },
-        "description": "The objectified relationship (IfcRelAssociatesLibrary) handles the assignment of a library item (items of the select IfcLibrarySelect) to subtypes of IfcObjectDefinition or IfcPropertyDefinition.",
+        "description": "The objectified relationship (IfcRelAssociatesLibrary) handles the assignment of a library item (items of the select IfcLibrarySelect) to subtypes of IfcObjectDefinition or IfcPropertyDefinition. The relationship is used to assign a library reference or a more detailed link to a library information to objects, property sets or types. A single library reference can be applied to multiple items. The inherited attribute RelatedObjects define the items to which the library association is applied. The attribute RelatingLibrary is the reference to a library reference, applied to the item(s).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelassociateslibrary.htm"
     },
     "IfcRelAssociatesMaterial": {
         "attributes": {
             "RelatingMaterial": "Material definition assigned to the elements or element types."
         },
-        "description": "IfcRelAssociatesMaterial is an objectified relationship between a material definition and elements or element types to which this material definition applies.",
+        "description": "IfcRelAssociatesMaterial is an objectified relationship between a material definition and elements or element types to which this material definition applies. The material definition can be: - assigned to an element occurrence as a specific usage of a layer set or profile set - assigned to an element occurrence or element type as a layer set, profile set, constituent set or a single material Materials can be arranged by layers and applied to layered elements. Typical elements are walls and slabs. - An IfcMaterialLayerSet, for layered elements with an indication of the layering direction and individual layer thicknesses - An IfcMaterialLayerSetUsage, i.e. a material layer set with positioning information along the reference axis or surface of the element. NOTE As a material layer set usage is an occurrence based information, that applies to each individual element, it cannot be assigned to an element type. Material can be applied to profiles. Typical elements using profile material are beam, column, member - An IfcMaterialProfileSet, i.e. a set of material assigned to a set of profiles, with a single material assigned to a single profile as the default. - An IfcMaterialProfileSetUsage, i.e. a material profile set with positioning information relative to the element axis, also refered to as cardinal point. NOTE As a material profile set usage is an occurrence based information, that applies to each individual element, it cannot be assigned to an element type. Materials can be arranged by identified parts of a component based element. Typical elements are dorrs/windows (with components such as lining, framing and glazing), or distribution elements. - An IfcMaterialConstituentSet, for component based elements with an indication of the component by keyword to which the material consituent applies. NOTE See the material use definitions at each applicable subtype of IfcElement or IfcElementType for a provision of these keywords. As a fallback, or in cases where only a single material information is needed, material information can be directly associated - A single IfcMaterial for any element where the material use definition does not prohibits its direct association - An IfcMaterialList, e.g. for composite elements, without an information, how the different materials are arranged. DEPRECATED The use of IfcMaterialList is deprecated in IFC4 onwards. Use IfcMaterialConstituentSet instead. The IfcRelAssociatesMaterial relationship is a special type of the IfcRelAssociates relationship. It can be applied to subtypes of IfcElement and subtypes of IfcElementType. - The IfcElement has an inverse relation to its material definition by the HasAssociations attribute, inherited from IfcObject. - The IfcElementType has an inverse relation to its material definition by the HasAssociations attribute, inherited from IfcPropertyDefinition. If both, the element occurrence (by an instance of IfcElement) and the element type (by an instance of IfcElementType, connected through IfcRelDefinesByType) have an associated material, then the material associated to the element occurrence overrides the material associated to the element type. Informal Propositions: - An IfcMaterialLayerSetUsage shall not be associated with a subtype of IfcElementType, it should only be associated with individual occurrences - An IfcMaterialProfileSetUsage shall not be associated with a subtype of IfcElementType, it should only be associated with individual occurrences",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelassociatesmaterial.htm"
     },
     "IfcRelConnects": {
@@ -5426,7 +5426,7 @@
             "RelatedElement": "Reference to a subtype of _IfcElement_ that is connected by the connection relationship in the role of _RelatedElement_.",
             "RelatingElement": "Reference to a subtype of _IfcElement_ that is connected by the connection relationship in the role of _RelatingElement_."
         },
-        "description": "The IfcRelConnectsElements objectified relationship provides the generalization of the connectivity between elements. It is a 1 to 1 relationship. The concept of two elements being physically or logically connected is described independently from the connecting elements. The connectivity may be related to the shape representation of the connected entities by providing a connection geometry.",
+        "description": "The IfcRelConnectsElements objectified relationship provides the generalization of the connectivity between elements. It is a 1 to 1 relationship. The concept of two elements being physically or logically connected is described independently from the connecting elements. The connectivity may be related to the shape representation of the connected entities by providing a connection geometry. - In this case the geometrical constraints of the connection are provided by the optional relationship to the IfcConnectionGeometry. The connection geometry is provided as a point, curve or surface within the local placement coordinate systems of the connecting elements. - If the connection geometry is omitted then the connection is provided as a logical connection. Under this circumstance, the connection point, curve or surface has to be recalculated by the receiving application.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelconnectselements.htm"
     },
     "IfcRelConnectsPathElements": {
@@ -5436,7 +5436,7 @@
             "RelatingConnectionType": "Indication of the connection type in relation to the path of the _RelatingObject_.",
             "RelatingPriorities": "Overriding priorities at this connection. It overrides the standard priority given at the wall layer provided by _IfcMaterialLayer_._Priority_. The list of _RelatingProperties_ corresponds to the list of _IfcMaterialLayerSet_._MaterialLayers_ of the element referenced by _RelatingObject_."
         },
-        "description": "The IfcRelConnectsPathElements relationship provides the connectivity information between two elements, which have path information.",
+        "description": "The IfcRelConnectsPathElements relationship provides the connectivity information between two elements, which have path information. The objectified relationship provides the additional information required to describe the connection between two path based elements that might have single or multiple layers of material. The connection type specifies where at the path based element a connection is given (at the start, in the middle or at the end). The connection is described by a connection geometry, given within the object coordinate systems of the RelatingElement and of the RelatedElement. In case of IfcWallStandardCase as the RelatingElement and RelatedElement the connection geometry is provided by the subtype IfcConnectionCurveGeometry. Both curves indicate the so called \"end cap\", i.e. the curve that trims the wall outer edges (being parallel along the wall axis) at the end.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcrelconnectspathelements.htm"
     },
     "IfcRelConnectsPortToElement": {
@@ -5444,7 +5444,7 @@
             "RelatedElement": "Reference to an _IfcDistributionElement_ that has ports assigned.",
             "RelatingPort": "Reference to an Port that is connected by the objectified relationship."
         },
-        "description": "IfcRelConnectsPortToElement is a relationship between a distribution element and dynamically connected ports where connections are realised to other distribution elements.",
+        "description": "IfcRelConnectsPortToElement is a relationship between a distribution element and dynamically connected ports where connections are realised to other distribution elements. Ports contained in different elements are connected to each other using the IfcRelConnectsPorts relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelconnectsporttoelement.htm"
     },
     "IfcRelConnectsPorts": {
@@ -5453,7 +5453,7 @@
             "RelatedPort": "Reference to the second port that is connected by the objectified relationship.",
             "RelatingPort": "Reference to the first port that is connected by the objectified relationship."
         },
-        "description": "An IfcRelConnectsPorts relationship defines the relationship that is made between two ports at their point of connection. It may include the connection geometry between two ports.",
+        "description": "An IfcRelConnectsPorts relationship defines the relationship that is made between two ports at their point of connection. It may include the connection geometry between two ports. The objectified relationship IfcRelConnectsPorts is required for defining how two instances of IfcPort connect together. Each of the ports is logically contained within the IfcDistributionElement by using the ordered collection IfcRelNests.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelconnectsports.htm"
     },
     "IfcRelConnectsStructuralActivity": {
@@ -5473,14 +5473,14 @@
             "RelatingStructuralMember": "Reference to an instance of IfcStructuralMember (or its subclasses) which is connected to the specified structural connection.",
             "SupportedLength": "Defines the 'supported length' of this structural connection. See Fig. for more detail."
         },
-        "description": "The entity IfcRelConnectsStructuralMember defines all needed properties describing the connection between structural members and structural connection objects (nodes or supports).",
+        "description": "The entity IfcRelConnectsStructuralMember defines all needed properties describing the connection between structural members and structural connection objects (nodes or supports). Use Definition Point Connection Instances of the entity IfcRelConnectsStructuralMember shall be used to describe a connection between an instance of IfcStructuralPointConnection and either an instance of IfcStructuralCurveMember or IfcStructuralSurfaceMember. The RelatedStructuralConnection for point connections has to be of type IfcStructuralPointConnection. Curve Connection Instances of the entity IfcRelConnectsStructuralMember shall be used to describe a connection between an instance of IfcStructuralCurveConnection and an instance of either IfcStructuralCurveMember or IfcStructuralSurfaceMember. The RelatedStructuralConnection for curve connections has to be of type IfcStructuralCurveConnection. Surface Connection Instances of the entity IfcRelConnectsStructuralMember shall be used to describe a connection between an instance of IfcStructuralSurfaceConnection and an instance of IfcStructuralSurfaceMember. The RelatedStructuralConnection for curve connections has to be of type IfcStructuralSurfaceConnection. Coordinate System for Applied Conditions All values defined by AppliedCondition or AdditionalConditions are given within the coordinate system provided by ConditionCoordinateSystem, which is defined relative to the local coordinate system of the structural member. If the ConditionCoordinateSystem is not defined, the local coordinate system of the structural member is used instead. Supported Length Optionally a supported length can be given, which specifies the length (or width) of the physical connection along a curve connection. Figure 1 illustrates the appropriate definition of support lengths.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcrelconnectsstructuralmember.htm"
     },
     "IfcRelConnectsWithEccentricity": {
         "attributes": {
             "ConnectionConstraint": "The connection constraint explicitly states the eccentricity between a structural member and a structural connection by means of two topological objects (vertex and vertex, or edge and edge, or face and face)."
         },
-        "description": "The entity IfcRelConnectsWithEccentricity adds the definition of eccentricity to the connection between a structural member and a structural connection (representing either a node or support).",
+        "description": "The entity IfcRelConnectsWithEccentricity adds the definition of eccentricity to the connection between a structural member and a structural connection (representing either a node or support). Use Definition Point Connection ConnectionConstraint shall be of type IfcConnectionPointGeometry and shall refer to two instances of IfcVertexPoint. Curve Connection ConnectionConstraint shall be of type IfcConnectionCurveGeometry and shall refer to two instances of IfcEdge or subtypes. Surface Connection ConnectionConstraint shall be of type IfcConnectionSurfaceGeometry and shall refer to two instances of IfcFaceSurface.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcrelconnectswitheccentricity.htm"
     },
     "IfcRelConnectsWithRealizingElements": {
@@ -5488,7 +5488,7 @@
             "ConnectionType": "The type of the connection given for informal purposes, it may include labels, like 'joint', 'rigid joint', 'flexible joint', etc.",
             "RealizingElements": "Defines the elements that realize a connection relationship."
         },
-        "description": "IfcRelConnectsWithRealizingElements defines a generic relationship that is made between two elements that require the realization of that relationship by means of further realizing elements.",
+        "description": "IfcRelConnectsWithRealizingElements defines a generic relationship that is made between two elements that require the realization of that relationship by means of further realizing elements. An IfcRelConnectsWithRealizingElements is a specialization of IfcRelConnectsElement where the connecting operation has the additional attribute of (one or many) realizing elements that may be used to realize or further qualify the relationship. It is defined as a ternary relationship.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelconnectswithrealizingelements.htm"
     },
     "IfcRelContainedInSpatialStructure": {
@@ -5496,7 +5496,7 @@
             "RelatedElements": "Set of products, which are contained within this level of the spatial structure hierarchy.",
             "RelatingStructure": "Spatial structure element, within which the element is contained. Any element can only be contained within one element of the project spatial structure."
         },
-        "description": "This objectified relationship, IfcRelContainedInSpatialStructure, is used to assign elements to a certain level of the spatial project structure. Any element can only be assigned once to a certain level of the spatial structure. The question, which level is relevant for which type of element, can only be answered within the context of a particular project and might vary within the various regions.",
+        "description": "This objectified relationship, IfcRelContainedInSpatialStructure, is used to assign elements to a certain level of the spatial project structure. Any element can only be assigned once to a certain level of the spatial structure. The question, which level is relevant for which type of element, can only be answered within the context of a particular project and might vary within the various regions. The containment relationship of an element within a spatial structure has to be a hierarchical relationship; an element can only be contained within a single spatial structure element. The reference relationship between an element and the spatial structure need not be hierarchical; that is, an element can reference many spatial structure elements. Predefined spatial structure elements to which elements can be assigned are - site as IfcSite - building as IfcBuilding - storey as IfcBuildingStorey - space as IfcSpace Occurrences of the same element type can be assigned to different spatial structure elements depending on the context of the occurrence. Figure 1 shows the use of IfcRelContainedInSpatialStructure to assign a stair and two walls to two different levels within the spatial structure.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelcontainedinspatialstructure.htm"
     },
     "IfcRelCoversBldgElements": {
@@ -5504,7 +5504,7 @@
             "RelatedCoverings": "Relationship to the set of coverings that are assigned to this element.",
             "RelatingBuildingElement": "Relationship to the element that is covered. It includes building elements for coverings such as flooring or cladding, or distribution elements for coverings such as sleeving or wrapping."
         },
-        "description": "The IfcRelCoversBldgElements relationship is an objectified relationship between an element and one to many coverings, which cover that element.",
+        "description": "The IfcRelCoversBldgElements relationship is an objectified relationship between an element and one to many coverings, which cover that element. The IFC specification provides two relationships: - IfcRelCoversBldgElements to assign coverings to elements. NOTE This relationship is now deprecated and replaced by IfcRelAggregates. - IfcRelCoversSpaces to assign coverings to spaces NOTE This relationship is now deprecated and replaced by IfcRelContainedInSpatialStructure. Whether the relationship between the covering and the space, or between the covering and the element, is regarded as primary, has to be determined within the context of a model view definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcrelcoversbldgelements.htm"
     },
     "IfcRelCoversSpaces": {
@@ -5512,7 +5512,7 @@
             "RelatedCoverings": "Relationship to the set of coverings covering that cover surfaces of this space.",
             "RelatingSpace": "Relationship to the space object that is covered."
         },
-        "description": "The objectified relationship, IfcRelCoversSpace, relates a space object to one or many coverings, which faces (or is assigned to) the space.",
+        "description": "The objectified relationship, IfcRelCoversSpace, relates a space object to one or many coverings, which faces (or is assigned to) the space. The IFC specification provides two relationships: - IfcRelCoversBldgElements to assign coverings to elements. NOTE This relationship is now deprecated and replaced by IfcRelAggregates. - IfcRelCoversSpaces to assign coverings to spaces NOTE This relationship is now deprecated and replaced by IfcRelContainedInSpatialStructure. Whether the relationship between the covering and the space, or between the covering and the element, is regarded as primary, has to be determined within the context of a model view definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcrelcoversspaces.htm"
     },
     "IfcRelDeclares": {
@@ -5520,15 +5520,15 @@
             "RelatedDefinitions": "Set of object or property definitions that are assigned to a context and to which the unit and representation context definitions of that context apply.",
             "RelatingContext": "Reference to the _IfcProject_ to which additional information is assigned."
         },
-        "description": "The objectified relationship IfcRelDeclares handles the declaration of objects (subtypes of IfcObject) or properties (subtypes of IfcPropertyDefinition) to a project or project library (represented by IfcProject, or IfcProjectLibrary).",
+        "description": "The objectified relationship IfcRelDeclares handles the declaration of objects (subtypes of IfcObject) or properties (subtypes of IfcPropertyDefinition) to a project or project library (represented by IfcProject, or IfcProjectLibrary). The relationship handles the assignment of other objects, like IfcActor, or IfcTypeObject to the project, or project libary. The attribute RelatedDefinitions provides the references to the first level objects, that are the elements within the context. All other objects that relate to the first level objects are also defined in the context. The RelatingContext is the project, or project library that comprises all elements. The unit assignments and the presentation contexts defined at IfcProject or IfcProjectLibrary apply to all these elements.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcreldeclares.htm"
     },
     "IfcRelDecomposes": {
-        "description": "The decomposition relationship, IfcRelDecomposes, defines the general concept of elements being composed or decomposed. The decomposition relationship denotes a whole/part hierarchy with the ability to navigate from the whole (the composition) to the parts and vice versa.",
+        "description": "The decomposition relationship, IfcRelDecomposes, defines the general concept of elements being composed or decomposed. The decomposition relationship denotes a whole/part hierarchy with the ability to navigate from the whole (the composition) to the parts and vice versa. Decompositions may be constrained by requiring both, the whole and its parts, to be of the same type - thus establishing a nesting relationship. Or they may require some form of physical containment, thus establishing special types of aggregation relationships. Decompositions imply a dependency, i.e. the definition of the whole depends on the definition of the parts and the parts depend on the existence of the whole. The decomposition relationship can be applied in a recursive manner, i.e. a decomposed element can be part in another decomposition. Cyclic references have to be prevented at application level.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcreldecomposes.htm"
     },
     "IfcRelDefines": {
-        "description": "A generic and abstract relationship which subtypes are used to:",
+        "description": "A generic and abstract relationship which subtypes are used to: - assign a object type to an object occurrence - assign a property set to an object instance - assign a property set template to a property set",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcreldefines.htm"
     },
     "IfcRelDefinesByObject": {
@@ -5536,7 +5536,7 @@
             "RelatedObjects": "Objects being part of an object occurrence decomposition, acting as the \"reflecting parts\" in the relationship.",
             "RelatingObject": "Object being part of an object type decomposition, acting as the \"declaring part\" in the relationship."
         },
-        "description": "The objectified relationship IfcRelDefinesByObject defines the relationship between an object taking part in an object type decomposition and an object occurrences taking part in an occurrence decomposition of that type.",
+        "description": "The objectified relationship IfcRelDefinesByObject defines the relationship between an object taking part in an object type decomposition and an object occurrences taking part in an occurrence decomposition of that type. The IfcRelDefinesByObject is a 1-to-N relationship, as it allows for the assignment of one declaring object information to a single or to many reflected objects. Those objects then share the same object property sets and, for subtypes of IfcProduct, the eventually assigned representation maps. Only objects that take part in a type decomposition and in an occurrence decomposition of the same type can be connected by the IfcRelDefinesByObject relationship. The IfcRelDefinesByObject links the decomposed object type part, also called the \"declaring part\" with the occurrence of that part inside the occurrence of the decomposed type, also called the \"reflected part\", as shown in Figure 1. The IfcRelDefinesByObject can be used together with the shape representations of the product type as shown in Figure 2. The IfcShapeRepresentation of the \"declaring part\" is referenced by the \"reflected part\". The IfcObjectPlacement of the model occurrence (the whole) determines the position within the project context.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcreldefinesbyobject.htm"
     },
     "IfcRelDefinesByProperties": {
@@ -5544,7 +5544,7 @@
             "RelatedObjects": "Reference to the objects (or single object) to which the property definition applies.",
             "RelatingPropertyDefinition": "Reference to the property set definition for that object or set of objects."
         },
-        "description": "The objectified relationship IfcRelDefinesByProperties defines the relationships between property set definitions and objects. Properties are aggregated in property sets. Property sets can be either directly assigned to occurrence objects using this relationship, or assigned to an object type and assigned via that type to occurrence objects. The assignment of an IfcPropertySet to an IfcTypeObject is not handled via this objectified relationship, but through the direct relationship HasPropertySets at IfcTypeObject.",
+        "description": "The objectified relationship IfcRelDefinesByProperties defines the relationships between property set definitions and objects. Properties are aggregated in property sets. Property sets can be either directly assigned to occurrence objects using this relationship, or assigned to an object type and assigned via that type to occurrence objects. The assignment of an IfcPropertySet to an IfcTypeObject is not handled via this objectified relationship, but through the direct relationship HasPropertySets at IfcTypeObject. The IfcRelDefinesByProperties is an N-to-N relationship, as it allows for the assignment of one or more property sets to one or more objects. Those objects then share the same property definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcreldefinesbyproperties.htm"
     },
     "IfcRelDefinesByTemplate": {
@@ -5552,7 +5552,7 @@
             "RelatedPropertySets": "One or many property sets or quantity sets that obtain their definitions from the single property set template.",
             "RelatingTemplate": "Property set template that provides the common definition of related property sets."
         },
-        "description": "The objectified relationship IfcRelDefinesByTemplate defines the relationships between property set template and property sets. Common information about property sets, e.g. the applicable name, description, contained properties, is defined by the property set template and assigned to all property sets.",
+        "description": "The objectified relationship IfcRelDefinesByTemplate defines the relationships between property set template and property sets. Common information about property sets, e.g. the applicable name, description, contained properties, is defined by the property set template and assigned to all property sets. The IfcRelDefinesByTemplate is a 1-to-N relationship, as it allows for the assignment of one property set template to a single or to many property sets or quantity sets. Those property sets then share the same property set template definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcreldefinesbytemplate.htm"
     },
     "IfcRelDefinesByType": {
@@ -5560,7 +5560,7 @@
             "RelatedObjects": "",
             "RelatingType": "Reference to the type (or style) information for that object or set of objects."
         },
-        "description": "The objectified relationship IfcRelDefinesByType defines the relationship between an object type and object occurrences. The IfcRelDefinesByType is a 1-to-N relationship, as it allows for the assignment of one type information to a single or to many objects. Those objects then share the same object type, and the property sets and properties assigned to the object type.",
+        "description": "The objectified relationship IfcRelDefinesByType defines the relationship between an object type and object occurrences. The IfcRelDefinesByType is a 1-to-N relationship, as it allows for the assignment of one type information to a single or to many objects. Those objects then share the same object type, and the property sets and properties assigned to the object type. The IfcRelDefinesByType links the object type definition with the object occurrence. Both may define properties by assigning an IfcPropertySet, including one or many subtypes of IfcProperty to either the object type or object occurrence, as shown in Figure 1. There are several scenarios to define the same property set on the object type definition and object occurrence side: - All properties for all object occurrences of a common object type have the same value - then only the object type definition has a property set assigned. - All properties for all object occurrences are different, that is there are no common property values for the object type definition - then each of the object occurrence has a property set assigned. - Some properties within the same property set have common values and are assigned to the object type definition and some are occurrence specific and assigned (with potentially different values) to the object occurrences - then: The sum of all properties within a given property set applicable to an object occurrence is the union of properties assigned to the object type definition plus the properties assigned to the object occurrence. If the object occurrence has a property with the same IfcProperty.Name in an IfcPropertySet, as the corresponding object type definition, then the occurrence property value overrides the type property value. The following table provides an example of assigning",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcreldefinesbytype.htm"
     },
     "IfcRelFillsElement": {
@@ -5568,7 +5568,7 @@
             "RelatedBuildingElement": "Reference to ~~building~~ element that occupies fully or partially the associated opening.",
             "RelatingOpeningElement": "Opening Element being filled by virtue of this relationship."
         },
-        "description": "IfcRelFillsElement is an objectified relationship between an opening element and an element that fills (or partially fills) the opening element. It is an one-to-one relationship.",
+        "description": "IfcRelFillsElement is an objectified relationship between an opening element and an element that fills (or partially fills) the opening element. It is an one-to-one relationship. As shown in Figure 1, the insertion of a door into a wall is represented by two separate relationships. First the door opening is created within the wall by IfcWall(StandardCase) <-- IfcRelVoidsElement --> IfcOpeningElement, then the door is inserted within the opening by IfcOpeningElement <-- IfcRelFillsElement --> IfcDoor.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelfillselement.htm"
     },
     "IfcRelFlowControlElements": {
@@ -5576,7 +5576,7 @@
             "RelatedControlElements": "References control elements which may be used to impart control on the Distribution Element.",
             "RelatingFlowElement": "Relationship to a distribution flow element"
         },
-        "description": "This objectified relationship between a distribution flow element occurrence and one-to-many control element occurrences indicates that the control element(s) sense or control some aspect of the flow element. It is applied to IfcDistributionFlowElement and IfcDistributionControlElement.",
+        "description": "This objectified relationship between a distribution flow element occurrence and one-to-many control element occurrences indicates that the control element(s) sense or control some aspect of the flow element. It is applied to IfcDistributionFlowElement and IfcDistributionControlElement. This relationship may be used to indicate an operational relationship such as an actuator operating a valve, damper, or switch. It may also be used to indicate a sensing relationship such as a sensor detecting conditions of fluid flow. This relationship implies a sensing or controlling relationship; if elements are merely connected without any control relationship, then IfcRelConnectsElements should be used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcrelflowcontrolelements.htm"
     },
     "IfcRelInterferesElements": {
@@ -5587,7 +5587,7 @@
             "RelatedElement": "Reference to a subtype of _IfcElement that is the _RelatedElement_ in the interference relationship. Depending on the value of _ImpliedOrder_ the _RelatedElement_ may carry the notion to be the element from which the interference geometry should not be subtracted._",
             "RelatingElement": "Reference to a subtype of _IfcElement that is the _RelatingElement_ in the interference relationship. Depending on the value of _ImpliedOrder_ the _RelatingElement_ may carry the notion to be the element from which the interference geometry should be subtracted._"
         },
-        "description": "The IfcRelInterferesElements objectified relationship indicates that two elements interfere. Interference is a spatial overlap between the two elements. It is a 1 to 1 relationship. The concept of two elements interfering physically or logically is described independently from the elements. The interference may be related to the shape representation of the entities by providing an interference geometry.",
+        "description": "The IfcRelInterferesElements objectified relationship indicates that two elements interfere. Interference is a spatial overlap between the two elements. It is a 1 to 1 relationship. The concept of two elements interfering physically or logically is described independently from the elements. The interference may be related to the shape representation of the entities by providing an interference geometry. - When the interference geometry is available it can be passed by the optional attribute InterferenceGeometry pointing to IfcConnectionGeometry. The connection geometry is provided as a point, curve, surface, or volume within the local placement coordinate systems of the connecting elements. The IfcConnectionVolumeGeometry is the default type to be used for interference in 3D space, as indicated in e.g. clash detections. - If the interference geometry is omitted then the interference is provided as a logical relationship. Under this circumstance, the connection point, curve, surface, or solid has to be recalculated by the receiving application. The RelatingElement and RelatedElement define the two elements in the relationship, that may have different roles. This is controlled by the attribute ImpliedOrder. - ImpliedOrder=TRUE The RelatingElement constitutes the primary element of the interference relationship. If the interference is to be resolved by subtracting the overlapping part, it should be subtracted from the RelatingElement. The net result would be the RelatingElement subtracted by the InterferenceGeometry. This would be the case in interference relationships where the RelatedElement creates a void in the RelatingElement dynamically. - ImpliedOrder=FALSE The RelatingElement and RelatedElement have no priority among each other. If the interference is to be resolved then no information about whether the InterferenceGeometry should be subtracted from the RelatingElement or thed RelatedElement can be traced. This would be the case for clash detection results. - ImpliedOrder=UNKNOWN No information about the priorities is provided.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelinterfereselements.htm"
     },
     "IfcRelNests": {
@@ -5595,7 +5595,7 @@
             "RelatedObjects": "The object definitions, either non-product object occurrences or non-product object types, that are being nestes. They are defined as the parts in the ordered whole/part relationship -  i.e. there is an implied order among the parts expressed by the position within the list of _RelatedObjects_.",
             "RelatingObject": "The object definition, either an non-product object type or a non-product object occurrence, that represents the nest. It is the whole within the whole/part relationship."
         },
-        "description": "The nesting relationship IfcRelNests is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The nesting relationship can be applied to all non physical subtypes of object and object types, namely processes, controls (like cost items), and resources. It can also be applied to physical subtypes of object and object types, namely elements having ports. The nesting implies an order among the nested parts.",
+        "description": "The nesting relationship IfcRelNests is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The nesting relationship can be applied to all non physical subtypes of object and object types, namely processes, controls (like cost items), and resources. It can also be applied to physical subtypes of object and object types, namely elements having ports. The nesting implies an order among the nested parts. Decompositions imply a dependency, i.e. the definition of the whole depends on the definition of the parts and the parts depend on the existence of the whole. The behaviour that is implied from the dependency has to be established inside the applications.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelnests.htm"
     },
     "IfcRelProjectsElement": {
@@ -5603,7 +5603,7 @@
             "RelatedFeatureElement": "Reference to the _IfcFeatureElementAddition_ that defines an addition to the volume of the element, by using a Boolean addition operation. An example is a projection at the associated element.",
             "RelatingElement": "Element at which a projection is created by the associated _IfcProjectionElement_."
         },
-        "description": "The IfcRelProjectsElement is an objectified relationship between an element and one projection element that creates a modifier to the shape of the element. The relationship is defined to be a 1:1 relationship, if an element has more than one projection, several relationship objects have to be used, each pointing to a different projection element. The IfcRelProjectsElement establishes an aggregation relationship between the main element and a sub ordinary addition feature.",
+        "description": "The IfcRelProjectsElement is an objectified relationship between an element and one projection element that creates a modifier to the shape of the element. The relationship is defined to be a 1:1 relationship, if an element has more than one projection, several relationship objects have to be used, each pointing to a different projection element. The IfcRelProjectsElement establishes an aggregation relationship between the main element and a sub ordinary addition feature. The IfcRelProjectsElement implies a Boolean operation of addition for the geometric bodies of the element and the feature element. As with all decomposition relationships it determines: - existence dependency - the RelatedFeatureElement cannot exist without the RelatingElement - hierarchical and non-cyclical relationship - the IfcRelProjectsElement can only alter a single IfcElement - no spatial containment - the IfcFeatureElementAddition as related element never participates in the hiearchical spatial containment relationship IfcRelContainedInSpatialStructure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelprojectselement.htm"
     },
     "IfcRelReferencedInSpatialStructure": {
@@ -5611,7 +5611,7 @@
             "RelatedElements": "Set of products, which are referenced within this level of the spatial structure hierarchy. > NOTE  Referenced elements are contained elsewhere within the spatial structure, they are referenced additionally by this spatial structure element, e.g., because they span several stories.",
             "RelatingStructure": "Spatial structure element, within which the element is referenced. Any element can be contained within zero, one or many elements of the project spatial and zoning structure."
         },
-        "description": "The objectified relationship, IfcRelReferencedInSpatialStructure is used to assign elements in addition to those levels of the project spatial structure, in which they are referenced, but not primarily contained.",
+        "description": "The objectified relationship, IfcRelReferencedInSpatialStructure is used to assign elements in addition to those levels of the project spatial structure, in which they are referenced, but not primarily contained. Any element can be referenced to zero, one or several levels of the spatial structure. Whereas the IfcRelContainsInSpatialStructure relationship is required to be hierarchical (an element can only be contained in exactly one spatial structure element), the IfcRelReferencedInSpatialStructure is not restricted to be hierarchical. Predefined spatial structure elements to which elements can be assigned are - site as IfcSite - building as IfcBuilding - storey as IfcBuildingStorey - space as IfcSpace Elements can also be references in a spatial zone that is provided as IfcSpatialZone. Figure 1 shows the use of IfcRelContainedInSpatialStructure and IfcRelReferencedInSpatialStructure to assign an IfcCurtainWall to two different levels within the spatial structure. It is primarily contained within the ground floor, and additionally referenced within the first and second floor.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelreferencedinspatialstructure.htm"
     },
     "IfcRelSequence": {
@@ -5622,7 +5622,7 @@
             "TimeLag": "Time duration of the sequence, it is the time lag between the     predecessor and the successor as specified by the     SequenceType.",
             "UserDefinedSequenceType": "Allows for specification of user defined type of the sequence     beyond the enumeration values (START_START, START_FINISH,     FINISH_START, FINISH_FINISH) provided by _SequenceType_     attribute of type _IfcSequenceEnum_. When a value is     provided for attribute _UserDefinedSequenceType_ in     parallel the attribute _SequenceType_ shall have     enumeration value USERDEFINED."
         },
-        "description": "IfcRelSequence is a sequential relationship between processes where one process must occur before the other in time and where the timing of the relationship may be described as a type of sequence. The relating process (IfcRelSequence.RelatingProcess) is considered to be the predecessor in the relationship (has precedence) whilst the related process (IfcRelSequence.RelatedProcess) is the successor.",
+        "description": "IfcRelSequence is a sequential relationship between processes where one process must occur before the other in time and where the timing of the relationship may be described as a type of sequence. The relating process (IfcRelSequence.RelatingProcess) is considered to be the predecessor in the relationship (has precedence) whilst the related process (IfcRelSequence.RelatedProcess) is the successor. IfcRelSequence is defined as one-to-one relationship; therefore it assigns one predecessor to one successor. Use definitions IfcRelSequence is used to describe the logical sequence relationship that exists between two processes. This logical relationship identifies that there is a predecessor or relating process and a successor or related process. In IFC, there may be one predecessor and one successor in the relationship. Many occurrences of IfcRelSequence may exist to describe the sequence relationships of a predecessor task with many successor tasks or of many predecessor tasks with one successor task, thus enabling a m:n sequence relationship between tasks. Please note that sequence relationships can be used to define dependencies between process occurrences but also between process types (for further information see IfcRelDefinesByObject and IfcTaskType). In case of defining dependencies between process occurrences sequence relationships should stay within the limits of a directed, non-cyclic graph. A sequence type may be set for a sequence. For tasks assigned to a work schedule, it is expected that the sequence type will be asserted. For a process map, where the sequence relationship between processes is simply a logical flow, it need not be asserted. A time lag may be assigned to a sequence, and the sequence type defines the way in which the time lag applies to the sequence either as a ratio or percentage of time duration (e.g. start successor task when predecessor is 50% complete) or as a time measure (e.g. start successor task 1 week after commencement of the predecessor task). Care should be used when assigning a time lag to a sequence depending on the setting of the sequence type since there is no checking that the time lag value is in keeping with the sequence type set.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprocessextension/lexical/ifcrelsequence.htm"
     },
     "IfcRelServicesBuildings": {
@@ -5630,7 +5630,7 @@
             "RelatedBuildings": "Spatial structure elements (including site, building, storeys) that are serviced by the system.",
             "RelatingSystem": "System that services the Buildings."
         },
-        "description": "The IfcRelServicesBuildings is an objectified relationship that defines the relationship between a system and the sites, buildings, storeys, spaces, or spatial zones, it serves. Examples of systems are:",
+        "description": "The IfcRelServicesBuildings is an objectified relationship that defines the relationship between a system and the sites, buildings, storeys, spaces, or spatial zones, it serves. Examples of systems are: - building service systems (heating, cooling, waste water system) represented by instances of IfcDistributionSystem; - building systems (fenestration, shading) represented by instances of IfcBuildingSystem; - zones as collection of logically grouped spaces represented by instances of IfcZone - idealized structural analysis systems represented by instances of IfcStructuralAnalysisModel.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelservicesbuildings.htm"
     },
     "IfcRelSpaceBoundary": {
@@ -5641,7 +5641,7 @@
             "RelatedBuildingElement": "Reference to ~~Building~~ Element, that defines the Space Boundaries.",
             "RelatingSpace": "Reference to one spaces that is delimited by this boundary."
         },
-        "description": "The space boundary defines the physical or virtual delimiter of a space by the relationship IfcRelSpaceBoundary to the surrounding elements.",
+        "description": "The space boundary defines the physical or virtual delimiter of a space by the relationship IfcRelSpaceBoundary to the surrounding elements. - In the case of a physical space boundary, the placement and shape of the boundary may be given, and the building element, providing the boundary, is referenced, - In the case of a virtual space boundary, the placement and shape of the boundary may be given, and a virtual element is referenced. The IfcRelSpaceBoundary is defined as an objectified relationship that handles the element to space relationship by objectifying the relationship between an element and the space it bounds. It is given as a one-to-one relationship, but allows each element (including virutal elements and openings) to define many such relationship and each space to be defined by many such relationships. Space boundaries are always defined as seen from the space. In general two basic types of space boundaries are distinguished: - 1^st^ level space boundary: defined as boundaries of the space, not taking into account any change in building element or spaces on the other side. - 2^nd^ level space boundary: defined as boundary taking any change in building element or spaces on the other side into account. It can be further distinguished into 2^nd^ level type A: There is a space on the other side. 2^nd^ level type B: There is a building element on the other side. The differences between the 1^st^ and 2^nd^ level space boundaries is identified by: - 1^st^ level: SELF\\IfcRoot.Name = \"1stLevel\" SELF\\IfcRootDescription = NIL - 2^nd^ level: SELF\\IfcRoot.Name = \"2ndLevel\" SELF\\IfcRootDescription = \"2a\", or \"2b\" Differentiation between physical and virtual space boundary is illustrated in Figure 1 and Figure 42. As shown in Figure 41, if the IfcRelSpaceBoundary is used to express a virtual boundary, the attribute PhysicalOrVirtualBoundary has to be set to VIRTUAL. The attribute RelatedBuildingElement shall point to an instance of IfcVirtualElement. If the correct location is of interest, the attribute ConnectionGeometry is required. As shown in Figure 42, if the IfcRelSpaceBoundary is used to express a physical boundary between two spaces, the attribute PhysicalOrVirtualBoundary has to be set to PHYSICAL. The attribute RelatedBuildingElement has to be given and points to the element providing the space boundary. The attribute ConnectionGeometry may be inserted, in this case it describes the physical space boundary geometically, or it may be omited, in that case it describes a physical space boundary logically. The IfcRelSpaceBoundary may have geometry attached. If geometry is not attached, the relationship between space and building element is handled only on a logical level. If geometry is attached, it is given within the local coordinate systems of the space. The geometric representation (through the ConnectionGeometry attribute) is defined using either 2D curve geometry or 3D surface geometry for space boundaries. In most view definitions the 3D connection surface geometry is required. - 1^st^ level space boundary: only connection geometry for related space shall be provided only surface connection geometry shall be provided only the following surface representations are supported: IfcSurfaceOfLinearExtrusion IfcCurveBoundedPlane IfcCurveBoundedSurface IfcFaceBasedSurfaceModel - 2^nd^ level space boundary: only connection geometry for related space shall be provided only surface connection geometry shall be provided only the following surface representations are supported: IfcCurveBoundedPlane with restrictions to have polygonal boundaries only IfcFaceBasedSurfaceModel Surface connection geometry The following constraints apply to the surface connection geometry representation: - planar boundaries: IfcSurfaceOfLinearExtrusion defined by a SweptCurve being an IfcArbitraryOpenProfileDef with straight segements, or IfcCurveBoundedPlane - curved boundaries IfcSurfaceOfLinearExtrusion defined by a SweptCurve being an IfcArbitraryOpenProfileDef with curves segements, or IfcCurveBoundedSurface with a BasisSurface being a non planar surface, such as IfcCylindricalSurface, or IfcFaceBasedSurfaceModel if already faceted. Curve connection geometry The following constraints apply to the 2D curve representation: - Curve: IfcPolyline, IfcTrimmedCurve or IfcCompositeCurve",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelspaceboundary.htm"
     },
     "IfcRelSpaceBoundary1stLevel": {
@@ -5649,7 +5649,7 @@
             "InnerBoundaries": "Reference to the inner boundaries of the space boundary. Inner boundaries are defined by the space boundaries of openings, doors and windows.",
             "ParentBoundary": "Reference to the host, or parent, space boundary within which this inner boundary is defined."
         },
-        "description": "The 1st level space boundary defines the physical or virtual delimiter of a space by the relationship IfcRelSpaceBoundary1stLevel to the surrounding elements. 1st level space boundaries are characterizeda by:",
+        "description": "The 1st level space boundary defines the physical or virtual delimiter of a space by the relationship IfcRelSpaceBoundary1stLevel to the surrounding elements. 1st level space boundaries are characterizeda by: - 1st level space boundaries are the boundaries of a space defined by the surfaces of building elements bounding this space (physical space boundaries) or by virtual surfaces provided by an adjacent space with no dividing wall. - 1st level space boundaries do not consider any change of material in the bounding building elements, or different spaces/zones behind a wall or slab (floor or ceiling). - 1st level space boundaries are differentiated in two ways: virtual or physical and internal,external, or undefined (internal and external) e.g. for a wall that is partially inside and outside. - 1st level space boundaries form a closed shell around the space (so long as the space is completely enclosed) and include overlapping boundaries representing openings (filled or not) in the building elements (see implementers agreement below). 1st level space boundaries define a space by its boundary surfaces without taking anything on the other side of the bounding elements into account. Relationship Use Definitions As shown in Figure 1, the attribute ParentBoundary with inverse InnerBoundaries is provided to link the space boundaries of doors, windows, and openings to the parent boundary, such as of a wall or slab. Geometry Use Definitions See the definition at the supertype IfcRelSpaceBoundary for guidance on using the connection geometry for first level space boundaries.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelspaceboundary1stlevel.htm"
     },
     "IfcRelSpaceBoundary2ndLevel": {
@@ -5657,7 +5657,7 @@
             "CorrespondingBoundary": "Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element.",
             "Corresponds": "Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element."
