New usecase for adding conversion based units

src/blenderbim/blenderbim/bim/export_ifc.py

@@ -27,6 +27,8 @@ import addon_utils
 import ifcopenshell
 import ifcopenshell.api
 import ifcopenshell.util.placement
+import blenderbim.tool as tool
+import blenderbim.core.style
 from blenderbim.bim.ifc import IfcStore
 
 
@@ -105,7 +107,7 @@ class IfcExporter:
                 continue
             try:
                 if isinstance(obj, bpy.types.Material):
-                    bpy.ops.bim.update_style_colours(material=obj.name)
+                    blenderbim.core.style.update_style_colours(tool.Ifc, tool.Style, obj=obj)
                 else:
                     bpy.ops.bim.update_representation(obj=obj.name)
             except ReferenceError:

src/blenderbim/blenderbim/bim/module/aggregate/operator.py

@@ -97,5 +97,5 @@ class AddAggregate(bpy.types.Operator):
         aggregate = bpy.data.objects.new("Assembly", None)
         aggregate_collection.objects.link(aggregate)
         bpy.ops.bim.assign_class(obj=aggregate.name, ifc_class="IfcElementAssembly")
-        bpy.ops.bim.assign_object(related_object=obj.name, relating_object=aggregate.name)
+        core.assign_object(tool.Ifc, tool.Aggregate, tool.Collector, relating_obj=aggregate, related_obj=obj)
         return {"FINISHED"}

src/blenderbim/blenderbim/bim/module/geometry/operator.py

@@ -25,6 +25,7 @@ import ifcopenshell.util.representation
 import logging
 import ifcopenshell.api
 import blenderbim.core.geometry as core
+import blenderbim.core.style
 import blenderbim.tool as tool
 from blenderbim.bim.ifc import IfcStore
 from blenderbim.bim import import_ifc
@@ -108,7 +109,7 @@ class AddRepresentation(bpy.types.Operator):
             return {"FINISHED"}
 
         [
-            bpy.ops.bim.add_style(material=s.material.name)
+            blenderbim.core.style.add_style(tool.Ifc, tool.Style, obj=s.material)
             for s in obj.material_slots
             if s.material and not s.material.BIMMaterialProperties.ifc_style_id
         ]

src/blenderbim/blenderbim/bim/module/project/operator.py

@@ -69,7 +69,7 @@ class CreateProject(bpy.types.Operator):
         building_storey = bpy.data.objects.new(self.get_name("IfcBuildingStorey", "My Storey"), None)
 
         bpy.ops.bim.assign_class(obj=project.name, ifc_class="IfcProject")
-        bpy.ops.bim.assign_unit()
+        blenderbim.core.unit.assign_scene_units(tool.Ifc, tool.Unit)
 
         model = blenderbim.core.context.add_context(
             tool.Ifc, context_type="Model", context_identifier="", target_view="", parent=0

src/blenderbim/blenderbim/bim/module/spatial/data.py

@@ -64,4 +64,4 @@ class SpatialData:
 
     @classmethod
     def is_directly_contained(cls):
-        return bool(getattr(tool.Ifc.get_entity(bpy.context.active_object), "ContainedInStructure"))
+        return bool(getattr(tool.Ifc.get_entity(bpy.context.active_object), "ContainedInStructure", False))

src/blenderbim/blenderbim/bim/module/unit/__init__.py

@@ -20,6 +20,7 @@ import bpy
 from . import ui, prop, operator
 
 classes = (
+    operator.AssignSceneUnits,
     operator.AssignUnit,
     operator.UnassignUnit,
     operator.LoadUnits,

src/blenderbim/blenderbim/bim/module/unit/data.py

@@ -0,0 +1,38 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import blenderbim.tool as tool
+
+
+def refresh():
+    UnitsData.is_loaded = False
+
+
+class UnitsData:
+    data = {}
+    is_loaded = False
+
+    @classmethod
+    def load(cls):
+        cls.data = {"total_units": cls.get_total_units()}
+        cls.is_loaded = True
+
+    @classmethod
+    def get_total_units(cls):
+        ifc = tool.Ifc.get()
+        return len(ifc.by_type("IfcDerivedUnit") + ifc.by_type("IfcNamedUnit") + ifc.by_type("IfcMonetaryUnit"))

src/blenderbim/blenderbim/bim/module/unit/operator.py

@@ -21,274 +21,131 @@ import json
 import ifcopenshell.api
 import ifcopenshell.util.unit
 import blenderbim.bim.helper
+import blenderbim.bim.handler
+import blenderbim.tool as tool
+import blenderbim.core.unit as core
 from blenderbim.bim.ifc import IfcStore
 from ifcopenshell.api.unit.data import Data
 
 
-class AssignUnit(bpy.types.Operator):
+class Operator:
+    def execute(self, context):
+        IfcStore.execute_ifc_operator(self, context)
+        blenderbim.bim.handler.refresh_ui_data
+        return {"FINISHED"}
+
+
+class AssignSceneUnits(bpy.types.Operator, Operator):
+    bl_idname = "bim.assign_scene_units"
+    bl_label = "Assign Scene Units"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def _execute(self, context):
+        core.assign_scene_units(tool.Ifc, tool.Unit)
+
+
+class AssignUnit(bpy.types.Operator, Operator):
     bl_idname = "bim.assign_unit"
     bl_label = "Assign Unit"
     bl_options = {"REGISTER", "UNDO"}
     unit: bpy.props.IntProperty()
 
-    def execute(self, context):
-        return IfcStore.execute_ifc_operator(self, context)
-
     def _execute(self, context):
-        self.file = IfcStore.get_file()
+        core.assign_unit(tool.Ifc, tool.Unit, unit=tool.Ifc.get().by_id(self.unit))
-        if self.unit:
-            ifcopenshell.api.run("unit.assign_unit", self.file, units=[self.file.by_id(self.unit)])
-        else:
-            ifcopenshell.api.run("unit.assign_unit", self.file, **self.get_units(context))
-        Data.load(self.file)
-        if self.unit:
-            bpy.ops.bim.load_units()
-        return {"FINISHED"}
-
-    def get_units(self, context):
-        scene = context.scene
-        units = {
-            "length": {
-                "ifc": None,
-                "is_metric": scene.unit_settings.system != "IMPERIAL",
-                "raw": scene.unit_settings.length_unit,
-            },
-            "area": {
-                "ifc": None,
-                "is_metric": scene.unit_settings.system != "IMPERIAL",
-                "raw": scene.unit_settings.length_unit,
-            },
-            "volume": {
-                "ifc": None,
-                "is_metric": scene.unit_settings.system != "IMPERIAL",
-                "raw": scene.unit_settings.length_unit,
-            },
-        }
-        for data in units.values():
-            if data["raw"] == "ADAPTIVE":
-                if data["is_metric"]:
-                    data["raw"] = "METERS"
-                else:
-                    data["raw"] = "FEET"
-        return units
 
 
-class UnassignUnit(bpy.types.Operator):
+class UnassignUnit(bpy.types.Operator, Operator):
     bl_idname = "bim.unassign_unit"
     bl_label = "Unassign Unit"
     bl_options = {"REGISTER", "UNDO"}
     unit: bpy.props.IntProperty()
 
-    def execute(self, context):
-        return IfcStore.execute_ifc_operator(self, context)
-
     def _execute(self, context):
-        self.file = IfcStore.get_file()
+        core.unassign_unit(tool.Ifc, tool.Unit, unit=tool.Ifc.get().by_id(self.unit))
-        ifcopenshell.api.run("unit.unassign_unit", IfcStore.get_file(), units=[self.file.by_id(self.unit)])
-        Data.load(self.file)
-        bpy.ops.bim.load_units()
-        return {"FINISHED"}
 
 
-class LoadUnits(bpy.types.Operator):
+class LoadUnits(bpy.types.Operator, Operator):
     bl_idname = "bim.load_units"
     bl_label = "Load Units"
     bl_options = {"REGISTER", "UNDO"}
 
-    def execute(self, context):
+    def _execute(self, context):
-        props = context.scene.BIMUnitProperties
+        core.load_units(tool.Unit)
-        props.units.clear()
-
-        for ifc_definition_id, unit in Data.units.items():
-            name = unit.get("Name", "")
-
-            if unit["type"] == "IfcMonetaryUnit":
-                name = unit["Currency"]
-
-            if unit["type"] == "IfcSIUnit" and unit["Prefix"]:
-                if "_" in name:
-                    name_components = name.split("_")
-                    name = f"{name_components[0]} {unit['Prefix']}{name_components[1]}"
-                else:
-                    name = f"{unit['Prefix']}{name}"
-
-            icon = "MOD_MESHDEFORM"
-            if unit["type"] == "IfcSIUnit":
-                icon = "SNAP_GRID"
-            elif unit["type"] == "IfcMonetaryUnit":
-                icon = "COPY_ID"
-
-            unit_type = unit.get("UserDefinedType", None)
-            if not unit_type:
-                unit_type = unit.get("UnitType", None)
-            if unit["type"] == "IfcMonetaryUnit":
-                unit_type = "CURRENCY"
-
-            new = props.units.add()
-            new.ifc_definition_id = ifc_definition_id
-            new.name = name
-            new.unit_type = unit_type
-            new.is_assigned = ifc_definition_id in Data.unit_assignment
-            new.icon = icon
-
-        props.is_editing = True
-        bpy.ops.bim.disable_editing_unit()
-        return {"FINISHED"}
 