         },
-        "description": "The 2nd level space boundary defines the physical or virtual delimiter of a space by the relationship IfcRelSpaceBoundary2ndLevel to the surrounding elements. 2nd level space boundaries are characterized by:",
+        "description": "The 2nd level space boundary defines the physical or virtual delimiter of a space by the relationship IfcRelSpaceBoundary2ndLevel to the surrounding elements. 2nd level space boundaries are characterized by: - 2nd level space boundaries still represent building elements that bound the space, but are more granular in that they are subdivided in any of the following cases: Differences in materials and/or material assemblies (for example, a wainscot or paneling on the lower portion of a wall). Differences in spaces or zones on the other side of the building element (or virtual boundary) represented by the space boundary (for example, two different spaces on the other side of a wall) - 2nd level space boundaries are differentiated in two ways: virtual or physical and internal or external, whereby any space boundary that is both internal and external has to be split into segments being either or. - 2nd level space boundaries represent both sides of a heat transfer surface separated by the thickness of the building element. They can be further differentiated in: Type 2a that occurs when there is a space on the opposite side of the building element providing the space boundary Type 2b occurs if there is a building element on the opposite side of the building element providing the space boundary. - The connection geometry of 2nd level space boundaries is restricted to planar surfaces only. This means that curved surfaces must be segmented. 2nd level space boundaries define the heat transfer surfaces on both sides of building elements that separate spaces. The generation of 2nd level space boundaries has to take building elements and spaces on the other side into account. Relationship Use Definitions As shown in Figure 1, the attribute ParentBoundary with inverse InnerBoundaries is provided to link the space boundaries of doors, windows, and openings to the parent boundary, such as of a wall or slab. The attribute CorrespondingBoundary with inverse Corresponds is provided to link the pair of space boundaries on the opposite sides of the building element. Geometry Use Definitions See the definition at the supertype IfcRelSpaceBoundary for guidance on using the connection geometry for second level space boundaries.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelspaceboundary2ndlevel.htm"
     },
     "IfcRelVoidsElement": {
@@ -5665,11 +5665,11 @@
             "RelatedOpeningElement": "Reference to the feature subtraction element which defines a void in the associated element.",
             "RelatingBuildingElement": "Reference to element in which a void is created by associated feature subtraction element."
         },
-        "description": "IfcRelVoidsElement is an objectified relationship between a building element and one opening element that creates a void in the element. It is a one-to-one relationship. This relationship implies a Boolean operation of subtraction between the geometric bodies of the element and the opening.",
+        "description": "IfcRelVoidsElement is an objectified relationship between a building element and one opening element that creates a void in the element. It is a one-to-one relationship. This relationship implies a Boolean operation of subtraction between the geometric bodies of the element and the opening. As shown in Figure 1, the insertion of a void into a wall is represented by the relationship IfcRelVoidsElement. The opening is created within the wall by IfcWall(StandardCase) o-- IfcRelVoidsElement --o IfcOpeningElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcrelvoidselement.htm"
     },
     "IfcRelationship": {
-        "description": "IfcRelationship is the abstract generalization of all objectified relationships in IFC. Objectified relationships are the preferred way to handle relationships among objects. This allows to keep relationship specific properties directly at the relationship and opens the possibility to later handle relationship specific behavior.",
+        "description": "IfcRelationship is the abstract generalization of all objectified relationships in IFC. Objectified relationships are the preferred way to handle relationships among objects. This allows to keep relationship specific properties directly at the relationship and opens the possibility to later handle relationship specific behavior. There are two different types of relationships, 1-to-1 relationships and 1-to-many relationship. used within the subtypes of IfcRelationship. The following convention applies to all subtypes: - The two sides of the objectified relationship are named Relating+<name of relating object> and Related+<name of related object> - In case of the 1-to-many relationship, the related side of the relationship shall be an aggregate being a set 1:N",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcrelationship.htm"
     },
     "IfcReparametrisedCompositeCurveSegment": {
@@ -5689,7 +5689,7 @@
             "RepresentationMap": "Use of the representation within an _IfcRepresentationMap_. If used, this _IfcRepresentation_ may be assigned to many representations as one of its _Items_ using an _IfcMappedItem_. Using _IfcRepresentationMap_ is the way to share one representation (often of type _IfcShapeRepresentation_) by many products.",
             "RepresentationType": "The description of the type of a representation context. The representation type defines the type of geometry or topology used for representing the product representation. More information is given at the subtypes _IfcShapeRepresentation_ and _IfcTopologyRepresentation_.   The supported values for context type are to be specified by implementers agreements."
         },
-        "description": "The IfcRepresentation defines the general concept of representing product properties and in particular the product shape.",
+        "description": "The IfcRepresentation defines the general concept of representing product properties and in particular the product shape. Representation Use Definition Each representation, either IfcShapeRepresentation, or IfcTopologyRepresentation shall have a well defined: - ContextOfItems: Reference to an IfcGeometricRepresentationContext as agreed for this representation. - RepresentationIdentifier: Name of the representation, for example, 'Body' for 3D shape, 'FootPrint' for 2D ground view, 'Axis' for reference axis. - RepresentationType: Name for the geometric, or topological representation type, for example, 'SweptSolid' for 3D swept solids, 'Brep' for boundary representation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcrepresentation.htm"
     },
     "IfcRepresentationContext": {
@@ -5706,7 +5706,7 @@
             "LayerAssignment": "Assignment of the representation item to a single or multiple layer(s). The _LayerAssignments_ can override a _LayerAssignments_ of the _IfcRepresentation_ it is used  within the list of _Items_.",
             "StyledByItem": "Reference to the _IfcStyledItem_ that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve."
         },
-        "description": "The IfcRepresentationItem is used within an IfcRepresentation (directly or indirectly through other IfcRepresentationItem's) to represent an IfcProductRepresentation. Most commonly these IfcRepresentationItem's are geometric or topological representation items, that can (but not need to) have presentation style infomation assigned.",
+        "description": "The IfcRepresentationItem is used within an IfcRepresentation (directly or indirectly through other IfcRepresentationItem's) to represent an IfcProductRepresentation. Most commonly these IfcRepresentationItem's are geometric or topological representation items, that can (but not need to) have presentation style infomation assigned. In case that presentation style information is applied, it can be either applied by an IfcStyledItem, or by an assignment to an IfcPresentationLayerWithStyle. If both are present, and both style assignments include the same subtype of IfcPresentationStyle, then the style assigned by IfcStyledItem takes priority. Figure 1 shows an instance diagram explaining the use of IfcStyledItem and IfcPresentationLayerWithStyle to apply presentation styles. Figure 2 shows in instance diagram explaining the override of IfcPresentationLayerWithStyle by IfcStyledItem to apply presentation styles.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcrepresentationitem.htm"
     },
     "IfcRepresentationMap": {
@@ -5716,7 +5716,7 @@
             "MappedRepresentation": "A representation that is mapped to at least one mapped item.",
             "MappingOrigin": "An axis2 placement that defines the position about which the mapped representation is mapped."
         },
-        "description": "An IfcRepresentationMap defines the base definition (also referred to as block, cell or macro) called MappedRepresentation within the MappingOrigin. The MappingOrigin defines the coordinate system in which the MappedRepresentation is defined.",
+        "description": "An IfcRepresentationMap defines the base definition (also referred to as block, cell or macro) called MappedRepresentation within the MappingOrigin. The MappingOrigin defines the coordinate system in which the MappedRepresentation is defined. The RepresentationMap is used through an IfcMappeditem in one or several IfcShapeRepresentation's. An Cartesian transformation operator can be applied to transform the MappedRepresentation into the placement coordinate system of the shape representation. The transformation of the representation map is restricted to be a Cartesian transformation mapping (translation, rotation, mirroring and scaling).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcrepresentationmap.htm"
     },
     "IfcResource": {
@@ -5725,7 +5725,7 @@
             "LongDescription": "A detailed description of the resource (e.g. the skillset for a labor resource).",
             "ResourceOf": "Set of relationships to other objects, e.g. products, processes, controls, resources or actors, for which this resource object is a resource."
         },
-        "description": "IfcResource contains the information needed to represent the costs, schedule, and other impacts from the use of a thing in a process. It is not intended to use IfcResource to model the general properties of the things themselves, while an optional linkage from IfcResource to the things to be used can be specified (specifically, the relationship from subtypes of IfcResource to IfcProduct through the IfcRelAssignsToResource relationship).",
+        "description": "IfcResource contains the information needed to represent the costs, schedule, and other impacts from the use of a thing in a process. It is not intended to use IfcResource to model the general properties of the things themselves, while an optional linkage from IfcResource to the things to be used can be specified (specifically, the relationship from subtypes of IfcResource to IfcProduct through the IfcRelAssignsToResource relationship). There are two basic intended uses of IfcResource. First, if the attributes of the thing are not needed for the purpose of the use of IfcResource, or the types of things are not explicitly modeled in IFC yet, then the linkage between the resource and the thing doesn't have to be instantiated in the system. That is, the attributes of IfcResource (or its subtypes) alone are sufficient to represent the use of the thing as a resource for the purpose of the project. Second, if the attributes of the thing are needed for the use of IfcResource objects, and they are modeled explicitly as objects, then the IfcResource instances can be linked to the instances of the type of the things being referenced. Things that might be used as resources and that are already modeled in the IFC include physical products, people and organizations, and materials. The relationship object IfcRelAssignsToResource is provided for this approach. The inherited attribute ObjectType is used as a textual code that identifies the resource type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcresource.htm"
     },
     "IfcResourceApprovalRelationship": {
@@ -5741,7 +5741,7 @@
             "RelatedResourceObjects": "The properties to which a constraint is to be related.",
             "RelatingConstraint": "The constraint that is to be related."
         },
-        "description": "An IfcResourceConstraintRelationship is a relationship entity that enables a constraint to be related to one or more resource level objects.",
+        "description": "An IfcResourceConstraintRelationship is a relationship entity that enables a constraint to be related to one or more resource level objects. An IfcResourceConstraintRelationship allows for the specification of a constraint to be applied to many entity types. An important case is to apply constraints to properties. The constraints applied therefore enable a property to carry values identifying requirements as well as those identifying the fulfilment of those requirements.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstraintresource/lexical/ifcresourceconstraintrelationship.htm"
     },
     "IfcResourceLevelRelationship": {
@@ -5779,14 +5779,14 @@
             "Axis": "Axis about which revolution will take place.",
             "AxisLine": "The line of the axis of revolution. IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(Axis.Location,    IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(Axis.Z,1.0))"
         },
-        "description": "An IfcRevolvedAreaSolid is a solid created by revolving a cross section provided by a profile definition about an axis.",
+        "description": "An IfcRevolvedAreaSolid is a solid created by revolving a cross section provided by a profile definition about an axis. The resulting solid is positioned by the IfcSweptAreaSolid.Position relative to the object coordinate system. If provided, it allows to reposition the revolved solid. If not provided, it defaults to the current object coordinate system. The axis and the cross section shall be in the same plane, prior to any repositioning. Informal Propositions: - The AxisLine shall lie in the plane of the SweptArea (as defined at supertype IfcSweptAreaSolid). - The AxisLine shall not intersect the interior of the SweptArea (as defined at supertype IfcSweptAreaSolid). - The Angle shall be between 0\u00b0 and 360\u00b0, or 0 and 2\u03c0 (depending on the unit type for IfcPlaneAngleMeasure). Texture Use Definition For side faces, textures are aligned facing upright along the sides with origin at the first point of an arbitrary profile, and following the outer bound of the profile counter-clockwise (as seen from above). For parameterized profiles, the origin is defined at the +Y extent for rounded profiles (having no sharp edge) and the first sharp edge counter-clockwise from the +Y extent for all other profiles. Textures are stretched or repeated on each side along the outer boundary of the profile according to RepeatS. Textures are stretched or repeated on each side along the outermost (longest) revolution path according to RepeatT, where coordinates are compressed towards the axis of revolution. For top and bottom caps, textures are aligned facing front-to-back, with the origin at the minimum X and Y extent. Textures are stretched or repeated on the top and bottom to the extent of each face according to RepeatS and RepeatT. For profiles with voids, textures are aligned facing upright along the inner side with origin at the first point of an arbitrary profile, and following the inner bound of the profile clockwise (as seen from above). For parameterized profiles, the origin of inner sides is defined at the +Y extent for rounded profiles (having no sharp edge such as hollow ellipses or rounded rectangles) and the first sharp edge clockwise from the +Y extent for all other profiles.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcrevolvedareasolid.htm"
     },
     "IfcRevolvedAreaSolidTapered": {
         "attributes": {
             "EndSweptArea": ""
         },
-        "description": "IfcRevolvedAreaSolidTapered is defined by revolving a cross section along a circular arc. The cross section may change along the revolving sweep from the shape of the start cross section into the shape of the end cross section. Corresponding vertices of the start and end cross sections are then connected. The bounded surface may have holes which will sweep into holes in the solid.",
+        "description": "IfcRevolvedAreaSolidTapered is defined by revolving a cross section along a circular arc. The cross section may change along the revolving sweep from the shape of the start cross section into the shape of the end cross section. Corresponding vertices of the start and end cross sections are then connected. The bounded surface may have holes which will sweep into holes in the solid. The rotation axis is defined by: - Start point: SELF\\IfcSweptAreaSolid.Position.Location - Direction: SELF\\IfcRevolvedAreaSolid.Axis - Rotation axis: SELF\\IfcRevolvedAreaSolid.AxisLine, created from start point and direction by appying a 1 unit magnitude. - Orientation: Positive angles are applied clockwise when looking into the positive direction of the rotation axis. The start cross section is defined by SELF\\IfcSweptAreaSolid.SweptArea: - A bounded planar surface lying in the XY plane of the position coordinate system defined by SELF\\IfcSweptAreaSolid.Position.P[1] and SELF\\IfcSweptAreaSolid.Position.P[2] - The rotation axis lies in the plane of the start cross section but shall not intersect the interior of the start cross section. The end cross section is defined by EndSweptArea: - A bounded planar surface lying in the XY plane of the position coordinate system defined by rotating the start position coordinates provided by SELF\\IfcSweptAreaSolid.Position around the rotation axis by the angle given by SELF\\IfcRevolvedAreaSolid.Angle. - The end cross section is topologically similar to the start cross section (having the same number of vertices and edges). The end cross section can either be defined by the same paramteric profile using different parameter values, or by a 2D Cartesian transformation of the start profile within the end cross section plane. The solid is generated by transforming the start cross section into to end cross section. A start face, an end face (each defined by start and end cross sections), and one or more lateral faces. Each lateral face is a ruled surface defined by a pair of corresponding edges of the start and end section. The ruled surfaces are constructed in the cylindrical coordinate space defined by the supertype IfcRevolvedAreaSolid. Informal Propositions: - Mirroring within IfcDerivedProfileDef.Operator shall not be used",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcrevolvedareasolidtapered.htm"
     },
     "IfcRightCircularCone": {
@@ -5794,7 +5794,7 @@
             "BottomRadius": "The radius of the cone at the base.",
             "Height": "The distance between the base of the cone and the apex."
         },
-        "description": "The IfcRightCircularCone is a Construction Solid Geometry (CSG) 3D primitive. It is a solid with a circular base and a point called apex as the top. The tapers from the base to the top. The axis from the center of the circular base to the apex is perpendicular to the base. The inherited Position attribute defines the IfcAxisPlacement3D and provides the location and orientation of the cone:",
+        "description": "The IfcRightCircularCone is a Construction Solid Geometry (CSG) 3D primitive. It is a solid with a circular base and a point called apex as the top. The tapers from the base to the top. The axis from the center of the circular base to the apex is perpendicular to the base. The inherited Position attribute defines the IfcAxisPlacement3D and provides the location and orientation of the cone: - SELF\\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcCsgPrimitive3D.Position.Location: The center of the circular area being the bottom face of the cone. - SELF\\IfcCsgPrimitive3D.Position.Position[3]: The z-axis of the inherited placement coordinate system provides the center axis of the IfcRightCircularCone, and the apex is at the Height value applied to the positive direction of the z-axis. The BottomRadius defines the circular base at the xy-plane of the placement coordinate system. Figure 1 illustrates geometric parameters of the cone. The cone is positioned within its own placement coordinate system. The origin is the center of the bottom circular disk, that lies in the XY plane. The apex lies on the positive z axis at [0, 0, Height]. Texture use definition On the circular side, textures are aligned facing upright with origin at the back (+Y direction) revolving counter-clockwise. Textures are stretched or repeated to the extent of the base circumference according to RepeatS. Textures are compressed linearly going upwards towards the top point according to RepeatT. On the bottom face, textures are aligned facing front-to-back, with the center of the circle aligned to the center of the texture. Figure 2 illustrates default texture mapping with a clamped texture (RepeatS=False and RepeatT=False). The image on the left shows the texture where the S axis points to the right and the T axis points up. The image on the right shows the texture applied to the geometry where the X axis points back to the right, the Y axis points back to the left, and the Z axis points up.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcrightcircularcone.htm"
     },
     "IfcRightCircularCylinder": {
@@ -5802,11 +5802,11 @@
             "Height": "The distance between the planar circular faces of the cylinder.",
             "Radius": "The radius of the cylinder."
         },
-        "description": "The IfcRightCircularCylinder is a Construction Solid Geometry (CSG) 3D primitive. It is a solid with a circular base and top. The cylindrical surface between if formed by points at a fixed distance from the axis of the cylinder. The inherited Position attribute defines the IfcAxisPlacement3D and provides:",
+        "description": "The IfcRightCircularCylinder is a Construction Solid Geometry (CSG) 3D primitive. It is a solid with a circular base and top. The cylindrical surface between if formed by points at a fixed distance from the axis of the cylinder. The inherited Position attribute defines the IfcAxisPlacement3D and provides: - SELF\\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcCsgPrimitive3D.Position.Location: The center of the circular area being the bottom face of the cylinder. - SELF\\IfcCsgPrimitive3D.Position.Position[3]: The z axis provides the center axis and the height is measured from the origin along the positive direction of the z axis. Figure 1 illustrates geometric parameters of the cylinder. The cylinder is positioned within its own placement coordiante system. The origin is the center of the bottom circular disk, that lies in the XY plane. The center of the top circular disk is on the positive z axis at [0, 0, Height]. Texture use definition On the circular side, textures are aligned facing upright with origin at the back (+Y direction) revolving counter-clockwise. Textures are stretched or repeated to the extent of the circumference according to RepeatS. Textures are stretched or repeated to the extent of the Height according to RepeatT. On the top and bottom faces, textures are aligned facing front-to-back, with the center of the circle aligned to the center of the texture. Figure 2 illustrates default texture mapping with a clamped texture (RepeatS=False and RepeatT=False). The image on the left shows the texture where the S axis points to the right and the T axis points up. The image on the right shows the texture applied to the geometry where the X axis points back to the right, the Y axis points back to the left, and the Z axis points up.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcrightcircularcylinder.htm"
     },
     "IfcRoof": {
-        "description": "A roof is the covering of the top part of a building, it protects the building against the effects of wheather.",
+        "description": "A roof is the covering of the top part of a building, it protects the building against the effects of wheather. The IfcRoof shall either be represented: - as a roof assembly that aggregates all parts (slabs, rafters and purlins, or other included roofs, such as dormers) with own shape representaion, or - as a single roof without decomposition including all shape representations directly at the roof entity.",
         "predefined_types": {
             "BARREL_ROOF": "A roof or ceiling having a semicylindrical form.",
             "BUTTERFLY_ROOF": "A roof having two slopes, each descending inward from the eaves.",
@@ -5827,7 +5827,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcroof.htm"
     },
     "IfcRoofType": {
-        "description": "The building element type IfcRoofType defines commonly shared information for occurrences of roofs. The set of shared information may include:",
+        "description": "The building element type IfcRoofType defines commonly shared information for occurrences of roofs. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a roof type specification indicating the specific product information that is common to all occurrences of that product type. The IfcRoofType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcRoofType are represented by instances of IfcRoof. Refer to the documentation at IfcRoof for supported property sets, materials, and composition.",
         "predefined_types": {
             "BARREL_ROOF": "A roof or ceiling having a semicylindrical form.",
             "BUTTERFLY_ROOF": "A roof having two slopes, each descending inward from the eaves.",
@@ -5861,7 +5861,7 @@
         "attributes": {
             "RoundingRadius": "Radius of the circular arcs by which all four corners of the rectangle are equally rounded."
         },
-        "description": "IfcRoundedRectangleProfileDef defines a rectangle with equally rounded corners as the profile definition used by the swept surface geometry or the swept area solid. It is given by the X extent, the Y extent, and the radius for the rounded corners, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, that is, in the center of the bounding box.",
+        "description": "IfcRoundedRectangleProfileDef defines a rectangle with equally rounded corners as the profile definition used by the swept surface geometry or the swept area solid. It is given by the X extent, the Y extent, and the radius for the rounded corners, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, that is, in the center of the bounding box. Figure 1 illustrates parameters of the rounded rectangle profile definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcroundedrectangleprofiledef.htm"
     },
     "IfcSIUnit": {
@@ -5892,7 +5892,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcplumbingfireprotectiondomain/lexical/ifcsanitaryterminal.htm"
     },
     "IfcSanitaryTerminalType": {
-        "description": "The flow terminal type IfcSanitaryTerminalType defines commonly shared information for occurrences of sanitary terminals. The set of shared information may include:",
+        "description": "The flow terminal type IfcSanitaryTerminalType defines commonly shared information for occurrences of sanitary terminals. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a sanitary terminal type specification indicating the specific product information that is common to all occurrences of that product type. The IfcSanitaryTerminalType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcSanitaryTerminalType are represented by instances of IfcSanitaryTerminal. Refer to the documentation at IfcSanitaryTerminal for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BATH": "Sanitary appliance for immersion of the human body or parts of it.",
             "BIDET": "Waste water appliance for washing the excretory organs while sitting astride the bowl.",
@@ -5919,7 +5919,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcschedulingtime.htm"
     },
     "IfcSeamCurve": {
-        "description": "An IfcSeamCurve is a 3-dimensional curve that has additional representations provided by exactly two distinct pcurves describing the same curve at the two extreme ends of a closed parametric surface.",
+        "description": "An IfcSeamCurve is a 3-dimensional curve that has additional representations provided by exactly two distinct pcurves describing the same curve at the two extreme ends of a closed parametric surface. Figure 1 shows an instance diagram explaining the use of IfcSeamCurve as a boundary curve of an IfcCylindricalSurface.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcseamcurve.htm"
     },
     "IfcSectionProperties": {
@@ -5928,7 +5928,7 @@
             "SectionType": "An indicator whether a specific piece of a cross section is uniform or tapered in longitudinal direction.",
             "StartProfile": "The cross section profile at the start point of the longitudinal section."
         },
-        "description": "IfcSectionProperties defines the cross section properties for a single longitudinal piece of a cross section. It is a special-purpose helper class for IfcSectionReinforcementProperties.",
+        "description": "IfcSectionProperties defines the cross section properties for a single longitudinal piece of a cross section. It is a special-purpose helper class for IfcSectionReinforcementProperties. The section piece may be either uniform or tapered. In the latter case an end profile should also be provided. The start and end profiles are assumed to be of the same profile type. Generally only rectangular or circular cross section profiles are assumed to be used.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcsectionproperties.htm"
     },
     "IfcSectionReinforcementProperties": {
@@ -5940,7 +5940,7 @@
             "SectionDefinition": "Definition of the cross section profile and longitudinal section type.",
             "TransversePosition": "The position for the section reinforcement properties in transverse direction."
         },
-        "description": "IfcSectionReinforcementProperties defines the cross section properties of reinforcement for a single longitudinal piece of a cross section with a specific reinforcement usage type.",
+        "description": "IfcSectionReinforcementProperties defines the cross section properties of reinforcement for a single longitudinal piece of a cross section with a specific reinforcement usage type. Several sets of cross section reinforcement properties represented by instances of IfcReinforcementProperties may be attached to the section reinforcement properties (IfcReinforcementDefinitionProperties of IfcStructuralElementsDomain schema), one for each combination of steel grades and reinforcement bar types and sizes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcsectionreinforcementproperties.htm"
     },
     "IfcSectionedSpine": {
@@ -5950,7 +5950,7 @@
             "Dim": "The dimensionality of the spine curve is always 3. 3",
             "SpineCurve": "A single composite curve, that defines the spine curve. Each of the composite curve segments correspond to the part between two cross-sections."
         },
-        "description": "An IfcSectionedSpine is a representation of the shape of a three dimensional object composed by a number of planar cross sections, and a spine curve. The shape is defined between the first element of cross sections and the last element of the cross sections. A sectioned spine may be used to represent a surface or a solid but the interpolation of the shape between the cross sections is not defined.",
+        "description": "An IfcSectionedSpine is a representation of the shape of a three dimensional object composed by a number of planar cross sections, and a spine curve. The shape is defined between the first element of cross sections and the last element of the cross sections. A sectioned spine may be used to represent a surface or a solid but the interpolation of the shape between the cross sections is not defined. All cross sections have to define areas by a closed profile to allow for the representation of a solid. All cross sections have to define curves by an open or closed profile to allow for the representation of a surface. The cross sections are defined by subtypes of IfcProfileDef, where the consecutive profiles may be derived by a transformation of the start profile or the previous consecutive profile. The spine curve shall be of type IfcCompositeCurve, each of its segments represented by IfcCompositeCurveSegment shall correspond to the part between exactly two consecutive cross-sections. Figure 1 illustrates an example of an IfcSectionedSpine. - The SpineCurve is given by an IfcCompositeCurve with two Segments. The Segments[1] has a ParentCurve of type IfcPolyline and a Transition = CONTSAMEGRADIENT. The Segments[2] has a ParentCurve of type IfcTrimmedCurve and a Transition = DISCONTINUOUS. - Each CrossSectionPosition lies at a start or end point of the Segments. - Each CrossSections are inserted by the CrossSectionPositions. The first two cross sections are of type IfcRectangleProfileDef, the third is of type IfcDerivedProfileDef. Figure 2 illustrates the final result of the IfcSectionedSpine. The body (shown transparently) is not fully defined by the exchange definition. Informal Propositions: - none of the cross sections, after being placed by the cross section positions, shall intersect - none of the cross sections, after being placed by the cross section positions, shall lie in the same plane - the local origin of each cross section position shall lie at the beginning or end of a composite curve segment.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcsectionedspine.htm"
     },
     "IfcSensor": {
@@ -5986,7 +5986,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcbuildingcontrolsdomain/lexical/ifcsensor.htm"
     },
     "IfcSensorType": {
-        "description": "The distribution control element type IfcSensorType defines commonly shared information for occurrences of sensors. The set of shared information may include:",
+        "description": "The distribution control element type IfcSensorType defines commonly shared information for occurrences of sensors. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a sensor type specification indicating the specific product information that is common to all occurrences of that product type. The IfcSensorType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcSensorType are represented by instances of IfcSensor. Refer to the documentation at IfcSensor for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CO2SENSOR": "A device that senses or detects carbon dioxide.",
             "CONDUCTANCESENSOR": "A device that senses or detects electrical conductance.",
@@ -6029,7 +6029,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcshadingdevice.htm"
     },
     "IfcShadingDeviceType": {
-        "description": "The building element type IfcShadingDeviceType defines commonly shared information for occurrences of shading devices. The set of shared information may include:",
+        "description": "The building element type IfcShadingDeviceType defines commonly shared information for occurrences of shading devices. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a shading device type specification indicating the specific product information that is common to all occurrences of that product type. The IfcShadingDeviceType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcShadingDeviceType are represented by instances of IfcShadingDevice. Refer to the documentation at IfcShadingDevice for supported property sets, materials, and composition.",
         "predefined_types": {
             "AWNING": "A rooflike shelter of canvas or other material extending over a doorway, from the top of a window, over a deck, or similar, in order to provide protection, as from the sun.",
             "JALOUSIE": "A blind with adjustable horizontal slats for admitting light and air while excluding direct sun and rain.",
@@ -6047,18 +6047,18 @@
             "ProductDefinitional": "An indication that the shape aspect is on the physical boundary of the product definition shape. If the value of this attribute is TRUE, it shall be asserted that the shape aspect being identified is on such a boundary. If the value is FALSE, it shall be asserted that the shape aspect being identified is not on such a boundary. If the value is UNKNOWN, it shall be asserted that it is not known whether or not the shape aspect being identified is on such a boundary.  --- EXAMPLE: Would be FALSE for a center line, identified as shape aspect; would be TRUE for a cantilever. ---",
             "ShapeRepresentations": "List of ~~shape~~ representations. Each member defines a valid representation of a particular type within a particular representation context as being an aspect (or part) of a product definition."
         },
-        "description": "IfcShapeAspect allows for grouping of shape representation items that represent aspects (or components) of the shape of a product. Thereby shape representations of components of the product shape represent a distinctive part to a product that can be explicitly addressed.",
+        "description": "IfcShapeAspect allows for grouping of shape representation items that represent aspects (or components) of the shape of a product. Thereby shape representations of components of the product shape represent a distinctive part to a product that can be explicitly addressed. The IfcShapeAspect's may have distinct material information or other distict characteristics that differs from other parts of the product shape representation. Figure 1 indicates the association of material characteristics to shape aspects. Informal Propositions: - If ShapeRepresentations points to shape representations that are part of an IfcProductDefinitionShape, PartOfProductDefinitionShape must refer to this instance of IfcProductDefinitionShape. - If ShapeRepresentations points to shape representations that are part of an IfcRepresentationMap, PartOfProductDefinitionShape must refer to this instance of IfcRepresentationMap.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcshapeaspect.htm"
     },
     "IfcShapeModel": {
         "attributes": {
             "OfShapeAspect": "Reference to the shape aspect, for which it is the shape representation."
         },
-        "description": "IfcShapeModel represents the concept of a particular geometric and/or topological representation of a product's shape or a product component's shape within a representation context. This representation context has to be a geometric representation context (with the exception of topology representations without associated geometry). The two subtypes are IfcShapeRepresentation to cover geometric models that represent a shape, and IfcTopologyRepresentation to cover the conectivity of a product or product component. The topology may or may not have geometry associated.",
+        "description": "IfcShapeModel represents the concept of a particular geometric and/or topological representation of a product's shape or a product component's shape within a representation context. This representation context has to be a geometric representation context (with the exception of topology representations without associated geometry). The two subtypes are IfcShapeRepresentation to cover geometric models that represent a shape, and IfcTopologyRepresentation to cover the conectivity of a product or product component. The topology may or may not have geometry associated. The IfcShapeModel can be a shape representation (geometric and/or topologogical) of a product (via IfcProductDefinitionShape), or a shape representation (geometric and/or topologogical) of a component of a product shape (via IfcShapeAspect).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcshapemodel.htm"
     },
     "IfcShapeRepresentation": {
-        "description": "The IfcShapeRepresentation represents the concept of a particular geometric representation of a product or a product component within a specific geometric representation context. The inherited attribute RepresentationType is used to define the geometric model used for the shape representation (e.g. 'SweptSolid', or 'Brep'), the inherited attribute RepresentationIdentifier is used to denote the kind of the representation captured by the IfcShapeRepresentation (e.g. 'Axis', 'Body', etc.).",
+        "description": "The IfcShapeRepresentation represents the concept of a particular geometric representation of a product or a product component within a specific geometric representation context. The inherited attribute RepresentationType is used to define the geometric model used for the shape representation (e.g. 'SweptSolid', or 'Brep'), the inherited attribute RepresentationIdentifier is used to denote the kind of the representation captured by the IfcShapeRepresentation (e.g. 'Axis', 'Body', etc.). Several representation identifiers for shape representation are included as predefined values for RepresentationIdentifier. Table 1 indicates the defined list of values for RepresentationIdentifier. Several representation types for shape representation are included as predefined values for RepresentationType. Table 2 indicates the defined list of values for RepresentationType.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcshaperepresentation.htm"
     },
     "IfcShellBasedSurfaceModel": {
@@ -6066,7 +6066,7 @@
             "Dim": "The space dimensionality of this class, it is always 3. 3",
             "SbsmBoundary": ""
         },
-        "description": "An IfcShellBasedSurfaceModel represents the shape by a set of open or closed shells. The connected faces within the shell have a dimensionality 2 and are placed in a coordinate space of dimensionality 3.",
+        "description": "An IfcShellBasedSurfaceModel represents the shape by a set of open or closed shells. The connected faces within the shell have a dimensionality 2 and are placed in a coordinate space of dimensionality 3. Informal Propositions: - The dimensionality of the shell based surface model is 2. - The shells shall not overlap or intersect except at common faces, edges or vertices.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcshellbasedsurfacemodel.htm"
     },
     "IfcSimpleProperty": {
@@ -6084,7 +6084,7 @@
             "SecondaryUnit": "Secondary unit assigned to the definition of the property. It should be provided, if the _PropertyType_ is set to: * P_TABLEVALUE: determining the _IfcPropertyTableValue.DefinedUnit_",
             "TemplateType": "Property type defining whether the property template defines a property with a single value, a bounded value, a list value, a table value, an enumerated value, or a reference value. Or the quantity type defining whether the template defines a quantity with a length, area, volume, weight or time value. > NOTE  the value of this property determines the correct use of the _PrimaryUnit_, _SecondaryUnit_, _PrimaryDataType_, _SecondaryDataType_, and _Expression_ attributes."
         },
-        "description": "The IfcSimplePropertyTemplate defines the template for all dynamically extensible properties, either the subtypes of IfcSimpleProperty, or the subtypes of IfcPhysicalSimpleQuantity. The individual property templates are interpreted according to their Name attribute and may have a predefined template type, property units, and property measure types. The correct interpretation of the attributes:",
+        "description": "The IfcSimplePropertyTemplate defines the template for all dynamically extensible properties, either the subtypes of IfcSimpleProperty, or the subtypes of IfcPhysicalSimpleQuantity. The individual property templates are interpreted according to their Name attribute and may have a predefined template type, property units, and property measure types. The correct interpretation of the attributes: - PrimaryUnit - SecondaryUnit - PrimaryMeasureType - SecondaryMeasureType is determined by the TemplateType. The attributes Enumerators and Expression only apply to instances of IfcSimplePropertyTemplate having a particular TemplateType. The TemplateType also controls, which subtype of either IfcSimpleProperty or IfcPhysicalSimpleQuantity shall be used for property occurrences corresponding to this template. The IfcSimplePropertyTemplate is part of the set of templates included in the IfcPropertySetTemplate. The template can be accessed throught the inverse attribute PartOfPsetTemplate The IfcPropertySetTemplate may define one or several instances of IfcPropertySet (or IfcElementQuantity). The definition assignment is established by the objectified relationship IfcRelDefinesByTemplate as shown in Figure 1. There is no direct link between an IfcSimplePropertyTemplate and a subtype of either IfcSimpleProperty or IfcPhysicalSimpleQuantity. The definition relationship between the template and the individual properties (or quantities) is established by the Name attributes.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcsimplepropertytemplate.htm"
     },
     "IfcSite": {
@@ -6095,11 +6095,11 @@
             "RefLongitude": "World Longitude at reference point (most likely defined in legal description). Defined as integer values for degrees, minutes, seconds, and, optionally, millionths of seconds with respect to the world geodetic system WGS84. > NOTE  Longitudes are measured relative to the geodetic zero meridian, nominally the same as the Greenwich prime meridian: longitudes west of the zero meridian have negative values - from 0 till -180, longitudes east of the zero meridian have positive values - from 0 till -180.  > EXAMPLE  Chicago Harbor Light has according to WGS84 a longitude -87.35.40 (or 87.35.40W) and a latitude 41.53.30 (or 41.53.30N).",
             "SiteAddress": "Address given to the site for postal purposes."
         },
-        "description": "A site is a defined area of land, possibly covered with water, on which the project construction is to be completed. A site may be used to erect, retrofit or turn down building(s), or for other construction related developments.",
+        "description": "A site is a defined area of land, possibly covered with water, on which the project construction is to be completed. A site may be used to erect, retrofit or turn down building(s), or for other construction related developments. A site may include a definition of the single geographic reference point for this site (global position using WGS84 with Longitude, Latitude and Elevation). The precision is provided up to millionth of a second and it provides an absolute placement in relation to the real world as used in exchange with geospational information systems. If asserted, the Longitude, Latitude and Elevation establish the point in WGS84 where the point 0.,0.,0. of the LocalPlacement of IfcSite is situated. The geometrical placement of the site, defined by the IfcLocalPlacement, shall be always relative to the spatial structure element, in which this site is included, or absolute, i.e. to the world coordinate system, as established by the geometric representation context of the project. The world coordinate system, established at the IfcProject.RepresentationContexts, may include a definition of the true north within the XY plane of the world coordinate system, if provided, it can be obtained at IfcGeometricRepresentationContext.TrueNorth. A project may span over several connected or disconnected sites. Therefore site complex provides for a collection of sites included in a project. A site can also be decomposed in parts, where each part defines a site section. This is defined by the composition type attribute of the supertype IfcSpatialStructureElements which is interpreted as follow: - COMPLEX = site complex - ELEMENT = site - PARTIAL = site section The IfcSite is used to build the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). Figure 1 shows the IfcSite as part of the spatial structure. In addition to the logical spatial structure, also the placement hierarchy is shown. In this example the spatial structure hierarchy and the placement hierarchy are identical. Figure 2 describes the heights and elevations of the IfcSite. It is used to provide the geographic longitude, latitude, and height above sea level for the origin of the site. The origin of the site is the local placement. The provision of longitude, latitude, height at the IfcSite for georeferencing is provided for upward compatibility reasons. It requires a single instance of IfcSite and WGS84 as coordinate reference system. For exact georeferencing (or referencing to any other geographic coordinate system other than WSG84) the entities IfcCoordinateReferenceSystem and IfcMapConversion have to be used to define an exact mapping of the project engineering coordinate system to the geographic (or map) coordinate system. - reference height of site is provided by: IfcSite.RefElevation, it is given according to the height datum used at this location. - the reference height of each building situated at the site is given againt the same height datum used at this location. - the elevations of each storey belonging to each building are given as local height relative to the reference height of the building.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcsite.htm"
     },
     "IfcSlab": {
-        "description": "A slab is a component of the construction that normally encloses a space vertically. The slab may provide the lower support (floor) or upper construction (roof slab) in any space in a building.",
+        "description": "A slab is a component of the construction that normally encloses a space vertically. The slab may provide the lower support (floor) or upper construction (roof slab) in any space in a building. Only the core or constructional part of this construction is considered to be a slab. The upper finish (flooring, roofing) and the lower finish (ceiling, suspended ceiling) are considered to be coverings. A special type of slab is the landing, described as a floor section to which one or more stair flights or ramp flights connect. There are two main representations for slab occurrences: - IfcSlab with IfcMaterialLayerSetUsage is used for all occurrences of slabs, that are prismatic and where the thickness parameter can be fully described by the IfcMaterialLayerSetUsage. These slabs are always represented geometrically by a 'SweptSolid' geometry (or by a 'Clipping' geometry based on 'SweptSolid'), if a 3D geometric representation is assigned. NOTE The entity IfcSlabStandardCase has been deprecated, IfcSlab with IfcMaterialLayerSetUsage is used instead. - IfcSlab without IfcMaterialLayerSetUsage is used for all other occurrences of slabs, particularly for slabs with changing thickness, or slabs with non planar surfaces, and slabs having only 'SweptSolid' or 'Brep' geometry, or if a more parametric representation is not intended.",
         "predefined_types": {
             "BASESLAB": "The slab is used to represent a floor slab against the ground (and thereby being a part of the foundation). Another name is mat foundation.",
             "FLOOR": "The slab is used to represent a floor slab.",
@@ -6111,15 +6111,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcslab.htm"
     },
     "IfcSlabElementedCase": {
-        "description": "The IfcSlabElementedCase defines a slab with certain constraints for the provision of its components. The IfcSlabElementedCase handles all cases of slabs, that are decomposed into parts:",
+        "description": "The IfcSlabElementedCase defines a slab with certain constraints for the provision of its components. The IfcSlabElementedCase handles all cases of slabs, that are decomposed into parts: - having components being assigned to the IfcSlabElementedCase using the IfcRelAggregates relationship accessible by the inverse relationship IsDecomposedBy. - applying the constraint that the parts within the decomposition shall be of type IfcElementAssembly, IfcBeam, IfcMember, IfcPlate, IfcBuildingElementPart or IfcBuildingElementProxy. Voiding Use Definition: As shown in Figure 1, openings within the composite slab are directly assigned to IfcSlabElementedCase using IfcRelVoidsElement pointing to IfcOpeningElement and apply to all aggregated parts. If individual parts have cutting and other voiding features, then the decomposed parts have a separate voiding relationship IfcRelVoidsElement pointing to IfcVoidingFeature.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcslabelementedcase.htm"
     },
     "IfcSlabStandardCase": {
-        "description": "The standard slab, IfcSlabStandardCase, defines a slab with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcSlabStandardCase handles all cases of slabs, that:",
+        "description": "The standard slab, IfcSlabStandardCase, defines a slab with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcSlabStandardCase handles all cases of slabs, that: - have a reference to the IfcMaterialLayerSetUsage defining the material layers of the slab with thicknesses - are based on an extrusion of a planar surface as defined by the slab profile - have a constant thickness along the extrusion direction - are consistent in using the correct material layer set offset to the base planar surface in regard to the shape representation - are extruded either perpendicular or slanted to the plane surface The definitions of slab openings and niches are the same as given at the supertype IfcSlab. The same agreements to the special types of slabs, as defined in the PredefinedType attribute apply as well.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcslabstandardcase.htm"
     },
     "IfcSlabType": {
-        "description": "The element type IfcSlabType defines commonly shared information for occurrences of slabs. The set of shared information may include:",
+        "description": "The element type IfcSlabType defines commonly shared information for occurrences of slabs. The set of shared information may include: - common properties within shared property sets - common material information - common material layer definitions - common shape representations It is used to define a slab specification (i.e. the specific product information, that is common to all occurrences of that product type). Slab types may be exchanged without being already assigned to occurrences. The occurrences of the IfcSlabType within building models are represented by instances of IfcSlabStandardCase if the IfcSlabType has a single associated IfcMaterialLayerSet; otherwise they are represented by instances of IfcSlab, or IfcSlabElementedCase. Informal Propositions: - The material assignment, if provided using the IfcRelAssociatesMaterial relationship, shall not reference the IfcMaterialLayerSetUsage.",
         "predefined_types": {
             "BASESLAB": "The slab is used to represent a floor slab against the ground (and thereby being a part of the foundation). Another name is mat foundation.",
             "FLOOR": "The slab is used to represent a floor slab.",
@@ -6136,7 +6136,7 @@
             "SlippageY": "Slippage in y-direction of the coordinate system defined by the instance which uses this resource object.",
             "SlippageZ": "Slippage in z-direction of the coordinate system defined by the instance which uses this resource object."