 
-class DisableUnitEditingUI(bpy.types.Operator):
+class DisableUnitEditingUI(bpy.types.Operator, Operator):
     bl_idname = "bim.disable_unit_editing_ui"
     bl_label = "Disable Unit Editing UI"
     bl_options = {"REGISTER", "UNDO"}
 
-    def execute(self, context):
+    def _execute(self, context):
-        context.scene.BIMUnitProperties.is_editing = False
+        core.disable_unit_editing_ui(tool.Unit)
-        return {"FINISHED"}
 
 
-class RemoveUnit(bpy.types.Operator):
+class RemoveUnit(bpy.types.Operator, Operator):
     bl_idname = "bim.remove_unit"
     bl_label = "Remove Unit"
     bl_options = {"REGISTER", "UNDO"}
     unit: bpy.props.IntProperty()
 
-    def execute(self, context):
-        return IfcStore.execute_ifc_operator(self, context)
-
     def _execute(self, context):
-        props = context.scene.BIMUnitProperties
+        core.remove_unit(tool.Ifc, tool.Unit, unit=tool.Ifc.get().by_id(self.unit))
-        self.file = IfcStore.get_file()
-        ifcopenshell.api.run("unit.remove_unit", self.file, **{"unit": self.file.by_id(self.unit)})
-        Data.load(self.file)
-        bpy.ops.bim.load_units()
-        return {"FINISHED"}
 
 
-class AddMonetaryUnit(bpy.types.Operator):
+class AddMonetaryUnit(bpy.types.Operator, Operator):
     bl_idname = "bim.add_monetary_unit"
     bl_label = "Add Monetary Unit"
     bl_options = {"REGISTER", "UNDO"}
 
-    def execute(self, context):
-        return IfcStore.execute_ifc_operator(self, context)
-
     def _execute(self, context):
-        props = context.scene.BIMUnitProperties
+        core.add_monetary_unit(tool.Ifc, tool.Unit)
-        self.file = IfcStore.get_file()
-        ifcopenshell.api.run("unit.add_monetary_unit", self.file)
-        Data.load(self.file)
-        bpy.ops.bim.load_units()
-        return {"FINISHED"}
 
 
-class AddSIUnit(bpy.types.Operator):
+class AddSIUnit(bpy.types.Operator, Operator):
     bl_idname = "bim.add_si_unit"
     bl_label = "Add SI Unit"
     bl_options = {"REGISTER", "UNDO"}
-
+    unit_type: bpy.props.StringProperty()
-    def execute(self, context):
-        return IfcStore.execute_ifc_operator(self, context)
 
     def _execute(self, context):
-        props = context.scene.BIMUnitProperties
+        core.add_si_unit(tool.Ifc, tool.Unit, unit_type=self.unit_type)
-        self.file = IfcStore.get_file()
-        ifcopenshell.api.run(
-            "unit.add_si_unit",
-            self.file,
-            unit_type=props.named_unit_types,
-            name=ifcopenshell.util.unit.si_type_names[props.named_unit_types],
-        )
-        Data.load(self.file)
-        bpy.ops.bim.load_units()
-        return {"FINISHED"}
 
 
-class AddContextDependentUnit(bpy.types.Operator):
+class AddContextDependentUnit(bpy.types.Operator, Operator):
     bl_idname = "bim.add_context_dependent_unit"
     bl_label = "Add Context Dependent Unit"
     bl_options = {"REGISTER", "UNDO"}
-
+    name: bpy.props.StringProperty()
-    def execute(self, context):
+    unit_type: bpy.props.StringProperty()
-        return IfcStore.execute_ifc_operator(self, context)
 
     def _execute(self, context):
-        props = context.scene.BIMUnitProperties
+        core.add_context_dependent_unit(tool.Ifc, tool.Unit, unit_type=self.unit_type, name=self.name)
-        self.file = IfcStore.get_file()
-        ifcopenshell.api.run(
-            "unit.add_context_dependent_unit", self.file, unit_type=props.named_unit_types, name="THINGAMAJIG"
-        )
-        Data.load(self.file)
-        bpy.ops.bim.load_units()
-        return {"FINISHED"}
 
 
-class EnableEditingUnit(bpy.types.Operator):
+class EnableEditingUnit(bpy.types.Operator, Operator):
     bl_idname = "bim.enable_editing_unit"
     bl_label = "Enable Editing Unit"
     bl_options = {"REGISTER", "UNDO"}
     unit: bpy.props.IntProperty()
 
-    def execute(self, context):
+    def _execute(self, context):
-        props = context.scene.BIMUnitProperties
+        core.enable_editing_unit(tool.Unit, unit=tool.Ifc.get().by_id(self.unit))
-        props.unit_attributes.clear()
-        data = Data.units[self.unit]
-        blenderbim.bim.helper.import_attributes(
-            data["type"],
-            props.unit_attributes,
-            data,
-            lambda name, prop, data: self.import_attributes(name, prop, data, context),
-        )
-        props.active_unit_id = self.unit
-        return {"FINISHED"}
-
-    def import_attributes(self, name, prop, data, context):
-        if name == "Dimensions" and data["type"] != "IfcSIUnit":
-            new = context.scene.BIMUnitProperties.unit_attributes.add()
-            new.name = name
-            new.is_null = data[name] is None
-            new.is_optional = False
-            new.data_type = "string"
-            new.string_value = json.dumps([e for e in IfcStore.get_file().by_id(data["id"]).Dimensions])
-            return True
 
 
-class DisableEditingUnit(bpy.types.Operator):
+class DisableEditingUnit(bpy.types.Operator, Operator):
     bl_idname = "bim.disable_editing_unit"
     bl_label = "Disable Editing Unit"
     bl_options = {"REGISTER", "UNDO"}
 
-    def execute(self, context):
+    def _execute(self, context):
-        context.scene.BIMUnitProperties.active_unit_id = 0
+        core.disable_editing_unit(tool.Unit)
-        return {"FINISHED"}
 
 
-class EditUnit(bpy.types.Operator):
+class EditUnit(bpy.types.Operator, Operator):
     bl_idname = "bim.edit_unit"
     bl_label = "Edit Unit"
     bl_options = {"REGISTER", "UNDO"}
-
+    unit: bpy.props.IntProperty()
-    def execute(self, context):
-        return IfcStore.execute_ifc_operator(self, context)
 
     def _execute(self, context):
-        props = context.scene.BIMUnitProperties
+        core.edit_unit(tool.Ifc, tool.Unit, unit=tool.Ifc.get().by_id(self.unit))
-        attributes = blenderbim.bim.helper.export_attributes(props.unit_attributes, self.export_attributes)
-        self.file = IfcStore.get_file()
-        unit = self.file.by_id(props.active_unit_id)
-        if unit.is_a("IfcMonetaryUnit"):
-            ifcopenshell.api.run("unit.edit_monetary_unit", self.file, **{"unit": unit, "attributes": attributes})
-        elif unit.is_a("IfcDerivedUnit"):
-            ifcopenshell.api.run("unit.edit_derived_unit", self.file, **{"unit": unit, "attributes": attributes})
-        elif unit.is_a("IfcNamedUnit"):
-            ifcopenshell.api.run("unit.edit_named_unit", self.file, **{"unit": unit, "attributes": attributes})
-        Data.load(IfcStore.get_file())
-        bpy.ops.bim.load_units()
-        return {"FINISHED"}
-
-    def export_attributes(self, attributes, prop):
-        if prop.name == "Dimensions":
-            try:
-                attributes[prop.name] = json.loads(prop.get_value())
-            except:
-                attributes[prop.name] = (0, 0, 0, 0, 0, 0, 0)
-            return True

src/blenderbim/blenderbim/bim/module/unit/prop.py

@@ -69,7 +69,7 @@ class Unit(PropertyGroup):
     name: StringProperty(name="Name")
     unit_type: StringProperty(name="Unit Type")
     is_assigned: BoolProperty(name="Is Assigned")
-    icon: StringProperty(name="Icon")
+    ifc_class: StringProperty(name="IFC Class")
     ifc_definition_id: IntProperty(name="IFC Definition ID")
 
 

src/blenderbim/blenderbim/bim/module/unit/ui.py

@@ -19,7 +19,7 @@
 import blenderbim.bim.helper
 from bpy.types import Panel, UIList
 from blenderbim.bim.ifc import IfcStore
-from ifcopenshell.api.unit.data import Data
+from blenderbim.bim.module.unit.data import UnitsData
 
 
 class BIM_PT_units(Panel):
@@ -36,13 +36,13 @@ class BIM_PT_units(Panel):
         return file
 
     def draw(self, context):
-        self.file = IfcStore.get_file()
+        if not UnitsData.is_loaded:
-        if not Data.is_loaded:
+            UnitsData.load()
-            Data.load(self.file)
+
         self.props = context.scene.BIMUnitProperties
 