         },
-        "description": "Describes slippage in support conditions or connection conditions. Slippage means that a relative displacement may occur in a support or connection before support or connection reactions are awoken.",
+        "description": "Describes slippage in support conditions or connection conditions. Slippage means that a relative displacement may occur in a support or connection before support or connection reactions are awoken. Applicability: - Point supports and connections, - curve supports and connections, - surface supports and connections.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcslippageconnectioncondition.htm"
     },
     "IfcSolarDevice": {
@@ -6150,7 +6150,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcsolardevice.htm"
     },
     "IfcSolarDeviceType": {
-        "description": "The energy conversion device type IfcSolarDeviceType defines commonly shared information for occurrences of solar devices. The set of shared information may include:",
+        "description": "The energy conversion device type IfcSolarDeviceType defines commonly shared information for occurrences of solar devices. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a solar device type specification indicating the specific product information that is common to all occurrences of that product type. The IfcSolarDeviceType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcSolarDeviceType are represented by instances of IfcSolarDevice. Refer to the documentation at IfcSolarDevice for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "NOTDEFINED": "Undefined type.",
             "SOLARCOLLECTOR": "A device that converts solar radiation into thermal energy (heating water, etc.).",
@@ -6172,7 +6172,7 @@
             "ElevationWithFlooring": "Level of flooring of this space; the average shall be taken, if the space ground surface is sloping or if there are level differences within this space.",
             "HasCoverings": "Reference to _IfcCovering_ by virtue of the objectified relationship _IfcRelCoversSpaces_. It defines the concept of a space having coverings assigned. Those coverings may represent different flooring, or tiling areas.  > NOTE  Coverings are often managed by the space, and not by the building element, which they cover."
         },
-        "description": "A space represents an area or volume bounded actually or theoretically. Spaces are areas or volumes that provide for certain functions within a building.",
+        "description": "A space represents an area or volume bounded actually or theoretically. Spaces are areas or volumes that provide for certain functions within a building. A space is associated to a building storey (or in case of exterior spaces to a site). A space may span over several connected spaces. Therefore a space group provides for a collection of spaces included in a storey. A space can also be decomposed in parts, where each part defines a partial space. This is defined by the CompositionType attribute of the supertype IfcSpatialStructureElement which is interpreted as follow: - COMPLEX = space group - ELEMENT = space - PARTIAL = partial space The IfcSpace is used to build the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). The spatial structure elements are linked together by using the objectified relationship IfcRelAggregates. Figure 1 shows the IfcSpace as part of the spatial structure. It also serves as the spatial container for space related elements. The following guidelines should apply for using the Name, Description, LongName and ObjectType attributes. - Name holds the unique name (or space number) from the plan. - Description holds any additional information field the user may have specified, there are no further recommendations. - LongName holds the full name of the space, it is often used in addition to the Name, if a number is assigned to the room, then the descriptive name is exchanged as LongName. - ObjectType holds the space type, i.e. usually the functional category of the space . Figure 2 describes the heights and elevations of the IfcSpace. - elevation of the space (top of construction slab) equals elevation of storey: provided by IfcBuildingStorey.Elevation relative to em>IfcBuilding.ElevationOfRefHeight - elevation of the space flooring (top of flooring on top of slab): provided by IfcSpace.ElevationWithFlooring relative to IfcBuilding.ElevationOfRefHeight - height of space (top of slab below to bottom of slab above): provided by BaseQuantity with Name=\"Height\" - floor height of space (top of slab below to top of flooring): provided by BaseQuantity with Name=\"FinishFloorHeight\" - net height of space (top of flooring to bottom of suspended ceiling): provided by BaseQuantity with Name=\"FinishCeilingHeight\"",
         "predefined_types": {
             "EXTERNAL": "",
             "GFA": "Gross Floor Area - a specific kind of space for each building story that includes all net area and construction area (also the external envelop). Provision of such a specific space is often required by regulations.",
@@ -6185,7 +6185,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcspace.htm"
     },
     "IfcSpaceHeater": {
-        "description": "Space heaters utilize a combination of radiation and/or natural convection using a heating source such as electricity, steam or hot water to heat a limited space or area. Examples of space heaters include radiators, convectors, baseboard and finned-tube heaters.",
+        "description": "Space heaters utilize a combination of radiation and/or natural convection using a heating source such as electricity, steam or hot water to heat a limited space or area. Examples of space heaters include radiators, convectors, baseboard and finned-tube heaters. IfcUnitaryEquipment should be used for packaged units supporting a combination of heating, cooling, and/or dehumidification; IfcCoil should be used for coil-based floor heating.",
         "predefined_types": {
             "CONVECTOR": "A heat-distributing unit that operates with gravity-circulated air.",
             "NOTDEFINED": "Undefined space heater type.",
@@ -6195,7 +6195,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcspaceheater.htm"
     },
     "IfcSpaceHeaterType": {
-        "description": "The flow terminal type IfcSpaceHeaterType defines commonly shared information for occurrences of space heaters. The set of shared information may include:",
+        "description": "The flow terminal type IfcSpaceHeaterType defines commonly shared information for occurrences of space heaters. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a space heater type specification indicating the specific product information that is common to all occurrences of that product type. The IfcSpaceHeaterType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcSpaceHeaterType are represented by instances of IfcSpaceHeater. Refer to the documentation at IfcSpaceHeater for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CONVECTOR": "A heat-distributing unit that operates with gravity-circulated air.",
             "NOTDEFINED": "Undefined space heater type.",
@@ -6208,7 +6208,7 @@
         "attributes": {
             "LongName": "Long name for a space type, used for informal purposes. It should be used, if available, in conjunction with the inherited _Name_ attribute. > NOTE  In many scenarios the _Name_ attribute refers to the short name or number of a space type, and the _LongName_ refers to the full descriptive name."
         },
-        "description": "A space represents an area or volume bounded actually or theoretically. Spaces are areas or volumes that provide for certain functions within a building.",
+        "description": "A space represents an area or volume bounded actually or theoretically. Spaces are areas or volumes that provide for certain functions within a building. The IfcSpaceType defines a list of commonly shared defines commonly shared information for occurrences of spaces. The set of shared information may include: - common properties within shared property sets - common shape representations It is used to define an space specification (i.e. the specific space information, that is common to all occurrences of that space type. Space types may be exchanged without being already assigned to occurrences. The occurrences of IfcSpaceType are represented by instances of IfcSpace.",
         "predefined_types": {
             "EXTERNAL": "",
             "GFA": "Gross Floor Area - a specific kind of space for each building story that includes all net area and construction area (also the external envelop). Provision of such a specific space is often required by regulations.",
@@ -6227,29 +6227,29 @@
             "ReferencesElements": "Set of spatial reference relationships, that holds those elements, which are referenced, but not contained, within this element of the project spatial structure.",
             "ServicedBySystems": "Set of relationships to systems, that provides a certain service to the spatial element for which it is defined. The relationship is handled by the objectified relationship _IfcRelServicesBuildings_."
         },
-        "description": "A spatial element is the generalization of all spatial elements that might be used to define a spatial structure or to define spatial zones.",
+        "description": "A spatial element is the generalization of all spatial elements that might be used to define a spatial structure or to define spatial zones. - a hierarchical spatial structure element as IfcSpatialStructureElement a spatial structure is a hiearchical decomposition of the project. That spatial structure is often used to provide a project structure to organize a building project. A spatial project structure might define as many levels of decomposition as necessary for the building project. Elements within the spatial project structure are site, building, storey, and space - a spatial zone as IfcSpatialZone a spatial zone is a non-hierarchical and potentially overlapping decomposition of the project under some functional consideration. a spatial zone might be used to represent a thermal zone, a lighting zone, a usable area zone. a spatial zone might be used to represent a horizontal spatial structure as used in civil works. a spatial zone might have its independent placement and shape representation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcspatialelement.htm"
     },
     "IfcSpatialElementType": {
         "attributes": {
             "ElementType": "The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute 'PredefinedType' is set to USERDEFINED."
         },
-        "description": "IfcSpatialElementType defines a list of commonly shared property set definitions of a spatial structure element and an optional set of product representations. It is used to define a spatial element specification (the specific element information, that is common to all occurrences of that element type).",
+        "description": "IfcSpatialElementType defines a list of commonly shared property set definitions of a spatial structure element and an optional set of product representations. It is used to define a spatial element specification (the specific element information, that is common to all occurrences of that element type). A spatial element type is used to define the common properties of a certain type of a spatial structure element that may be applied to many instances of that type to assign a specific style. Spatial element types (i.e. the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of subtypes of the abstract IfcSpatialElementType are represented by instances of subtypes of the abstract IfcSpatialElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcspatialelementtype.htm"
     },
     "IfcSpatialStructureElement": {
         "attributes": {
             "CompositionType": "Denotes, whether the predefined spatial structure element represents itself, or an aggregate (complex) or a part (part). The interpretation is given separately for each subtype of spatial structure element. If no _CompositionType_ is asserted, the dafault value 'ELEMENT' applies."
         },
-        "description": "A spatial structure element is the generalization of all spatial elements that might be used to define a spatial structure. That spatial structure is often used to provide a project structure to organize a building project.",
+        "description": "A spatial structure element is the generalization of all spatial elements that might be used to define a spatial structure. That spatial structure is often used to provide a project structure to organize a building project. A spatial project structure might define as many levels of decomposition as necessary for the building project. Elements within the spatial project structure are: - site as IfcSite - building as IfcBuilding - storey as IfcBuildingStorey - space as IfcSpace or aggregations or parts thereof. The composition type declares an element to be either an element itself, or an aggregation (complex) or a decomposition (part). The interpretation of these types is given at each subtype of IfcSpatialStructureElement. The IfcRelAggregates is defined as an 1-to-many relationship and used to establish the relationship between exactly two levels within the spatial project structure. Finally the highest level of the spatial structure is assigned to IfcProject using the IfcRelAggregates. The subtypes of IfcSpatialStructureElement relate to other elements and systems by establishing the following relationships: - Containment of elements : IfcRelContainedInSpatialStructure by inverse attribute ContainsElements, used to assign any element, like building elements, MEP elements, etc. to the spatial structure element in which they are primarily contained. - Reference of elements : IfcRelReferencedInSpatialStructure by inverse attribute ReferencesElements, used to reference any element, like building elements, MEP elements, etc. in spatial structure elements, other then the one, where it is contained. - Reference of systems : IfcRelServicesBuildings by inverse attribute ServicedBySystems, used to reference a sytem, like a building service or electrical distribution system, a zonal system, or a structural analysis system, that is assigned to this spatial structure element. The subtypes of IfcSpatialStructureElement relate to each other by using the IfcRelAggregates relationship to build the project spatial structure. Figure 1 shows the use of IfcRelAggregates to establish a spatial structure including site, building, building section and storey. More information is provided at the level of the subtypes. Informal Propositions: - The spatial project structure, established by the IfcRelAggregates, shall be acyclic. - A site should not be (directly or indirectly) associated to a building, storey or space. - A building should not be (directly or indirectly) associated to a storey or space. - A storey should not be (directly or indirectly) associated to a space.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcspatialstructureelement.htm"
     },
     "IfcSpatialStructureElementType": {
-        "description": "The element type (IfcSpatialStructureElementType) defines a list of commonly shared property set definitions of a spatial structure element and an optional set of product representations. It is used to define an element specification (i.e. the specific element information, that is common to all occurrences of that element type).",
+        "description": "The element type (IfcSpatialStructureElementType) defines a list of commonly shared property set definitions of a spatial structure element and an optional set of product representations. It is used to define an element specification (i.e. the specific element information, that is common to all occurrences of that element type). A spatial structure element type is used to define the common properties of a certain type of a spatial structure element that may be applied to many instances of that type to assign a specific style. Spatial structure element types (the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of subtypes of the abstract IfcSpatialStructureElementType are represented by instances of subtypes of IfcSpatialStructureElement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcspatialstructureelementtype.htm"
     },
     "IfcSpatialZone": {
-        "description": "A spatial zone is a non-hierarchical and potentially overlapping decomposition of the project under some functional consideration. A spatial zone might be used to represent a thermal zone, a construction zone, a lighting zone, a usable area zone. A spatial zone might have its independent placement and shape representation.",
+        "description": "A spatial zone is a non-hierarchical and potentially overlapping decomposition of the project under some functional consideration. A spatial zone might be used to represent a thermal zone, a construction zone, a lighting zone, a usable area zone. A spatial zone might have its independent placement and shape representation. The IfcSpatialZone inherits and declares these attributes that shall have the following meaning: - Name: A number or designator provided by the user or system for the spatial element, e.g. a space number \"1-003\", could also be a running number provided by default by the application - LongName: Name of the spatial element provided by the user, e.g. a space name \"Office\". - Description: Any additional description provided by the user, e.g. a space description \"Corner office with habour view\". - ObjectType: reserved for typing of spatial elements in case of PredefinedType = .USERDEFINED., restrictions on applicable values might be published in view definitions or implementer agreements. Physical elements that are referenced by this spatial zone are related using the IfcRelReferencedInSpatialStructure relationship as it is a non-hierarchical assignment in addition to the hierarchical spatial containment within a subtype of IfcSpatialStructureElement. Also spaces, that referenced by this spatial zone are related using the IfcRelReferencedInSpatialStructure relationship. The IfcSpatialZone itself can also be referenced by another spatial element using IfcRelReferencedInSpatialStructure.",
         "predefined_types": {
             "CONSTRUCTION": "The spatial zone is used to represent a construction zone for the production process.",
             "FIRESAFETY": "The spatial zone is used to represent a fire safety zone, or fire compartment.",
@@ -6268,7 +6268,7 @@
         "attributes": {
             "LongName": "Long name for a spatial zone type, used for informal purposes. It should be used, if available, in conjunction with the inherited _Name_ attribute. > NOTE  In many scenarios the _Name_ attribute refers to the short name or number of a spatial zone, and the _LongName_ refers to the full descriptive name."
         },
-        "description": "The IfcSpatialZoneType defines a list of commonly shared property set definitions of a space and an optional set of product representations. It is used to define a space specification (i.e. the specific space information, that is common to all occurrences of that space type).",
+        "description": "The IfcSpatialZoneType defines a list of commonly shared property set definitions of a space and an optional set of product representations. It is used to define a space specification (i.e. the specific space information, that is common to all occurrences of that space type). A spatial zone type is used to define the common properties of a certain type of space that may be applied to many instances of that type to assign a specific style. Space types may be exchanged without being already assigned to occurrences. The occurrences of IfcSpatialZoneType are represented by instances of IfcSpatialZone.",
         "predefined_types": {
             "CONSTRUCTION": "The spatial zone is used to represent a construction zone for the production process.",
             "FIRESAFETY": "The spatial zone is used to represent a fire safety zone, or fire compartment.",
@@ -6287,14 +6287,14 @@
         "attributes": {
             "Radius": "The radius of the sphere."
         },
-        "description": "The IfcSphere is a Construction Solid Geometry (CSG) 3D primitive. It is a solid where all points at the surface have the same distance from the center point. The inherited Position attribute defines the IfcAxisPlacement3D and provides:",
+        "description": "The IfcSphere is a Construction Solid Geometry (CSG) 3D primitive. It is a solid where all points at the surface have the same distance from the center point. The inherited Position attribute defines the IfcAxisPlacement3D and provides: - SELF\\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcCsgPrimitive3D.Position.Location: The center of the sphere. - SELF\\IfcCsgPrimitive3D.Position.Position[3]: The z axis points at its positve direction towards the north pole, and by its negative directions towards the south pole. Texture Use Definition Textures are aligned facing upright with origin at the back (+Y direction) revolving counter-clockwise. Textures are stretched or repeated to the extent of the circumference at the equator according to RepeatS and RepeatT. Figure 2 illustrates default texture mapping with a clamped texture (RepeatS=False and RepeatT=False). The image on the left shows the texture where the S axis points to the right and the T axis points up. The image on the right shows the texture applied to the geometry where the X axis points back to the right, the Y axis points back to the left, and the Z axis points up.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcsphere.htm"
     },
     "IfcSphericalSurface": {
         "attributes": {
             "Radius": "The radius of the sphere."
         },
-        "description": "The IfcSphericalSurface is a bounded elementary surface. The inherited Position attribute defines the IfcAxisPlacement3D and provides:",
+        "description": "The IfcSphericalSurface is a bounded elementary surface. The inherited Position attribute defines the IfcAxisPlacement3D and provides: - SELF\\IfcElementarySurface.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcElementarySurface.Position.Location: The center of the spherical surface. - SELF\\IfcElementarySurface.Position.Position[3]: The z axis points at its positve direction towards the north pole, and by its negative directions towards the south pole.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcsphericalsurface.htm"
     },
     "IfcStackTerminal": {
@@ -6309,7 +6309,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcplumbingfireprotectiondomain/lexical/ifcstackterminal.htm"
     },
     "IfcStackTerminalType": {
-        "description": "The flow terminal type IfcStackTerminalType defines commonly shared information for occurrences of stack terminals. The set of shared information may include:",
+        "description": "The flow terminal type IfcStackTerminalType defines commonly shared information for occurrences of stack terminals. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a stack terminal type specification indicating the specific product information that is common to all occurrences of that product type. The IfcStackTerminalType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcStackTerminalType are represented by instances of IfcStackTerminal. Refer to the documentation at IfcStackTerminal for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BIRDCAGE": "Guard cage, typically wire mesh, at the top of the stack preventing access by birds.",
             "COWL": "A cowling placed at the top of a stack to eliminate downdraft.",
@@ -6320,7 +6320,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcplumbingfireprotectiondomain/lexical/ifcstackterminaltype.htm"
     },
     "IfcStair": {
-        "description": "A stair is a vertical passageway allowing occupants to walk (step) from one floor level to another floor level at a different elevation. It may include a landing as an intermediate floor slab.",
+        "description": "A stair is a vertical passageway allowing occupants to walk (step) from one floor level to another floor level at a different elevation. It may include a landing as an intermediate floor slab. The IfcStair shall either be represented: - as a stair assembly entity that aggregates all parts (stair flight, landing, etc. with own representations), or - as a single stair entity without decomposition including all representation directly at the stair entity.",
         "predefined_types": {
             "CURVED_RUN_STAIR": "A stair extending from one level to another without turns or winders. The stair is consisting of one curved flight.",
             "DOUBLE_RETURN_STAIR": "A stair having one straight flight to a wide quarterspace landing, and two side flights from that landing into opposite directions. The stair is making a 90&deg; turn. The direction of traffic is determined by the walking line.",
@@ -6348,7 +6348,7 @@
             "RiserHeight": "Vertical distance from tread to tread. The riser height is supposed to be equal for all stairs in a stair flight.",
             "TreadLength": "Horizontal distance from the front to the back of the tread. The tread length is supposed to be equal for all steps of the stair flight."
         },
-        "description": "A stair flight is an assembly of building components in a single \"run\" of stair steps (not interrupted by a landing). The stair steps and any stringers are included in the stair flight. A winder is also regarded a part of a stair flight.",
+        "description": "A stair flight is an assembly of building components in a single \"run\" of stair steps (not interrupted by a landing). The stair steps and any stringers are included in the stair flight. A winder is also regarded a part of a stair flight. An IfcStairFlight is normally aggregated by an IfcStair through the IfcRelAggregates relationship, the stair flight is then included in the set of IfcRelAggregates.RelatedObjects. An IfcStairFlight normally connects the floor slab of zero to two different storeys (or partial storeys, or landings) within a building. The connection relationship between the IfcStairFlight and the IfcSlab can be expressed using the IfcRelConnectsElements relationship.",
         "predefined_types": {
             "CURVED": "A stair flight with a curved walking line.",
             "FREEFORM": "A stair flight with a free form walking line (and outer boundaries).",
@@ -6361,7 +6361,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcstairflight.htm"
     },
     "IfcStairFlightType": {
-        "description": "The building element type IfcStairFlightType defines commonly shared information for occurrences of stair flights. The set of shared information may include:",
+        "description": "The building element type IfcStairFlightType defines commonly shared information for occurrences of stair flights. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a stair flight type specification indicating the specific product information that is common to all occurrences of that product type. The IfcStairFlightType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcStairFlightType are represented by instances of IfcStairFlight. Refer to the documentation at IfcStairFlight for supported property sets, materials, and composition.",
         "predefined_types": {
             "CURVED": "A stair flight with a curved walking line.",
             "FREEFORM": "A stair flight with a free form walking line (and outer boundaries).",
@@ -6374,7 +6374,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcstairflighttype.htm"
     },
     "IfcStairType": {
-        "description": "The building element type IfcStairType defines commonly shared information for occurrences of stairs. The set of shared information may include:",
+        "description": "The building element type IfcStairType defines commonly shared information for occurrences of stairs. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a stair type specification indicating the specific product information that is common to all occurrences of that product type. The IfcStairType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcStairType are represented by instances of IfcStair. Refer to the documentation at IfcStair for supported property sets, materials, and composition.",
         "predefined_types": {
             "CURVED_RUN_STAIR": "A stair extending from one level to another without turns or winders. The stair is consisting of one curved flight.",
             "DOUBLE_RETURN_STAIR": "A stair having one straight flight to a wide quarterspace landing, and two side flights from that landing into opposite directions. The stair is making a 90&deg; turn. The direction of traffic is determined by the walking line.",
@@ -6399,7 +6399,7 @@
         "attributes": {
             "DestabilizingLoad": "Indicates if this action may cause a stability problem. If it is 'FALSE', no further investigations regarding stability problems are necessary."
         },
-        "description": "A structural action is a structural activity that acts upon a structural item or building element.",
+        "description": "A structural action is a structural activity that acts upon a structural item or building element. Relationship use definition Structural actions are grouped into either an IfcStructuralLoadGroup of predefined type LOAD_GROUP or, more often, an IfcStructuralLoadCase. This is accomplished via the inverse relationship HasAssignments and an IfcRelAssignsToGroup relationship object. IfcStructuralLoadGroup.LoadGroupFor or IfcStructuralLoadCase.LoadGroupFor respectively refers to the structural analysis model(s) in which the loads are used. It is furthermore possible to establish relationships between actions in one analysis model and reactions in another analysis model which cause the actions. For example, a support reaction from one structural system may be taken over as a load onto another supporting structural system. This is expressed by means of the inverse relationship ReferencedBy of the action and an IfcRelAssignsToProduct relationship object. IfcRelAssignsToProduct.Name is set to 'Causes' and IfcRelAssignsToProduct.RelatedObjects refers to an instance of a subtype of IfcStructuralReaction.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralaction.htm"
     },
     "IfcStructuralActivity": {
@@ -6408,7 +6408,7 @@
             "AssignedToStructuralItem": "Reference to the _IfcRelConnectsStructuralActivity_ relationship by which activities are connected with structural items.",
             "GlobalOrLocal": "Indicates whether the load directions refer to the global coordinate system (global to the analysis model, i.e. as established by _IfcStructuralAnalysisModel.SharedPlacement_) or to the local coordinate system (local to the activity or connected item, as established by an explicit or implied representation and its parameter space).  > NOTE, the informal definition of _IfcRepresentationResource.IfcGlobalOrLocalEnum_ doe s not distinguish between \"global coordinate system\" and \"world coordinate system\". On the other hand, this distinction is necessary in the _IfcStructuralAnalysisDomain_ where the shared \"global\" coordinate system of an analysis model may very well not be the same as the project-wide world coordinate system.  > NOTE  In the scope of _IfcStructuralActivity.GlobalOrLocal_, the meaning of GLOBAL_COORDS is therefore not to be taken as world coordinate system but as the analysis model specific shared coordinate system. In contrast, LOCAL_COORDS is to be taken as coordinates which are local to individual structural items and activities, as established by subclass-specific geometry use definitions."
         },
-        "description": "The abstract entity IfcStructuralActivity combines the definition of actions (such as forces, displacements, etc.) and reactions (support reactions, internal forces, deflections, etc.) which are specified by using the basic load definitions from the IfcStructuralLoadResource.",
+        "description": "The abstract entity IfcStructuralActivity combines the definition of actions (such as forces, displacements, etc.) and reactions (support reactions, internal forces, deflections, etc.) which are specified by using the basic load definitions from the IfcStructuralLoadResource. The differentiation between actions and reactions is realized by instantiating objects either from subclasses of IfcStructuralAction or IfcStructuralReaction respectively. They inherit commonly needed attributes from the abstract superclass IfcStructuralActivity, notably the relationship which connects actions or reactions with connections, analysis members, or elements (subtypes of IfcStructuralItem or IfcElement). *Coordinate Systems*: The following coordinate systems are distinguished: - The so-called global coordinate system is the coordinate system shared by all items and activities which are grouped in a common IfcStructuralAnalysisModel. This coordinate system is established by an ObjectPlacement. (This coordinate system is not necessarily the same as the IfcProject's world coordinate system.) - The so-called local coordinate system is a coordinate system local to a structural item (connection or member). This coordinate system is established by a Representation in conjunction with further use definitions and attributes of subtypes of IfcStructuralItem. Representation items in topology representations are always given within the ObjectPlacement, i.e. in so-called global coordinates (global with respect to the IfcStructuralAnalysisModel to which this activity belongs). Locations of the load objects in the AppliedLoad attribute (if of type IfcStructuralLoadConfiguration) are always given in local coordinates. Directions of the load objects in the AppliedLoad attribute refer to global or local coordinates according to the GlobalOrLocal attribute. The ObjectPlacement and Representation are sometimes not explicitly instantiated; instead they may be implied as described below. Global and local coordinate systems are then determined in the same way as with explicit placement and representation. *Topology Use Definitions*: Instances of IfcStructuralActivity which are connected with a structural item of same dimensionality, i.e. - a point action or reaction connected with a point item (IfcStructuralPointConnection), - a curve action or reaction connected with a curve item (IfcStructuralCurveConnection, IfcStructuralCurveMember), or - a surface action or reaction connected with a surface item (IfcStructuralSurfaceConnection, IfcStructuralSurfaceMember) and which acts on the entire surface of the item and is not specified by isocontours shall not have an ObjectPlacement nor a Representation. It is implied that the placement and representation of the IfcStructuralActivity is the same as the ones of the IfcStructuralItem. Instances of IfcStructuralActivity which are connected with - a curve item (IfcStructuralCurveConnection, IfcStructuralCurveMember) and act on a point of the item - a surface item (IfcStructuralSurfaceConnection, IfcStructuralSurfaceMember) and act on a point or on a curve or on a part of the surface of the item shall have a topology representation as specified below. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item in a Representation of type IfcTopologyRepresentation. Instances of IfcStructuralActivity which are connected with - a surface item (IfcStructuralSurfaceConnection, IfcStructuralSurfaceMember) and are specified by isocontours shall have a shape representation as specified below. It includes a placement and a product representation. The IfcProductRepresentation shall be given by items in a Representation of type IfcShapeRepresentation. Shape representation and topology representation may be combined. Local Placement The local placement for IfcStructuralActivity is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which establishes a global coordinate system which shall be common to all items and activities in an IfcStructuralAnalysisModel. Topology Representation Instances of IfcStructuralActivity which act on parts of a surface item shall have a topology representation given by a face with underlying surface geometry, IfcFaceSurface, which should be the single item of IfcTopologyRepresentation.Items. The surface establishes a local coordinate system of the activity: - The origin of surface parameters u,v is the origin of the local coordinate system. - The local x and y directions follow the tangents on the surface and are in parallel with and directed like u and v respectively. - The local z direction is in parallel with and directed like the surface normal. Instances of IfcStructuralActivity which act on a curve on a surface item shall have a topology representation given by an edge (IfcEdge or subtype), which should be the single item of IfcTopologyRepresentation.Items. The curve geometry shall be compatible with the surface geometry of the connected item. In conjunction with this surface, the curve establishes a local coordinate system of the activity: - The origin of the curve parameter u is the origin of the local coordinate system. - The local x direction follows the tangent on the curve and is directed like u. - The local z direction is in parallel with and directed like the surface normal of the connected surface item. - The local x,y,z directions form a right-handed Cartesian coordinate system. Instances of IfcStructuralActivity which act on a single point on a curve or surface item shall have a topology representation given by an IfcVertexPoint, which should be the single item of IfcTopologyRepresentation.Items. The point geometry shall be compatible with the curve or surface geometry of the connected item. The local coordinate system of the activity is oriented by the curve or surface geometry of the connected item as described above for activities with edge or face topology. Shape Representation Instances of IfcStructuralActivity which act on a surface item and are specified by isocontours (level sets) shall have a shape representation given by a set of curves on a surface, IfcPCurve. The basis surface shall comply with or preferably be identical with the surface of the structural item to which the activity is connected. The representation identifier and type of this geometric representation is:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralactivity.htm"
     },
     "IfcStructuralAnalysisModel": {
@@ -6418,7 +6418,7 @@
             "OrientationOf2DPlane": "If the selected model type (_PredefinedType_) describes a 2D system, the orientation defines the analysis plane (P[1], P[2]) and the normal to the analysis plane (P[3]).  This is needed because structural items and activities are always defined in three-dimensional space even if they are meant to be analysed in a two-dimensional manner.  * In case of predefined type IN_PLANE_LOADING_2D, the analysis is to be performed within the projection into the P[1], P[2] plane. * In case of predefined type OUT_PLANE_LOADING_2D, only the P[3] component of loads and their effects is meant to be analyzed. This is used for beam grids and for typical slab analyses. * In case of predefined type LOADING_3D, _OrientationOf2DPlane_ shall be omitted.",
             "SharedPlacement": "Object placement which shall be common to all items and activities which are grouped into this instance of _IfcStructuralAnalysisModel_.  This placement establishes a coordinate system which is referred to as 'global coordinate system' in use definitions of various classes of structural items and activities.  > NOTE  Most commonly, but not necessarily, the _SharedPlacement_ is an _IfcLocalPlacement_ whose z axis is parallel with the z axis of the _IfcProject_'s world coordinate system and directed like the WCS z axis (i.e. pointing \"upwards\") or directed against the WCS z axis (i.e. points \"downwards\").  > NOTE  Per informal proposition, this attribute is **not optional** as soon as at least one _IfcStructuralItem_ is grouped into the instance of _IfcStructuralAnalysisModel_."
         },
-        "description": "The IfcStructuralAnalysisModel is used to assemble all information needed to represent a structural analysis model. It encompasses certain general properties (such as analysis type), references to all contained structural members, structural supports or connections, as well as loads and the respective load results.",
+        "description": "The IfcStructuralAnalysisModel is used to assemble all information needed to represent a structural analysis model. It encompasses certain general properties (such as analysis type), references to all contained structural members, structural supports or connections, as well as loads and the respective load results. Important functionalities for the description of an analysis model are derived from existing IFC entities: - From IfcSystem it inherits the ability to couple the analysis model via IfcRelServicesBuildings to one or more _IfcBuilding_s as necessary. - From IfcGroup it inherits the inverse attribute IsGroupedBy, pointing to the relationship class IfcRelAssignsToGroup. This allows to group structural members (instances of IfcStructuralMember), and supports (instances of IfcStructuralConnection) which belong to a specific analysis model. NOTE Loads (as instances of IfcStructuralAction) are not included through IsGroupedBy. Loads are assigned through the LoadedBy attribute relationship, using load groups as a grouping mechanism. Only top-level load groups should be referenced via LoadedBy, i.e. load combinations if any load combinations exist, or load cases if no load combinations exist in this analysis model. NOTE Results (as instances of IfcStructuralReaction) are not included through IsGroupedBy. Results are assigned through the HasResults attribute relationship, using result groups as a grouping mechanism. - From IfcObject it inherits the inverse attribute IsDecomposedBy pointing to the relationship class IfcRelNests. It provides the hierarchy between the separate (partial) analysis models. Informal Propositions: - If one or more structural item (instance of a subtype of IfcStructuralItem) is grouped into an IfcStructuralAnalysisModel, the attribute SharedPlacement shall be provided with a value. - The ObjectPlacement_s of all structural items which are grouped into the same instance of _IfcStructuralAnalysisModel shall refer to the same instance of IfcObjectPlacement as IfcStructuralAnalysisModel.SharedPlacement.",
         "predefined_types": {
             "IN_PLANE_LOADING_2D": "",
             "LOADING_3D": "",
@@ -6447,7 +6447,7 @@
         "attributes": {
             "ProjectedOrTrue": "Defines whether load values are given per true length of the curve on which they act, or per length of the projection of the curve in load direction.  The latter is only applicable to loads which act in global coordinate directions."
         },
-        "description": "A structural curve action defines an action which is distributed over a curve. A curve action may be connected with a curve member or curve connection, or surface member or surface connection.",
+        "description": "A structural curve action defines an action which is distributed over a curve. A curve action may be connected with a curve member or curve connection, or surface member or surface connection. *Coordinate Systems*: See definitions at IfcStructuralActivity. *Topology Use Definitions*: Standard Case: If connected with a curve item, instances of IfcStructuralCurveAction shall not have an ObjectPlacement nor a Representation. It is implied that the placement and representation of the IfcStructuralActivity is the same as the ones of the member or connection. Special Case 1: If connected with a surface item, instances of IfcStructuralCurveAction shall have an ObjectPlacement and Representation, containing an IfcEdgeCurve. See IfcStructuralActivity for further definitions. Special Case 2: If not connected with a structural item (which may happen in an incomplete or conceptual model), a curve action should have an ObjectPlacement and Representation, containing an IfcEdgeCurve. See IfcStructuralActivity for further definitions. Informal Propositions: - If the curve action is of the predefined type CONST, SINUS, or PARABOLA, SELF\\IfcStructuralActivity.AppliedLoad must not be of type IfcStructuralLoadConfiguration. In case of SINUS and PARABOLA, the load item defines the maximum of the load at the centre of the load distribution. - If the curve action is of the predefined type LINEAR, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two items. - If the curve action is of the predefined type POLYGONAL, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain three or more items. - If the curve action is of the predefined type DISCRETE, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two or more items. - In case of types LINEAR, POLYGONAL, and DISCRETE, the load items shall have one-dimensional IfcStructuralLoadConfiguration.Locations, defining the location of the load samples in local coordinates of the curve action. The load items shall be provided in ascending order according to their locations. The first and the last load item define the extent of the load distribution. - Point actions must be of type DISCRETE, thus contain two or more load points. (Single point loads are modeled by IfcStructuralPointAction.) - All items in SELF\\IfcStructuralActivity.AppliedLoad\\IfcStructuralLoadConfiguration.Values shall be of the same entity type.",
         "predefined_types": {
             "CONST": "The load has a constant value over its entire extent.",
             "DISCRETE": "The load is specified as a series of discrete load points.",
@@ -6465,14 +6465,14 @@
         "attributes": {
             "Axis": "Direction which is used in the definition of the local z axis.  _Axis_ is specified relative to the so-called global coordinate system, i.e. the _SELF\\IfcProduct.ObjectPlacement_.  > NOTE  It is desirable and usually possible that many instances of _IfcStructuralCurveConnection_ and _IfcStructuralCurveMember_ share a common instance of _IfcDirection_ as their _Axis_ attribute."
         },
-        "description": "Instances of IfcStructuralCurveConnection describe edge 'nodes', i.e. edges where two or more surface members are joined, or edge supports. Edge curves may be straight or curved.",
+        "description": "Instances of IfcStructuralCurveConnection describe edge 'nodes', i.e. edges where two or more surface members are joined, or edge supports. Edge curves may be straight or curved. *Coordinate Systems*: See definitions at IfcStructuralItem. The local coordinate system is established by the reference curve given by topology representation and by the attribute Axis. The local x axis is parallel with the tangent on the reference curve. The local z axis is located in the surface which is created by sweeping Axis along the reference curve and is directed according to Axis. The local y axis is directed such that x,y,z form a right-handed Cartesian coordinate system.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralcurveconnection.htm"
     },
     "IfcStructuralCurveMember": {
         "attributes": {
             "Axis": "Direction which is used in the definition of the local z axis.  _Axis_ is specified relative to the so-called global coordinate system, i.e. the _SELF\\IfcProduct.ObjectPlacement_.  > NOTE  It is desirable and usually possible that many instances of _IfcStructuralCurveConnection_ and _IfcStructuralCurveMember_ share a common instance of _IfcDirection_ as their _Axis_ attribute."
         },
-        "description": "Instances of IfcStructuralCurveMember describe edge members, i.e. structural analysis idealizations of beams, columns, rods etc.. Curve members may be straight or curved.",
+        "description": "Instances of IfcStructuralCurveMember describe edge members, i.e. structural analysis idealizations of beams, columns, rods etc.. Curve members may be straight or curved. *Coordinate Systems*: See definitions at IfcStructuralItem. The local coordinate system is established by the reference curve given by topology representation and by the attribute Axis. The local x axis is parallel with the tangent on the reference curve. The local z axis is located in the surface which is created by sweeping Axis along the reference curve and is directed according to Axis. The local y axis is directed such that x,y,z form a right-handed Cartesian coordinate system.",
         "predefined_types": {
             "CABLE": "A tension member which is able to carry transverse loads only under large deflection.",
             "COMPRESSION_MEMBER": "A member without tensional stiffness.",
@@ -6485,11 +6485,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralcurvemember.htm"
     },
     "IfcStructuralCurveMemberVarying": {
-        "description": "This entity describes edge members with varying profile properties. Each instance of IfcStructuralCurveMemberVarying is composed of two or more instances of IfcStructuralCurveMember with differing profile properties. These subordinate members relate to the instance of IfcStructuralCurveMemberVarying by IfcRelAggregates.",
+        "description": "This entity describes edge members with varying profile properties. Each instance of IfcStructuralCurveMemberVarying is composed of two or more instances of IfcStructuralCurveMember with differing profile properties. These subordinate members relate to the instance of IfcStructuralCurveMemberVarying by IfcRelAggregates. *Coordinate Systems*: See definitions at IfcStructuralItem and IfcStructuralCurveMember. The local coordinates of the aggregate are derived from those of its parts. Length measures in local x direction of the aggregate depend on continuity and lengths of the parts. The Axis of the aggregate shal be the same as the Axis of the part at the start of the aggregate. *Material Use Definition* Only the individual parts (direct instances of IfcStructuralCurveMember) carry material and profile information.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralcurvemembervarying.htm"
     },
     "IfcStructuralCurveReaction": {
-        "description": "This entity defines a reaction which occurs distributed over a curve. A curve reaction may be connected with a curve member or curve connection, or surface member or surface connection.",
+        "description": "This entity defines a reaction which occurs distributed over a curve. A curve reaction may be connected with a curve member or curve connection, or surface member or surface connection. *Coordinate Systems*: See definitions at IfcStructuralActivity. *Topology Use Definitions*: Standard Case: If connected with a curve item, instances of IfcStructuralCurveRection shall not have an ObjectPlacement nor a Representation. It is implied that the placement and representation of the IfcStructuralActivity is the same as the ones of the member or connection. Special Case: If connected with a surface item, instances of IfcStructuralCurveReaction shall have an ObjectPlacement and Representation, containing an IfcEdgeCurve. See IfcStructuralActivity for further definitions. Informal Propositions: - If the curve reaction is of the predefined type CONST, SELF\\IfcStructuralActivity.AppliedLoad must not be of type IfcStructuralLoadConfiguration. - If the curve reaction is of the predefined type LINEAR, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two items. - If the curve reaction is of the predefined type POLYGONAL, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain three or more items. - If the curve action is of the predefined type DISCRETE, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two or more items. - In case of types LINEAR, POLYGONAL, and DISCRETE, the load items shall have one-dimensional IfcStructuralLoadConfiguration.Locations, defining the location of the result samples in local coordinates of the curve reaction. The load items shall be provided in ascending order according to their locations. The first and the last load item define the extent of the result distribution. - If the curve reaction is of the predefined type EQUIDISTANT, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two or more items. IfcStructuralLoadConfiguration.Locations shall be omitted as it is implicit. The load items shall be provided in ascending order. The first and the last load item are located at the beginning and end of the result distribution, respectively. - All items in SELF\\IfcStructuralActivity.AppliedLoad\\IfcStructuralLoadConfiguration.Values shall be of the same entity type.",
         "predefined_types": {
             "CONST": "The load has a constant value over its entire extent.",
             "DISCRETE": "The load is specified as a series of discrete load points.",
@@ -6507,7 +6507,7 @@
         "attributes": {
             "AssignedStructuralActivity": "Inverse relationship to all structural activities (i.e. to actions or reactions) which are assigned to this structural member."