         row = self.layout.row(align=True)
-        row.label(text="{} Units Found".format(len(Data.units)), icon="SNAP_GRID")
+        row.label(text="{} Units Found".format(UnitsData.data["total_units"]), icon="SNAP_GRID")
         if self.props.is_editing:
             row.operator("bim.disable_unit_editing_ui", text="", icon="CANCEL")
         else:
@@ -60,10 +60,13 @@ class BIM_PT_units(Panel):
             pass  # TODO
         elif self.props.unit_classes == "IfcSIUnit":
             row.prop(self.props, "named_unit_types", text="")
-            row.operator("bim.add_si_unit", text="", icon="ADD")
+            op = row.operator("bim.add_si_unit", text="", icon="ADD")
+            op.unit_type = self.props.named_unit_types
         elif self.props.unit_classes == "IfcContextDependentUnit":
             row.prop(self.props, "named_unit_types", text="")
-            row.operator("bim.add_context_dependent_unit", text="", icon="ADD")
+            op = row.operator("bim.add_context_dependent_unit", text="", icon="ADD")
+            op.name = "THINGAMAJIG"
+            op.unit_type = self.props.named_unit_types
 
         self.layout.template_list(
             "BIM_UL_units",
@@ -85,8 +88,14 @@ class BIM_UL_units(UIList):
     def draw_item(self, context, layout, data, item, icon, active_data, active_propname):
         props = context.scene.BIMUnitProperties
         if item:
+            icon = "MOD_MESHDEFORM"
+            if item.ifc_class == "IfcSIUnit":
+                icon = "SNAP_GRID"
+            elif item.ifc_class == "IfcMonetaryUnit":
+                icon = "COPY_ID"
+
             row = layout.row(align=True)
-            row.label(text=item.unit_type or "No Type", icon=item.icon)
+            row.label(text=item.unit_type or "No Type", icon=icon)
             row.label(text=item.name or "Unnamed")
 
             if item.is_assigned:

src/blenderbim/blenderbim/core/tool.py

@@ -130,6 +130,22 @@ class Surveyor:
     def get_absolute_matrix(cls, obj): pass
 
 
+@interface
+class Unit:
+    def clear_active_unit(cls): pass
+    def disable_editing_units(cls): pass
+    def enable_editing_units(cls): pass
+    def export_unit_attributes(cls): pass
+    def get_scene_unit_name(cls, unit_type): pass
+    def get_scene_unit_si_prefix(cls): pass
+    def get_si_name_from_unit_type(cls, unit_type): pass
+    def get_unit_class(cls, unit): pass
+    def import_unit_attributes(cls, unit): pass
+    def import_units(cls): pass
+    def is_scene_unit_metric(cls): pass
+    def set_active_unit(cls, unit): pass
+
+
 @interface
 class Voider:
     def can_void(cls, opening, element): pass

src/blenderbim/blenderbim/core/unit.py

@@ -0,0 +1,99 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+
+def assign_scene_units(ifc, unit):
+    length_name = unit.get_scene_unit_name("length")
+    area_name = unit.get_scene_unit_name("area")
+    volume_name = unit.get_scene_unit_name("volume")
+
+    if unit.is_scene_unit_metric():
+        prefix = unit.get_scene_unit_si_prefix()
+        lengthunit = ifc.run("unit.add_si_unit", unit_type="LENGTHUNIT", name=length_name, prefix=prefix)
+        areaunit = ifc.run("unit.add_si_unit", unit_type="AREAUNIT", name=area_name, prefix=prefix)
+        volumeunit = ifc.run("unit.add_si_unit", unit_type="VOLUMEUNIT", name=volume_name, prefix=prefix)
+    else:
+        lengthunit = ifc.run("unit.add_conversion_based_unit", name=length_name)
+        areaunit = ifc.run("unit.add_conversion_based_unit", name=area_name)
+        volumeunit = ifc.run("unit.add_conversion_based_unit", name=volume_name)
+
+    ifc.run("unit.assign_unit", units=[lengthunit, areaunit, volumeunit])
+
+
+def assign_unit(ifc, unit_tool, unit=None):
+    ifc.run("unit.assign_unit", units=[unit])
+    unit_tool.import_units()
+
+
+def unassign_unit(ifc, unit_tool, unit=None):
+    ifc.run("unit.unassign_unit", units=[unit])
+    unit_tool.import_units()
+
+
+def load_units(unit):
+    unit.import_units()
+    unit.enable_editing_units()
+
+
+def disable_unit_editing_ui(unit):
+    unit.disable_editing_units()
+
+
+def remove_unit(ifc, unit_tool, unit=None):
+    ifc.run("unit.remove_unit", unit=unit)
+    unit_tool.import_units()
+
+
+def add_monetary_unit(ifc, unit):
+    result = ifc.run("unit.add_monetary_unit")
+    unit.import_units()
+    return result
+
+
+def add_si_unit(ifc, unit, unit_type=None):
+    result = ifc.run("unit.add_si_unit", unit_type=unit_type, name=unit.get_si_name_from_unit_type(unit_type))
+    unit.import_units()
+    return result
+
+
+def add_context_dependent_unit(ifc, unit, unit_type=None, name=None):
+    result = ifc.run("unit.add_context_dependent_unit", unit_type=unit_type, name=name)
+    unit.import_units()
+    return result
+
+
+def enable_editing_unit(unit_tool, unit=None):
+    unit_tool.set_active_unit(unit)
+    unit_tool.import_unit_attributes(unit)
+
+
+def disable_editing_unit(unit):
+    unit.clear_active_unit()
+
+
+def edit_unit(ifc, unit_tool, unit=None):
+    attributes = unit_tool.export_unit_attributes()
+    unit_class = unit_tool.get_unit_class(unit)
+    if unit_class == "IfcMonetaryUnit":
+        ifc.run("unit.edit_monetary_unit", unit=unit, attributes=attributes)
+    elif unit_class == "IfcDerivedUnit":
+        ifc.run("unit.edit_derived_unit", unit=unit, attributes=attributes)
+    elif unit_class == "IfcNamedUnit":
+        ifc.run("unit.edit_named_unit", unit=unit, attributes=attributes)
+    unit_tool.import_units()
+    unit_tool.clear_active_unit()