         },
-        "description": "The abstract entity IfcStructuralItem is the generalization of structural members and structural connections, that is, analysis idealizations of elements in the building model. It defines the relation between structural members and connections with structural activities (actions and reactions).",
+        "description": "The abstract entity IfcStructuralItem is the generalization of structural members and structural connections, that is, analysis idealizations of elements in the building model. It defines the relation between structural members and connections with structural activities (actions and reactions). Relationships between elements in the building model and structural items as their idealizations can be expressed by instances of IfcRelAssignsToProduct. *Coordinate Systems*: The following coordinate systems are distinguished: - The so-called global coordinate system is the coordinate system shared by all items and activities which are grouped in a common IfcStructuralAnalysisModel. This coordinate system is established by SELF\\IfcProduct.ObjectPlacement. (This coordinate system is not necessarily the same as the IfcProject's world coordinate system.) - The so-called local coordinate system is a coordinate system local to a structural item (connection or member). This coordinate system is established by a Representation (attribute inherited from IfcProduct) in conjunction with further use definitions and attributes of subtypes of IfcStructuralItem. Representation items in topology representations are always given within the ObjectPlacement, i.e. in so-called global coordinates (global with respect to the IfcStructuralAnalysisModel to which this item belongs). The usage of local coordinate systems is further defined in subtypes. *Topology Use Definitions*: Instances of IfcStructuralItem shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item in a Representation of type IfcTopologyRepresentation. Local Placement The local placement for IfcStructuralItem is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which establishes a global coordinate system which shall be common to all items and activities in an IfcStructuralAnalysisModel. Topology Representation Instances of IfcStructuralItem shall have a topology representation given by an instance of a subtype of IfcTopologicalRepresentationItem, which should be the single item of IfcTopologyRepresentation.Items. Depending on the dimensionality of the structural item, one of the following types of toplogical representation items shall be used: - Point connections shall be represented by an IfcVertexPoint with an underlying IfcCartesianPoint. The Cartesian point is the reference point of the connection in the so-called global coordinate system. The following labels are used in the IfcTopologyRepresentation: RepresentationIdentifier: 'Reference' RepresentationType: 'Vertex' - Curve members and curve connections shall either be represented by an IfcOrientedEdge, IfcEdgeCurve, or IfcEdge. The curve to which the IfcEdgeCurve (or an IfcOrientedEdge's underlying IfcEdgeCurve) refers to is the reference curve of the structural item in the global coordinate system. Start and end vertex of the edge shall be IfcVertexPoint_s with underlying _IfcCartesianPoint_s. The following labels are used in the _IfcTopologyRepresentation: RepresentationIdentifier: 'Reference' RepresentationType: 'Edge' NOTE While an IfcEdge (or IfcOrientedEdge with underlying IfcEdge) does not provide an explicit underlying curve geometry, it may be used to imply an underlying straight line as reference curve with the origin of the curve parameter at the start vertex point. - Surface members and surface connections shall be represented by an IfcFaceSurface. The underlying surface defines the reference surface of the structural surface item in the global coordiante system. All edges in the bounds of the face shall conform to the rules for edge representations of structural curve item. The following labels are used in the IfcTopologyRepresentation: RepresentationIdentifier: 'Reference' RepresentationType: 'Face' The reference point, reference curve, or reference surface partially or completely defines the local coordinate system of the represented structural item according to the following rules. In all cases, The local x,y,z directions form a right-handed Cartesian coordinate system. Structural point items - The reference point in the representation is the origin of the local coordinate system of the structural item. - The axes of the local coordiante system are either parallel with and directed like the so-called global coordinate axes, or are oriented according to definitions at the respective subtype of IfcStructuralItem. Structural curve items - The u parameter origin of the reference curve in the representation is the origin of the local coordinate system of the structural item. - The local x axis is parallel with the tangent on the curve and directed like the u parameter direction. - The local y and z axes are oriented according to definitions at the respective subtypes of IfcStructuralItem. Structural surface items - The u,v parameter origin of the reference surface in the representation is the origin of the local coordinate system of the structural item. - The local x and y directions follow the tangents on the surface and are in parallel with and directed like u and v respectively. - The local z direction is in parallel with and directed like the surface normal. Informal Propositions: - The ObjectPlacement_s of all structural items which are grouped into the same instance of _IfcStructuralAnalysisModel shall refer to the same instance of IfcObjectPlacement.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralitem.htm"
     },
     "IfcStructuralLinearAction": {
@@ -6533,7 +6533,7 @@
             "Locations": "Locations of the load samples or result samples, given within the local coordinate system defined by the instance which uses this resource object.  Each item in the list of locations pertains to the values list item at the same list index.  This attribute is optional for configurations in which the locations are implicitly known from higher-level definitions.",
             "Values": "List of load or result values."
         },
-        "description": "This class combines one or more load or result values in a 1- or 2-dimensional configuration.",
+        "description": "This class combines one or more load or result values in a 1- or 2-dimensional configuration. Informal Propositions: - All items in Values shall be of the same type. - If the loads or results comprise a curve activity, 1-dimensional locations shall be given, measured locally along the curve. The location shall not exceed the bounds of the curve actvity. The load samples and corresponding locations shall be given in ascending order of locations. - If the loads or results comprise a surface activity, 2-dimensional locations shall be given, measured in the surface activity's local x and y directions. The location shall not exceed the bounds of the surface activity.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcstructuralloadconfiguration.htm"
     },
     "IfcStructuralLoadGroup": {
@@ -6545,7 +6545,7 @@
             "Purpose": "Description of the purpose of this instance. Among else, possible values of the Purpose of load combinations are 'SLS', 'ULS', 'ALS' to indicate serviceability, ultimate, or accidental limit state.",
             "SourceOfResultGroup": "Results which were computed using this load group."
         },
-        "description": "The entity IfcStructuralLoadGroup is used to structure the physical impacts. By using the grouping features inherited from IfcGroup, instances of IfcStructuralAction (or its subclasses) and of IfcStructuralLoadGroup can be used to define load groups, load cases and load combinations. (See also IfcLoadGroupTypeEnum.)",
+        "description": "The entity IfcStructuralLoadGroup is used to structure the physical impacts. By using the grouping features inherited from IfcGroup, instances of IfcStructuralAction (or its subclasses) and of IfcStructuralLoadGroup can be used to define load groups, load cases and load combinations. (See also IfcLoadGroupTypeEnum.) Informal Propositions: - Load groups of type LOAD_GROUP shall only contain instances of IfcStructuralAction. - Load groups of type LOAD_CASE shall always be instantiated from the subtype IfcStructuralLoadCase, not directly from the generic type IfcStructuralLoadGroup itself. - Instances of IfcStructuralLoadCase shall only contain instances of IfcStructuralAction or/ and instances of IfcStructuralLoadGroup of type LOAD_GROUP. - Load groups of type LOAD_COMBINATION shall only contain instances of IfcStructuralLoadCase.",
         "predefined_types": {
             "LOAD_CASE": "Groups LOAD_GROUPs and instances of subtypes of _IfcStructuralAction_.\n      It should be used as a container for loads with the same origin.",
             "LOAD_COMBINATION": "An intermediate level between LOAD_CASE and LOAD_COMBINATION.  This level is obsolete and deprecated.  Before the introduction of _IfcRelAssignsToGroupByFactor_, the purpose of this level was to provide a factor with which one or more LOAD_CASEs occur in a LOAD_COMBINATION.",
@@ -6628,7 +6628,7 @@
             "DeltaTY": "Non-uniform temperature change, specified as the difference of the temperature change at the outer fibre of the positive y direction minus the temperature change at the outer fibre of the negative y direction of the analysis member.  > NOTE  A positive non-uniform temperature change in y induces a negative curvature of the member about z, or a positive bending moment about z if there are respective restraints. y and z are local member axes.",
             "DeltaTZ": "Non-uniform temperature change, specified as the difference of the temperature change at the outer fibre of the positive z direction minus the temperature change at the outer fibre of the negative z direction of the analysis member.  > NOTE  A positive non-uniform temperature change in z induces a positive curvature of the member about y, or a negative bending moment about y if there are respective restraints. y and z are local member axes."
         },
-        "description": "An instance of the entity IfcStructuralLoadTemperature shall be used to define actions which are caused by a temperature change. As shown in Figure 1, the change of temperature is given with a constant value which is applied to the complete section and values for temperature differences between outer fibres of the section.",
+        "description": "An instance of the entity IfcStructuralLoadTemperature shall be used to define actions which are caused by a temperature change. As shown in Figure 1, the change of temperature is given with a constant value which is applied to the complete section and values for temperature differences between outer fibres of the section. !(../../../../../../figures/structuralloadtemperature.gif \"Figure 1 \u2014 Structural load temperature\")",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcstructuralloadtemperature.htm"
     },
     "IfcStructuralMember": {
@@ -6643,22 +6643,22 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralplanaraction.htm"
     },
     "IfcStructuralPointAction": {
-        "description": "This entity defines an action which acts on a point. A point action is typically connected with a point connection. It may also be connected with a curve member or curve connection, or surface member or surface connection.",
+        "description": "This entity defines an action which acts on a point. A point action is typically connected with a point connection. It may also be connected with a curve member or curve connection, or surface member or surface connection. *Coordinate Systems*: See definitions at IfcStructuralActivity. *Topology Use Definitions*: Standard Case: If connected with a point item, instances of IfcStructuralPointAction shall not have an ObjectPlacement nor a Representation. It is implied that the placement and representation of the action is the same as the structural item. Special Case 1: If connected with a curve item or surface item, instances of IfcStructuralPointAction shall have an ObjectPlacement and Representation, containing an IfcVertexPoint. See IfcStructuralActivity for further definitions. Special Case 2: If not connected with a structural item (which may happen in an incomplete or conceptual model), a point action should have an ObjectPlacement and Representation, containing an IfcVertexPoint. See IfcStructuralActivity for further definitions.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralpointaction.htm"
     },
     "IfcStructuralPointConnection": {
         "attributes": {
             "ConditionCoordinateSystem": "Defines a coordinate system used for the description of the support condition properties in _SELF\\IfcStructuralConnection.SupportCondition_, specified relative to the global coordinate system (global to the structural analysis model) established by _SELF.\\IfcProduct.ObjectPlacement_.  If left unspecified, the placement _IfcAxis2Placement3D_((x,y,z), ?, ?) is implied with x,y,z being the coordinates of the reference point of this _IfcStructuralPointConnection_ and the default axes directions being in parallel with the global axes."
         },
-        "description": "Instances of IfcStructuralPointConnection describe structural nodes or point supports.",
+        "description": "Instances of IfcStructuralPointConnection describe structural nodes or point supports. *Coordinate Systems*: See definitions at IfcStructuralItem. The local coordinate system is established by the reference point given by topology representation and by the attribute ConditionCoordinateSystem.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralpointconnection.htm"
     },
     "IfcStructuralPointReaction": {
-        "description": "This entity defines a reaction which occurs at a point. A point reaction is typically connected with a point connection. It may also be connected with a curve member or curve connection, or surface member or surface connection.",
+        "description": "This entity defines a reaction which occurs at a point. A point reaction is typically connected with a point connection. It may also be connected with a curve member or curve connection, or surface member or surface connection. *Coordinate Systems*: See definitions at IfcStructuralActivity. *Topology Use Definitions*: Standard Case: If connected with a point item, instances of IfcStructuralPointReaction shall not have an ObjectPlacement nor a Representation. It is implied that the placement and representation of the reaction is the same as the structural item. Special Case 1: If connected with a curve item or surface item, instances of IfcStructuralPointReaction shall have an ObjectPlacement and Representation, containing an IfcVertexPoint. See IfcStructuralActivity for further definitions. Special Case 2: If not connected with a structural item (which may happen in an incomplete or conceptual model), a point action should have an ObjectPlacement and Representation, containing an IfcVertexPoint. See IfcStructuralActivity for further definitions.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralpointreaction.htm"
     },
     "IfcStructuralReaction": {
-        "description": "A structural reaction is a structural activity that results from a structural action imposed to a structural item or building element. Examples are support reactions, internal forces, and deflections.",
+        "description": "A structural reaction is a structural activity that results from a structural action imposed to a structural item or building element. Examples are support reactions, internal forces, and deflections. Structural reactions are grouped into IfcStructuralResultGroup_s via the inverse relationship _HasAssignments and an IfcRelAssignsToGroup relationship object. IfcStructuralResultGroup.ResultGroupFor finally refers to the structural analysis model in which the results occur. It is furthermore possible to establish relationships between reactions in one analysis model and actions which they cause in another analysis model. For example, a support reaction from one structural system may be taken over as a load onto another supporting structural system. This is expressed by means of the inverse relationship HasAssignments of the reaction and an IfcRelAssignsToProduct relationship object. IfcRelAssignsToProduct.Name is set to 'Causes' and IfcRelAssignsToProduct.RelatingProduct refers to an instance of a subtype of IfcStructuralAction.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralreaction.htm"
     },
     "IfcStructuralResultGroup": {
@@ -6675,7 +6675,7 @@
         "attributes": {
             "ProjectedOrTrue": "Defines whether load values are given per true lengths of the surface on which they act, or per lengths of the projection of the surface in load direction.  The latter is only applicable to loads which act in global coordinate directions."
         },
-        "description": "This entity defines an action which is distributed over a surface. A surface action may be connected with a surface member or surface connection.",
+        "description": "This entity defines an action which is distributed over a surface. A surface action may be connected with a surface member or surface connection. *Coordinate Systems*: See definitions at IfcStructuralActivity. *Topology Use Definitions*: Standard Case: If connected with a surface item and acting on its entirety, instances of IfcStructuralCurveAction shall not have an ObjectPlacement nor a Representation. It is implied that the placement and representation of the IfcStructuralActivity is the same as the ones of the member or connection. Special Case 1: If connected with a surface item but acting only on a part of it, instances of IfcStructuralSurfaceAction shall have an ObjectPlacement and Representation, containing an IfcFaceSurface which topologically defines the loaded part of the surface. See IfcStructuralActivity for further definitions. Special Case 2: If not connected with a structural item (which may happen in an incomplete or conceptual model), a surface action should have an ObjectPlacement and Representation, containing an IfcFaceSurface. See IfcStructuralActivity for further definitions. Informal Propositions: - If the surface action is of the predefined type CONST, SELF\\IfcStructuralActivity.AppliedLoad must not be of type IfcStructuralLoadConfiguration. - If the surface action is of the predefined type BILINEAR, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain three items with two-dimensional IfcStructuralLoadConfiguration.Locations, defining the location of the load samples in local coordinates of the surface action. - If the surface action is of the predefined type DISCRETE, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two or more items with two-dimensional locations. - Point loads must be of type DISCRETE, thus contain two or more load points. (Single point loads are modeled by IfcStructuralPointLoad.) - All items in SELF\\IfcStructuralActivity.AppliedLoad\\IfcStructuralLoadConfiguration.Values shall be of the same entity type.",
         "predefined_types": {
             "BILINEAR": "The load value is bilinearly distributed over the load's extent.",
             "CONST": "The load has a constant value over its entire extent.",
@@ -6687,14 +6687,14 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfaceaction.htm"
     },
     "IfcStructuralSurfaceConnection": {
-        "description": "Instances of IfcStructuralSurfaceConnection describe face 'nodes', i.e. faces where two or more surface members are joined, or face supports. Face surfaces may be planar or curved.",
+        "description": "Instances of IfcStructuralSurfaceConnection describe face 'nodes', i.e. faces where two or more surface members are joined, or face supports. Face surfaces may be planar or curved. *Coordinate Systems*: See definitions at IfcStructuralItem. The local coordinate system is established by the reference surface given by topology representation. *Topology Use Definitions*: Instances of IfcStructuralSurfaceConnection shall have a topology representation which consists of one IfcFaceSurface, representing the reference surface of the surface connection. See definitions at IfcStructuralItem for further specifications.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfaceconnection.htm"
     },
     "IfcStructuralSurfaceMember": {
         "attributes": {
             "Thickness": "Defines the typically understood thickness of the structural surface member, measured normal to its reference surface."
         },
-        "description": "Instances of IfcStructuralSurfaceMember describe face members, that is, structural analysis idealizations of slabs, walls, and shells. Surface members may be planar or curved.",
+        "description": "Instances of IfcStructuralSurfaceMember describe face members, that is, structural analysis idealizations of slabs, walls, and shells. Surface members may be planar or curved. *Coordinate Systems*: See definitions at IfcStructuralItem. The local coordinate system is established by the reference surface given by topology representation. *Material Use Definition* The material of direct instances IfcStructuralSurfaceMember (in contrast to instances of the subtype IfcStructuralSurfaceMemberVarying) is defined by IfcMaterial and attached by the IfcRelAssociatesMaterial.RelatingMaterial. It is accessible by the inverse HasAssociations relationship. The material is specified minimally by a name which corresponds with an agreed upon standardized structural material designation. An external reference to the source which specifies the material designation should be provided. Alternatively, structural material properties may be provided by means of IfcMechanicalMaterialProperties and IfcExtendedMaterialProperties. Direct instances of IfcStructuralSurfaceMember are assumed to be located centrically relative to their reference surface. Their depth is provided in the attribute Thickness.",
         "predefined_types": {
             "BENDING_ELEMENT": "A member with capacity to carry out-of-plane loads, i.e. a plate.",
             "MEMBRANE_ELEMENT": "A member with capacity to carry in-plane loads, for example a shear wall.",
@@ -6705,11 +6705,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfacemember.htm"
     },
     "IfcStructuralSurfaceMemberVarying": {
-        "description": "This entity describes surface members with varying section properties. The properties are provided by means of Pset_StructuralSurfaceMemberVaryingThickness via IfcRelDefinesByProperties, or by means of aggregation: An instance of IfcStructuralSurfaceMemberVarying may be composed of two or more instances of IfcStructuralSurfaceMember with differing section properties. These subordinate members relate to the instance of IfcStructuralSurfaceMemberVarying by IfcRelAggregates.",
+        "description": "This entity describes surface members with varying section properties. The properties are provided by means of Pset_StructuralSurfaceMemberVaryingThickness via IfcRelDefinesByProperties, or by means of aggregation: An instance of IfcStructuralSurfaceMemberVarying may be composed of two or more instances of IfcStructuralSurfaceMember with differing section properties. These subordinate members relate to the instance of IfcStructuralSurfaceMemberVarying by IfcRelAggregates. *Coordinate Systems*: See definitions at IfcStructuralItem and IfcStructuralSurfaceMember. The local coordinates of an aggregate are generally undefined since continuity of local coordinates of the parts is not ensured. *Material Use Definition* In case of aggregation, only the individual parts (direct instances of IfcStructuralSurfaceMember) carry material and thickness information. Otherwise, definitions at IfcStructuralSurfaceMember apply.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfacemembervarying.htm"
     },
     "IfcStructuralSurfaceReaction": {
-        "description": "This entity defines a reaction which occurs distributed over a surface. A surface reaction may be connected with a surface member or surface connection.",
+        "description": "This entity defines a reaction which occurs distributed over a surface. A surface reaction may be connected with a surface member or surface connection. *Coordinate Systems*: See definitions at IfcStructuralActivity. *Topology Use Definitions*: See definitions at IfcStructuralActivity. Informal Propositions: - If the surface reaction is of the predefined type CONST, SELF\\IfcStructuralActivity.AppliedLoad must not be of type IfcStructuralLoadConfiguration. - If the surface reaction is of the predefined type BILINEAR, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain three items with two-dimensional IfcStructuralLoadConfiguration.Locations, defining the location of the result samples in local coordinates of the surface reaction. - If the surface reaction is of the predefined type DISCRETE, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two or more items with two-dimensional locations. - If the surface reaction is of the predefined type ISOCONTOUR, SELF\\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain the same number of items as the set SELF.IfcProduct.Representation.Representations[?].Items. Each item in the load configuration shall have a two-dimensional location, defining the location of the result samples in local coordinates of the surface reaction. Each item in SELF\\IfcStructuralActivity.AppliedLoad shall be located at exactly one of the isocontours. NOTE The set of representation items is unordered, hence result locations are required to correlate result values and isocontours. NOTE Isocontours are represented as IfcPCurves which are defined in terms of surface parameters u,v, while result locations are given in local surface item coordinates x,y. It is strongly recommended that the surface parameterization u,v is scaled 1:1 in order to avoid different scales of u,v versus x,y. If u,v are scaled 1:1 and the IfcPCurve's base surface is identical with the surface item's base surface, u,v and local x,y are identical. - All items in SELF\\IfcStructuralActivity.AppliedLoad\\IfcStructuralLoadConfiguration.Values shall be of the same entity type.",
         "predefined_types": {
             "BILINEAR": "The load value is bilinearly distributed over the load's extent.",
             "CONST": "The load has a constant value over its entire extent.",
@@ -6721,7 +6721,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfacereaction.htm"
     },
     "IfcStyleModel": {
-        "description": "IfcStyleModel represents the concept of a particular presentation style defined for a material (or other characteristic) of a product or a product component within a representation context. This representation context may (but has not to be) a geometric representation context.",
+        "description": "IfcStyleModel represents the concept of a particular presentation style defined for a material (or other characteristic) of a product or a product component within a representation context. This representation context may (but has not to be) a geometric representation context. IfcStyleModel can be a style representation (presentation style) of a material (via IfcMaterialDefinitionRepresentation), potentially differentiated for different representation contexts (for example, different material hatching depending on the scale of the target representation context).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcstylemodel.htm"
     },
     "IfcStyledItem": {
@@ -6730,15 +6730,15 @@
             "Name": "The word, or group of words, by which the styled item is referred to.",
             "Styles": "Representation styles which are assigned, either to an geometric representation item, or to a material definition."
         },
-        "description": "The IfcStyledItem holds presentation style information for products, either explicitly for an IfcGeometricRepresentationItem being part of an IfcShapeRepresentation assigned to a product, or by assigning presentation information to IfcMaterial being assigned as other representation for a product.",
+        "description": "The IfcStyledItem holds presentation style information for products, either explicitly for an IfcGeometricRepresentationItem being part of an IfcShapeRepresentation assigned to a product, or by assigning presentation information to IfcMaterial being assigned as other representation for a product. - If the IfcStyledItem is used within a reference from an IfcProductDefinitionShape then one Item shall be provided. - If the IfcStyledItem is used within a reference from an IfcMaterialDefinitionRepresentation then no Item shall be provided. Use Definition Figure 1 illustrates use of IfcStyledItem for the two usage examples: - As a presentation for a geometric representation item - As a presentation for a material definition",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcstyleditem.htm"
     },
     "IfcStyledRepresentation": {
-        "description": "The IfcStyledRepresentation represents the concept of a styled presentation being a representation of a product or a product component, like material. within a representation context. This representation context does not need to be (but may be) a geometric representation context.",
+        "description": "The IfcStyledRepresentation represents the concept of a styled presentation being a representation of a product or a product component, like material. within a representation context. This representation context does not need to be (but may be) a geometric representation context. A styled representation has to include one or several styled items with the associated style information (curve, symbol, text, fill area, or surface styles). It shall not contain the geometric representation items that are styled.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcstyledrepresentation.htm"
     },
     "IfcSubContractResource": {
-        "description": "IfcSubContractResource is a construction resource needed in a construction process that represents a sub-contractor.",
+        "description": "IfcSubContractResource is a construction resource needed in a construction process that represents a sub-contractor. An IfcSubContractResource can be used in cost estimating and work planning with or without specifying the subcontractor and contract agreement. The purpose of an IfcSubContractResource is to indicate work of a particular type that is that is to be engaged through the use of a sub-contract. Its aim is to identify the description of the sub-contract work required. It can be used to identify the generic type of sub-contract resource that is required for a purpose without having to be specific about the actor (person or organization) providing the resource occurrence. It may be particularly useful when creating an overall plan for a process or processes. For instance, within maintenance or work planning there may be a known task that needs to be done which is planned to require an 'insulation specialist'. A subcontract resource may be described at various stages and levels of detail through its assignments: - Subcontract resource designated for particular tasks - Actors identified to request bids - Cost schedules (bids) received from actors - Project order (work order, change order, etc.) executed",
         "predefined_types": {
             "NOTDEFINED": "Undefined resource.",
             "PURCHASE": "Furnishing or supplying products.",
@@ -6748,7 +6748,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifcsubcontractresource.htm"
     },
     "IfcSubContractResourceType": {
-        "description": "The resource type IfcSubContractResourceType defines commonly shared information for occurrences of subcontract resources. The set of shared information may include:",
+        "description": "The resource type IfcSubContractResourceType defines commonly shared information for occurrences of subcontract resources. The set of shared information may include: - common productivities - common cost rates - common properties within shared property sets It is used to define a subcontract resource specification (the specific resource information that is common to all occurrences of that resource). Resource types may be exchanged without being already assigned to occurrences. Occurrences of the IfcSubContractResourceType are represented by instances of IfcSubContractResource.",
         "predefined_types": {
             "NOTDEFINED": "Undefined resource.",
             "PURCHASE": "Furnishing or supplying products.",
@@ -6761,14 +6761,14 @@
         "attributes": {
             "ParentEdge": "The Edge, or Subedge, which contains the Subedge."
         },
-        "description": "",
+        "description": "Informal Propositions: - The domain of the subedge is formally defined to be the domain of the parent edge, as trimmed by the subedge start vertex and subedge end vertex. - The start vertex and end vertex shall be within the union of the domains of the vertices of the parent edge and the domain of the parent edge.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcsubedge.htm"
     },
     "IfcSurface": {
         "attributes": {
             "Dim": "The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item."
         },
-        "description": "An IfcSurface is a 2-dimensional representation item positioned in 3-dimensional space. 2-dimensional means that each point at the surface can be defined by a 2-dimensional coordinate system, usually by u and v coordinates.",
+        "description": "An IfcSurface is a 2-dimensional representation item positioned in 3-dimensional space. 2-dimensional means that each point at the surface can be defined by a 2-dimensional coordinate system, usually by u and v coordinates. Informal Propositions: - A surface has non zero area. - A surface is arcwise connected.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcsurface.htm"
     },
     "IfcSurfaceCurve": {
@@ -6778,7 +6778,7 @@
             "Curve3D": "The curve which is the three-dimensional representation of the surface curve.",
             "MasterRepresentation": "The"
         },
-        "description": "An IfcSurfaceCurve is a 3-dimensional curve that has additional representations provided by one or two pcurves.",
+        "description": "An IfcSurfaceCurve is a 3-dimensional curve that has additional representations provided by one or two pcurves. Informal Propositions: - Where Curve3D and one or two pcurves exist they shall represent the same mathematical point set. (i.e., they shall coincide geometrically but may differ in parametrisation.) - The Curve3D and any associated pcurves shall agree with respect to their senses.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcsurfacecurve.htm"
     },
     "IfcSurfaceCurveSweptAreaSolid": {
@@ -6788,11 +6788,11 @@
             "ReferenceSurface": "The surface containing the _Directrix_.",
             "StartParam": "The parameter value on the _Directrix_ at which the sweeping operation commences. If no value is provided the start of the sweeping operation is at the start of the _Directrix_."
         },
-        "description": "The IfcSurfaceCurveSweptAreaSolid is the result of sweeping an area along a directrix that lies on a reference surface. The swept area is provided by a subtype of IfcProfileDef. The profile is placed by an implicit cartesian transformation operator at the start point of the sweep, where the profile normal agrees to the tangent of the directrix at this point, and the profile's x-axis agrees to the surface normal. At any point along the directrix, the swept profile origin lies on the directrix, the profile's normal points towards the tangent of the directrix, and the profile's x-axis is identical to the surface normal at this point.",
+        "description": "The IfcSurfaceCurveSweptAreaSolid is the result of sweeping an area along a directrix that lies on a reference surface. The swept area is provided by a subtype of IfcProfileDef. The profile is placed by an implicit cartesian transformation operator at the start point of the sweep, where the profile normal agrees to the tangent of the directrix at this point, and the profile's x-axis agrees to the surface normal. At any point along the directrix, the swept profile origin lies on the directrix, the profile's normal points towards the tangent of the directrix, and the profile's x-axis is identical to the surface normal at this point. The Directrix and the ReferenceSurface are positioned within the object coordinate system. The start of the sweeping operation is at the StartParam, the parameter value is provided based on the curve parameterization. If no StartParam is provided the start defaults to the begin of the directrix. The end of the sweeping operation is at the EndParam, the parameter value is provided based on the curve parameterization. If no EndParam is provided the end defaults to the end of the directrix. The geometric shape of the solid is not dependent upon the curve parameterization; the volume depends upon the area swept and the length of the Directrix. At any point of the directrix, a plane can be constructed. The origin of the position coordinate system of the implicit plane lies at the directrix. The Axis3 (the z-axis, or normal) of the position coordinate system is identical to the tangent of the directrix at this point, the Axis1 (the x axis, or u) of the position coordinate system is identical to the normal of the reference surface at this point. The Axis2 (the y axis, or v) is constructed. The resulting body of the swept solid is not repositioned if the inherited Position attribute is omitted. Otherwise the coordinate system established by the Position attribute is used to reposition the body relative to the object coordinate system. Informal Propositions: - The SweptArea shall lie in the implicit plane z = 0. - The Directrix shall lie on the ReferenceSurface.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcsurfacecurvesweptareasolid.htm"
     },
     "IfcSurfaceFeature": {
-        "description": "A surface feature is a modification at (onto, or into) of the surface of an element. Parts of the surface of the entire surface may be affected. The volume and mass of the element may be increased, remain unchanged, or be decreased by the surface feature, depending on manufacturing technology. However, any increase or decrease of volume is small compared to the total volume of the element.",
+        "description": "A surface feature is a modification at (onto, or into) of the surface of an element. Parts of the surface of the entire surface may be affected. The volume and mass of the element may be increased, remain unchanged, or be decreased by the surface feature, depending on manufacturing technology. However, any increase or decrease of volume is small compared to the total volume of the element. The standard use of instances of IfcSurfaceFeature is as a part of element type objects (instances of subtypes of IfcElementType). The part\u2013whole relationship is established by an aggregation relationship object, expressing the decomposition of an element type into one or more additive elements (element parts) and zero or more feature elements. *Containment Use Definition*: Surface features shall have no spatial containment relationship to the spatial structure since they are dependent on element types without spatial containment relationships or on an element occurrence with own spatial containment relationship. - The SELF\\IfcElement.ContainedInStructure relationship shall be NIL. *Geometry use definition*: The geometric representation of IfcSurfaceFeatureElement is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Local Placement The local placement for IfcSurfaceFeatureElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. - In case of features which are part of an element type, absolute placement into the type object's implied coordinate system shall be used. - In case of features which are voiding an element occurrence, the PlacementRelTo relationship of IfcLocalPlacement shall point to the local placement of the respective element. Shape representation Different shape representations may be used, depending on the nature of the feature and information requirements: - Symbolic representation, such as the two-dimensional bounding box of a tag. - A geometric set representing the geometric items of a mark. - Surface representations of treated parts of the lement surface by means of IfcShellBasedSurfaceModel. The faces within the surface model may be included into a B-Rep model within a representation map of the parent element type. Higher-level parameters (geometric and non-geometric) may be provided by property sets based on local agreements.",
         "predefined_types": {
             "MARK": "A point, line, cross, or other mark, applied for example for easier adjustment of elements during assembly.",
             "NOTDEFINED": "An undefined type of surface feature.",
@@ -6808,7 +6808,7 @@
             "ExtrudedDirection": "The direction of the extrusion.",
             "ExtrusionAxis": "The extrusion axis defined as vector. IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector (ExtrudedDirection, Depth)"
         },
-        "description": "The IfcSurfaceOfLinearExtrusion is a surface derived by sweeping a curve along a vector.",
+        "description": "The IfcSurfaceOfLinearExtrusion is a surface derived by sweeping a curve along a vector. Informal Propositions: - The surface shall not self-intersect",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcsurfaceoflinearextrusion.htm"
     },
     "IfcSurfaceOfRevolution": {
@@ -6816,7 +6816,7 @@
             "AxisLine": "The line coinciding with the axis of revolution. IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(AxisPosition.Location,    IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(AxisPosition.Z,1.0))",
             "AxisPosition": "A point on the axis of revolution and the direction of the axis of revolution."
         },
-        "description": "The IfcSurfaceOfRevolution is a surface derived by rotating a curve about an axis.",
+        "description": "The IfcSurfaceOfRevolution is a surface derived by rotating a curve about an axis. Informal Propositions: - The surface shall not self-intersect - The swept curve shall not be coincident with the axis line for any finite part of its legth.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcsurfaceofrevolution.htm"
     },
     "IfcSurfaceReinforcementArea": {
@@ -6843,7 +6843,7 @@
             "ReflectanceColour": "A coefficient that determines the extent that the light falling onto a surface is fully or partially reflected.  > NOTE  The factor can be measured physically and has three ratios for the red, green and blue part of the light.",
             "TransmissionColour": "Describes how the light falling on a body is totally or partially transmitted."
         },
-        "description": "IfcSurfaceStyleLighting is a container class for properties for calculation of physically exact illuminance related to a particular surface style.",
+        "description": "IfcSurfaceStyleLighting is a container class for properties for calculation of physically exact illuminance related to a particular surface style. Figure 1 shows the reflection and transmission components from an incident ray. The sum of the components for reflection and transmission is a value of 1.0 denoting that the incident ray is completely decomposed into reflection and transmission components. Each value of reflection and transmission is therefore within the range 0.0 to 1.0. All these factors can be measured physically and are ratios for the red, green and blue part of the light. These properties are defined in the model as Type IfcColorRGB with a factor for each colour.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcsurfacestylelighting.htm"
     },
     "IfcSurfaceStyleRefraction": {
@@ -6864,7 +6864,7 @@
             "SpecularHighlight": "The exponent or roughness part of the specular reflectance.",
             "TransmissionColour": "The transmissive part of the reflectance equation can be given as either a colour or a scalar factor. It only applies to materials which Transparency field is greater than zero. The transmissive colour field specifies the colour that passes through a transparant material (like the colour that shines through a glass). The transmissive factor defines the transmissive part, the transmissive colour is then defined by surface colour \\* transmissive factor."
         },
-        "description": "IfcSurfaceStyleRendering holds the properties for visualization related to a particular surface side style. It allows rendering properties to be defined by:",
+        "description": "IfcSurfaceStyleRendering holds the properties for visualization related to a particular surface side style. It allows rendering properties to be defined by: - a colour component (SurfaceColour attribute inherited from IfcSurfaceStyleShading) - a transparency component (Transparency attribute inherited from IfcSurfaceStyleShading) - a reflectance component, given either by applying reflectance factors to the surface colour: diffuse component (SurfaceColour * DiffuseFactor) transmission component (SurfaceColour * TransmissionFactor) diffuse transmission component (SurfaceColour * DiffuseTransmissionFactor) reflection component (SurfaceColour * ReflectionFactor) specular component (SurfaceColour * SpecularFactor attribute together with SpecularHighlight) or, by explicitly defining such factors as colours (DiffuseColour, TransmissionColour, DiffuseTransmissionColour, ReflectionColour and SpecularColour) - a displacement component, currently only given by a texture map with the TextureType = bump - a coverage component, currently only given by the alpha component of the texture map (2 or 4 component colour texture)",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcsurfacestylerendering.htm"
     },
     "IfcSurfaceStyleShading": {
@@ -6879,7 +6879,7 @@
         "attributes": {
             "Textures": "The textures applied to the surface. In case of more than one surface texture is included, the _IfcSurfaceStyleWithTexture_ defines a multi texture."
         },
-        "description": "The entity IfcSurfaceStyleWithTextures allows to include image textures in surface styles. These image textures can be applied repeating across the surface or mapped with a particular scale upon the surface.",
+        "description": "The entity IfcSurfaceStyleWithTextures allows to include image textures in surface styles. These image textures can be applied repeating across the surface or mapped with a particular scale upon the surface. The entity IfcSurfaceStyleWithTextures is part of the surface style table for presentation information assigned to surfaces for shading, rendering and lighting with textures. The mapping of the texture onto the surface or the solid is determined by the texture coordinates, in absense of an IfcTextureCoordinate assigned to each surface texture, a default mapping of the texture to the geometric face or surface applies. Surface textures included in the IfcSurfaceStyleWithTextures are two dimensional map formats. They define 2D images that contain an array of colour values describing the texture. Depending on the number of IfcSurfaceTextures being included in the list of Textures the IfcSurfaceStyleWithTextures either describes a single texture, or a multi texture. - single texture: a single surface texture is applied to the styled geometric item (entirely or partly) with optional repetition and texture transformation - multi texture: two or more surface textures are applied to the styled geometric item (entirely or partly) with optional repetition, texture transformation or texture coordinate mapping being specific for each texture. Informal Propositions: - Only one instance of IfcSurfaceStyleWithTextures shall be referenced by an IfcStyledItem and be assigned to an IfcGeometricRepresentationItem",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcsurfacestylewithtextures.htm"
     },
     "IfcSurfaceTexture": {
@@ -6892,7 +6892,7 @@
             "TextureTransform": "The _TextureTransform_ defines a 2D transformation that is applied to the texture coordinates. It affects the way texture coordinates are applied to the surfaces of geometric representation itesm. The 2D transformation supports changes to the size, orientation, and position of textures on shapes. Mirroring is not allowed to be used in the _IfcCartesianTransformationOperator_",
             "UsedInStyles": ""
         },
-        "description": "An IfcSurfaceTexture provides a 2-dimensional image-based texture map. It can either be given by referencing an external image file through an URL reference (IfcImageTexture), including the image file as a blob (long binary) into the data set (IfcBlobTexture), or by explicitly including an array of pixels (IfcPixelTexture).",
+        "description": "An IfcSurfaceTexture provides a 2-dimensional image-based texture map. It can either be given by referencing an external image file through an URL reference (IfcImageTexture), including the image file as a blob (long binary) into the data set (IfcBlobTexture), or by explicitly including an array of pixels (IfcPixelTexture). The following definitions from ISO/IEC 19775-1 X3D Architecture and base components (X3D Specification) apply: - Texture: An image used in a texture map to create visual appearance effects when applied to geometry nodes. - Texture map: A texture plus the general parameters necessary for mapping the texture to geometry. Texture are defined by 2D images that contain an array of colour values describing the texture. The texture values are interpreted differently depending on the number of components in the texture and the specifics of the image format. In general, texture may be described using one of the following forms: - Intensity textures (one-component) - Intensity plus alpha opacity textures (two-component) - Full RGB textures (three-component) - Full RGB plus alpha opacity textures (four-component) Figure 1 illustrates the texture coordinate system. The following definitions from ISO/IEC 19775-1 X3D Architecture and base components (X3D Specification) on texture coordinates apply: - Texture maps are defined in a 2D coordinate system (s, t) that ranges from [0.0, 1.0] in both directions. The bottom edge of the image corresponds to the S-axis of the texture map, and left edge of the image corresponds to the T-axis of the texture map. The lower-left pixel of the image corresponds to s=0, t=0, and the top-right pixel of the image corresponds to s=1, t=1. Texture maps may be viewed as two dimensional colour functions that, given an (s, t) coordinate, return a colour value colour(s, t). If multiple surface textures are included in the IfcSurfaceStyleWithTextures applying them to a geometric item, a mode and optional parameters can be included that blending operations. The RepeatS and RepeatT Boolean flags control whether the texture map is repeated outside the [0.0, 1.0] texture coordinate range, when applied to a geometric surface, or clamped to lie within the [0.0, 1.0] range. The TextureTransform applies a 2D non-uniform transformation to the texture before it is applied to a geometric surface. The following definitions from ISO/IEC 19775-1 X3D Architecture and base components (X3D Specification) apply: - These parameters support changes to the size, orientation, and position of textures on shapes. Note that these operations appear reversed when viewed on the surface of geometry. For example, a scale value of (2 2) will scale the texture coordinates and have the net effect of shrinking the texture size by a factor of 2 (texture coordinates are twice as large and thus cause the texture to repeat). A translation of (0.5 0.0) translates the texture coordinates +.5 units along the S-axis and has the net effect of translating the texture \u22120.5 along the S-axis on the geometry's surface. A rotation of \u03c0/2 of the texture coordinates results in a \u2212\u03c0/2 rotation of the texture on the geometry. - The center field specifies a translation offset in texture coordinate space about which the rotation and scale fields are applied. The scale field specifies a scaling factor in S and T of the texture coordinates about the center point. scale values shall be in the range (\u2212\u221e,\u221e). The rotation field specifies a rotation in radians of the texture coordinates about the center point after the scale has been applied. A positive rotation value makes the texture coordinates rotate counterclockwise about the centre, thereby rotating the appearance of the texture itself clockwise. The translation field specifies a translation of the texture coordinates. The following conventions apply: center = TextureTransform.LocalOrigin; rotation = TextureTransform.Axis1 scale S = TextureTransform.Scale scale T = TextureTransform.Scale2",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcsurfacetexture.htm"
     },
     "IfcSweptAreaSolid": {
@@ -6900,7 +6900,7 @@
             "Position": "Position coordinate system for the resulting swept solid of the sweeping operation. The position coordinate system allows for re-positioning of the swept solid. If not provided, the swept solid remains within the position as determined by the cross section or by the directrix used for the sweeping operation.",
             "SweptArea": "The surface defining the area to be swept. It is given as a profile definition within the xy plane of the position coordinate system."
         },
-        "description": "An IfcSweptAreaSolid represents the 3D shape by a sweeping representation scheme allowing a two dimensional planar cross section to sweep through space.",
+        "description": "An IfcSweptAreaSolid represents the 3D shape by a sweeping representation scheme allowing a two dimensional planar cross section to sweep through space. The swept area is defined by a cross section, represented by a subtype if IfcProfileDef, that is provided as a closed two-dimensional boundary on an implicit plane. The swept area is defined in the xy plane of the object coordinate system. The sweeping operation is applied to the swept area as defined within the subtypes of IfcSweptAreaSolid, some subtypes require an implicit transformation of the swept area to the start position of the sweep. The optional _Positio_n coordinate system allows for re-positioning the resulting swept solid relative to the object coordinate system.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcsweptareasolid.htm"
     },
     "IfcSweptDiskSolid": {
@@ -6911,14 +6911,14 @@
             "Radius": "The _Radius_ of the circular disk to be swept along the _directrix_. Denotes the outer radius, if an _InnerRadius_ is applied.",
             "StartParam": "The parameter value on the _Directrix_ at which the sweeping operation commences. If no value is provided the start of the sweeping operation is at the start of the Directrix.."
         },
-        "description": "An IfcSweptDiskSolid represents the 3D shape by a sweeping representation scheme allowing a two dimensional circularly bounded plane to sweep along a three dimensional Directrix through space.",
+        "description": "An IfcSweptDiskSolid represents the 3D shape by a sweeping representation scheme allowing a two dimensional circularly bounded plane to sweep along a three dimensional Directrix through space. The StartParam and EndParam parameter are optional, if not provided they default to the start and end of the Directrix. Only if the Directrix is given by a bounded or by a closed curve, it is permissible to omit the values of StartParam and EndParam. If the transitions between consecutive segments of the Directrix are not tangent continuous, the resulting solid is created by a miter at half angle between the two segments. Informal proposition restricts the permissible angle between two non-tangent continuous segments. Figure 1 illustrates an example. - Directrix given as IfcIndexedPolyCurve, having linear and circular arc segments, that are tangent continuous between each segments - Directrix being a bounded and open curve - No StartParam and EndParam are provided, start and end default to start and end of the bounded curve of the Directrix Informal Propositions: - If the Directrix curve definition is not tangent continuous, the transition between the segments has to be within an acceptable limit of tangent discontinuity. Very sharp edges may result in nearly impossible miter. Implementer agreements may define acceptable limits for tangent discontinuity. - The segments of the Directrix shall be long enough to apply the Radius. In case of an arc segment forming part of the Directrix, its radius shall be greater then the disk Radius - The Directrix shall not be based on an intersecting curve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcsweptdisksolid.htm"
     },
     "IfcSweptDiskSolidPolygonal": {
         "attributes": {
             "FilletRadius": "The fillet that is equally applied to all transitions between the segments of the _IfcPolyline_, providing the geometric representation for _the Directrix_. If omited, no fillet is applied to the segments."
         },
-        "description": "The IfcSweptDiskSolidPolygonal is a IfcSweptDiskSolid where the Directrix is restricted to be provided by an poly line only. An optional FilletRadius attribute can be asserted, it is then applied as a fillet to all transitions between the segments of the poly line.",
+        "description": "The IfcSweptDiskSolidPolygonal is a IfcSweptDiskSolid where the Directrix is restricted to be provided by an poly line only. An optional FilletRadius attribute can be asserted, it is then applied as a fillet to all transitions between the segments of the poly line. Informal Propositions: - The FilletRadius, if provided, has to be smaller then or equal to the length of the start and end segment of the IfcPolyline, and smaller then or equal to one half of the lenght of the shortest inner segment.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcsweptdisksolidpolygonal.htm"
     },
     "IfcSweptSurface": {
@@ -6926,11 +6926,11 @@
             "Position": "Position coordinate system for the swept surface, provided by a profile definition within the XY plane of the _Position_ coordinates. If not provided, the position of the profile being swept is determined by the object coordinate system. In this case, the swept surface is not repositioned.",
             "SweptCurve": "The curve to be swept in defining the surface. The curve is defined as a profile within the position coordinate system."
         },
-        "description": "An IfcSweptSurface is a surface defined by sweeping a curve. The swept surface is defined by a open or closed curve, represented by a subtype if IfcProfileDef, that is provided as a two-dimensional curve on an implicit plane, and by the sweeping operation.",
+        "description": "An IfcSweptSurface is a surface defined by sweeping a curve. The swept surface is defined by a open or closed curve, represented by a subtype if IfcProfileDef, that is provided as a two-dimensional curve on an implicit plane, and by the sweeping operation. - The swept curve is defined by positioning the profile in the xy plane of the object coordinate system, - The sweeping operation is applied to the swept curve as defined within the subtypes of IfcSweptSurface; The optional _Positio_n coordinate system allows for re-positioning the resulting swept surface relative to the object coordinate system.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcsweptsurface.htm"
     },
     "IfcSwitchingDevice": {
-        "description": "A switch is used in a cable distribution system (electrical circuit) to control or modulate the flow of electricity.",
+        "description": "A switch is used in a cable distribution system (electrical circuit) to control or modulate the flow of electricity. Switches include those used for electrical power, communications, audio-visual, or other distribution system types as determined by the available ports.",
         "predefined_types": {
             "CONTACTOR": "An electrical device used to control the flow of power in a circuit on or off.",
             "DIMMERSWITCH": "A dimmer switch has variable positions, and may adjust electrical power or other setting (according to the switched port type).",
@@ -6947,7 +6947,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcswitchingdevice.htm"
     },
     "IfcSwitchingDeviceType": {
-        "description": "The flow controller type IfcSwitchingDeviceType defines commonly shared information for occurrences of switching devices. The set of shared information may include:",
+        "description": "The flow controller type IfcSwitchingDeviceType defines commonly shared information for occurrences of switching devices. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a switching device type specification indicating the specific product information that is common to all occurrences of that product type. The IfcSwitchingDeviceType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcSwitchingDeviceType are represented by instances of IfcSwitchingDevice. Refer to the documentation at IfcSwitchingDevice for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CONTACTOR": "An electrical device used to control the flow of power in a circuit on or off.",
             "DIMMERSWITCH": "A dimmer switch has variable positions, and may adjust electrical power or other setting (according to the switched port type).",
@@ -6981,7 +6981,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedfacilitieselements/lexical/ifcsystemfurnitureelement.htm"
     },
     "IfcSystemFurnitureElementType": {
-        "description": "The furnishing element type IfcSystemFurnitureElementType defines commonly shared information for occurrences of system furniture elements. The set of shared information may include:",
+        "description": "The furnishing element type IfcSystemFurnitureElementType defines commonly shared information for occurrences of system furniture elements. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a system furniture element type specification indicating the specific product information that is common to all occurrences of that product type. The IfcSystemFurnitureElementType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcSystemFurnitureElementType are represented by instances of IfcSystemFurnitureElement. Refer to the documentation at IfcSystemFurnitureElement for supported property sets, materials, and composition.",
         "predefined_types": {
             "NOTDEFINED": "Undefined type.",
             "PANEL": "Vertical panel used to divide work spaces.",
@@ -7002,7 +7002,7 @@
             "WebSlope": "Slope of flange of the profile.",
             "WebThickness": "Constant wall thickness of web (= ts)."
         },
-        "description": "IfcTShapeProfileDef defines a section profile that provides the defining parameters of a T-shaped section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box.",
+        "description": "IfcTShapeProfileDef defines a section profile that provides the defining parameters of a T-shaped section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box. Figure 1 illustrates parameters of the T-shape profile definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifctshapeprofiledef.htm"
     },
     "IfcTable": {
@@ -7014,7 +7014,7 @@
             "NumberOfHeadings": "The number of headings in a table. This is restricted by WR3 to max. one. SIZEOF(QUERY( Temp <* Rows | Temp.IsHeading))",
             "Rows": "Reference to information content of rows."
         },
-        "description": "An IfcTable is a data structure for the provision of information in the form of rows and columns. Each instance may have IfcTableColumn instances that define the name, description and units for each column. The rows of information are stored as a list of IfcTableRow objects.",
+        "description": "An IfcTable is a data structure for the provision of information in the form of rows and columns. Each instance may have IfcTableColumn instances that define the name, description and units for each column. The rows of information are stored as a list of IfcTableRow objects. Limitation: For backwards compatibility, the rows of an IfcTable object are constrained to have the same number of cells. The first row of the table provides the number of cells. All other rows are forced to include the same number of cells. This is enforced by the WR2. Figure 1 illustrates table use. !(../../../../../../figures/ifctable_image1.gif \"Figure 1 \u2014 Table use\") Figure 2 depicts how tables were structured prior to IFC4. !(../../../../../../figures/ifctable_image2.gif \"Figure 2 \u2014 Table use alternative\")",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcutilityresource/lexical/ifctable.htm"
     },
     "IfcTableColumn": {
@@ -7025,7 +7025,7 @@
             "ReferencePath": "The _ReferencePath_ indicates a relative path to the object and attribute for which data within this column is to be applied.   For constraints, such path is relative to the _IfcObjectDefinition_ associated by _IfcRelAssociatesConstraint_.RelatedObjects. For a constraint to be satisified, exactly one row of the table must match the referenced object for all columns where the _ReferencePath_ attribute is set.",
             "Unit": "The _Unit_ indicates the unit of measure to be used for this column's data. If not provided, then project default units are assumed. If _ReferencePath_ is provided, the the unit must be of the same measure as the referenced attribute."
         },
-        "description": "An IfcTableColumn is a data structure that captures column information for use in an IfcTable. Each instance defines the identifier, name, description, and units of measure that are applicable to the columnar data associated with the IfcTableRow objects.",
+        "description": "An IfcTableColumn is a data structure that captures column information for use in an IfcTable. Each instance defines the identifier, name, description, and units of measure that are applicable to the columnar data associated with the IfcTableRow objects. The use of IfcTableColumn supersedes the IsHeading flag associated with IfcTableRow.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcutilityresource/lexical/ifctablecolumn.htm"
     },
     "IfcTableRow": {
@@ -7033,7 +7033,7 @@
             "IsHeading": "Flag which identifies if the row is a heading row or a row which contains row values.  > NOTE - If the row is a heading, the flag takes the value = TRUE.",
             "RowCells": "The data value of the table cell.."
         },
-        "description": "IfcTableRow contains data for a single row within an IfcTable.",
+        "description": "IfcTableRow contains data for a single row within an IfcTable. Limitation: For backward compatibility, all IfcTableRow objects referenced by an IfcTable shall have the same number of Row Cells. The actual number of Cells shall be taken from the number of cells of the first IfcTableRow for that table. The number of Cells is calculated by the derived attribute NumberOfCellsInRow in the associated IfcTable.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcutilityresource/lexical/ifctablerow.htm"
     },
     "IfcTank": {
@@ -7052,7 +7052,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifctank.htm"
     },
     "IfcTankType": {
-        "description": "The flow storage device type IfcTankType defines commonly shared information for occurrences of tanks. The set of shared information may include:",
+        "description": "The flow storage device type IfcTankType defines commonly shared information for occurrences of tanks. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a tank type specification indicating the specific product information that is common to all occurrences of that product type. The IfcTankType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcTankType are represented by instances of IfcTank. Refer to the documentation at IfcTank for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "BASIN": "An arbitrary open tank type.",
             "BREAKPRESSURE": "An open container that breaks the hydraulic pressure in a distribution system, typically located between the fluid reservoir and the fluid supply points. A typical break pressure tank allows the flow to discharge into the atmosphere, thereby reducing its hydrostatic pressure to zero.",
@@ -7074,7 +7074,7 @@
             "TaskTime": "Time related information for the task.",
             "WorkMethod": "The method of work used in carrying out a task.      > NOTE  This attribute should not be used if the work method is specified for the _IfcTaskType_"
         },
-        "description": "An IfcTask is an identifiable unit of work to be carried out in a construction project.",
+        "description": "An IfcTask is an identifiable unit of work to be carried out in a construction project. A task is typically used to describe an activity for the construction or installation of products, but is not limited to these types. For example it might be used to describe design processes, move operations and other design, construction and operation related activities as well. Quantities of resources consumed by the task are dealt with by defining the IfcElementQuantity for the resource and not at the instance of IfcTask. Attribute use definition Each occurrence of IfcTask is given a name that is indicative of its content (IfcRoot.Name). A textual description of the task may be provided and this may be further elaborated by a narrative long description (IfcProcess.LongDescription). A work method may be declared for the method of work used in carrying out a task. A task is identified as being either a milestone task or not. A milestone task is defined by the marker IsMilestone. and has no duration. A status and priority for each task may also be set. Time and duration use definition Compared to previous IFC releases, basic task time information (scheduled start time, scheduled finish time, duration) is now directly attached to IfcTask through the TaskTime attribute. Regular tasks are defined through IfcTaskTime. Recurring tasks are defined through IfcTaskTimeRecurring. In case a regular task is derived from a recurring task both tasks should be linked together through a IfcRelNests relationship, where IfcRelNests.IsNestedBy points to the recurring task and IfcRelNests.Nests points to all regular tasks that have been derived from the recurring task. Representation of other activities The use definitions for IfcTask have been generalised to represent other activities as well, including activities that had been defined by own entities in previous IFC releases. This includes - Order actions - Move operations IfcTask represents an order that might be carried out by a Helpdesk acting the role of interface for the organization between the facility user and the functional requirement of fulfilling their needs. The actual task represented by the IfcTask entity is turning a request into an order and initiating the action that will enable the order to be completed. The IfcProjectOrder or one of its subtypes including maintenance work order, is related to the IfcTask using IfcRelAssignsToControl. IfcTask can also be used to describe an activity that moves people, groups within an organization or complete organizations together with their associated furniture and equipment from one place to another. It thus replaces the previous IFC entity IfcMove. The functionality is represented in IfcTask as follows: - Move from: The place from which actors and their associated equipment are moving. Use IfcRelAssignsToProcess where RelatingProcess points to the task and RelatedObjects holds the location(s) from which to move. - Move to: The place to which actors and their associated equipment are moving. Use IfcRelAssignsToProduct where RelatedObjects points to the task(s) and RelatingProduct points to the location to which to move. - Punch list: A list of points concerning a move that require attention. Use LongDescription or else identify sub-tasks to track punch list items individually via IfcRelNests.",
         "predefined_types": {
             "ATTENDANCE": "Attendance or waiting on other things happening.",
             "CONSTRUCTION": "Constructing or building something.",
@@ -7113,7 +7113,7 @@
             "StatusTime": "The date or time at which the status of the tasks within the schedule is analyzed.",
             "TotalFloat": "The difference between the duration available to carry out a task and the scheduled duration of the task. It is a calculated elapsed time value. > NOTE  Total Float time may be calculated as being the difference between the scheduled duration of a task and the available duration from earliest start to latest finish. Float time may be either positive, zero or negative. Where it is zero or negative, the task becomes critical."
         },
-        "description": "IfcTaskTime captures the time-related information about a task including the different types (actual or scheduled) of starting and ending times.",
+        "description": "IfcTaskTime captures the time-related information about a task including the different types (actual or scheduled) of starting and ending times. All given values should be provided by the application; the IFC schema does not deal with dependencies between task time values. There is also no consistency check through where rules that guarantee a meaningful population of time values. Thus, an application is responsible to provide reasonable values and, if an application receives task times, has to make consistency checks by their own. IfcTaskTime furthermore provides a generic mechanism to differentiate between user given time values and time values derived from user given time values and other constraints such as work calendars and assigned resources.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifctasktime.htm"
     },
     "IfcTaskTimeRecurring": {
@@ -7127,7 +7127,7 @@
         "attributes": {
             "WorkMethod": "The method of work used in carrying out a task."
         },
-        "description": "An IfcTaskType defines a particular type of task that may be specified for use within a work control.",
+        "description": "An IfcTaskType defines a particular type of task that may be specified for use within a work control. An IfcTaskType provides for all forms of types of task that may be specified. It is a reference definition for a unit of work that may be broken down into (a sequence of) subtasks. Please note that a reference definition can not be part of a workflow definition, i.e. IfcTaskType instances define the most abstract level of a reference process without dependencies to other reference processes. Usage of IfcTaskType defines the parameters for one or more occurrences of IfcTask. Parameters may be specified through property sets that may be enumerated in the IfcTaskTypeEnum data type or through explict attributes of IfcTaskType. Task occurrences (IfcTask entities) are linked to the task type through the IfcRelDefinesByType relationship. Figure 1 shows the definition of a task type that is part of a task template library. Please note that in this example the task type is further subdivided into tasks that define task times (for example, duration) and/or a task sequence.",
         "predefined_types": {
             "ATTENDANCE": "Attendance or waiting on other things happening.",
             "CONSTRUCTION": "Constructing or building something.",
@@ -7191,7 +7191,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifctendonanchor.htm"
     },
     "IfcTendonAnchorType": {
-        "description": "The reinforcing element type IfcTendonAnchorType defines commonly shared information for occurrences of tendon anchors. The set of shared information may include:",
+        "description": "The reinforcing element type IfcTendonAnchorType defines commonly shared information for occurrences of tendon anchors. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a tendon anchor type specification indicating the specific product information that is common to all occurrences of that product type. The IfcTendonAnchorType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcTendonAnchorType are represented by instances of IfcTendonAnchor. Material Use Definition A material or material constituent set may be associated. Geometry Use Definition The IfcTendonAnchorType may define the shared geometric representation for many tendon anchor occurrences. The RepresentationMaps attribute refers to a list of IfcRepresentationMap's, that allow for multiple geometric representations.",
         "predefined_types": {
             "COUPLER": "The anchor is an intermediate device which connects two tendons.",
             "FIXED_END": "The anchor fixes the end of a tendon.",
@@ -7207,7 +7207,7 @@
             "NominalDiameter": "The nominal diameter defining the cross-section size of the prestressed part of the tendon.",
             "SheathDiameter": "Diameter of the sheeth (duct) around the tendon, if there is one with this type of tendon."
         },
-        "description": "The reinforcing element type IfcTendonType defines commonly shared information for occurrences of tendons. The set of shared information may include:",
+        "description": "The reinforcing element type IfcTendonType defines commonly shared information for occurrences of tendons. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a tendon type specification indicating the specific product information that is common to all occurrences of that product type. The IfcTendonType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcTendonType are represented by instances of IfcTendon. Material Use Definition An associated material denotes the steel grade, preferrably via material classification. A material constituent set or material profile set may be associated if the cable, bonding mortar or corrosion protection, and tendon sheeth are to be described together by the material association. Geometry Use Definition The IfcTendonType may define the shared geometric representation for many tendon occurrences. The RepresentationMaps attribute refers to a list of IfcRepresentationMap's, that allow for multiple geometric representations.",
         "predefined_types": {
             "BAR": "The tendon is configured as a bar.",
             "COATED": "The tendon is coated.",
@@ -7225,7 +7225,7 @@
             "HasColours": "Reference to the indexed colour map providing the corresponding colour RGB values to the faces of the subtypes of _IfcTessellatedFaceSet_.",
             "HasTextures": "Reference to the indexed texture map providing the corresponding texture coordinates to the vertices bounding the faces of the subtypes of _IfcTessellatedFaceSet_."
         },
-        "description": "The IfcTessellatedFaceSet is a boundary representation topological model limited to planar faces and straight edges. It may represent an approximation of an analytical surface or solid that may be provided in addition to its tessellation as a separate shape representation. The IfcTessellatedFaceSet provides a compact data representation of an connected face set using indices into ordered lists of vertices, normals, colours, and texture maps.",
+        "description": "The IfcTessellatedFaceSet is a boundary representation topological model limited to planar faces and straight edges. It may represent an approximation of an analytical surface or solid that may be provided in addition to its tessellation as a separate shape representation. The IfcTessellatedFaceSet provides a compact data representation of an connected face set using indices into ordered lists of vertices, normals, colours, and texture maps. The IfcTessellatedFaceSet is an abstract supertype of tesselated face sets each imposing specific constraints on face generation for tessellation, such as triangulation (with or without strip and fans), or quadrilaterals, or polygonal faces (with or without inner loops). The following attributes apply to all subtypes: - The Coordinates are the ordered list of Cartesian points representing the vertices of the tessellated item. An index list, defined at the level of subtypes, uses the points, identified by index position, to construct the polylines that represent the faces. - The HasColours inverse relation provides an indexed colour map with an corresponding list of indices providing a colour for each face of the tessellated face set. - The HasTextures inverse relation provides an indexed texture map with an corresponding list of indices providing texture coordinates that map to the geometric coordinates of the polylines representing the faces. Each face of the tessellated face set shall have: - at least three non-coincident vertices; - vertices that define a planar polygon; - vertices that define a non-self-intersecting polygon.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifctessellatedfaceset.htm"
     },
     "IfcTessellatedItem": {
@@ -7238,7 +7238,7 @@
             "Path": "The writing direction of the text literal.",
             "Placement": "An _IfcAxis2Placement_ that determines the placement and orientation of the presented string."
         },
-        "description": "The text literal is a geometric representation item which describes a text string using a string literal and additional position and path information. The text size and appearance is determined by the IfcTextStyle that is associated to the IfcTextLiteral through an IfcStyledItem.",
+        "description": "The text literal is a geometric representation item which describes a text string using a string literal and additional position and path information. The text size and appearance is determined by the IfcTextStyle that is associated to the IfcTextLiteral through an IfcStyledItem. The text string is placed within the planar extent (the box) defined within the subtype IfcTextLiteralWithExtent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationdefinitionresource/lexical/ifctextliteral.htm"
     },
     "IfcTextLiteralWithExtent": {
@@ -7246,7 +7246,7 @@
             "BoxAlignment": "The alignment of the text literal relative to its position.",
             "Extent": "The extent in the x and y direction of the text literal."
         },
-        "description": "The text literal with extent is a text literal with the additional explicit information of the planar extent. An alignment attribute defines how the text box is aligned to the placement and how it may expand if additional lines of text need to be added.",
+        "description": "The text literal with extent is a text literal with the additional explicit information of the planar extent. An alignment attribute defines how the text box is aligned to the placement and how it may expand if additional lines of text need to be added. Figure 1 shows the use of planar extent and box alignment to position the text string The planar extent defines the box model within which the text is placed. Padding maybe defined in the text style that offsets the text from the box to its inside.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationdefinitionresource/lexical/ifctextliteralwithextent.htm"
     },
     "IfcTextStyle": {
@@ -7256,7 +7256,7 @@
             "TextFontStyle": "The style applied to the text font for its visual appearance. It defines the font family, font style, weight and size.",
             "TextStyle": "The style applied to the text block for its visual appearance."
         },
-        "description": "The IfcTextStyle is a presentation style for annotations that place a text in model space. The IfcTextStyle provides the text style for presentation information assigned to IfcTextLiteral's. The style is defined by color, text font characteristics, and text box characteristics.",
+        "description": "The IfcTextStyle is a presentation style for annotations that place a text in model space. The IfcTextStyle provides the text style for presentation information assigned to IfcTextLiteral's. The style is defined by color, text font characteristics, and text box characteristics. An IfcTextStyle is instantiated with: - TextCharacterAppearance: IfcTextStyleForDefinedFont - TextStyle: IfcTextStyleTextModel - TextFontStyle: IfcTextStyleFontModel An IfcTextStyle is assigned to IfcTextLiteral through the IfcStyledItem entity.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifctextstyle.htm"
     },
     "IfcTextStyleFontModel": {
@@ -7267,7 +7267,7 @@
             "FontVariant": "The font variant property selects between normal and small-caps.    > NOTE  It has been introduced for later compliance to full CSS1 support.",
             "FontWeight": "The font weight property selects the weight of the font.    > NOTE  Values other then 'normal' and 'bold' have been introduced for later compliance to full CSS1 support."
         },
-        "description": "",
+        "description": "- The user agent makes (or accesses) a database of relevant CSS1 properties of all the fonts of which the UA is aware. The UA may be aware of a font because it has been installed locally or it has been previously downloaded over the web. If there are two fonts with exactly the same properties, one of them is ignored. - At a given element and for each character in that element, the UA assembles the font-properties applicable to that element. Using the complete set of properties, the UA uses the 'font-family' property to choose a tentative font family. The remaining properties are tested against the family according to the matching criteria described with each property. If there are matches for all the remaining properties, then that is the matching font face for the given element. - If there is no matching font face within the 'font-family' being processed by step 2, and if there is a next alternative 'font-family' in the font set, then repeat step 2 with the next alternative 'font-family'. - If there is a matching font face, but it doesn't contain a glyph for the current character, and if there is a next alternative 'font-family' in the font sets, then repeat step 2 with the next alternative 'font-family'. - If there is no font within the family selected in 2, then use a UA-dependent default 'font-family' and repeat step 2, using the best match that can be obtained within the default font. (The above algorithm can be optimized to avoid having to revisit the CSS1 properties for each character.) The per-property matching rules from (2) above are as follows: - 'font-style' is tried first. 'italic' will be satisfied if there is either a face in the UA's font database labeled with the CSS keyword 'italic' (preferred) or 'oblique'. Otherwise the values must be matched exactly or font-style will fail. - 'font-variant' is tried next. 'normal' matches a font not labeled as 'small-caps'; 'small-caps' matches (1) a font labeled as 'small-caps', (2) a font in which the small caps are synthesized, or (3) a font where all lowercase letters are replaced by upper case letters. A small-caps font may be synthesized by electronically scaling uppercase letters from a normal font. - 'font-weight' is matched next, it will never fail. (See 'font-weight' below.) - 'font-size' must be matched within a UA-dependent margin of tolerance. (Typically, sizes for scalable fonts are rounded to the nearest whole pixel, while the tolerance for bitmapped fonts could be as large as 20%.) Further computations, are based on the 'font-size' value that is used, not the one that is specified. The inherited Name attribute is used to define the font name, particularly in cases, where no (list of) font families are provided.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifctextstylefontmodel.htm"
     },
     "IfcTextStyleForDefinedFont": {
@@ -7311,7 +7311,7 @@
             "MappedTo": "The face that defines the corresponding list of points along the bounding poly loop of the face outer bound. > NOTE  The face may have additional inner loops. The _IfcTextureMap_ and its _Vertices_ only correspond with the coordinates of the _IfcPolyloop_ representing the outer bound.",
             "Vertices": "List of texture coordinate vertices that are applied to the corresponding points of the polyloop defining a face bound."
         },
-        "description": "An IfcTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to surfaces of vertex based geometry models, such as",
+        "description": "An IfcTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to surfaces of vertex based geometry models, such as - IfcFacetedBrep - IfcFacetedBrepWithVoids - IfcFaceBasedSurfaceModel - IfcShellBasedSurfaceModel The IfcTextureMap has a list of TextureVertex, that corresponds to the points of the outer face bound of the vertex based geometry item. The corresponding pair of lists is: - the list of Polygon of the IfcFaceOuterBound of type IfcCartesianPoint, and - the list of Vertices of type IfcTextureVertex. Each IfcTextureVertex (given as S, T coordinates of the 2-dimension texture coordinate system) corresponds to the geometric coordinates of the IfcCartesianPoint (given as 3-dimension X, Y, and Z coordinates within the object coordinate system of the geometric item). Informal Propositions: - The IfcFace referenced in AppliedTo shall be used by the vertex based geometry, to which this texture map is assigned to by through the IfcStyledItem.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifctexturemap.htm"
     },
     "IfcTextureVertex": {
@@ -7325,7 +7325,7 @@
         "attributes": {
             "TexCoordsList": "List of texture vertices defined by S-coordinate and T-coordinate."
         },
-        "description": "The IfcTextureVertexList defines an ordered collection of texture vertices. Each texture vertex is a two-dimensional vertex provided by a fixed list of two texture coordinates. The attribute TexCoordsList is a two-dimensional list, where",
+        "description": "The IfcTextureVertexList defines an ordered collection of texture vertices. Each texture vertex is a two-dimensional vertex provided by a fixed list of two texture coordinates. The attribute TexCoordsList is a two-dimensional list, where - first dimension is an unbounded list representing each texture vertex; - second dimension is a fixed list of two list members, where [1] is the S-coordinate, and [2] the T-coordinate of the texture vertex.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifctexturevertexlist.htm"
     },
     "IfcTimePeriod": {
@@ -7333,7 +7333,7 @@
             "EndTime": "End time of the time period.",
             "StartTime": "Start time of the time period."
         },
-        "description": "IfcTimePeriod defines a time period given by a start and end time. Both time definitions consider the time zone and allow for the daylight savings offset.",
+        "description": "IfcTimePeriod defines a time period given by a start and end time. Both time definitions consider the time zone and allow for the daylight savings offset. A time period is defined by a start and an end time, which is defined by IfcTime. The given time period should be within reasonable values (for example, the start time must be before the end time). It is furthermore expected that both time definitions use the same time zone and, if given, the same daylight saving offset.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifctimeperiod.htm"
     },
     "IfcTimeSeries": {
@@ -7348,14 +7348,14 @@
             "Unit": "The unit to be assigned to all values within the time series. Note that mixing units is not allowed. If the value is not given, the global unit for the type of _IfcValue_, as defined at _IfcProject.UnitsInContext_ is used.",
             "UserDefinedDataOrigin": "Value of the data origin if DataOrigin attribute is USERDEFINED."
         },
-        "description": "A time series is a set of a time-stamped data entries. It allows a natural association of data collected over intervals of time. Time series can be regular or irregular. In regular time series data arrive predictably at predefined intervals. In irregular time series some or all time stamps do not follow a repetitive pattern and unpredictable bursts of data may arrive at unspecified points in time.",
+        "description": "A time series is a set of a time-stamped data entries. It allows a natural association of data collected over intervals of time. Time series can be regular or irregular. In regular time series data arrive predictably at predefined intervals. In irregular time series some or all time stamps do not follow a repetitive pattern and unpredictable bursts of data may arrive at unspecified points in time. The modeling of buildings and their performance involves data that are generated and recorded over a period of time. Such data cover a large spectrum, from weather data to schedules of all kinds to status measurements to reporting to everything else that has a time related aspect. Their correct placement in time is essential for their proper understanding and use, and the IfcTimeSeries subtypes provide the appropriate data structures to accommodate these types of data.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifctimeseries.htm"
     },
     "IfcTimeSeriesValue": {
         "attributes": {
             "ListValues": "A list of time-series values. At least one value is required."
         },
-        "description": "A time series value is a list of values that comprise the time series. At least one value must be supplied. Applications are expected to normalize values by applying the following three rules:",
+        "description": "A time series value is a list of values that comprise the time series. At least one value must be supplied. Applications are expected to normalize values by applying the following three rules: - All time (universal, local, daylight savings, and solar) is normalized against the ISO 8601 standard GMT/UTC (Universal Coordinated Time). - Any rollover is handled by the application providing the data. Rollover occurs, for example, when the measurement device resets itself while measuring and the recording data do not include the data measured before the reset. - The normalized data refer to the preceding time unit. The time series example shown in Figure 1 below contains four time points: Time \"a\" indicates the beginning of the time series and the associated datum has no relevance. Data at time points \"b,\" \"c\" and \"d\" are associated with values 1, 2 and 3, respectively.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifctimeseriesvalue.htm"
     },
     "IfcTopologicalRepresentationItem": {
@@ -7363,7 +7363,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifctopologicalrepresentationitem.htm"
     },
     "IfcTopologyRepresentation": {
-        "description": "IfcTopologyRepresentation represents the concept of a particular topological representation of a product or a product component within a representation context. This representation context does not need to be (but may be) a geometric representation context. Several representation types for shape representation are included as predefined types:",
+        "description": "IfcTopologyRepresentation represents the concept of a particular topological representation of a product or a product component within a representation context. This representation context does not need to be (but may be) a geometric representation context. Several representation types for shape representation are included as predefined types: The representation type is given as a string value at the inherited attribute 'RepresentationType'.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifctopologyrepresentation.htm"
     },
     "IfcToroidalSurface": {
@@ -7371,11 +7371,11 @@
             "MajorRadius": "The major radius of the torus.",
             "MinorRadius": "The minor radius of the torus."
         },
-        "description": "The IfcToroidalSurface is a bounded elementary surface. It is constructed by completely revolving a circle around an axis line. The inherited Position attribute defines the IfcAxisPlacement3D and provides:",
+        "description": "The IfcToroidalSurface is a bounded elementary surface. It is constructed by completely revolving a circle around an axis line. The inherited Position attribute defines the IfcAxisPlacement3D and provides: - SELF\\IfcElementarySurface.Position: The location and orientation of the axis system for the primitive. - SELF\\IfcElementarySurface.Position.Location: The center of the toroidal surface. - SELF\\IfcElementarySurface.Position.Position[3]: The axis of revolution of the toroidal surface \u03c3(u,v) = C + (R + r_cos _v)((cos_u_)x + (sin u))y) + r(sin_v_))z where the parametrisation range is 0 \u2264 u, v \u2264 360 degrees. u and v are angular parameters and when numerical values are specified they shall use the current units for plane angle measure. In the placement coordinate system defined above, the surface is represented by the equation S = 0, where The positive direction of the normal to the surface at any point on the surface is given by The unit normal is given by The sense of this normal is away from the nearest point on the circle of radius R with centre C. A manifold surface will be produced if the major radius is greater than the minor radius. If this condition is not fulfilled, the resulting surface will be self-intersecting.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifctoroidalsurface.htm"
     },
     "IfcTransformer": {
-        "description": "A transformer is an inductive stationary device that transfers electrical energy from one circuit to another.",
+        "description": "A transformer is an inductive stationary device that transfers electrical energy from one circuit to another. IfcTransformer is used to transform electric power; conversion of electric signals for other purposes is handled at other entities: IfcController converts arbitrary signals, IfcAudioVisualAppliance converts signals for audio or video streams, and IfcCommunicationsAppliance converts signals for data or other communications usage.",
         "predefined_types": {
             "CURRENT": "A transformer that changes the current between circuits.",
             "FREQUENCY": "A transformer that changes the frequency between circuits.",
@@ -7388,7 +7388,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifctransformer.htm"
     },
     "IfcTransformerType": {
-        "description": "The energy conversion device type IfcTransformerType defines commonly shared information for occurrences of transformers. The set of shared information may include:",
+        "description": "The energy conversion device type IfcTransformerType defines commonly shared information for occurrences of transformers. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a transformer type specification indicating the specific product information that is common to all occurrences of that product type. The IfcTransformerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcTransformerType are represented by instances of IfcTransformer. Refer to the documentation at IfcTransformer for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "CURRENT": "A transformer that changes the current between circuits.",
             "FREQUENCY": "A transformer that changes the frequency between circuits.",
@@ -7401,7 +7401,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifctransformertype.htm"
     },
     "IfcTransportElement": {
-        "description": "A transport element is a generalization of all transport related objects that move people, animals or goods within a building or building complex. The IfcTransportElement defines the occurrence of a transport element, that (if given), is expressed by the IfcTransportElementType.",
+        "description": "A transport element is a generalization of all transport related objects that move people, animals or goods within a building or building complex. The IfcTransportElement defines the occurrence of a transport element, that (if given), is expressed by the IfcTransportElementType. Depending on local classification systems transport elements and transportation systems in buildings are either considered as part of a building system, or as part of a building service system. Within IFC they are considered as part of a building system and may have to be mapped appropriately.",
         "predefined_types": {
             "CRANEWAY": "A crane way system, normally including the crane rails, fasteners and the crane. It is primarily used to move heavy goods in a factory or other industry buildings.",
             "ELEVATOR": "Elevator or lift being a transport device to move people of good vertically.",
@@ -7414,7 +7414,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifctransportelement.htm"
     },
     "IfcTransportElementType": {
-        "description": "The element type IfcTransportElementType defines commonly shared information for occurrences of transport elements. The set of shared information may include:",
+        "description": "The element type IfcTransportElementType defines commonly shared information for occurrences of transport elements. The set of shared information may include: - common properties within shared property sets - common material information - common shape representations It is used to define a transport element specification (i.e. the specific product information that is common to all occurrences of that beam type). Transport element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences. The occurrences of the IfcTransportElementType are represented by instances of IfcTransportElement (or its subtypes).",
         "predefined_types": {
             "CRANEWAY": "A crane way system, normally including the crane rails, fasteners and the crane. It is primarily used to move heavy goods in a factory or other industry buildings.",
             "ELEVATOR": "Elevator or lift being a transport device to move people of good vertically.",
@@ -7433,7 +7433,7 @@
             "TopXOffset": "Offset from the beginning of the top line to the bottom line, measured along the implicit x-axis.",
             "YDim": "The extent of the distance between the parallel bottom and top lines measured along the implicit y-axis."
         },
-        "description": "IfcTrapeziumProfileDef defines a trapezium as the profile definition used by the swept surface geometry or the swept area solid. It is given by its Top X and Bottom X extent and its Y extent as well as by the offset of the Top X extend, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, that is, in the center of the bounding box.",
+        "description": "IfcTrapeziumProfileDef defines a trapezium as the profile definition used by the swept surface geometry or the swept area solid. It is given by its Top X and Bottom X extent and its Y extent as well as by the offset of the Top X extend, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, that is, in the center of the bounding box. Figure 1 illustrates parameters of the trapezium profile definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifctrapeziumprofiledef.htm"
     },
     "IfcTriangulatedFaceSet": {
@@ -7444,7 +7444,7 @@
             "NumberOfTriangles": "Derived number of triangles used for this triangulation. SIZEOF(CoordIndex)",
             "PnIndex": "The list of integers defining the locations in the _IfcCartesianPointList3D_ to obtain the point coordinates for the indices withint the _CoordIndex_. If the _PnIndex_ is not provided the indices point directly into the _IfcCartesianPointList3D_."
         },
-        "description": "The IfcTriangulatedFaceSet is a tessellated face set with all faces being bound by triangles. The faces are constructed by implicit polylines defined by three Cartesian points. Depending on the value of the attribute Closed the instance of IfcTriangulatedFaceSet represents:",
+        "description": "The IfcTriangulatedFaceSet is a tessellated face set with all faces being bound by triangles. The faces are constructed by implicit polylines defined by three Cartesian points. Depending on the value of the attribute Closed the instance of IfcTriangulatedFaceSet represents: - if TRUE, a boundary represention (or B-rep); - if FALSE, a face based surface representation. The coordinates of each point are provided by a one-based index into an ordered list of Cartesian points provided by the two-dimensional list CoordIndex, where - the first dimension of the two-dimensional list addresses the list of triangular faces; - the second dimension of the two-dimensional list provides exactly three indices. Each index points to a Cartesian point being a vertex of the triangle. Depending on the provision of PnIndex the indices point either directly into the IfcCartesianPointList3D referenced by Coordinates defined at the supertype IfcTessellatedFaceSet, or they point into the PnIndex where the integer values at that position provides the location of the coordinate values within the IfcCartesianPointList3D. See Figure 1 for the handling of point index. See Figure 2 for using the IfcTriangulatedFaceSet without (as default) and with using the PnIndex. Optionally normals can be provided. Only normals per vector are supported allowing for visually curved triangles when the three normals of the corresponding three vertices of a triangle are not co-linear to the normal of the triangular face. If they are identical, normals shall be omited. Normals are provided by the two-dimensional list Normals, where - the first dimension of the two-dimensional list addresses the corresponding list of vertex indices of the triangular faces; - the second dimension of the two-dimensional list provides exactly three real values to determine the direction of the normal at this vertex of the triangle. The indices in the CoordIndex point into the list of Normals. The indices of CoordIndex are applied to both points, either directly directly, or via the PnIndex and normals. See Figure 3 for handling of normals. Figure 4 shows the use of IfcTriangulatedFaceSet without annotation. The diagram of the IfcTriangulatedFaceSet represents the indices and the ordered list into which the indices point. The index starts with 1 (indexed as 1 to N), if the greatest index in CoordIndex in N, then the IfcCartesianPointList shall have N lists of 3:3 coordinates. Informal Propositions: - If Closed = TRUE, the same topological constraints as imposed by an faceted boundary representation shall be safisfied. In particular: each face shall be unique; each edge shall be used by exactly two boundaries of faces; the topological normal at each point on the boundary of the triangulated face set shall point away from the mater ial of the solid.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifctriangulatedfaceset.htm"
     },
     "IfcTrimmedCurve": {
@@ -7455,7 +7455,7 @@
             "Trim1": "The first trimming point which may be specified as a Cartesian point, as a real parameter or both.",
             "Trim2": "The second trimming point which may be specified as a Cartesian point, as a real parameter or both."
         },
-        "description": "An IfcTrimmedCurve is a bounded curve that is trimmed at both ends. The trimming points may be provided by a Cartesian point or by a parameter value, based on the parameterization of the BasisCurve. The SenseAgreement attribute indicates whether the direction of the IfcTrimmedCurve agrees with or is opposed to the direction of the BasisCurve.",
+        "description": "An IfcTrimmedCurve is a bounded curve that is trimmed at both ends. The trimming points may be provided by a Cartesian point or by a parameter value, based on the parameterization of the BasisCurve. The SenseAgreement attribute indicates whether the direction of the IfcTrimmedCurve agrees with or is opposed to the direction of the BasisCurve. At least one of these shall be specified at each end of the curve. The SenseAgreement makes it possible to unambiguously define any segment of a closed curve such as a circle. The combinations of sense and ordered end points make it possible to define four distinct directed segments connecting two different points on a circle or other closed curve. For this purpose cyclic properties of the parameter range are assumed; for example, 370 degrees is equivalent to 10 degrees. In the above equations t~1~ is the value given by Trim1 or the parameter value corresponding to point 1 and t~2~ is the value given by Trim2 or the parameter value corresponding to point 2. The resultant IfcTrimmedCurve has a parameter ranging from 0 at the first trimming point to |t~2~ - t~1~| at the second trimming point. Informal Propositions: - Where both the parameter value and the Cartesian point exist for Trim1 and Trim2 they shall be consistent. (i.e., the BasisCurve evaluated at the parameter value shall coincide with the specified point). - When a Cartesian point is specified by Trim1 or by Trim2 it shall lie on the BasisCurve. - Except the case of a closed BasisCurve where both parameter 1 and parameter 2 exist, they shall be consistent with the sense flag, i.e., (sense = parameter 1 < parameter 2). Or, for every open curve where both parameter 1 and parameter 2 exist, they shall be consistent with the SenseAgreement, i.e., SenseAgreement = (parameter 1 < parameter 2). - If both parameter 1 and parameter 2 exist, then parameter 1 <> parameter 2. For a closed base curve, e.g. IfcCircle or IfcEllipse, this also applies to the cyclic properties, as 360' is equal to 0', parameter 1 = 360' and parameter 2 = 0' are treated as being equal and therefore violating this proposition. - When a parameter value is specified by Trim1 or Trim2 it shall lie within the parametric range of the BasisCurve.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifctrimmedcurve.htm"
     },
     "IfcTubeBundle": {
@@ -7468,7 +7468,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifctubebundle.htm"
     },
     "IfcTubeBundleType": {
-        "description": "The energy conversion device type IfcTubeBundleType defines commonly shared information for occurrences of tube bundles. The set of shared information may include:",
+        "description": "The energy conversion device type IfcTubeBundleType defines commonly shared information for occurrences of tube bundles. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a tube bundle type specification indicating the specific product information that is common to all occurrences of that product type. The IfcTubeBundleType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcTubeBundleType are represented by instances of IfcTubeBundle. Refer to the documentation at IfcTubeBundle for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "FINNED": "Finned tube bundle type.",
             "NOTDEFINED": "Undefined tube bundle type.",
@@ -7482,7 +7482,7 @@
             "HasPropertySets": "Set ~~list~~ of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type.",
             "Types": "Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type."
         },
-        "description": "The object type defines the specific information about a type, being common to all occurrences of this type. It refers to the specific level of the well recognized generic - specific - occurrance modeling paradigm. The IfcTypeObject gets assigned to the individual object instances (the occurrences) via the IfcRelDefinesByType relationship.",
+        "description": "The object type defines the specific information about a type, being common to all occurrences of this type. It refers to the specific level of the well recognized generic - specific - occurrance modeling paradigm. The IfcTypeObject gets assigned to the individual object instances (the occurrences) via the IfcRelDefinesByType relationship. The object type is represented by a set of property set definitions. The attached property sets describe the available alpha-numeric information about the object type. and are used to define all common properties that apply to all object occurrences of that type. Object types may be exchanged without being already assigned to objects. An object type may have an indication of the library (or catalogue) from which its definition originates. This association is handled by the inherited HasAssociations relationship pointing to IfcRelAssociatesLibrary.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifctypeobject.htm"
     },
     "IfcTypeProcess": {
@@ -7492,7 +7492,7 @@
             "OperatesOn": "Set of relationships to other objects, e.g. products, processes, controls, resources or actors that are operated on by the process type. > HISTORY New inverse relationship in IFC4.",
             "ProcessType": "The type denotes a particular type that indicates the process further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute 'PredefinedType' is set to USERDEFINED."