src/blenderbim/blenderbim/tool/__init__.py

@@ -25,3 +25,4 @@ from blenderbim.tool.ifc import Ifc
 from blenderbim.tool.owner import Owner
 from blenderbim.tool.style import Style
 from blenderbim.tool.surveyor import Surveyor
+from blenderbim.tool.unit import Unit

src/blenderbim/blenderbim/tool/unit.py

@@ -0,0 +1,157 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import bpy
+import json
+import ifcopenshell
+import blenderbim.core.tool
+import blenderbim.tool as tool
+
+
+class Unit(blenderbim.core.tool.Unit):
+    @classmethod
+    def clear_active_unit(cls):
+        bpy.context.scene.BIMUnitProperties.active_unit_id = 0
+
+    @classmethod
+    def disable_editing_units(cls):
+        bpy.context.scene.BIMUnitProperties.is_editing = False
+
+    @classmethod
+    def enable_editing_units(cls):
+        bpy.context.scene.BIMUnitProperties.is_editing = True
+
+    @classmethod
+    def export_unit_attributes(cls):
+        def callback(attributes, prop):
+            if prop.name == "Dimensions":
+                try:
+                    attributes[prop.name] = json.loads(prop.get_value())
+                except:
+                    attributes[prop.name] = (0, 0, 0, 0, 0, 0, 0)
+                return True
+
+        props = bpy.context.scene.BIMUnitProperties
+        return blenderbim.bim.helper.export_attributes(props.unit_attributes, callback=callback)
+
+    @classmethod
+    def get_scene_unit_name(cls, unit_type):
+        props = bpy.context.scene.unit_settings
+        is_metric = props.system == "METRIC" or props.system == "NONE"
+
+        if is_metric:
+            name = "METRE"
+        elif props.length_unit == "MILES":
+            name = "mile"
+        elif props.length_unit == "FEET" or props.length_unit == "ADAPTIVE":
+            name = "foot"
+        elif props.length_unit == "INCHES":
+            name = "inch"
+        elif props.length_unit == "THOU":
+            name = "thou"
+
+        if unit_type == "length":
+            return name
+        elif unit_type == "area":
+            if is_metric:
+                return f"SQUARE_{name}"
+            return f"square {name}"
+        elif unit_type == "volume":
+            if is_metric:
+                return f"CUBIC_{name}"
+            return f"cubic {name}"
+
+    @classmethod
+    def get_scene_unit_si_prefix(cls):
+        props = bpy.context.scene.unit_settings
+        if props.length_unit == "ADAPTIVE" or props.length_unit == "METERS":
+            return
+        return props.length_unit.replace("METERS", "")
+
+    @classmethod
+    def get_si_name_from_unit_type(cls, unit_type):
+        return ifcopenshell.util.unit.si_type_names.get(unit_type, None)
+
+    @classmethod
+    def get_unit_class(cls, unit):
+        return unit.is_a()
+
+    @classmethod
+    def import_unit_attributes(cls, unit):
+        def callback(name, prop, data):
+            if name == "Dimensions" and data["type"] != "IfcSIUnit":
+                new = bpy.context.scene.BIMUnitProperties.unit_attributes.add()
+                new.name = name
+                new.is_null = data[name] is None
+                new.is_optional = False
+                new.data_type = "string"
+                new.string_value = json.dumps([e for e in tool.Ifc.get().by_id(data["id"]).Dimensions])
+                return True
+
+        props = bpy.context.scene.BIMUnitProperties
+        props.unit_attributes.clear()
+        blenderbim.bim.helper.import_attributes2(unit, props.unit_attributes, callback=callback)
+
+    @classmethod
+    def import_units(cls):
+        props = bpy.context.scene.BIMUnitProperties
+        props.units.clear()
+
+        units = []
+        for unit_class in ["IfcDerivedUnit", "IfcMonetaryUnit", "IfcNamedUnit"]:
+            units += tool.Ifc.get().by_type(unit_class)
+
+        assigned_units = tool.Ifc.get().by_type("IfcUnitAssignment")
+        if assigned_units:
+            assigned_units = assigned_units[0].Units
+
+        for unit in units:
+            name = ""
+            if unit.is_a("IfcMonetaryUnit"):
+                name = unit.Currency
+            elif not unit.is_a("IfcDerivedUnit"):
+                name = unit.Name or ""
+
+            if unit.is_a("IfcSIUnit") and unit.Prefix:
+                if "_" in name:
+                    name_components = name.split("_")
+                    name = f"{name_components[0]} {unit.Prefix}{name_components[1]}"
+                else:
+                    name = f"{unit.Prefix}{name}"
+
+            if unit.is_a("IfcMonetaryUnit"):
+                unit_type = "CURRENCY"
+            else:
+                unit_type = getattr(unit, "UserDefinedType", None)
+                if not unit_type:
+                    unit_type = getattr(unit, "UnitType", None)
+
+            new = props.units.add()
+            new.ifc_definition_id = unit.id()
+            new.name = name
+            new.unit_type = unit_type
+            new.is_assigned = unit in assigned_units
+            new.ifc_class = unit.is_a()
+
+    @classmethod
+    def is_scene_unit_metric(cls):
+        return bpy.context.scene.unit_settings.system in ["METRIC", "NONE"]
+
+    @classmethod
+    def set_active_unit(cls, unit):
+        bpy.context.scene.BIMUnitProperties.active_unit_id = unit.id()

src/blenderbim/pytest.ini

@@ -4,6 +4,8 @@ markers =
     context
     geometry
     owner
-    void
     pset_template
     spatial
+    style
+    unit
+    void

src/blenderbim/test/bim/feature/unit.feature

@@ -0,0 +1,71 @@
+@unit
+Feature: Unit
+
+Scenario: Assign scene units
+    Given an empty IFC project
+    When I press "bim.assign_scene_units"
+    Then nothing happens
+
+Scenario: Assign unit
+    Given an empty IFC project
+    And the variable "unit" is "{ifc}.by_type('IfcSIUnit')[0].id()"
+    When I press "bim.assign_unit(unit={unit})"
+    Then nothing happens
+
+Scenario: Unassign unit
+    Given an empty IFC project
+    And the variable "unit" is "{ifc}.by_type('IfcSIUnit')[0].id()"
+    When I press "bim.unassign_unit(unit={unit})"
+    Then nothing happens
+
+Scenario: Load units
+    Given an empty IFC project
+    When I press "bim.load_units"
+    Then nothing happens
+
+Scenario: Disable unit editing UI
+    Given an empty IFC project
+    And I press "bim.load_units"
+    When I press "bim.disable_unit_editing_ui"
+    Then nothing happens
+
+Scenario: Remove unit
+    Given an empty IFC project
+    And the variable "unit" is "{ifc}.by_type('IfcSIUnit')[0].id()"
+    When I press "bim.remove_unit(unit={unit})"
+    Then nothing happens
+
+Scenario: Add monetary unit
+    Given an empty IFC project
+    When I press "bim.add_monetary_unit"
+    Then nothing happens
+
+Scenario: Add SI unit
+    Given an empty IFC project
+    When I press "bim.add_si_unit(unit_type='LENGTHUNIT')"
+    Then nothing happens
+
+Scenario: Add context dependent unit
+    Given an empty IFC project
+    When I press "bim.add_context_dependent_unit(name='THINGAMAJIGS', unit_type='LENGTHUNIT')"
+    Then nothing happens
+
+Scenario: Enable editing unit
+    Given an empty IFC project
+    And the variable "unit" is "{ifc}.by_type('IfcSIUnit')[0].id()"
+    When I press "bim.enable_editing_unit(unit={unit})"
+    Then nothing happens
+
+Scenario: Disable editing unit
+    Given an empty IFC project
+    And the variable "unit" is "{ifc}.by_type('IfcSIUnit')[0].id()"
+    And I press "bim.enable_editing_unit(unit={unit})"
+    When I press "bim.disable_editing_unit"
+    Then nothing happens
+
+Scenario: Edit unit
+    Given an empty IFC project
+    And the variable "unit" is "{ifc}.by_type('IfcSIUnit')[0].id()"
+    And I press "bim.enable_editing_unit(unit={unit})"
+    When I press "bim.edit_unit(unit={unit})"
+    Then nothing happens

src/blenderbim/test/core/bootstrap.py

@@ -98,6 +98,13 @@ def container():
     prophet.verify()
 