         },
-        "description": "IfcTypeProcess defines a specific (or type) definition of a process or activity without being assigned to a schedule or a time. It is used to define a process or activity specification, that is, the specific process or activity information that is common to all occurrences that are defined for that process or activity type.",
+        "description": "IfcTypeProcess defines a specific (or type) definition of a process or activity without being assigned to a schedule or a time. It is used to define a process or activity specification, that is, the specific process or activity information that is common to all occurrences that are defined for that process or activity type. An IfcTypeProcess may have a list of property set attached. Values of these properties are common to all occurrences of that process or activity type. The type occurrence relationship is realized using the objectified relationship IfcRelDefinesByType. Subtypes of IfcTypeProcess may be exchanged without being already assigned to subtypes of IfcProcess.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifctypeprocess.htm"
     },
     "IfcTypeProduct": {
@@ -7501,7 +7501,7 @@
             "RepresentationMaps": "List of unique representation maps. Each representation map describes a block definition of the shape of the product style. By providing more than one representation map, a multi-view block definition can be given.",
             "Tag": "The tag (or label) identifier at the particular type of a product, e.g. the article number (like the EAN). It is the identifier at the specific level."
         },
-        "description": "IfcTypeProduct defines a type definition of a product without being already inserted into a project structure (without having a placement), and not being included in the geometric representation context of the project. It is used to define a product specification, that is, the specific product information that is common to all occurrences of that product type.",
+        "description": "IfcTypeProduct defines a type definition of a product without being already inserted into a project structure (without having a placement), and not being included in the geometric representation context of the project. It is used to define a product specification, that is, the specific product information that is common to all occurrences of that product type. An IfcTypeProduct may have a list of property set attached and an optional set of product representations. Values of these properties and the representation maps are common to all occurrences of that product type. The type-occurrence relationship is realized using the objectified relationship IfcRelDefinesByType. The representations at the occurrence level (represented by subtypes of IfcProduct) can override the specific representations at the type level: - for geometric representations, a Cartesian transformation operator can be applied at the occurrence level. - for property sets, a property within an occurrence property set, assigned at the product occurrence, overrides the same property assigned to the product type. An IfcTypeProduct may be exchanged without being already assigned to subtypes of IfcProduct.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifctypeproduct.htm"
     },
     "IfcTypeResource": {
@@ -7511,7 +7511,7 @@
             "ResourceOf": "Set of relationships to other objects, e.g. products, processes, controls, resources or actors to which this resource type is a resource. > HISTORY New inverse relationship in IFC4.",
             "ResourceType": "The type denotes a particular type that indicates the resource further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute 'PredefinedType' is set to USERDEFINED."
         },
-        "description": "IfcTypeResource defines a specific (or type) definition of a resource. It is used to define a resource specification (the specific resource, that is common to all occurrences that are defined for that resource) and could act as a resource template.",
+        "description": "IfcTypeResource defines a specific (or type) definition of a resource. It is used to define a resource specification (the specific resource, that is common to all occurrences that are defined for that resource) and could act as a resource template. An IfcTypeResource may have a list of property sets attached. Values of these properties are common to all occurrences of that resource type. The type occurrence relationship is realized using the objectified relationship IfcRelDefinesByType. Subtypes of IfcTypeResource may be exchanged without being already assigned to subtypes of IfcResource.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifctyperesource.htm"
     },
     "IfcUShapeProfileDef": {
@@ -7524,18 +7524,18 @@
             "FlangeWidth": "Flange lengths, see illustration above (= b).",
             "WebThickness": "Constant wall thickness of web (= ts)."
         },
-        "description": "IfcUShapeProfileDef defines a section profile that provides the defining parameters of a U-shape (channel) section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box.",
+        "description": "IfcUShapeProfileDef defines a section profile that provides the defining parameters of a U-shape (channel) section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box. Figure 1 illustrates parameters of the U-shape profile definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcushapeprofiledef.htm"
     },
     "IfcUnitAssignment": {
         "attributes": {
             "Units": "Units to be included within a unit assignment."
         },
-        "description": "IfcUnitAssignment indicates a set of units which may be assigned. Within an IfcUnitAssigment each unit definition shall be unique; that is, there shall be no redundant unit definitions for the same unit type such as length unit or area unit. For currencies, there shall be only a single IfcMonetaryUnit within an IfcUnitAssignment.",
+        "description": "IfcUnitAssignment indicates a set of units which may be assigned. Within an IfcUnitAssigment each unit definition shall be unique; that is, there shall be no redundant unit definitions for the same unit type such as length unit or area unit. For currencies, there shall be only a single IfcMonetaryUnit within an IfcUnitAssignment. All measures used in the geometric representation items are directly defined by the IfcUnitAssignment. The minimum set of units that shall be declared by the unit assignment has to include length unit and plane angle units if the IFC data set includes shape representations.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcunitassignment.htm"
     },
     "IfcUnitaryControlElement": {
-        "description": "A unitary control element combines a number of control components into a single product, such as a thermostat or humidistat.",
+        "description": "A unitary control element combines a number of control components into a single product, such as a thermostat or humidistat. A unitary control element provides a housing for an aggregation of control or electrical distribution elements that, in combination, perform a singular (unitary) purpose. Each item in the aggregation may have its own geometric representation and location.",
         "predefined_types": {
             "ALARMPANEL": "A control element at which alarms are annunciated.",
             "CONTROLPANEL": "A control element at which devices that control or monitor the operation of a site, building or part of a building are located",
@@ -7551,7 +7551,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcbuildingcontrolsdomain/lexical/ifcunitarycontrolelement.htm"
     },
     "IfcUnitaryControlElementType": {
-        "description": "The distribution control element type IfcUnitaryControlElementType defines commonly shared information for occurrences of unitary control elements. The set of shared information may include:",
+        "description": "The distribution control element type IfcUnitaryControlElementType defines commonly shared information for occurrences of unitary control elements. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a unitary control element type specification indicating the specific product information that is common to all occurrences of that product type. The IfcUnitaryControlElementType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcUnitaryControlElementType are represented by instances of IfcUnitaryControlElement. Refer to the documentation at IfcUnitaryControlElement for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "ALARMPANEL": "A control element at which alarms are annunciated.",
             "CONTROLPANEL": "A control element at which devices that control or monitor the operation of a site, building or part of a building are located",
@@ -7580,7 +7580,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcunitaryequipment.htm"
     },
     "IfcUnitaryEquipmentType": {
-        "description": "The energy conversion device type IfcUnitaryEquipmentType defines commonly shared information for occurrences of unitary equipments. The set of shared information may include:",
+        "description": "The energy conversion device type IfcUnitaryEquipmentType defines commonly shared information for occurrences of unitary equipments. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a unitary equipment type specification indicating the specific product information that is common to all occurrences of that product type. The IfcUnitaryEquipmentType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcUnitaryEquipmentType are represented by instances of IfcUnitaryEquipment. Refer to the documentation at IfcUnitaryEquipment for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "AIRCONDITIONINGUNIT": "A unitary packaged air-conditioning unit typically used in residential or light commercial applications.",
             "AIRHANDLER": "A unitary air handling unit typically containing a fan, economizer, and coils.",
@@ -7622,7 +7622,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcvalve.htm"
     },
     "IfcValveType": {
-        "description": "The flow controller type IfcValveType defines commonly shared information for occurrences of valves. The set of shared information may include:",
+        "description": "The flow controller type IfcValveType defines commonly shared information for occurrences of valves. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a valve type specification indicating the specific product information that is common to all occurrences of that product type. The IfcValveType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcValveType are represented by instances of IfcValve. Refer to the documentation at IfcValve for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "AIRRELEASE": "Valve used to release air from a pipe or fitting.",
             "ANTIVACUUM": "Valve that opens to admit air if the pressure falls below atmospheric pressure.",
@@ -7660,21 +7660,21 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcvector.htm"
     },
     "IfcVertex": {
-        "description": "",
+        "description": "Informal Propositions: - The vertex has dimensionality 0. This is a fundamental property of the vertex. - The extent of a vertex is defined to be zero.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcvertex.htm"
     },
     "IfcVertexLoop": {
         "attributes": {
             "LoopVertex": "The vertex which defines the entire loop."
         },
-        "description": "",
+        "description": "Informal Propositions: - A vertex loop has zero extent and dimensionality. - The vertex loop has genus 0.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcvertexloop.htm"
     },
     "IfcVertexPoint": {
         "attributes": {
             "VertexGeometry": "The geometric point, which defines the position in geometric space of the vertex."
         },
-        "description": "",
+        "description": "Informal Propositions: - The domain of the vertex is formally defined to be the domain of its vertex point.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifctopologyresource/lexical/ifcvertexpoint.htm"
     },
     "IfcVibrationIsolator": {
@@ -7688,7 +7688,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcvibrationisolator.htm"
     },
     "IfcVibrationIsolatorType": {
-        "description": "The element component type IfcVibrationIsolatorType defines commonly shared information for occurrences of vibration isolators. The set of shared information may include:",
+        "description": "The element component type IfcVibrationIsolatorType defines commonly shared information for occurrences of vibration isolators. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements It is used to define a vibration isolator type specification indicating the specific product information that is common to all occurrences of that product type. The IfcVibrationIsolatorType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcVibrationIsolatorType are represented by instances of IfcVibrationIsolator. Refer to the documentation at IfcVibrationIsolator for supported property sets, materials, and composition.",
         "predefined_types": {
             "COMPRESSION": "Compression type vibration isolator.",
             "NOTDEFINED": "Undefined vibration isolator type.",
@@ -7698,7 +7698,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcvibrationisolatortype.htm"
     },
     "IfcVirtualElement": {
-        "description": "A virtual element is a special element used to provide imaginary boundaries, such as between two adjacent, but not separated, spaces. Virtual elements are usually not displayed and does not have quantities and other measures. Therefore IfcVirtualElement does not have material information and quantities attached.",
+        "description": "A virtual element is a special element used to provide imaginary boundaries, such as between two adjacent, but not separated, spaces. Virtual elements are usually not displayed and does not have quantities and other measures. Therefore IfcVirtualElement does not have material information and quantities attached. The IfcVirtualElement is mainly used to define a virtual boundary between two spaces. Figure 1 describes how to use IfcRelSpaceBoundary in conjunction with IfcVirtualElement to define space boundaries.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcvirtualelement.htm"
     },
     "IfcVirtualGridIntersection": {
@@ -7706,11 +7706,11 @@
             "IntersectingAxes": "Two grid axes which intersects at exactly one intersection (see also informal proposition at IfcGrid). If attribute OffsetDistances is omitted, the intersection defines the placement or ref direction of a grid placement directly. If OffsetDistances are given, the intersection is defined by the offset curves to the grid axes.",
             "OffsetDistances": "Offset distances to the grid axes. If given, it defines virtual offset curves to the grid axes. The intersection of the offset curves specify the virtual grid intersection."
         },
-        "description": "IfcVirtualGridIntersection defines the derived location of the intersection between two grid axes. Offset values may be given to set an offset distance to the grid axis for the calculation of the virtual grid intersection.",
+        "description": "IfcVirtualGridIntersection defines the derived location of the intersection between two grid axes. Offset values may be given to set an offset distance to the grid axis for the calculation of the virtual grid intersection. The two intersecting axes (IntersectingAxes) define the intersection point, which exact location (in terms of the Cartesian point representing the intersection) has to be calculated from the geometric representation of the two participating curves. Offset values may be given (OffsetDistances). If given, the position within the list of OffsetDistances corresponds with the position within the list of IntersectingAxes. Therefore: - OffsetDistances[1] sets the offset to IntersectingAxes[1], - OffsetDistances[2] sets the offset to IntersectingAxes[2], and - OffsetDistances[3] sets the offset to the virtual intersection in direction of the orientation of the cross product of IntersectingAxes[1] and the orthogonal complement of the IntersectingAxes[1] (which is the positive or negative direction of the z axis of the design grid position). The following figures explain the usage of the OffsetDistances and IntersectingAxes attributes. The distance of the offset curve (OffsetDistances[n]) is measured from the basis curve. The distance may be positive, negative or zero. A positive value of distance defines an offset in the direction which is normal to the curve in the sense of an anti-clockwise rotation through 90 degrees from the tangent vector T at the given point. (This is in the direction of orthogonal complement(T).) This can be reverted by the SameSense attribute at IfcGridAxis which may switch the sense of the AxisCurve. Informal Propositions: - Both, IntersectingAxes[1] and IntersectingAxes[2] shall be two IfcGridAxis defined by the same IfcGrid. - IntersectingAxes[1] and IntersectingAxes[2] shall not be part of the same row of grid axes, i.e. both shall not be within the same set of IfcGrid.UAxes or IfcGrid.VAxes of the corresponding IfcGrid.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcvirtualgridintersection.htm"
     },
     "IfcVoidingFeature": {
-        "description": "A voiding feature is a modification of an element which reduces its volume. Such a feature may be manufactured in different ways, for example by cutting, drilling, or milling of members made of various materials, or by inlays into the formwork of cast members made of materials such as concrete.",
+        "description": "A voiding feature is a modification of an element which reduces its volume. Such a feature may be manufactured in different ways, for example by cutting, drilling, or milling of members made of various materials, or by inlays into the formwork of cast members made of materials such as concrete. The standard use of instances of IfcVoidingFeature is as a part of element type objects (instances of subtypes of IfcElementType). The part\u2013whole relationship is established by an aggregation relationship object, expressing the decomposition of an element type into one or more additive elements (element parts) and zero or more feature elements. Containment Use Definition Voiding features shall have no spatial containment relationship to the spatial structure since they are dependent on element types without spatial containment relationships or on an element occurrence with own spatial containment relationship. - The SELF\\IfcElement.ContainedInStructure relationship shall be NIL.",
         "predefined_types": {
             "CHAMFER": "A skewed plane end cut, removing material only across a part of the profile of the voided element.",
             "CUTOUT": "An internal cutout (creating an opening) or external cutout (creating a recess) of arbitrary shape.  The edges between cutting planes may be overcut or undercut, i.e. rounded.",
@@ -7724,7 +7724,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcvoidingfeature.htm"
     },
     "IfcWall": {
-        "description": "The wall represents a vertical construction that bounds or subdivides spaces. Wall are usually vertical, or nearly vertical, planar elements, often designed to bear structural loads. A wall is however not required to be load bearing.",
+        "description": "The wall represents a vertical construction that bounds or subdivides spaces. Wall are usually vertical, or nearly vertical, planar elements, often designed to bear structural loads. A wall is however not required to be load bearing. There are two main representations for for wall occurrences: - IfcWall with IfcMaterialLayerSetUsage is used for all occurrences of walls, that have a non-changing thickness along the wall path and where the thickness parameter can be fully described by a material layer set. These walls are always represented geometrically by an 'Axis' and a 'SweptSolid' shape representation (or by a 'Clipping' geometry based on 'SweptSolid'), if a 3D geometric representation is assigned. NOTE The entity IfcWallStandardCase has been deprecated, IfcWall with IfcMaterialLayerSetUsage is used instead. - IfcWall without IfcMaterialLayerSetUsage is used for all other occurrences of wall, particularly for walls with changing thickness along the wall path (e.g. polygonal walls), or walls with a non-rectangular cross sections (e.g. L-shaped retaining walls), and walls having an extrusion axis that is unequal to the global Z axis of the project (i.e. non-vertical walls), or walls having only 'Brep', or 'SurfaceModel' geometry, or if a more parametric representation is not intended.",
         "predefined_types": {
             "ELEMENTEDWALL": "A stud wall framed with studs and faced with sheetings, sidings, wallboard, or plasterwork.",
             "MOVABLE": "A movable wall that is either movable, such as folding wall or a sliding wall, or can be easily removed as a removable partitioning or mounting wall. Movable walls do normally not define space boundaries and often belong to the furnishing system.",
@@ -7741,15 +7741,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcwall.htm"
     },
     "IfcWallElementedCase": {
-        "description": "The IfcWallElementedCase defines a wall with certain constraints for the provision of its components. The IfcWallElementedCase handles all cases of walls, that are decomposed into parts:",
+        "description": "The IfcWallElementedCase defines a wall with certain constraints for the provision of its components. The IfcWallElementedCase handles all cases of walls, that are decomposed into parts: - having components being assigned to the IfcWallElementedCase using the IfcRelAggregates relationship accessible by the inverse relationship IsDecomposedBy. Parts within the decomposition are usually be of type: - IfcBuildingElementPart for wall layer, insolation layers and similar - IfcMember for studs, posts and similar elements, - IfcElementAssembly for other aggregates, or - IfcBuildingElementProxy.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcwallelementedcase.htm"
     },
     "IfcWallStandardCase": {
-        "description": "The IfcWallStandardCase defines a wall with certain constraints for the provision of parameters and with certain constraints for the geometric representation. The IfcWallStandardCase handles all cases of walls, that are extruded vertically:",
+        "description": "The IfcWallStandardCase defines a wall with certain constraints for the provision of parameters and with certain constraints for the geometric representation. The IfcWallStandardCase handles all cases of walls, that are extruded vertically: - along the positive z axis of the wall object coordinate system, and - along the positve z axis of the global (world) coordinate system and have a single thickness along the path for each wall layer, i.e.: - parallel sides for straight walls - co-centric sides for curved walls. and have either: - a straight line axis (straight wall), or - a circular arc axis (round wall). and shall not have - aggregated components, that is, parts aggregated to a wall by IfcRelAggregates - shape representation for 'Body' not being an extrusion, or clipped extrusion The following parameter have to be provided: - Wall height, taken from the depth of extrusion, provided by the geometric representation. - Wall thickness, taken from the material layer set usage, attached to the wall - Wall offset from axis, taken from the material layer set usage, attached to the wall The IfcWallStandardCase requires the provision of the wall axis either a straight line that is parallel to the x-axis of the object coordinate system, or a circular arc where the tangent at start is parallel to the x-axis of the object coordinate system. The direction of the wall axis shall be the positive direction of that x-axis. The material of the wall is defined by the IfcMaterialLayerSetUsage and is attached by the IfcRelAssociatesMaterial objectified relationship. It is accessible by the inverse HasAssociations relationship. The material layer set usage has to be given (enforced by where rule). An 'Axis' and a 'Body' shape representation has to be provided, and it is invalid to exchange a 'Tessellation', 'SurfaceModel', 'Brep' or 'MappedRepresentation' representation for the 'Body' shape representation of the IfcWallStandardCase.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcwallstandardcase.htm"
     },
     "IfcWallType": {
-        "description": "The element type IfcWallType defines commonly shared information for occurrences of walls. The set of shared information may include:",
+        "description": "The element type IfcWallType defines commonly shared information for occurrences of walls. The set of shared information may include: - common properties within shared property sets - common material information - common material layer definitions - common shape representations It is used to define a wall specification (i.e. the specific product information, that is common to all occurrences of that product type). Wall types may be exchanged without being already assigned to occurrences. Occurrences of the IfcWallType within building models are represented by instances of IfcWallStandardCase if the IfcWallType has a single associated IfcMaterialLayerSet; otherwise they are represented by instances of IfcWall, or IfcWallElementedCase. Occurrences of the IfcWallType within structural analysis models are represented by instances of IfcStructuralSurfaceMember, or its applicable subtypes. Informal Propositions: - The material assignment, if provided using the IfcRelAssociatesMaterial relationship, shall not reference the IfcMaterialLayerSetUsage.",
         "predefined_types": {
             "ELEMENTEDWALL": "A stud wall framed with studs and faced with sheetings, sidings, wallboard, or plasterwork.",
             "MOVABLE": "A movable wall that is either movable, such as folding wall or a sliding wall, or can be easily removed as a removable partitioning or mounting wall. Movable walls do normally not define space boundaries and often belong to the furnishing system.",
@@ -7766,7 +7766,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcwalltype.htm"
     },
     "IfcWasteTerminal": {
-        "description": "A waste terminal has the purpose of collecting or intercepting waste from one or more sanitary terminals or other fluid waste generating equipment and discharging it into a single waste/drainage system.",
+        "description": "A waste terminal has the purpose of collecting or intercepting waste from one or more sanitary terminals or other fluid waste generating equipment and discharging it into a single waste/drainage system. A waste terminal provides for all forms of trap and waste point that collects discharge from a sanitary terminal and discharges it into a waste/drainage subsystem or that collects waste from several terminals and passes it into a single waste/drainage subsystem. This includes the P and S traps from soil sanitary terminals, sinks, and basins as well as floor wastes and gully traps that provide collection points.",
         "predefined_types": {
             "FLOORTRAP": "Pipe fitting, set into the floor, that retains liquid to prevent the passage of foul air",
             "FLOORWASTE": "Pipe fitting, set into the floor, that collects waste water and discharges it to a separate trap.",
@@ -7781,7 +7781,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcplumbingfireprotectiondomain/lexical/ifcwasteterminal.htm"
     },
     "IfcWasteTerminalType": {
-        "description": "The flow terminal type IfcWasteTerminalType defines commonly shared information for occurrences of waste terminals. The set of shared information may include:",
+        "description": "The flow terminal type IfcWasteTerminalType defines commonly shared information for occurrences of waste terminals. The set of shared information may include: - common properties with shared property sets - common representations - common materials - common composition of elements - common ports It is used to define a waste terminal type specification indicating the specific product information that is common to all occurrences of that product type. The IfcWasteTerminalType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcWasteTerminalType are represented by instances of IfcWasteTerminal. Refer to the documentation at IfcWasteTerminal for supported property sets, materials, composition, and ports.",
         "predefined_types": {
             "FLOORTRAP": "Pipe fitting, set into the floor, that retains liquid to prevent the passage of foul air",
             "FLOORWASTE": "Pipe fitting, set into the floor, that collects waste water and discharges it to a separate trap.",
@@ -7802,7 +7802,7 @@
             "PartitioningType": "Type defining the general layout of the window in terms of the partitioning of panels.  > NOTE  The _PartitioningType_ shall only be used, if no type object _IfcWindowType_ is assigned, providing its own _IfcWindowType.PartitioningType_.",
             "UserDefinedPartitioningType": "Designator for the user defined partitioning type, shall only be provided, if the value of _PartitioningType_ is set to USERDEFINED."
         },
-        "description": "The window is a building element that is predominately used to provide natural light and fresh air. It includes vertical opening but also horizontal opening such as skylights or light domes. It includes constructions with swinging, pivoting, sliding, or revolving panels and fixed panels. A window consists of a lining and one or several panels.",
+        "description": "The window is a building element that is predominately used to provide natural light and fresh air. It includes vertical opening but also horizontal opening such as skylights or light domes. It includes constructions with swinging, pivoting, sliding, or revolving panels and fixed panels. A window consists of a lining and one or several panels. The IfcWindow defines a particular occurrence of a window inserted in the spatial context of a project. A window can: - be inserted into an IfcOpeningElement using the IfcRelFillsElement relationship, then the IfcWindow has an inverse attribute FillsVoids provided, NOTE Model View Definitions or implementer agreements may restrict the relationship to only include one window (or door) into one opening. - be part of an element assembly, often an IfcCurtainWall, using the IfcRelAggregates relationship, then the inverse attribute Decomposes is provided. - or be a \"free standing\" window, then the IfcWindow has no inverse attributes FillsVoids or Decomposes provided. There are two main representations for window occurrences: - IfcWindow with a shape representation having RepresentationIdenfifier='Profile' is used for all occurrences of windows, that have a 'Profile' shape representation defined to which a set of shape parameters for lining and framing properties apply. Additionally it requires the provision of an IfcWindowType that references one IfcWindowLiningProperties and on to many IfcWindowPanelProperties. NOTE The entity IfcWindowStandardCase has been deprecated. - IfcWindow used for all other occurrences of windows, particularly for windows having only 'Brep', or 'SurfaceModel' geometry without applying shape parameters. The actual parameter of the window and/or its shape is defined at the IfcWindow as the object occurrence definition, or by the IfcWindowType as the object type definition . The following parameters are provided: - at the IfcWindow for occurrence specific parameters. The IfcWindow specifies: - the window width and height the window opening direction (by the y-axis of the ObjectPlacement) - at the IfcWindowType to which the IfcWindow is related by the inverse relationship IsTypedBy pointing to IfcRelDefinesByType, for type parameters common to all occurrences of the same type. - the partitioning type (single panel, double panel, tripel panel, more panels) the operation type (swing, tilt and turn, pivot revolve, fixed case ment, etc.) the window panel hinge side (by using two different styles for right and left opening windows) the construction material type the particular attributes for the lining by the IfcWindowLiningProperties the particular attributes for the panels by the IfcWindowPanelProperties Parameteric Representation using parameters at IfcWindowType The parameters, which define the shape of the IfcWindow, are given at the IfcWindowType and the property sets, which are included in the IfcWindowType. The IfcWindow only defines the local placement. The overall size of the IfcWindow to be used to apply the lining or panel parameter provided by the IfcWindowType is determined by the IfcShapeRepresentation with the RepresentationIdentifier = 'Profile'. Only in case of an IfcWindow inserted into an IfcOpeningElement using the IfcRelFillsElement relatioship, having a horizontal extrusion (along the y-axis of the IfcDoor), the overall size is determined by the extrusion profile of the IfcOpeningElement. Figure 1 illustrates the insertion of a window into the IfcOpeningElement by creating an instance of IfcWindow with PartitioningType = DoublePanelHorizontal. The parameters OverallHeight and OverallWidth show the extent of the window in the positive Z and X axis of the local placement of the window. The lining and the transom are created by the given parameters. Figure 2 illustrates the final window (DoublePanelHorizontal) with first panel having PanelPosition = TOP, OperationType = BOTTOMHUNG and second panel having PanelPosition = BOTTOM and OperationType = TILTANDTURNLEFTHAND. Window opening operation by window type The parameters that defines the shape of the IfcWindow, are given at the IfcWindowType and the property sets, which are included in the IfcWindowType. The IfcWindow only defines the local placement which determines the opening direction of the window. The overall layout of the IfcWindow is determined by its IfcWindowType.PartitioningType. Each window panel has its own operation type, provided by IfcWindowPanelProperties.OperationType. All window panels are assumed to open into the same direction (if relevant for the particular window panel operation. The hindge side (whether a window opens to the left or to the right) is determined by the IfcWindowPanelProperties.OperationType. Figure 3 illustrates window operation types.",
         "predefined_types": {
             "LIGHTDOME": "A special window that lies horizonally in a roof slab opening.",
             "NOTDEFINED": "Undefined window element.",
@@ -7827,7 +7827,7 @@
             "ShapeAspectStyle": "Optional link to a shape aspect definition, which points to the part of the geometric representation of the window style, which is used to represent the lining.",
             "TransomThickness": "Thickness of the transom (horizontal separator of window panels within a window), measured parallel to the window elevation plane. The transom is part of the lining and the transom depth is assumed to be identical to the lining depth. If the _TransomThickness_ is set to zero (and the _TransomOffset_ set to a positive length), then the window is divided vertically without a physical divider."
         },
-        "description": "The window lining is the outer frame which enables the window to be fixed in position. The window lining is used to hold the window panels or other casements. The parameter of the IfcWindowLiningProperties define the geometrically relevant parameter of the lining.",
+        "description": "The window lining is the outer frame which enables the window to be fixed in position. The window lining is used to hold the window panels or other casements. The parameter of the IfcWindowLiningProperties define the geometrically relevant parameter of the lining. The IfcWindowLiningProperties are included in the set of properties of IfcWindowStyle.HasPropertySets. More information about the window lining can be included in the same set of the IfcWindowType using another IfcPropertySet for dynamic extensions. The IfcWindowLiningProperties does not hold a geometric representation. However it defines parameters which can be used to create the shape of the window type(which is inserted by the IfcWindow into the spatial context of the project) as shown in Figure 1. The parameters at the IfcWindowLiningProperties define a standard window lining, including (if given) a mullion and a transom (for horizontal and vertical splits). The outer boundary of the lining is determined by the 'Profile' shape representation assigned to the IfcWindow, which inserts the IfcWindowType.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcwindowliningproperties.htm"
     },
     "IfcWindowPanelProperties": {
@@ -7838,11 +7838,11 @@
             "PanelPosition": "Position of this panel within the overall window style.",
             "ShapeAspectStyle": "Optional link to a shape aspect definition, which points to the part of the geometric representation of the window style, which is used to represent the panel."
         },
-        "description": "A window panel is a casement, that is, a component, fixed or opening, consisting essentially of a frame and the infilling. The infilling of a window panel is normally glazing. The way of operation is defined in the operation type.",
+        "description": "A window panel is a casement, that is, a component, fixed or opening, consisting essentially of a frame and the infilling. The infilling of a window panel is normally glazing. The way of operation is defined in the operation type. The IfcWindowPanelProperties are used to parametrically describe the shape and operation of window panels. The parametric definition can be added solely or additionally to the explicit shape representation of the window. The IfcWindowType can define windows consisting of more then one panel. In this case, one instance of IfcWindowPanelProperties has to be included for each window panel. The PanelPosition attribute, in conjunction with the IfcWindowType.OperationType attribute, determines to which panel the IfcWindowPanelProperties_apply. The _IfcWindowPanelProperties are included in the list of properties (HasPropertySets) of the IfcWindowStyle. More information about the window panel can be included in the same list of the IfcWindowType using the IfcPropertySet for dynamic extensions. The IfcWindowPanelProperties does not hold an own geometric representation. However it defines parameter, which can be used to create the shape of the IfcWindowType (which is inserted by the IfcWindow into the spatial context of the project). The parameters at the IfcWindowPanelProperties define a standard window panel. The outer boundary of the lining is determined by the 'Profile' shape representation assigned to the IfcWindow, which inserts the IfcWindowType. It has to take the lining parameter into account as well. The position of the window panel within the overall window is determined by the PanelPosition attribute. As shown in Figure 1, the panel is applied to the position within the lining as defined by the panel position attribute. The following parameter apply to that panel: FrameDepth, FrameThickness.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcwindowpanelproperties.htm"
     },
     "IfcWindowStandardCase": {
-        "description": "The standard window, IfcWindowStandardCase, defines a window with certain constraints for the provision of operation types, opening directions, frame and lining parameters, construction types and with certain constraints for the geometric representation. The IfcWindowStandardCase handles all cases of windows, that:",
+        "description": "The standard window, IfcWindowStandardCase, defines a window with certain constraints for the provision of operation types, opening directions, frame and lining parameters, construction types and with certain constraints for the geometric representation. The IfcWindowStandardCase handles all cases of windows, that: - are inserted into an opening, represented by IfcOpeningElement, using the IfcRelFillsElement relationship - have a local placement relative to this opening, and with the y-axis of the placement pointing into the opening direction - have a profile geometry, represented by IfcShapeRepresentation.RepresentationIdentifier=\"Profile\" as a closed curve to which the window parameter apply. The profile represents a rectangle within the xz plane of the local placement - have a reference to an IfcWindowType to define the opening direction and the operation type (swinging, sliding, folding, etc.) of the window. The attribute OperationType shall be provided and not being UNDEFINED, and the attribute ParameterTakesPrecedence shall be \"TRUE\". - have a single IfcWindowLiningProperties and a set of IfcWindowPanelProperties instances included in the set of HasPropertySets at IfcWindowType The geometric representation of IfcWindowStandardCase is defined using the following multiple shape representations for its definition: - Profile: a three-dimensional closed curve within a particular shape representation. The profile is used to apply the parameter of the parametric window representation. The profile around the edges of the opening is used to apply the window lining and window panel shape parameter. - Body: A SweptSolid, SurfaceModel, or Brep Representation or a CSG additionally defining the 3D shape of the standard window in addition to the parametric representation by applying the IfcWindowLiningProperties and an the IfcWindowPanelProperties to the Profile representation.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcwindowstandardcase.htm"
     },
     "IfcWindowStyle": {
@@ -7852,7 +7852,7 @@
             "ParameterTakesPrecedence": "The Boolean value reflects, whether the parameter given in the attached lining and panel properties exactly define the geometry (TRUE), or whether the attached style shape take precedence (FALSE). In the last case the parameter have only informative value.",
             "Sizeable": "The Boolean indicates, whether the attached ShapeStyle can be sized (using scale factor of transformation), or not (FALSE). If not, the ShapeStyle should be inserted by the IfcWindow (using IfcMappedItem) with the scale factor = 1."
         },
-        "description": "The window style defines a particular style of windows, which may be included into the spatial context of the building model through instances of IfcWindow. A window style defines the overall parameter of the window style and refers to the particular parameter of the lining and one (or several) panels through IfcWindowLiningProperties and IfcWindowPanelProperties.",
+        "description": "The window style defines a particular style of windows, which may be included into the spatial context of the building model through instances of IfcWindow. A window style defines the overall parameter of the window style and refers to the particular parameter of the lining and one (or several) panels through IfcWindowLiningProperties and IfcWindowPanelProperties. The window entity (IfcWindow) defines a particular occurrence of a window inserted in the spatial context of a project. The actual parameter of the window and/or its shape is defined at the IfcWindowStyle, to which the IfcWindow related by the inverse relationship IsDefinedBy pointing to IfcRelDefinesByType. The IfcWindowStyle also defines the particular attributes for the lining (IfcWindowLiningProperties) and panels (IfcWindowPanelProperties). The IfcWindowStyle defines the baseline geometry, or the representation map, for all occurrences of the window style, given by the IfcWindow, pointing to this style. The representation of the window style may be given by the agreed set of minimal parameters, defined for the window lining and the window panel(s), or it may be given by a geometric representation used by the IfcRepresentationMap. The attribute ParameterTakesPrecedence decides, whether the set of parameters can be used to exactly represent the shape of the window style (TRUE), or whether the attached IfcRepresentationMap holds the exact representation (FALSE). The IfcWindowStyleOperationTypeEnum defines the general layout of the window style. Depending on the enumerator, the appropriate instances of IfcWindowLiningProperties and IfcWindowPanelProperties are attached in the list of HasPropertySets. See geometry use definitions there.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcwindowstyle.htm"
     },
     "IfcWindowType": {
@@ -7861,7 +7861,7 @@
             "PartitioningType": "Type defining the general layout of the window type in terms of the partitioning of panels.",
             "UserDefinedPartitioningType": "Designator for the user defined partitioning type, shall only be provided, if the value of _PartitioningType_ is set to USERDEFINED."
         },
-        "description": "The element type IfcWindowType defines commonly shared information for occurrences of windows. The set of shared information may include:",
+        "description": "The element type IfcWindowType defines commonly shared information for occurrences of windows. The set of shared information may include: - common properties within shared property sets - common material information - common partitioning of panels - common operation types of panels - common shape representations A window type defines the particular parameter of the lining and one (or several) panels through the IfcWindowLiningProperties and the IfcWindowPanelProperties as predefined property sets applicable to windows only. It is used to define a window specification, or window style (the specific product information that is common to all occurrences of that window type). Window types may be exchanged without being already assigned to occurrences. Occurrences of the IfcWindowType within building models are represented by instances of IfcWindow or IfcWindowStandardCase. Geometry Use Definitions: The IfcWindowType may define the common shape of window occurrences. The common shape can be defined by - applying shape parameters defined within the associated IfcWindowLiningProperties and IfcWindowPanelProperties applied to the 'Profile' geometric representation. It is only applicable if the IfcWindowType has only occurrences of type IfcWindowStandardCase (See geometric use definition of IfcWindowStandardCase for further information). - applying the RepresentationMaps attribute to refer to a list of IfcRepresentationMap's, that allow for multiple geometric representations (e.g. with IfcShapeRepresentation's having an RepresentationIdentifier 'Box', 'Profile', 'FootPrint', or 'Body') NOTE The product shape representations are defined as RepresentationMaps (attribute of the supertype IfcTypeProduct), which get assigned by an element occurrence instance through the IfcShapeRepresentation.Item[n] being an IfcMappedItem. See IfcTypeProduct for further information. NOTE The values of attributes RepresentationIdentifier and RepresentationType of IfcShapeRepresentation are restricted in the same way as those for IfcWindow and IfcWindowStandardCase",
         "predefined_types": {
             "LIGHTDOME": "A special window that lies horizonally in a roof slab opening.",
             "NOTDEFINED": "Undefined window element.",
@@ -7876,7 +7876,7 @@
             "ExceptionTimes": "Set of times periods that define exceptions (non-working     times) for the given working times including the base     calendar, if provided.",
             "WorkingTimes": "Set of times periods that are regarded as an initial set-up     of working times. Exception times can then further restrict     these working times."
         },
-        "description": "An IfcWorkCalendar defines working and non-working time periods for tasks and resources. It enables to define both specific time periods, such as from 7:00 till 12:00 on 25th August 2009, as well as repetitive time periods based on frequently used recurrence patterns, such as each Monday from 7:00 till 12:00 between 1st March 2009 and 31st December 2009.",
+        "description": "An IfcWorkCalendar defines working and non-working time periods for tasks and resources. It enables to define both specific time periods, such as from 7:00 till 12:00 on 25th August 2009, as well as repetitive time periods based on frequently used recurrence patterns, such as each Monday from 7:00 till 12:00 between 1st March 2009 and 31st December 2009. A work calendar is a subtype of IfcControl and thus inherits the feature for controlling other objects through IfcRelAssignsToControl, which is used to define a work calendar for tasks (IfcTask) and resources (IfcResource). It also inherits a name and description attribute, whereas a name shall be given and a description may be given as an indication of its content and usage. The definition of time periods can be derived from a base calendar and/or modified/defined by a set of working times and non-working exception times. All time periods defined by IfcWorkCalendar.ExceptionTimes override the time periods inherited from the base calendar (base calendar is defined as the next applicable calendar for the task or resource). Thus, exception times replace the working times from the base calendar. Figure 1 shows the definition of a work calendar, which is defined by a set of work times and exception times. The work times are defined as recurring patterns with optional boundaries (applying from and/or to a specific date). The shown example defines a simple work calendar with working times Monday to Thursday 8:00 to 12:00 and 13:00 to 17:00, Friday 8:00 to 14:00 and as exception every 1st Monday in a month the work starts one hour later - i.e. the working time on every 1st Monday in a month is overriden to be 9:00 to 12:00 and 13:00 to 17:00. Both the working time and the exception time is valid for the period of 01.09.2010 till 30.08.2011.",
         "predefined_types": {
             "FIRSTSHIFT": "Belongs to the first shift.",
             "NOTDEFINED": "",
@@ -7896,11 +7896,11 @@
             "StartTime": "The start time of the schedule.",
             "TotalFloat": "The total time float of the entire work schedule."
         },
-        "description": "An IfcWorkControl is an abstract supertype which captures information that is common to both IfcWorkPlan and IfcWorkSchedule.",
+        "description": "An IfcWorkControl is an abstract supertype which captures information that is common to both IfcWorkPlan and IfcWorkSchedule. A work control may have resources assigned to it. This is handled by the IfcRelAssignsToControl relationship. A work control should also define a context that gives further information about its usage. If no special context information is required then the IfcProject instance as a global context should be used instead. An explicit link between the work control and the IfcProject via IfcRelDeclares should then be provided. The attribute IfcWorkControl.Purpose is used to define the purpose of either a work schedule or a work plan. In the case of IfcWorkPlan, the purpose attribute can be used to determine if the work plan is for cost estimating, task scheduling or some other defined purpose.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprocessextension/lexical/ifcworkcontrol.htm"
     },
     "IfcWorkPlan": {
-        "description": "An IfcWorkPlan represents work plans in a construction or a facilities management project.",
+        "description": "An IfcWorkPlan represents work plans in a construction or a facilities management project. A work plan contains a set of work schedules for different purposes (including construction and facilities management). Contained work schedules are defined through the IfcRelAggregates relationship. Through inheritance from IfcWorkControl it is also possible to define references to activities (for example, IfcTask) and resources used in the work plan. A work plan has information such as start date, finish date, total free float, and so on. IfcWorkPlan can also refer to the construction project represented by the single IfcProject instance (please also check the definition of IfcWorkControl). Figure 1 shows the backbone structure of a work plan that defines (1) contained work schedules through IfcRelAggregates and (2), if not assigned otherwise to contained work schedules, assigned tasks and resources through IfcRelAssignsToControl. If an assigned IfcTask is a root-level task, such task must be declared on the IfcProject using the IfcRelDeclares relationship.",
         "predefined_types": {
             "ACTUAL": "A control in which actual items undertaken are indicated.",
             "BASELINE": "A control that is a baseline from which changes that are made later can be recognized.",
@@ -7911,7 +7911,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprocessextension/lexical/ifcworkplan.htm"
     },
     "IfcWorkSchedule": {
-        "description": "An IfcWorkSchedule represents a task schedule of a work plan, which in turn can contain a set of schedules for different purposes.",
+        "description": "An IfcWorkSchedule represents a task schedule of a work plan, which in turn can contain a set of schedules for different purposes. Declaration Use Definition IfcWorkSchedule can reference a project (the single IfcProject instance) via IfcRelDeclares. Figure 1 shows the backbone structure of a work schedule that defines (1) a context through IfcRelDeclares (not necessarily the project) and (2) controls tasks (typically the schedule summary task) and resources. Please note that a work calendar shall be assigned to the summary task and not the work schedule. If an assigned IfcTask is a root-level task, such task must be declared on the IfcProject using the IfcRelDeclares relationship.",
         "predefined_types": {
             "ACTUAL": "A control in which actual items undertaken are indicated.",
             "BASELINE": "A control that is a baseline from which changes that are made later can be recognized.",
@@ -7927,7 +7927,7 @@
             "RecurrencePattern": "Recurrence pattern that defines a time period, which, if given, is     valid within the time period defined by     _IfcWorkTime.Start_ and _IfcWorkTime.Finish_.",
             "Start": "Start date of the work time (0:00), that might be further     restricted by a recurrence pattern."
         },
-        "description": "IfcWorkTime defines time periods that are used by IfcWorkCalendar for either describing working times or non-working exception times. Besides start and finish dates, a set of time periods can be given by various types of recurrence patterns.",
+        "description": "IfcWorkTime defines time periods that are used by IfcWorkCalendar for either describing working times or non-working exception times. Besides start and finish dates, a set of time periods can be given by various types of recurrence patterns. A work time should have a meaningful name that describes the time periods (for example, working week, holiday name). Non-recurring time periods should have a start date (IfcWorkTime.Start) and a finish date (IfcWorkTime.Finish). In that case it is assumed that the time period begins at 0:00 on the start date and ends at 24:00 on the finish date. The start and finish date is optional if a recurrence pattern is given (IfcWorkTime.RecurrencePattern). They then restrict never-ending recurrence patterns.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcworktime.htm"
     },
     "IfcZShapeProfileDef": {
@@ -7939,7 +7939,7 @@
             "FlangeWidth": "Flange length, see illustration above (= b).",
             "WebThickness": "Constant wall thickness of web, see illustration above (= ts)."
         },
-        "description": "IfcZShapeProfileDef defines a section profile that provides the defining parameters of a Z-shape section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box.",
+        "description": "IfcZShapeProfileDef defines a section profile that provides the defining parameters of a Z-shape section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box. Figure 1 illustrates parameters of the Z-shape profile definition.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifczshapeprofiledef.htm"
     },
     "IfcZone": {
diff --git a/src/ifcopenshell-python/ifcopenshell/util/schema/ifc4_types.json b/src/ifcopenshell-python/ifcopenshell/util/schema/ifc4_types.json
index d8f2b9d3a6..083a37425d 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/schema/ifc4_types.json
+++ b/src/ifcopenshell-python/ifcopenshell/util/schema/ifc4_types.json
@@ -1,10 +1,10 @@
 {
     "IfcAbsorbedDoseMeasure": {
-        "description": "IfcAbsorbedDoseMeasure is a measure of the absorbed radioactivity dose.",
+        "description": "IfcAbsorbedDoseMeasure is a measure of the absorbed radioactivity dose. Usually measured in Gray (Gy, J/kg). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcabsorbeddosemeasure.htm"
     },
     "IfcAccelerationMeasure": {
-        "description": "IfcAccelerationMeasure is a measure of acceleration.",
+        "description": "IfcAccelerationMeasure is a measure of acceleration. Usually measured in m/s2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcaccelerationmeasure.htm"
     },
     "IfcActionRequestTypeEnum": {
@@ -48,7 +48,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcbuildingcontrolsdomain/lexical/ifcalarmtypeenum.htm"
     },
     "IfcAmountOfSubstanceMeasure": {
-        "description": "An amount of substance measure is the value for the quantity of a substance when compared with the number of atoms in 0.012 kg of carbon 12.",
+        "description": "An amount of substance measure is the value for the quantity of a substance when compared with the number of atoms in 0.012 kg of carbon 12. Usually measure in mole (mol). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcamountofsubstancemeasure.htm"
     },
     "IfcAnalysisModelTypeEnum": {
@@ -60,23 +60,23 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcanalysistheorytypeenum.htm"
     },
     "IfcAngularVelocityMeasure": {
-        "description": "IfcAngularVelocityMeasure is a measure of the velocity of a body measured in terms of angle subtended per unit time.",
+        "description": "IfcAngularVelocityMeasure is a measure of the velocity of a body measured in terms of angle subtended per unit time. Usually measured in radians/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcangularvelocitymeasure.htm"
     },
     "IfcAppliedValueSelect": {
-        "description": "IfcAppliedValueSelect defines a value to be calculated within a formula.",
+        "description": "IfcAppliedValueSelect defines a value to be calculated within a formula. Types are used as follows: - IfcValue: A constant value using project default units. - IfcMeasureWithUnit: A constant value using specified units. - IfcReference: A value referenced on an object attribute. For cost values, the following guidance applies: - IfcMeasureWithUnit allows the specification of both the actual figure for the value together with the currency in which the value is represented. - Selecting IfcMonetaryMeasure allows the specification only of the value, the currency being as set by the global context. - Selecting IfcRatioMeasure assumes that the amount is a percentage or other REAL number. Note that if the amount is normally specified as -20%, then this figure will need to be converted to a multiplier of 0.8",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifccostresource/lexical/ifcappliedvalueselect.htm"
     },
     "IfcArcIndex": {
-        "description": "The IfcArcIndex describes a single circular arc segment within a poly curve by providing a list on indices. The first index is the start point of the circular arc, the second index is a point on arc, the third index is the end point of the circular arc. The three points shall not be co-linear.",
+        "description": "The IfcArcIndex describes a single circular arc segment within a poly curve by providing a list on indices. The first index is the start point of the circular arc, the second index is a point on arc, the third index is the end point of the circular arc. The three points shall not be co-linear. Informal Propositions: - The second index, resolving to a point on arc, shall resolve into a Cartesian point that has approximately the same distance to the start point and the end point of the circular arc. This is due to avoid numeric instability, if the point on arc is too close to either the start or the end point.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcarcindex.htm"
     },
     "IfcAreaDensityMeasure": {
-        "description": "IfcAreaDensityMeasure is a measure of the density of a two-dimensional object and is calculated as the mass per unit area.",
+        "description": "IfcAreaDensityMeasure is a measure of the density of a two-dimensional object and is calculated as the mass per unit area. Usually measured in kg/m2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcareadensitymeasure.htm"
     },
     "IfcAreaMeasure": {
-        "description": "An area measure is the value of the extent of a surface.",
+        "description": "An area measure is the value of the extent of a surface. Usually measured in square metre (m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcareameasure.htm"
     },
     "IfcArithmeticOperatorEnum": {
@@ -124,7 +124,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcboilertypeenum.htm"
     },
     "IfcBoolean": {
-        "description": "IfcBoolean is a defined data type of simple data type Boolean. It is required since a select type (IfcSimpleValue) cannot directly include simple types in its select list. A Boolean type can have value TRUE or FALSE.",
+        "description": "IfcBoolean is a defined data type of simple data type Boolean. It is required since a select type (IfcSimpleValue) cannot directly include simple types in its select list. A Boolean type can have value TRUE or FALSE. Type: BOOLEAN",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcboolean.htm"
     },
     "IfcBooleanOperand": {
@@ -136,7 +136,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricmodelresource/lexical/ifcbooleanoperator.htm"
     },
     "IfcBoxAlignment": {
-        "description": "The box alignment specifies the alignment of the text box relative to its position. The following string values shall be used:",
+        "description": "The box alignment specifies the alignment of the text box relative to its position. The following string values shall be used: - top-left - top-middle - top-right - middle-left - center - middle-right - bottom-left - bottom-middle - bottom-right Figure 1 illustrates alignment values. Figure 2 illustrates use of alignment values together with the placement and planar extent.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationdefinitionresource/lexical/ifcboxalignment.htm"
     },
     "IfcBuildingElementPartTypeEnum": {
@@ -172,11 +172,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifccablesegmenttypeenum.htm"
     },
     "IfcCardinalPointReference": {
-        "description": "An IfcCardinalPointReference is an index reference to significant points of a section profile. This index is used to describe the spatial relationship between the section of a member and a reference axis of the same member.",
+        "description": "An IfcCardinalPointReference is an index reference to significant points of a section profile. This index is used to describe the spatial relationship between the section of a member and a reference axis of the same member. Indexes 1...9 refer to points at the bounding box of a profile. Indexes 10...19 refer to points defined by geometric centroid (usually centre of gravity) and shear centre, and their combinations with bounding box coordinates. In particular, the following index values are specified in this specification: - bottom left - bottom centre - bottom right - mid-depth left - mid-depth centre - mid-depth right - top left - top centre - top right - geometric centroid - bottom in line with the geometric centroid - left in line with the geometric centroid - right in line with the geometric centroid - top in line with the geometric centroid - shear centre - bottom in line with the shear centre - left in line with the shear centre - right in line with the shear centre - top in line with the shear centre Other index values are possible but outside the scope of this specification. Figure 1 illustrates cardinal point values. Figure 2 illustrates an example extrusion shape with arbitrary profile (IfcArbitraryClosedProfileDef), aligned \"mid-depth right\" on the member axis. The line of sight follows the extrusion direction Z which points into the drawing plane of above illustration. Hence, \"left\" is in the positive X direction of the IfcProfileDef. \"Top\" is in the positive Y direction of the IfcProfileDef.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifccardinalpointreference.htm"
     },
     "IfcChangeActionEnum": {
-        "description": "IfcChangeActionEnum identifies the type of change that might have occurred to the object during the last session (for example, added, modified, deleted). This information is required in a partial model exchange scenario so that an application or model server will know how an object might have been affected by the previous application. Valid enumerations are:",
+        "description": "IfcChangeActionEnum identifies the type of change that might have occurred to the object during the last session (for example, added, modified, deleted). This information is required in a partial model exchange scenario so that an application or model server will know how an object might have been affected by the previous application. Valid enumerations are: Consider Application A will create an IFC dataset that it wants to publish to others for modification and have the ability to subsequently merge these changes back into the original model. Before publication, it may want to set the IfcChangeActionEnum to NOCHANGE to establish a baseline so that other application changes can be easily identified. Application B then receives this IFC dataset and adds a new object and sets IfcChangeActionEnum to ADDED with Application B defined as the OwningApplication. Application B then modifies an existing object and (re)defines the LastModifiedDate to the time of the modification, LastModifyingUser to the IfcPersonAndOrganization making the change, and sets the LastModifyingApplication to Application B. When Application A receives this modified dataset, it can determine which objects have been added and modified by Application B and either merge or reject these changes as necessary. Consequently, the intent is that an application only modifies the value of IfcChangeActionEnum when it does something to the object, with the further intent that a model server is responsible for clearing the IfcChangeActionEnum back to NOCHANGE when it is ready to be republished.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcutilityresource/lexical/ifcchangeactionenum.htm"
     },
     "IfcChillerTypeEnum": {
@@ -216,7 +216,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifccommunicationsappliancetypeenum.htm"
     },
     "IfcComplexNumber": {
-        "description": "IfcComplexNumber is a representation of a complex number expressed as an array with two elements. The first element (index 1) denotes the real component which is the numerical component of a complex number whose square roots can be calculated explicitly. The second element (index 2) denotes the imaginary component which is the numerical component of a complex number whose square roots cannot be determined other than through the provision of the square of the imaginary number j where j\\^2 = -1. Note that the imaginary component may be referred to as i in certain references.",
+        "description": "IfcComplexNumber is a representation of a complex number expressed as an array with two elements. The first element (index 1) denotes the real component which is the numerical component of a complex number whose square roots can be calculated explicitly. The second element (index 2) denotes the imaginary component which is the numerical component of a complex number whose square roots cannot be determined other than through the provision of the square of the imaginary number j where j\\^2 = -1. Note that the imaginary component may be referred to as i in certain references. Type: ARRAY [1:2] OF REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifccomplexnumber.htm"
     },
     "IfcComplexPropertyTemplateTypeEnum": {
@@ -224,7 +224,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifccomplexpropertytemplatetypeenum.htm"
     },
     "IfcCompoundPlaneAngleMeasure": {
-        "description": "IfcCompoundPlaneAngleMeasure is a compound measure of plane angle in degrees, minutes, seconds, and optionally millionth-seconds of arc.",
+        "description": "IfcCompoundPlaneAngleMeasure is a compound measure of plane angle in degrees, minutes, seconds, and optionally millionth-seconds of arc. Type: LIST [3:4] OF INTEGER Value restrictions - The first integer measure is the number of degrees and is generally not range-restricted. However, when IfcCompoundPlaneAngleMeasure is used to express geographic coordinates, only latitudes of [-90, 90] and longitudes of [-180, 180] are used in practice. - The second integer measure is the number of minutes and shall be in the range (-60, 60). - The third integer measure is the number of seconds and shall be in the range (-60, 60). - The optional fourth integer measure is the number of millionth-seconds and shall be in the range (-1 000 000, 1 000 000). Signedness All measure components have the same sign (positive or negative). It is therefore trivial to convert between floating point representation (decimal degrees) and compound representation regardless whether the angle is greater or smaller than zero. Example: Use in string representations When a compound plane angle measure is formatted for display or printout, the signs of the fractional components will usually be discarded because, to a human reader, the sign of the first component alone already indicates the sense of the angle: Another often encountered display format of latitudes and longitudes is to omit the signs and print N, S, E, W indicators instead, for example, 50&deg;58'33\"S . When stored as IfcCompoundPlaneAngleMeasure however, a compound plane angle measure is always signed, with same sign of all components.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifccompoundplaneanglemeasure.htm"
     },
     "IfcCompressorTypeEnum": {
@@ -236,7 +236,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifccondensertypeenum.htm"
     },
     "IfcConnectionTypeEnum": {
-        "description": "This enumeration defines the different ways how path based elements (such as IfcWallStandardCase) can connect, as shown in Figure 1.",
+        "description": "This enumeration defines the different ways how path based elements (such as IfcWallStandardCase) can connect, as shown in Figure 1. The enumerated items shall be used in the following combinations:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcconnectiontypeenum.htm"
     },
     "IfcConstraintEnum": {
@@ -256,7 +256,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstructionmgmtdomain/lexical/ifcconstructionproductresourcetypeenum.htm"
     },
     "IfcContextDependentMeasure": {
-        "description": "The value of a physical quantity as defined within the exchange context.",
+        "description": "The value of a physical quantity as defined within the exchange context. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifccontextdependentmeasure.htm"
     },
     "IfcControllerTypeEnum": {
@@ -284,7 +284,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedmgmtelements/lexical/ifccostscheduletypeenum.htm"
     },
     "IfcCountMeasure": {
-        "description": "A count measure is the value of a count of items.",
+        "description": "A count measure is the value of a count of items. Type: NUMBER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifccountmeasure.htm"
     },
     "IfcCoveringTypeEnum": {
@@ -304,7 +304,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifccurtainwalltypeenum.htm"
     },
     "IfcCurvatureMeasure": {
-        "description": "IfcCurvatureMeasure is a measure for curvature, which is defined as the change of slope per length. This is typically a computed value in structural analysis. It is usually measured in rad/m.",
+        "description": "IfcCurvatureMeasure is a measure for curvature, which is defined as the change of slope per length. This is typically a computed value in structural analysis. It is usually measured in rad/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifccurvaturemeasure.htm"
     },
     "IfcCurveFontOrScaledCurveFontSelect": {
@@ -336,19 +336,19 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcdataoriginenum.htm"
     },
     "IfcDate": {
-        "description": "The IfcData identifies a particular calender day, expressed by year, calender month and day in month. It is expressed by a string value following a particular lexical representation.",
+        "description": "The IfcData identifies a particular calender day, expressed by year, calender month and day in month. It is expressed by a string value following a particular lexical representation. The lexical representation for IfcDate is the YYYY-MM-DD, where YYYY represents the calendar year, MM the ordinal number of the calendar month, and DD the ordinal number of the day within the calendar month. No left truncation is allowed. An optional following time zone qualifier is allowed. To accommodate year values outside the range from 0001 to 9999, additional digits can be added to the left of this representation and a preceding \"-\" sign is allowed.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcdate.htm"
     },
     "IfcDateTime": {
-        "description": "The IfcDataTime identifies a particular point in time, expressed by hours, minutes and optional seconds elapsed within a calender day, expressed by year, calender month and day in month. It is expressed by a string value following a particular lexical representation.",
+        "description": "The IfcDataTime identifies a particular point in time, expressed by hours, minutes and optional seconds elapsed within a calender day, expressed by year, calender month and day in month. It is expressed by a string value following a particular lexical representation. This lexical representation for IfcDataTime is YYYY-MM-DDThh:mm:ss where \"YYYY\" represent the year, \"MM\" the month and \"DD\" the day, preceded by an optional leading \"-\" sign to indicate a negative year number. If the sign is omitted, \"+\" is assumed. The letter \"T\" is the date/time separator and \"hh\", \"mm\", \"ss\" represent hour, minute and second respectively. Additional digits can be used to increase the precision of fractional seconds if desired i.e the format ss.ss... with any number of digits after the decimal point is supported. The fractional seconds part is optional; other parts of the lexical form are not optional. To accommodate year values greater than 9999 additional digits can be added to the left of this representation. Leading zeros are required if the year value would otherwise have fewer than four digits; otherwise they are forbidden. The year 0000 is prohibited.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcdatetime.htm"
     },
     "IfcDayInMonthNumber": {
-        "description": "IfcDayInMonthNumber is an integer that defines the position of the specified day in a month.",
+        "description": "IfcDayInMonthNumber is an integer that defines the position of the specified day in a month. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcdayinmonthnumber.htm"
     },
     "IfcDayInWeekNumber": {
-        "description": "The IfcDayInWeekNumber is an integer that defines the position of the specified day in a week. The positions have the following meaning that assigns the ordinal day number in the week to the Calendar day name.",
+        "description": "The IfcDayInWeekNumber is an integer that defines the position of the specified day in a week. The positions have the following meaning that assigns the ordinal day number in the week to the Calendar day name. Ordinal day numbers map to calendar days as follows: - 1: Monday - 2: Tuesday - 3: Wednesday - 4: Thursday - 5: Friday - 6: Saturday - 7: Sunday",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcdayinweeknumber.htm"
     },
     "IfcDefinitionSelect": {
@@ -356,7 +356,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcdefinitionselect.htm"
     },
     "IfcDerivedMeasureValue": {
-        "description": "IfcDerivedMeasureValue is a select type for selecting between derived measure types.",
+        "description": "IfcDerivedMeasureValue is a select type for selecting between derived measure types. SELECT - IfcAbsorbedDoseMeasure - IfcAccelerationMeasure - IfcAngularVelocityMeasure - IfcAreaDensityMeasure - IfcCompoundPlaneAngleMeasure - IfcCurvatureMeasure - IfcDoseEquivalentMeasure - IfcDynamicViscosityMeasure - IfcElectricCapacitanceMeasure - IfcElectricChargeMeasure - IfcElectricConductanceMeasure - IfcElectricResistanceMeasure - IfcElectricVoltageMeasure - IfcEnergyMeasure - IfcForceMeasure - IfcFrequencyMeasure - IfcHeatFluxDensityMeasure - IfcHeatingValueMeasure - IfcIlluminanceMeasure - IfcInductanceMeasure - IfcIntegerCountRateMeasure - IfcIonConcentrationMeasure - IfcIsothermalMoistureCapacityMeasure - IfcKinematicViscosityMeasure - IfcLinearForceMeasure - IfcLinearMomentMeasure - IfcLinearStiffnessMeasure - IfcLinearVelocityMeasure - IfcLuminousFluxMeasure - IfcLuminousIntensityDistributionMeasure - IfcMagneticFluxDensityMeasure - IfcMagneticFluxMeasure - IfcMassDensityMeasure - IfcMassFlowRateMeasure - IfcMassPerLengthMeasure - IfcModulusOfElasticityMeasure - IfcModulusOfLinearSubgradeReactionMeasure - IfcModulusOfRotationalSubgradeReactionMeasure - IfcModulusOfSubgradeReactionMeasure - IfcMoistureDiffusivityMeasure - IfcMolecularWeightMeasure - IfcMomentOfInertiaMeasure - IfcMonetaryMeasure - IfcPHMeasure - IfcPlanarForceMeasure - IfcPowerMeasure - IfcPressureMeasure - IfcRadioActivityMeasure - IfcRotationalFrequencyMeasure - IfcRotationalMassMeasure - IfcRotationalStiffnessMeasure - IfcSectionModulusMeasure - IfcSectionalAreaIntegralMeasure - IfcShearModulusMeasure - IfcSoundPowerLevelMeasure - IfcSoundPowerMeasure - IfcSoundPressureLevelMeasure - IfcSoundPressureMeasure - IfcSpecificHeatCapacityMeasure - IfcTemperatureGradientMeasure - IfcTemperatureRateOfChangeMeasure - IfcThermalAdmittanceMeasure - IfcThermalConductivityMeasure - IfcThermalExpansionCoefficientMeasure - IfcThermalResistanceMeasure - IfcThermalTransmittanceMeasure - IfcTorqueMeasure - IfcVaporPermeabilityMeasure - IfcVolumetricFlowRateMeasure - IfcWarpingConstantMeasure - IfcWarpingMomentMeasure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcderivedmeasurevalue.htm"
     },
     "IfcDerivedUnitEnum": {
@@ -364,7 +364,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcderivedunitenum.htm"
     },
     "IfcDescriptiveMeasure": {
-        "description": "A descriptive measure is a human interpretable definition of a quantifiable value. The mode of interpretation has to be established for the exchange context.",
+        "description": "A descriptive measure is a human interpretable definition of a quantifiable value. The mode of interpretation has to be established for the exchange context. Type: STRING",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcdescriptivemeasure.htm"
     },
     "IfcDimensionCount": {
@@ -388,7 +388,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcdistributionporttypeenum.htm"
     },
     "IfcDistributionSystemEnum": {
-        "description": "This enumeration identifies different types of distribution systems. It is used to designate systems by their function as well as ports of devices within such systems to restrict connectivity to compatible connections.",
+        "description": "This enumeration identifies different types of distribution systems. It is used to designate systems by their function as well as ports of devices within such systems to restrict connectivity to compatible connections. Ports for cable carriers may be connected using IfcCableCarrierSegment and IfcCableCarrierFitting. Type objects for cable carrier segments and fittings (IfcCableCarrierSegmentType and IfcCableCarrierFittingType that are not specific to a particular system type may have ports with PredefinedType of NOTDEFINED which indicates that occurrences of such objects may connect to ports of any other cable-carrier based port. Valid enumerations for cable carriers are the same as that for cables, and may be asserted if ports of the contained cables are all of the same type.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcdistributionsystemenum.htm"
     },
     "IfcDocumentConfidentialityEnum": {
@@ -404,11 +404,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifcdocumentstatusenum.htm"
     },
     "IfcDoorPanelOperationEnum": {
-        "description": "This enumeration defines the basic ways how individual door panels operate as shown in Figure 1.",
+        "description": "This enumeration defines the basic ways how individual door panels operate as shown in Figure 1. The opening direction of the door panels is given by the local placement of the IfcDoor. The positive y-axis determines the direction as shown in Figure 2.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcdoorpaneloperationenum.htm"
     },
     "IfcDoorPanelPositionEnum": {
-        "description": "This enumeration defines the basic ways to describe the location of a door panel within a door lining.",
+        "description": "This enumeration defines the basic ways to describe the location of a door panel within a door lining. Figure 1 shows the designation of a door panel with PanelPosition = LEFT and a door panel with PanelPosition = RIGHT within a door style with OperationType = DOUBLE_DOOR_SINGLE_SWING. The position is given as shown in the XZ plane of the local placement, looking into the direction of the positive Y axis. !(../../../../../../figures/ifcdoorpanelpositionenum-fig01.gif \"Figure 1 \u2014 Door panel positions\")",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcdoorpanelpositionenum.htm"
     },
     "IfcDoorStyleConstructionEnum": {
@@ -416,7 +416,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcdoorstyleconstructionenum.htm"
     },
     "IfcDoorStyleOperationEnum": {
-        "description": "This enumeration defines the basic ways to describe how doors operate as shown in Figure 1.",
+        "description": "This enumeration defines the basic ways to describe how doors operate as shown in Figure 1. NOTE - Figures are shown in the ground view. - Figures (symbolic representation) depend on the national building code. - These figures are only shown as illustrations, the actual representation in the ground view might differ. - Open to the outside is declared as open into the direction of the positive y-axis, determined by the ObjectPlacement at IfcDoor - The location of the panel relative to the wall thickness is defined by the ObjectPlacement at IfcDoor, and the IfcDoorLiningProperties.LiningOffset parameter.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcdoorstyleoperationenum.htm"
     },
     "IfcDoorTypeEnum": {
@@ -424,15 +424,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcdoortypeenum.htm"
     },
     "IfcDoorTypeOperationEnum": {
-        "description": "This enumeration defines the basic ways to describe how doors operate, as shown in Figure 1. It combines the partitioning of the door into a single or multiple door panels and the operation types of that panels.",
+        "description": "This enumeration defines the basic ways to describe how doors operate, as shown in Figure 1. It combines the partitioning of the door into a single or multiple door panels and the operation types of that panels. In the most common case of swinging doors the IfcDoorTypeOperationEnum defined the hinge side (left hing or right hung) and the opening direction (opening to the left, opening to the right). Whether the door opens inwards or outwards is determined by the local coordinate system of the IfcDoor, or IfcDoorStandardCase. NOTE - Figures are shown in the ground view. - Figures (symbolic representation) depend on the national building code. - These figures are only shown as illustrations, the actual representation in the ground view might differ. - Open to the outside is declared as open into the direction of the positive y-axis, determined by the ObjectPlacement at IfcDoor - The location of the panel relative to the wall thickness is defined by the ObjectPlacement at IfcDoor, and the IfcDoorLiningProperties.LiningOffset parameter.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcdoortypeoperationenum.htm"
     },
     "IfcDoseEquivalentMeasure": {
-        "description": "IfcDoseEquivalentMeasure is a measure of the radioactive dose equivalent.",
+        "description": "IfcDoseEquivalentMeasure is a measure of the radioactive dose equivalent. Usually measured in Sievert (Sv, J/kg). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcdoseequivalentmeasure.htm"
     },
     "IfcDuctFittingTypeEnum": {
-        "description": "This enumeration is used to identify the primary purpose of a duct fitting. This is a very basic categorization mechanism to generically identify the duct fitting type. Subcategories of duct fittings are not enumerated.",
+        "description": "This enumeration is used to identify the primary purpose of a duct fitting. This is a very basic categorization mechanism to generically identify the duct fitting type. Subcategories of duct fittings are not enumerated. Enumerated Item Definitions: - BEND: A fitting with typically two ports used to change the direction of flow between connected elements. - CONNECTOR: Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two duct segments). - ENTRY: Entry fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., an outside air duct system intake opening). - EXIT: Exit fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., an exhaust air discharge opening). - JUNCTION: A fitting with typically more than two ports used to redistribute flow among the ports and/or to change the direction of flow between connected elements (e.g, tee, cross, wye, etc.). - OBSTRUCTION: A fitting with typically two ports used to obstruct or restrict flow between the connected elements (e.g., screen, perforated plate, etc.). - TRANSITION: A fitting with typically two ports having different shapes or sizes. Can also be used to change the direction of flow between connected elements. - USERDEFINED: User-defined fitting. - NOTDEFINED: Undefined fitting.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcductfittingtypeenum.htm"
     },
     "IfcDuctSegmentTypeEnum": {
@@ -444,11 +444,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcductsilencertypeenum.htm"
     },
     "IfcDuration": {
-        "description": "The IfcDuration identifies a quantity of time (or a \"lenght\" of an event occurring in time).",
+        "description": "The IfcDuration identifies a quantity of time (or a \"lenght\" of an event occurring in time). This lexical representation for IfcDataTime is PnYnMnDTnHnMnS, where nY represents the number of years, nM the number of months, nD the number of days, 'T' is the date/time separator, nH the number of hours, nM the number of minutes and nS the number of seconds. The number of seconds can include decimal digits to arbitrary precision.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcduration.htm"
     },
     "IfcDynamicViscosityMeasure": {
-        "description": "IfcDynamicViscosityMeasure is a measure of the viscous resistance of a medium.",
+        "description": "IfcDynamicViscosityMeasure is a measure of the viscous resistance of a medium. Usually measured in Pascal second (Pa s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcdynamicviscositymeasure.htm"
     },
     "IfcElectricApplianceTypeEnum": {
@@ -456,19 +456,19 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectricappliancetypeenum.htm"
     },
     "IfcElectricCapacitanceMeasure": {
-        "description": "IfcElectricCapacitanceMeasure is a measure of the electric capacitance.",
+        "description": "IfcElectricCapacitanceMeasure is a measure of the electric capacitance. Usually measured in Farad (F, C/V = A s/V). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcelectriccapacitancemeasure.htm"
     },
     "IfcElectricChargeMeasure": {
-        "description": "IfcElectricChargeMeasure is a measure of the electric charge.",
+        "description": "IfcElectricChargeMeasure is a measure of the electric charge. Usually measured in Coulomb (C, A s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcelectricchargemeasure.htm"
     },
     "IfcElectricConductanceMeasure": {
-        "description": "IfcElectricConductanceMeasure is a measure of the electric conductance.",
+        "description": "IfcElectricConductanceMeasure is a measure of the electric conductance. Usually measured in Siemens (S, 1/Ohm = A/V). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcelectricconductancemeasure.htm"
     },
     "IfcElectricCurrentMeasure": {
-        "description": "The value for the movement of electrically charged particles.",
+        "description": "The value for the movement of electrically charged particles. Usually measured in Ampere (A). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcelectriccurrentmeasure.htm"
     },
     "IfcElectricDistributionBoardTypeEnum": {
@@ -488,7 +488,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectricmotortypeenum.htm"
     },
     "IfcElectricResistanceMeasure": {
-        "description": "IfcElectricResistanceMeasure is a measure of the electric resistance.",
+        "description": "IfcElectricResistanceMeasure is a measure of the electric resistance. Usually measured in Ohm (V/A). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcelectricresistancemeasure.htm"
     },
     "IfcElectricTimeControlTypeEnum": {
@@ -496,7 +496,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcelectrictimecontroltypeenum.htm"
     },
     "IfcElectricVoltageMeasure": {
-        "description": "IfcElectricVoltageMeasure is a measure of electromotive force.",
+        "description": "IfcElectricVoltageMeasure is a measure of electromotive force. Usually measured in Volts (V, W/A). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcelectricvoltagemeasure.htm"
     },
     "IfcElementAssemblyTypeEnum": {
@@ -508,7 +508,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcelementcompositionenum.htm"
     },
     "IfcEnergyMeasure": {
-        "description": "IfcEnergyMeasure is a measure of energy required or used.",
+        "description": "IfcEnergyMeasure is a measure of energy required or used. Usually measured in Joules, (J, Nm). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcenergymeasure.htm"
     },
     "IfcEngineTypeEnum": {
@@ -556,7 +556,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcplumbingfireprotectiondomain/lexical/ifcfiresuppressionterminaltypeenum.htm"
     },
     "IfcFlowDirectionEnum": {
-        "description": "This enumeration defines the flow direction at a distribution port.",
+        "description": "This enumeration defines the flow direction at a distribution port. - For pipe-based ports, the direction is the physical flow direction. - For duct-based ports, the direction is the physical flow direction.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgserviceelements/lexical/ifcflowdirectionenum.htm"
     },
     "IfcFlowInstrumentTypeEnum": {
@@ -568,15 +568,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcflowmetertypeenum.htm"
     },
     "IfcFontStyle": {
-        "description": "The IfcFontStyle type defines whether the normal, the italic or the oblique faces within a font family shall be used. Values are:",
+        "description": "The IfcFontStyle type defines whether the normal, the italic or the oblique faces within a font family shall be used. Values are: - normal - italic - oblique",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcfontstyle.htm"
     },
     "IfcFontVariant": {
-        "description": "The IfcFontVariant type defines whether the normal or the small-caps faces within a font family shall be used. Values are:",
+        "description": "The IfcFontVariant type defines whether the normal or the small-caps faces within a font family shall be used. Values are: - normal - small-caps",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcfontvariant.htm"
     },
     "IfcFontWeight": {
-        "description": "The IfcFontWeight type defines the weight of the font. Values are:",
+        "description": "The IfcFontWeight type defines the weight of the font. Values are: - normal - bold - 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcfontweight.htm"
     },
     "IfcFootingTypeEnum": {
@@ -584,11 +584,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcfootingtypeenum.htm"
     },
     "IfcForceMeasure": {
-        "description": "IfcForceMeasure is a measure of the force.",
+        "description": "IfcForceMeasure is a measure of the force. Usually measured in Newton (N, kg m/s2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcforcemeasure.htm"
     },
     "IfcFrequencyMeasure": {
-        "description": "IfcFrequencyMeasure is a measure of the number of times that an item vibrates in unit time.",
+        "description": "IfcFrequencyMeasure is a measure of the number of times that an item vibrates in unit time. Usually measured in cycles/s or Hertz (Hz). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcfrequencymeasure.htm"
     },
     "IfcFurnitureTypeEnum": {
@@ -612,7 +612,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcrepresentationresource/lexical/ifcglobalorlocalenum.htm"
     },
     "IfcGloballyUniqueId": {
-        "description": "An IfcGloballyUniqueId holds an encoded string identifier that is used to uniquely identify an IFC object. An IfcGloballyUniqueId is a Globally Unique Identifier (GUID) which is an auto-generated 128-bit number. Since this identifier is required for all IFC object instances, it is desirable to compress it to reduce overhead. The encoding of the base 64 character set is shown below:",
+        "description": "An IfcGloballyUniqueId holds an encoded string identifier that is used to uniquely identify an IFC object. An IfcGloballyUniqueId is a Globally Unique Identifier (GUID) which is an auto-generated 128-bit number. Since this identifier is required for all IFC object instances, it is desirable to compress it to reduce overhead. The encoding of the base 64 character set is shown below: The resulting string is a fixed 22 character length string to be exchanged within the IFC exchange file structure.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcutilityresource/lexical/ifcgloballyuniqueid.htm"
     },
     "IfcGridPlacementDirectionSelect": {
@@ -624,7 +624,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcgridtypeenum.htm"
     },
     "IfcHatchLineDistanceSelect": {
-        "description": "The IfcHatchLineDistanceSelect is a selection between different ways to determine the distance and optionally the start point of hatch lines, either by an offset distance measure or by a vector.",
+        "description": "The IfcHatchLineDistanceSelect is a selection between different ways to determine the distance and optionally the start point of hatch lines, either by an offset distance measure or by a vector. The vector, if selected, acts as a one time repeat factor in the fill area style hatching for determining the origin of the repeated hatch line relative to the origin of the previous hatch line, Given the initial position of any hatch line, the one direction repeat factor determines two new positions according to the equation:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifchatchlinedistanceselect.htm"
     },
     "IfcHeatExchangerTypeEnum": {
@@ -632,7 +632,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcheatexchangertypeenum.htm"
     },
     "IfcHeatFluxDensityMeasure": {
-        "description": "IfcHeatFluxDensityMeasure is a measure of the density of heat flux within a body.",
+        "description": "IfcHeatFluxDensityMeasure is a measure of the density of heat flux within a body. Usually measured in W/m2 (J/s m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcheatfluxdensitymeasure.htm"
     },
     "IfcHeatingValueMeasure": {
@@ -644,23 +644,23 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifchumidifiertypeenum.htm"
     },
     "IfcIdentifier": {
-        "description": "An identifier is an alphanumeric string which allows an individual thing to be identified. It may not provide natural-language meaning.",
+        "description": "An identifier is an alphanumeric string which allows an individual thing to be identified. It may not provide natural-language meaning. Type: STRING of up to 255 characters Value restrictions As a merely machine-readable string for identification purposes, an identifier is usually machine-generated and locale-independent (in contrast to human-readable labels, IfcLabel).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcidentifier.htm"
     },
     "IfcIlluminanceMeasure": {
-        "description": "IfcIlluminanceMeasure is a measure of the illuminance.",
+        "description": "IfcIlluminanceMeasure is a measure of the illuminance. Usually measured in Lux (lx, Lumen/m2 = Candela Steradian/m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcilluminancemeasure.htm"
     },
     "IfcInductanceMeasure": {
-        "description": "IfcInductanceMeasure is a measure of the inductance.",
+        "description": "IfcInductanceMeasure is a measure of the inductance. Usually measure in Henry (H, Weber/A = V s/A). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcinductancemeasure.htm"
     },
     "IfcInteger": {
-        "description": "IfcInteger is a defined type of simple data type Integer. It is required since a select type (IfcSimpleValue) cannot include directly simple types in its select list.",
+        "description": "IfcInteger is a defined type of simple data type Integer. It is required since a select type (IfcSimpleValue) cannot include directly simple types in its select list. In principle, the domain of IfcInteger (being an Integer) is all integer numbers. Here the number of bits used for the IfcInteger representation is unconstrained, but in practice it is implementation specific. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcinteger.htm"
     },
     "IfcIntegerCountRateMeasure": {
-        "description": "IfcIntegerCountRateMeasure is a measure of the integer number of units flowing per unit time.",
+        "description": "IfcIntegerCountRateMeasure is a measure of the integer number of units flowing per unit time. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcintegercountratemeasure.htm"
     },
     "IfcInterceptorTypeEnum": {
@@ -680,7 +680,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcionconcentrationmeasure.htm"
     },
     "IfcIsothermalMoistureCapacityMeasure": {
-        "description": "IfcIsothermalMoistureCapacityMeasure is a measure of isothermal moisture capacity.",
+        "description": "IfcIsothermalMoistureCapacityMeasure is a measure of isothermal moisture capacity. Usually measured in m3/kg. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcisothermalmoisturecapacitymeasure.htm"
     },
     "IfcJunctionBoxTypeEnum": {
@@ -688,7 +688,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcjunctionboxtypeenum.htm"
     },
     "IfcKinematicViscosityMeasure": {
-        "description": "IfcKinematicViscosityMeasure is a measure of the viscous resistance of a medium to a moving body.",
+        "description": "IfcKinematicViscosityMeasure is a measure of the viscous resistance of a medium to a moving body. Usually measured in m2/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifckinematicviscositymeasure.htm"
     },
     "IfcKnotType": {
@@ -696,7 +696,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifcknottype.htm"
     },
     "IfcLabel": {
-        "description": "A label is the term by which something may be referred to. It is a string which represents the human-interpretable name of something and shall have a natural-language meaning.",
+        "description": "A label is the term by which something may be referred to. It is a string which represents the human-interpretable name of something and shall have a natural-language meaning. Type: STRING of up to 255 characters Value restrictions As a human-readable string for naming purposes, a label is usually human-specified and locale-dependent (in contrast to purely machine-readable identifiers, IfcIdentifier).",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifclabel.htm"
     },
     "IfcLaborResourceTypeEnum": {
@@ -708,7 +708,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifclamptypeenum.htm"
     },
     "IfcLanguageId": {
-        "description": "The IfcLanguageId identifies the language in which a natural language text is expressed. It uses a language tag to identify the language.",
+        "description": "The IfcLanguageId identifies the language in which a natural language text is expressed. It uses a language tag to identify the language. Type: IfcIdentifier",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifclanguageid.htm"
     },
     "IfcLayerSetDirectionEnum": {
@@ -720,7 +720,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationorganizationresource/lexical/ifclayereditem.htm"
     },
     "IfcLengthMeasure": {
-        "description": "An IfcLengthMeasure is the value of a distance.",
+        "description": "An IfcLengthMeasure is the value of a distance. Usually measured in millimeters (mm). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifclengthmeasure.htm"
     },
     "IfcLibrarySelect": {
@@ -732,7 +732,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationorganizationresource/lexical/ifclightdistributioncurveenum.htm"
     },
     "IfcLightDistributionDataSourceSelect": {
-        "description": "A goniometric light gets its intensity distribution function (how much light goes in any one direction) from one of two sources: (i) an industry-standard file, (ii) from distribution data passed directly via the IfcLightIntensityDistribution.",
+        "description": "A goniometric light gets its intensity distribution function (how much light goes in any one direction) from one of two sources: (i) an industry-standard file, (ii) from distribution data passed directly via the IfcLightIntensityDistribution. The light distribution provides the luminous intensity distribution according to some standardized light distribution curves. SELECT",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationorganizationresource/lexical/ifclightdistributiondatasourceselect.htm"
     },
     "IfcLightEmissionSourceEnum": {
@@ -748,19 +748,19 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifclineindex.htm"
     },
     "IfcLinearForceMeasure": {
-        "description": "IfcLinearForceMeasure is a measure of linear force.",
+        "description": "IfcLinearForceMeasure is a measure of linear force. Usually measured in N/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifclinearforcemeasure.htm"
     },
     "IfcLinearMomentMeasure": {
-        "description": "IfcLinearMomentMeasure is a measure of linear moment.",
+        "description": "IfcLinearMomentMeasure is a measure of linear moment. Usually measured in Nm/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifclinearmomentmeasure.htm"
     },
     "IfcLinearStiffnessMeasure": {
-        "description": "IfcLinearStiffnessMeasure is a measure of linear stiffness.",
+        "description": "IfcLinearStiffnessMeasure is a measure of linear stiffness. Usually measured in N/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifclinearstiffnessmeasure.htm"
     },
     "IfcLinearVelocityMeasure": {
-        "description": "IfcLinearVelocityMeasure is a measure of the velocity of a body measured in terms of distance moved per unit time.",
+        "description": "IfcLinearVelocityMeasure is a measure of the velocity of a body measured in terms of distance moved per unit time. Usually measured in m/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifclinearvelocitymeasure.htm"
     },
     "IfcLoadGroupTypeEnum": {
@@ -768,51 +768,51 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcloadgrouptypeenum.htm"
     },
     "IfcLogical": {
-        "description": "IfcLogical_IfcSimpleValue) cannot directly include simple types in its select list). Logical datatype can have values TRUE, FALSE or UNKNOWN._",
+        "description": "IfcLogical_IfcSimpleValue) cannot directly include simple types in its select list). Logical datatype can have values TRUE, FALSE or UNKNOWN._ Type: LOGICAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifclogical.htm"
     },
     "IfcLogicalOperatorEnum": {
-        "description": "IfcLogicalOperatorEnum is an enumeration that defines the logical operators that may be applied for the satisfaction of one or more operands (IfcConstraint) at a time.",
+        "description": "IfcLogicalOperatorEnum is an enumeration that defines the logical operators that may be applied for the satisfaction of one or more operands (IfcConstraint) at a time. Table 1 illustrates application of IfcLogicalOperatorEnum in a case of three operands, A, B and C, for each operator.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstraintresource/lexical/ifclogicaloperatorenum.htm"
     },
     "IfcLuminousFluxMeasure": {
-        "description": "IfcLuminousFluxMeasure is a measure of the luminous flux.",
+        "description": "IfcLuminousFluxMeasure is a measure of the luminous flux. Usually measured in Lumen (lm, Candela Steradian). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcluminousfluxmeasure.htm"
     },
     "IfcLuminousIntensityDistributionMeasure": {
-        "description": "IfcLuminousIntensityDistributionMeasure is a measure of the luminous intensity of a light source that changes according to the direction of the ray. It is normally based on some standardized distribution light distribution curves.",
+        "description": "IfcLuminousIntensityDistributionMeasure is a measure of the luminous intensity of a light source that changes according to the direction of the ray. It is normally based on some standardized distribution light distribution curves. Usually measured in Candela/Lumen (cd/lm) or (cd/klm). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcluminousintensitydistributionmeasure.htm"
     },
     "IfcLuminousIntensityMeasure": {
-        "description": "An IfcLuminousIntensityMeasure is the value for the brightness of a body.",
+        "description": "An IfcLuminousIntensityMeasure is the value for the brightness of a body. Usually measured in candela (cd). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcluminousintensitymeasure.htm"
     },
     "IfcMagneticFluxDensityMeasure": {
-        "description": "IfcMagneticFluxDensityMeasure is a measure of the magnetic flux density.",
+        "description": "IfcMagneticFluxDensityMeasure is a measure of the magnetic flux density. Usually measured in Tesla (T, Weber/m2 = V s/m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmagneticfluxdensitymeasure.htm"
     },
     "IfcMagneticFluxMeasure": {
-        "description": "IfcMagneticFluxMeasure is a measure of the magnetic flux.",
+        "description": "IfcMagneticFluxMeasure is a measure of the magnetic flux. Usually measured in Weber (Wb, V s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmagneticfluxmeasure.htm"
     },
     "IfcMassDensityMeasure": {
-        "description": "IfcMassDensityMeasure is a measure of the density of a medium.",
+        "description": "IfcMassDensityMeasure is a measure of the density of a medium. Usually measured in kg/m3. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmassdensitymeasure.htm"
     },
     "IfcMassFlowRateMeasure": {
-        "description": "IfcMassFlowRateMeasure is a measure of the mass of a medium flowing per unit time.",
+        "description": "IfcMassFlowRateMeasure is a measure of the mass of a medium flowing per unit time. Usually measured in kg/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmassflowratemeasure.htm"
     },
     "IfcMassMeasure": {
-        "description": "An IfcMassMeasure is the value of the amount of matter that a body contains.",
+        "description": "An IfcMassMeasure is the value of the amount of matter that a body contains. Usually measured in kilograms (kg) or grams (g). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmassmeasure.htm"
     },
     "IfcMassPerLengthMeasure": {
-        "description": "IfcMassPerLengthMeasure is a measure for mass per length. For example for rolled steel profiles the weight of an imaginary beam is usually expressed by kg/m length for cost calculation and structural analysis purposes.",
+        "description": "IfcMassPerLengthMeasure is a measure for mass per length. For example for rolled steel profiles the weight of an imaginary beam is usually expressed by kg/m length for cost calculation and structural analysis purposes. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmassperlengthmeasure.htm"
     },
     "IfcMaterialSelect": {
-        "description": "IfcMaterialSelect provides selection of either a material definition or a material usage definition that can be assigned to an element, a resource or another entity within this specification.",
+        "description": "IfcMaterialSelect provides selection of either a material definition or a material usage definition that can be assigned to an element, a resource or another entity within this specification. - IfcMaterialDefinition IfcMaterial IfcMaterialLayer IfcMaterialLayerSet IfcMaterialProfile IfcMaterialProfileSet IfcMaterialConstituent IfcMaterialConstituentSet - IfcMaterialUsageDefinition IfcMaterialLayerSetUsage IfcMaterialProfileSetUsage - IfcMaterialList",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmaterialresource/lexical/ifcmaterialselect.htm"
     },
     "IfcMeasureValue": {
@@ -832,19 +832,19 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcmembertypeenum.htm"
     },
     "IfcMetricValueSelect": {
-        "description": "IfcMetricValueSelect is a select type that enables selection of the data type for the value component of an IfcMetric.",
+        "description": "IfcMetricValueSelect is a select type that enables selection of the data type for the value component of an IfcMetric. Types are used as follows: - IfcValue: A constant value using project default units. - IfcMeasureWithUnit: A constant value using specified units. - IfcAppliedValue: A value calculated from a formula. - IfcTable: A value retrieved from a table. - IfcTimeSeries: A value that varies over time. - IfcReference: A value referenced on an object attribute.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcconstraintresource/lexical/ifcmetricvalueselect.htm"
     },
     "IfcModulusOfElasticityMeasure": {
-        "description": "IfcModulusOfElasticityMeasure is a measure of modulus of elasticity.",
+        "description": "IfcModulusOfElasticityMeasure is a measure of modulus of elasticity. Usually measured in N/m2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmodulusofelasticitymeasure.htm"
     },
     "IfcModulusOfLinearSubgradeReactionMeasure": {
-        "description": "IfcModulusOfLinearSubgradeReactionMeasure is a measure for modulus of linear subgrade reaction, which expresses the elastic bedding of a linear structural element per length, such as for a beam. It is typically measured in N/m\\^2.",
+        "description": "IfcModulusOfLinearSubgradeReactionMeasure is a measure for modulus of linear subgrade reaction, which expresses the elastic bedding of a linear structural element per length, such as for a beam. It is typically measured in N/m\\^2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmodulusoflinearsubgradereactionmeasure.htm"
     },
     "IfcModulusOfRotationalSubgradeReactionMeasure": {
-        "description": "IfcModulusOfRotationalSubgradeReactionMeasure is a measure for modulus of rotational subgrade reaction, which expresses the rotational elastic bedding of a linear structural element per length, such as for a beam. It is typically measured in Nm/(m*rad).",
+        "description": "IfcModulusOfRotationalSubgradeReactionMeasure is a measure for modulus of rotational subgrade reaction, which expresses the rotational elastic bedding of a linear structural element per length, such as for a beam. It is typically measured in Nm/(m*rad). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmodulusofrotationalsubgradereactionmeasure.htm"
     },
     "IfcModulusOfRotationalSubgradeReactionSelect": {
@@ -852,7 +852,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcmodulusofrotationalsubgradereactionselect.htm"
     },
     "IfcModulusOfSubgradeReactionMeasure": {
-        "description": "IfcModulusOfSubgradeReactionMeasure is a geotechnical measure describing interaction between foundation structures and the soil. May also be known as bedding measure.",
+        "description": "IfcModulusOfSubgradeReactionMeasure is a geotechnical measure describing interaction between foundation structures and the soil. May also be known as bedding measure. Usually measured in N/m3. Type: REAL Figure 1 illustrates elastic support of a planar member. !(../../../../../../figures/ifcmodulusofsubgradereactionmeasure.gif \"Figure 1 \u2014 Modulus of subgrade reaction measure\")",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmodulusofsubgradereactionmeasure.htm"
     },
     "IfcModulusOfSubgradeReactionSelect": {
@@ -864,23 +864,23 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralloadresource/lexical/ifcmodulusoftranslationalsubgradereactionselect.htm"
     },
     "IfcMoistureDiffusivityMeasure": {
-        "description": "IfcMoistureDiffusivityMeasure is a measure of moisture diffusivity.",
+        "description": "IfcMoistureDiffusivityMeasure is a measure of moisture diffusivity. Usually measured in m3/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmoisturediffusivitymeasure.htm"
     },
     "IfcMolecularWeightMeasure": {
-        "description": "IfcMolecularWeightMeasure is a measure of molecular weight of material (typically gas).",
+        "description": "IfcMolecularWeightMeasure is a measure of molecular weight of material (typically gas). Usually measured in g/mole. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmolecularweightmeasure.htm"
     },
     "IfcMomentOfInertiaMeasure": {
-        "description": "IfcMomentOfInertiaMeasure is a measure of moment of inertia.",
+        "description": "IfcMomentOfInertiaMeasure is a measure of moment of inertia. Usually measured in m4. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmomentofinertiameasure.htm"
     },
     "IfcMonetaryMeasure": {
-        "description": "A monetary measure is the value of an amount of money without regard to its currency.",
+        "description": "A monetary measure is the value of an amount of money without regard to its currency. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcmonetarymeasure.htm"
     },
     "IfcMonthInYearNumber": {
-        "description": "IfcMonthInYearNumber is an integer that defines the position of the specified month in a year.",
+        "description": "IfcMonthInYearNumber is an integer that defines the position of the specified month in a year. Calendar month numbers map to calendar month names as follows: - 1: January - 2: February - 3: March - 4: April - 5: May - 6: June - 7: July - 8: August - 9: September - 10: October - 11: November - 12: December Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifcmonthinyearnumber.htm"
     },
     "IfcMotorConnectionTypeEnum": {
@@ -888,11 +888,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcmotorconnectiontypeenum.htm"
     },
     "IfcNonNegativeLengthMeasure": {
-        "description": "A non-negative length measure is a length measure that is greater than or equal to zero.",
+        "description": "A non-negative length measure is a length measure that is greater than or equal to zero. Type: IfcLengthMeasure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcnonnegativelengthmeasure.htm"
     },
     "IfcNormalisedRatioMeasure": {
-        "description": "IfcNormalisedRatioMeasure is a dimensionless measure to express ratio values ranging from 0.0 to 1.0.",
+        "description": "IfcNormalisedRatioMeasure is a dimensionless measure to express ratio values ranging from 0.0 to 1.0. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcnormalisedratiomeasure.htm"
     },
     "IfcNullStyle": {
@@ -900,7 +900,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcnullstyle.htm"
     },
     "IfcNumericMeasure": {
-        "description": "An IfcNumericMeasure is the numeric value of a physical quantity.",
+        "description": "An IfcNumericMeasure is the numeric value of a physical quantity. Type: NUMBER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcnumericmeasure.htm"
     },
     "IfcObjectReferenceSelect": {
@@ -932,11 +932,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcphmeasure.htm"
     },
     "IfcParameterValue": {
-        "description": "An IfcParameterValue is the value which specifies the amount of a parameter in some parameter space.",
+        "description": "An IfcParameterValue is the value which specifies the amount of a parameter in some parameter space. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcparametervalue.htm"
     },
     "IfcPerformanceHistoryTypeEnum": {
-        "description": "This enumeration is used to identify the primary purpose of performance history. The IfcPerformanceHistoryTypeEnum contains the following:",
+        "description": "This enumeration is used to identify the primary purpose of performance history. The IfcPerformanceHistoryTypeEnum contains the following: - USERDEFINED: User-defined. - NOTDEFINED: Undefined.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifccontrolextension/lexical/ifcperformancehistorytypeenum.htm"
     },
     "IfcPermeableCoveringOperationEnum": {
@@ -968,11 +968,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcpipesegmenttypeenum.htm"
     },
     "IfcPlanarForceMeasure": {
-        "description": "IfcPlanarForceMeasure is a measure of force on an area.",
+        "description": "IfcPlanarForceMeasure is a measure of force on an area. Usually measured in N/m2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcplanarforcemeasure.htm"
     },
     "IfcPlaneAngleMeasure": {
-        "description": "An IfcPlaneAngleMeasure is the value of an angle in a plane.",
+        "description": "An IfcPlaneAngleMeasure is the value of an angle in a plane. Usually measured in radian (rad, m/m = 1), but also grads may be used. The grad unit has to be declared as a conversion based unit based on radian unit. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcplaneanglemeasure.htm"
     },
     "IfcPlateTypeEnum": {
@@ -984,23 +984,23 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcpointorvertexpoint.htm"
     },
     "IfcPositiveInteger": {
-        "description": "IfcPositiveInteger is a defined type based on simple data type Integer with the additional restriction to positive integers (excluding zero).",
+        "description": "IfcPositiveInteger is a defined type based on simple data type Integer with the additional restriction to positive integers (excluding zero). In principle, the domain of IfcInteger is all integer numbers larger than zero. Here the number of bits used for the IfcInteger representation is unconstrained, but in practice it is implementation specific. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcpositiveinteger.htm"
     },
     "IfcPositiveLengthMeasure": {
-        "description": "An IfcPositiveLengthMeasure is a length measure that is greater than zero.",
+        "description": "An IfcPositiveLengthMeasure is a length measure that is greater than zero. Type: IfcLengthMeasure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcpositivelengthmeasure.htm"
     },
     "IfcPositivePlaneAngleMeasure": {
-        "description": "An IfcPositivePlaneAngleMeasure is a plane angle measure that is greater than zero.",
+        "description": "An IfcPositivePlaneAngleMeasure is a plane angle measure that is greater than zero. Type: IfcPlaneAngleMeasure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcpositiveplaneanglemeasure.htm"
     },
     "IfcPositiveRatioMeasure": {
-        "description": "An IfcPositiveRatioMeasure is a ratio measure that is greater than zero.",
+        "description": "An IfcPositiveRatioMeasure is a ratio measure that is greater than zero. Type: IfcRatioMeasure",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcpositiveratiomeasure.htm"
     },
     "IfcPowerMeasure": {
-        "description": "IfcPowerMeasure is a measure of power required or used.",
+        "description": "IfcPowerMeasure is a measure of power required or used. Usually measured in Watts (W, J/s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcpowermeasure.htm"
     },
     "IfcPreferredSurfaceCurveRepresentation": {
@@ -1016,7 +1016,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcpresentationstyleselect.htm"
     },
     "IfcPressureMeasure": {
-        "description": "IfcPressureMeasure is a measure of the quantity of a medium acting on a unit area.",
+        "description": "IfcPressureMeasure is a measure of the quantity of a medium acting on a unit area. Usually measured in Pascals (Pa, N/m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcpressuremeasure.htm"
     },
     "IfcProcedureTypeEnum": {
@@ -1044,7 +1044,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedmgmtelements/lexical/ifcprojectordertypeenum.htm"
     },
     "IfcProjectedOrTrueLengthEnum": {
-        "description": "This enumeration type is needed for load definition and is only considered if the load values are given as global actions and if they define linear or planar loads (that is, one- or two-dimensionally distributed loads).",
+        "description": "This enumeration type is needed for load definition and is only considered if the load values are given as global actions and if they define linear or planar loads (that is, one- or two-dimensionally distributed loads). Figure 1 illustrates the interpretation of a load definition depending on the enumeration types IfcGlobalOrLocalEnum and IfcProjectedOrTrueLengthEnum.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcprojectedortruelengthenum.htm"
     },
     "IfcProjectionElementTypeEnum": {
@@ -1076,7 +1076,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcpumptypeenum.htm"
     },
     "IfcRadioActivityMeasure": {
-        "description": "IfcRadioActivityMeasure is a measure of activity of radionuclide.",
+        "description": "IfcRadioActivityMeasure is a measure of activity of radionuclide. Usually measured in Becquerel (Bq, 1/s). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcradioactivitymeasure.htm"
     },
     "IfcRailingTypeEnum": {
@@ -1088,15 +1088,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcrampflighttypeenum.htm"
     },
     "IfcRampTypeEnum": {
-        "description": "This enumeration defines the basic configuration of the ramp type in terms of the number and shape of ramp flights, as shown in Figure 1. The type also distinguished turns by landings. In addition the subdivision of the straight and changing direction ramps is included. The ramp configurations are given for ramps without and with one and two landings.",
+        "description": "This enumeration defines the basic configuration of the ramp type in terms of the number and shape of ramp flights, as shown in Figure 1. The type also distinguished turns by landings. In addition the subdivision of the straight and changing direction ramps is included. The ramp configurations are given for ramps without and with one and two landings. Ramps which are subdivided into more than two landings, or ramps with non-regular shapes are to be defined with type being USERDEFINED or NOTDEFINED.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcramptypeenum.htm"
     },
     "IfcRatioMeasure": {
-        "description": "An IfcRatioMeasure is the value of the relation between two physical quantities that are of the same kind.",
+        "description": "An IfcRatioMeasure is the value of the relation between two physical quantities that are of the same kind. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcratiomeasure.htm"
     },
     "IfcReal": {
-        "description": "IfcReal is a defined type of simple data type REAL. It is required since a select type (IfcSimpleValue), cannot directly include simple types in its select list.",
+        "description": "IfcReal is a defined type of simple data type REAL. It is required since a select type (IfcSimpleValue), cannot directly include simple types in its select list. In principle, the domain of IfcReal (being a Real) is all rational, irrational and scientific real numbers. Here the precision is unconstrained, but in practice it is implementation specific. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcreal.htm"
     },
     "IfcRecurrenceTypeEnum": {
@@ -1136,19 +1136,19 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcactorresource/lexical/ifcroleenum.htm"
     },
     "IfcRoofTypeEnum": {
-        "description": "This enumeration defines the basic configuration of the roof in terms of the different roof shapes, as illustrated in Figure 1.",
+        "description": "This enumeration defines the basic configuration of the roof in terms of the different roof shapes, as illustrated in Figure 1. Roofs which are subdivided into more than these basic shapes or roofs with non-regular shapes (free form roofs) have the type FREEFORM.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcrooftypeenum.htm"
     },
     "IfcRotationalFrequencyMeasure": {
-        "description": "IfcRotationalFrequencyMeasure is a measure of the number of cycles that an item revolves in unit time.",
+        "description": "IfcRotationalFrequencyMeasure is a measure of the number of cycles that an item revolves in unit time. Usually measured in cycles/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcrotationalfrequencymeasure.htm"
     },
     "IfcRotationalMassMeasure": {
-        "description": "The rotational mass measure denotes the inertia of a body with respect to angular acceleration.",
+        "description": "The rotational mass measure denotes the inertia of a body with respect to angular acceleration. It is usually measured in kg*m\\^2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcrotationalmassmeasure.htm"
     },
     "IfcRotationalStiffnessMeasure": {
-        "description": "IfcRotationalStiffnessMeasure is a measure of rotational stiffness.",
+        "description": "IfcRotationalStiffnessMeasure is a measure of rotational stiffness. Usually measured in Nm/rad. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcrotationalstiffnessmeasure.htm"
     },
     "IfcRotationalStiffnessSelect": {
@@ -1168,7 +1168,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcplumbingfireprotectiondomain/lexical/ifcsanitaryterminaltypeenum.htm"
     },
     "IfcSectionModulusMeasure": {
-        "description": "IfcSectionModulusMeasure is a measure for the resistance of a cross section against bending or torsional moment. It is usually measured in m\\^3.",
+        "description": "IfcSectionModulusMeasure is a measure for the resistance of a cross section against bending or torsional moment. It is usually measured in m\\^3. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcsectionmodulusmeasure.htm"
     },
     "IfcSectionTypeEnum": {
@@ -1176,7 +1176,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprofileresource/lexical/ifcsectiontypeenum.htm"
     },
     "IfcSectionalAreaIntegralMeasure": {
-        "description": "The sectional area integral measure is typically used in torsional analysis. It is usually measured in m\\^5.",
+        "description": "The sectional area integral measure is typically used in torsional analysis. It is usually measured in m\\^5. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcsectionalareaintegralmeasure.htm"
     },
     "IfcSegmentIndexSelect": {
@@ -1196,7 +1196,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcshadingdevicetypeenum.htm"
     },
     "IfcShearModulusMeasure": {
-        "description": "IfcShearModulusMeasure is a measure of shear modulus.",
+        "description": "IfcShearModulusMeasure is a measure of shear modulus. Usually measured in N/m2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcshearmodulusmeasure.htm"
     },
     "IfcShell": {
@@ -1208,7 +1208,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifckernel/lexical/ifcsimplepropertytemplatetypeenum.htm"
     },
     "IfcSimpleValue": {
-        "description": "IfcSimpleValue is a select type for selecting between simple value types.",
+        "description": "IfcSimpleValue is a select type for selecting between simple value types. SELECT - IfcInteger: Defined type of simple type INTEGER. - IfcReal: Defined type of simple type REAL. - IfcBoolean: Defined type of simple type BOOLEAN. - IfcLogical: Defined type of simple type LOGICAL. - IfcIdentifier: Defined type of simple type STRING for identification purposes. - IfcLabel: Defined type of simple type STRING for naming purposes. - IfcText: Defined type of simple type STRING for descriptive purposes. - IfcDateTime: Defined type of simple type STRING to represent a date and time. - IfcDate: Defined type of simple type STRING to represent a date. - IfcTime: Defined type of simple type STRING to represent a time. - IfcDuration: Defined type of simple type STRING to represent a duration. - IfcTimeStamp: Defined type of simple type INTEGER to represent a point in time by seconds elapsed since 1970.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcsimplevalue.htm"
     },
     "IfcSizeSelect": {
@@ -1224,7 +1224,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifcsolardevicetypeenum.htm"
     },
     "IfcSolidAngleMeasure": {
-        "description": "An IfcSolidAngleMeasure is the value of an angle in a solid.",
+        "description": "An IfcSolidAngleMeasure is the value of an angle in a solid. Usually measured in Steradians, (sr, m2/m2). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcsolidanglemeasure.htm"
     },
     "IfcSolidOrShell": {
@@ -1232,23 +1232,23 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometricconstraintresource/lexical/ifcsolidorshell.htm"
     },
     "IfcSoundPowerLevelMeasure": {
-        "description": "A sound power level measure is a measure of total radiated noise with units of decibels with a reference value of picowatts.",
+        "description": "A sound power level measure is a measure of total radiated noise with units of decibels with a reference value of picowatts. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcsoundpowerlevelmeasure.htm"
     },
     "IfcSoundPowerMeasure": {
-        "description": "A sound power measure is a measure of total radiated noise with units of watts (sonic energy per time unit).",
+        "description": "A sound power measure is a measure of total radiated noise with units of watts (sonic energy per time unit). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcsoundpowermeasure.htm"
     },
     "IfcSoundPressureLevelMeasure": {
-        "description": "A sound pressure level measure is a measure of the pressure fluctuations superimposed over the ambient pressure level with units of decibels with a reference value of micropascals.",
+        "description": "A sound pressure level measure is a measure of the pressure fluctuations superimposed over the ambient pressure level with units of decibels with a reference value of micropascals. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcsoundpressurelevelmeasure.htm"
     },
     "IfcSoundPressureMeasure": {
-        "description": "A sound pressure measure is a measure of the pressure fluctuations superimposed over the ambient pressure level with units of pascals.",
+        "description": "A sound pressure measure is a measure of the pressure fluctuations superimposed over the ambient pressure level with units of pascals. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcsoundpressuremeasure.htm"
     },
     "IfcSpaceBoundarySelect": {
-        "description": "The IfcSpaceBoundarySelect selects either an internal space for internal or external space boundaries, or an external spatial element for external space boundaries at the outer envelop of the building.",
+        "description": "The IfcSpaceBoundarySelect selects either an internal space for internal or external space boundaries, or an external spatial element for external space boundaries at the outer envelop of the building. SELECT - IfcSpace, - IfcExternalSpatialElement",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcspaceboundaryselect.htm"
     },
     "IfcSpaceHeaterTypeEnum": {
@@ -1264,11 +1264,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcproductextension/lexical/ifcspatialzonetypeenum.htm"
     },
     "IfcSpecificHeatCapacityMeasure": {
-        "description": "IfcSpecificHeatCapacityMeasure defines the specific heat of material: The heat energy absorbed per temperature unit.",
+        "description": "IfcSpecificHeatCapacityMeasure defines the specific heat of material: The heat energy absorbed per temperature unit. Usually measured in J / kg Kelvin. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcspecificheatcapacitymeasure.htm"
     },
     "IfcSpecularExponent": {
-        "description": "The IfcSpecularExponent defines the datatype for exponent determining the sharpness of the 'reflection'. The reflection is made sharper with large values of the exponent, such as 10.0. Small values, such as 1.0, decrease the specular fall-off.",
+        "description": "The IfcSpecularExponent defines the datatype for exponent determining the sharpness of the 'reflection'. The reflection is made sharper with large values of the exponent, such as 10.0. Small values, such as 1.0, decrease the specular fall-off. IfcSpecularExponent is of type REAL.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcspecularexponent.htm"
     },
     "IfcSpecularHighlightSelect": {
@@ -1276,7 +1276,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcspecularhighlightselect.htm"
     },
     "IfcSpecularRoughness": {
-        "description": "The IfcSpecularRoughness defines the datatype for the reflection resulting from the roughness of a surface through the height of surface impurities where the specular highlight is made sharper with small values for the roughness, such as 0.1. Applies to \"glass\", \"metal\", \"mirror\" and \"plastic\" reflection models. Larger values, close to 1.0 decrease the specular fall-off.",
+        "description": "The IfcSpecularRoughness defines the datatype for the reflection resulting from the roughness of a surface through the height of surface impurities where the specular highlight is made sharper with small values for the roughness, such as 0.1. Applies to \"glass\", \"metal\", \"mirror\" and \"plastic\" reflection models. Larger values, close to 1.0 decrease the specular fall-off. IfcSpecularRoughness is of type REAL. It is constraint to values between (and including) 0 and 1.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcspecularroughness.htm"
     },
     "IfcStackTerminalTypeEnum": {
@@ -1288,11 +1288,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcstairflighttypeenum.htm"
     },
     "IfcStairTypeEnum": {
-        "description": "This enumeration defines the basic configuration of the stair type in terms of the number of stair flights and the number of landings, as illustrated in Figure 1. The type also distinguished turns by windings or by landings. In addition the subdivision of the straight and changing direction stairs is included. The stair configurations are given for stairs without and with one, two or three landings.",
+        "description": "This enumeration defines the basic configuration of the stair type in terms of the number of stair flights and the number of landings, as illustrated in Figure 1. The type also distinguished turns by windings or by landings. In addition the subdivision of the straight and changing direction stairs is included. The stair configurations are given for stairs without and with one, two or three landings. Stairs which are subdivided into more than three landings, or stairs with non-regular shapes are to be defined with type being USERDEFINED or NOTDEFINED.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcstairtypeenum.htm"
     },
     "IfcStateEnum": {
-        "description": "The IfcStateEnum enumeration identifies the state or accessibility of the object (for example, read/write, locked).",
+        "description": "The IfcStateEnum enumeration identifies the state or accessibility of the object (for example, read/write, locked). Valid enumerations are:",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcutilityresource/lexical/ifcstateenum.htm"
     },
     "IfcStructuralActivityAssignmentSelect": {
@@ -1316,7 +1316,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfacemembertypeenum.htm"
     },
     "IfcStyleAssignmentSelect": {
-        "description": "The style assignment select is a selection of two wasy of assigning presentation styles to an IfcStyledItem.",
+        "description": "The style assignment select is a selection of two wasy of assigning presentation styles to an IfcStyledItem. - by directly assigning presentation styles as subtypes of IfcPresentationStyle - by assigning presentation stypes via an intermediate collection entity IfcPresentationStyleAssignment",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifcstyleassignmentselect.htm"
     },
     "IfcSubContractResourceTypeEnum": {
@@ -1360,11 +1360,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcprocessextension/lexical/ifctasktypeenum.htm"
     },
     "IfcTemperatureGradientMeasure": {
-        "description": "The temperature gradient measures the difference of a temperature per length, as for instance used in an external wall or its layers. It is usually measured in K/m.",
+        "description": "The temperature gradient measures the difference of a temperature per length, as for instance used in an external wall or its layers. It is usually measured in K/m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifctemperaturegradientmeasure.htm"
     },
     "IfcTemperatureRateOfChangeMeasure": {
-        "description": "The temperature rate of change measures the difference of a temperature per time (positive: rise, negative: fall), as for instance used with heat sensors. It is for example measured in K/s (Kelvin per second).",
+        "description": "The temperature rate of change measures the difference of a temperature per time (positive: rise, negative: fall), as for instance used with heat sensors. It is for example measured in K/s (Kelvin per second). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifctemperaturerateofchangemeasure.htm"
     },
     "IfcTendonAnchorTypeEnum": {
@@ -1376,15 +1376,15 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifctendontypeenum.htm"
     },
     "IfcText": {
-        "description": "An IfcText is an alphanumeric string of characters which is intended to be read and understood by a human being. It is for information purposes only.",
+        "description": "An IfcText is an alphanumeric string of characters which is intended to be read and understood by a human being. It is for information purposes only. Type: STRING",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifctext.htm"
     },
     "IfcTextAlignment": {
-        "description": "The IfcTextAlignment describes how text is aligned within the element. Values are:",
+        "description": "The IfcTextAlignment describes how text is aligned within the element. Values are: - left - right - center - justify",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifctextalignment.htm"
     },
     "IfcTextDecoration": {
-        "description": "The IfcTextDecoration describes decorations that are added to the text of an element. Values are:",
+        "description": "The IfcTextDecoration describes decorations that are added to the text of an element. Values are: - none - underline - overline - line-through",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifctextdecoration.htm"
     },
     "IfcTextFontName": {
@@ -1400,39 +1400,39 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationdefinitionresource/lexical/ifctextpath.htm"
     },
     "IfcTextTransformation": {
-        "description": "The IfcTextTransformation describes how the cases of characters are handled. Values are:",
+        "description": "The IfcTextTransformation describes how the cases of characters are handled. Values are: - capitalize: uppercases the first character of each word - uppercase: uppercases all letters of the element - lowercase: lowercases all letters of the element - none",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcpresentationappearanceresource/lexical/ifctexttransformation.htm"
     },
     "IfcThermalAdmittanceMeasure": {
-        "description": "IfcThermalAdmittanceMeasure is the measure of the ability of a surface to smooth out temperature variations.",
+        "description": "IfcThermalAdmittanceMeasure is the measure of the ability of a surface to smooth out temperature variations. Usually measured in Watt / m2 Kelvin. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcthermaladmittancemeasure.htm"
     },
     "IfcThermalConductivityMeasure": {
-        "description": "IfcThermalConductivityMeasure is a measure of thermal conductivity.",
+        "description": "IfcThermalConductivityMeasure is a measure of thermal conductivity. Usually measured in Watt / m Kelvin. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcthermalconductivitymeasure.htm"
     },
     "IfcThermalExpansionCoefficientMeasure": {
-        "description": "IfcThermalExpansionCoeffientMeasure is a measure of the thermal expansion coefficient of a material, which expresses its elongation (as a ratio) per temperature difference. It is usually measured in 1/K. A positive elongation per (positive) rise of temperature is expressed by a positive value.",
+        "description": "IfcThermalExpansionCoeffientMeasure is a measure of the thermal expansion coefficient of a material, which expresses its elongation (as a ratio) per temperature difference. It is usually measured in 1/K. A positive elongation per (positive) rise of temperature is expressed by a positive value. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcthermalexpansioncoefficientmeasure.htm"
     },
     "IfcThermalResistanceMeasure": {
-        "description": "IfcThermalResistanceMeasure is a measure of the resistance offered by a body to the flow of energy.",
+        "description": "IfcThermalResistanceMeasure is a measure of the resistance offered by a body to the flow of energy. Usually measured in m2 Kelvin/Watt.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcthermalresistancemeasure.htm"
     },
     "IfcThermalTransmittanceMeasure": {
-        "description": "IfcThermalTransmittanceMeasure is a measure of the rate at which energy is transmitted through a body.",
+        "description": "IfcThermalTransmittanceMeasure is a measure of the rate at which energy is transmitted through a body. Usually measured in Watts/m2 Kelvin. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcthermaltransmittancemeasure.htm"
     },
     "IfcThermodynamicTemperatureMeasure": {
-        "description": "A thermodynamic temperature measure is the value for the degree of heat of a body.",
+        "description": "A thermodynamic temperature measure is the value for the degree of heat of a body. Usually measured in degrees Kelvin (K). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcthermodynamictemperaturemeasure.htm"
     },
     "IfcTime": {
-        "description": "The IfcTime identifies a time within a day, expressed by hours, minutes and second. It is expressed by a string value following a particular lexical representation.",
+        "description": "The IfcTime identifies a time within a day, expressed by hours, minutes and second. It is expressed by a string value following a particular lexical representation. The lexical representation for IfcTime is: hh:mm:ss where where hh represents hours, mm minutes and ss seconds. Additional digits can be used to increase the precision of fractional seconds if desired i.e the format ss.ss... A time zone indicator may be provided by a representation of the different to the Coordinated Universal Time. It is appended with a sign [+/-] followed by hh and optionally :mm.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifctime.htm"
     },
     "IfcTimeMeasure": {
-        "description": "An IfcTimeMeasure is the value of the duration of periods.",
+        "description": "An IfcTimeMeasure is the value of the duration of periods. Measured in seconds (s) or days (d) or other units of time. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifctimemeasure.htm"
     },
     "IfcTimeOrRatioSelect": {
@@ -1444,11 +1444,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifctimeseriesdatatypeenum.htm"
     },
     "IfcTimeStamp": {
-        "description": "IfcTimeStamp is an indication of date and time by measuring the number of seconds which have elapsed since 1 January 1970, 00:00:00 UTC.",
+        "description": "IfcTimeStamp is an indication of date and time by measuring the number of seconds which have elapsed since 1 January 1970, 00:00:00 UTC. Type: INTEGER",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcdatetimeresource/lexical/ifctimestamp.htm"
     },
     "IfcTorqueMeasure": {
-        "description": "IfcTorqueMeasure is a measure of the torque or moment of a couple.",
+        "description": "IfcTorqueMeasure is a measure of the torque or moment of a couple. Usually measured in N m. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifctorquemeasure.htm"
     },
     "IfcTransformerTypeEnum": {
@@ -1456,7 +1456,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcelectricaldomain/lexical/ifctransformertypeenum.htm"
     },
     "IfcTransitionCode": {
-        "description": "The IfcTransitionCode indicated the continuity between consecutive segments of a curve or surface.",
+        "description": "The IfcTransitionCode indicated the continuity between consecutive segments of a curve or surface. Figure 1 illustrates transition types",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcgeometryresource/lexical/ifctransitioncode.htm"
     },
     "IfcTranslationalStiffnessSelect": {
@@ -1480,11 +1480,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifctubebundletypeenum.htm"
     },
     "IfcURIReference": {
-        "description": "The IfcURIReference provides for identifying a Uniform Resource Identifier (URI). A URI can be classified as a locator or a name or both, that is it may comprise a Uniform Resource Locator (URL) and/or a Uniform Resource Name (URN).",
+        "description": "The IfcURIReference provides for identifying a Uniform Resource Identifier (URI). A URI can be classified as a locator or a name or both, that is it may comprise a Uniform Resource Locator (URL) and/or a Uniform Resource Name (URN). - A Uniform Resource Locator, URL, is a string conforming to a standardized format, which refers to a resource on the internet (such as a document or an image) by its location. - A Uniform Resource Name, URN, is intended to serve as persistent, location-independent resource identifier and is designed to make it easy to map other namespaces (that share the properties of URNs) into URN-space.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcexternalreferenceresource/lexical/ifcurireference.htm"
     },
     "IfcUnit": {
-        "description": "A unit is a physical quantity, with a value of one, which is used as a standard in terms of which other quantities are expressed.",
+        "description": "SELECT - IfcNamedUnit: A unit which is identified by a name. - IfcDerivedUnit: A unit which is derived from an expression of units. - IfcMonetaryUnit: A unit for defining currencies.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcunit.htm"
     },
     "IfcUnitEnum": {
@@ -1500,7 +1500,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcunitaryequipmenttypeenum.htm"
     },
     "IfcValue": {
-        "description": "IfcValue is a select type for selecting between more specialised select types IfcSimpleValue, IfcMeasureValue and IfcDerivedMeasureValue.",
+        "description": "IfcValue is a select type for selecting between more specialised select types IfcSimpleValue, IfcMeasureValue and IfcDerivedMeasureValue. SELECT - IfcSimpleValue A select type for basic defined types of simple data type. - IfcMeasureValue A select type for basic measure types of ISO 10303-41. - IfcDerivedMeasureValue A select type for derived measure types.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcvalue.htm"
     },
     "IfcValveTypeEnum": {
@@ -1508,7 +1508,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifchvacdomain/lexical/ifcvalvetypeenum.htm"
     },
     "IfcVaporPermeabilityMeasure": {
-        "description": "IfcVaporPermeabilityMeasure is a measure of vapor permeability.",
+        "description": "IfcVaporPermeabilityMeasure is a measure of vapor permeability. Usually measured in kg / s m Pascal. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcvaporpermeabilitymeasure.htm"
     },
     "IfcVectorOrDirection": {
@@ -1524,11 +1524,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcstructuralelementsdomain/lexical/ifcvoidingfeaturetypeenum.htm"
     },
     "IfcVolumeMeasure": {
-        "description": "An IfcVolumeMeasure is the value of the solid content of a body.",
+        "description": "An IfcVolumeMeasure is the value of the solid content of a body. Usually measured in cubic metre (m3). Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcvolumemeasure.htm"
     },
     "IfcVolumetricFlowRateMeasure": {
-        "description": "IfcVolumetricFlowRateMeasure is a measure of the volume of a medium flowing per unit time.",
+        "description": "IfcVolumetricFlowRateMeasure is a measure of the volume of a medium flowing per unit time. Usually measured in m3/s. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcvolumetricflowratemeasure.htm"
     },
     "IfcWallTypeEnum": {
@@ -1536,11 +1536,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcwalltypeenum.htm"
     },
     "IfcWarpingConstantMeasure": {
-        "description": "IfcWarpingConstantMeasure is a measure for the warping constant or warping resistance of a cross section under torsional loading. It is usually measured in m\\^6.",
+        "description": "IfcWarpingConstantMeasure is a measure for the warping constant or warping resistance of a cross section under torsional loading. It is usually measured in m\\^6. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcwarpingconstantmeasure.htm"
     },
     "IfcWarpingMomentMeasure": {
-        "description": "The warping moment measure is a measure for the warping moment, which occurs in warping torsional analysis. It is usually measured in kN*m\\^2.",
+        "description": "The warping moment measure is a measure for the warping moment, which occurs in warping torsional analysis. It is usually measured in kN*m\\^2. Type: REAL",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcmeasureresource/lexical/ifcwarpingmomentmeasure.htm"
     },
     "IfcWarpingStiffnessSelect": {
@@ -1552,11 +1552,11 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcplumbingfireprotectiondomain/lexical/ifcwasteterminaltypeenum.htm"
     },
     "IfcWindowPanelOperationEnum": {
-        "description": "This enumeration defines the basic ways to describe how window panels operate, as shown in Figure 2.",
+        "description": "This enumeration defines the basic ways to describe how window panels operate, as shown in Figure 2. The opening direction of the window panels is given by the local placement of the IfcWindow. The positive y-axis determines the direction as shown in Figure 2. NOTE - Figures are shown as viewed from the outside (in direction of the positive y-axis). - Figures (symbolic representation) depend on the national building code - These figures are only shown as illustrations",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcwindowpaneloperationenum.htm"
     },
     "IfcWindowPanelPositionEnum": {
-        "description": "This enumeration defines the basic configuration of the window type in terms of the location of window panels. The window configurations are given for windows with one, two or three panels (including fixed panels) as shown in Figure 1. It corresponds to the OperationType of the IfcWindowStyle definition, which references the IfcWindowPanelProperties.",
+        "description": "This enumeration defines the basic configuration of the window type in terms of the location of window panels. The window configurations are given for windows with one, two or three panels (including fixed panels) as shown in Figure 1. It corresponds to the OperationType of the IfcWindowStyle definition, which references the IfcWindowPanelProperties. Windows which are subdivided into more than three panels have to be defined by the geometry only. The type of such windows is given by an IfcWindowType.OperationType = USERDEFINED or NOTDEFINED (see IfcWindowStyleOperationEnum for details). NOTE - The figures are shown as elevations in the XZ plane of the local placement of the window, looking into the direction of the positive Y axis. - These figures are only shown as illustrations.",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcwindowpanelpositionenum.htm"
     },
     "IfcWindowStyleConstructionEnum": {
@@ -1564,7 +1564,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcwindowstyleconstructionenum.htm"
     },
     "IfcWindowStyleOperationEnum": {
-        "description": "This enumeration defines the basic configuration of the window type in terms of the number of window panels and the subdivision of the total window. The window configurations are given for windows with one, two or three panels (including fixed panels) as shown in Figure 1.",
+        "description": "This enumeration defines the basic configuration of the window type in terms of the number of window panels and the subdivision of the total window. The window configurations are given for windows with one, two or three panels (including fixed panels) as shown in Figure 1. Windows which are subdivided into more than three panels have to be defined by the geometry only. The type of such windows is USERDEFINED. NOTE - The way how each panel operates is defined at the IfcWindowPanelProperties.OperationType. - The reference from the window panel to the location of that panel in the window style configuration is handled by the IfcWindowPanelProperties.PanelPosition. - The figures are shown as elevations in the XZ plane of the local placement of the window, looking into the direction of the positive Y axis. - These figures are only shown as illustrations",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcarchitecturedomain/lexical/ifcwindowstyleoperationenum.htm"
     },
     "IfcWindowTypeEnum": {
@@ -1572,7 +1572,7 @@
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcwindowtypeenum.htm"
     },
     "IfcWindowTypePartitioningEnum": {
-        "description": "This enumeration defines the basic configuration of the window type in terms of the number of window panels and the subdivision of the total window as shown in Figure 1. The window configurations are given for windows with one, two or three panels (including fixed panels).",
+        "description": "This enumeration defines the basic configuration of the window type in terms of the number of window panels and the subdivision of the total window as shown in Figure 1. The window configurations are given for windows with one, two or three panels (including fixed panels). Windows which are subdivided into more than three panels have to be defined by the geometry only. The type of such windows is USERDEFINED. NOTE - The way how each panel operates is defined at the IfcWindowPanelProperties.OperationType. - The reference from the window panel to the location of that panel in the window style configuration is handled by the IfcWindowPanelProperties.PanelPosition. - The figures are shown as elevations in the XZ plane of the local placement of the window, looking into the direction of the positive Y axis. - These figures are only shown as illustrations",
         "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcwindowtypepartitioningenum.htm"
     },
     "IfcWorkCalendarTypeEnum": {