 
+@pytest.fixture
+def unit():
+    prophet = Prophecy(blenderbim.core.tool.Unit)
+    yield prophet
+    prophet.verify()
+
+
 class Prophecy:
     def __init__(self, cls):
         self.subject = cls

src/blenderbim/test/core/test_unit.py

@@ -0,0 +1,154 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import blenderbim.core.unit as subject
+from test.core.bootstrap import ifc, unit
+
+
+class TestAssignSceneUnits:
+    def test_creating_and_assigning_metric_units(self, ifc, unit):
+        unit.is_scene_unit_metric().should_be_called().will_return(True)
+        unit.get_scene_unit_name("length").should_be_called().will_return("name")
+        unit.get_scene_unit_si_prefix().should_be_called().will_return("prefix")
+        ifc.run(
+            "unit.add_si_unit", unit_type="LENGTHUNIT", name="name", prefix="prefix"
+        ).should_be_called().will_return("lengthunit")
+
+        unit.get_scene_unit_name("area").should_be_called().will_return("name")
+        ifc.run("unit.add_si_unit", unit_type="AREAUNIT", name="name", prefix="prefix").should_be_called().will_return(
+            "areaunit"
+        )
+
+        unit.get_scene_unit_name("volume").should_be_called().will_return("name")
+        ifc.run(
+            "unit.add_si_unit", unit_type="VOLUMEUNIT", name="name", prefix="prefix"
+        ).should_be_called().will_return("volumeunit")
+
+        ifc.run("unit.assign_unit", units=["lengthunit", "areaunit", "volumeunit"]).should_be_called()
+        subject.assign_scene_units(ifc, unit)
+
+    def test_creating_and_assigning_imperial_units(self, ifc, unit):
+        unit.is_scene_unit_metric().should_be_called().will_return(False)
+        unit.get_scene_unit_name("length").should_be_called().will_return("lengthname")
+        ifc.run("unit.add_conversion_based_unit", name="lengthname").should_be_called().will_return("lengthunit")
+
+        unit.get_scene_unit_name("area").should_be_called().will_return("areaname")
+        ifc.run("unit.add_conversion_based_unit", name="areaname").should_be_called().will_return("areaunit")
+
+        unit.get_scene_unit_name("volume").should_be_called().will_return("volumename")
+        ifc.run("unit.add_conversion_based_unit", name="volumename").should_be_called().will_return("volumeunit")
+
+        ifc.run("unit.assign_unit", units=["lengthunit", "areaunit", "volumeunit"]).should_be_called()
+        subject.assign_scene_units(ifc, unit)
+
+
+class TestAssignUnit:
+    def test_run(self, ifc, unit):
+        ifc.run("unit.assign_unit", units=["unit"]).should_be_called()
+        unit.import_units().should_be_called()
+        subject.assign_unit(ifc, unit, unit="unit")
+
+
+class TestUnassignUnit:
+    def test_run(self, ifc, unit):
+        ifc.run("unit.unassign_unit", units=["unit"]).should_be_called()
+        unit.import_units().should_be_called()
+        subject.unassign_unit(ifc, unit, unit="unit")
+
+
+class TestLoadUnits:
+    def test_run(self, unit):
+        unit.import_units().should_be_called()
+        unit.enable_editing_units().should_be_called()
+        subject.load_units(unit)
+
+
+class TestDisableUnitEditingUI:
+    def test_run(self, unit):
+        unit.disable_editing_units().should_be_called()
+        subject.disable_unit_editing_ui(unit)
+
+
+class TestRemoveUnit:
+    def test_run(self, ifc, unit):
+        ifc.run("unit.remove_unit", unit="unit").should_be_called()
+        unit.import_units().should_be_called()
+        subject.remove_unit(ifc, unit, unit="unit")
+
+
+class TestAddMonetaryUnit:
+    def test_run(self, ifc, unit):
+        ifc.run("unit.add_monetary_unit").should_be_called().will_return("unit")
+        unit.import_units().should_be_called()
+        assert subject.add_monetary_unit(ifc, unit) == "unit"
+
+
+class TestAddSIUnit:
+    def test_run(self, ifc, unit):
+        unit.get_si_name_from_unit_type("unit_type").should_be_called().will_return("name")
+        ifc.run("unit.add_si_unit", unit_type="unit_type", name="name").should_be_called().will_return("unit")
+        unit.import_units().should_be_called()
+        assert subject.add_si_unit(ifc, unit, unit_type="unit_type") == "unit"
+
+
+class TestAddContextDependentUnit:
+    def test_run(self, ifc, unit):
+        ifc.run("unit.add_context_dependent_unit", unit_type="unit_type", name="name").should_be_called().will_return(
+            "unit"
+        )
+        unit.import_units().should_be_called()
+        assert subject.add_context_dependent_unit(ifc, unit, unit_type="unit_type", name="name") == "unit"
+
+
+class TestEnableEditingUnit:
+    def test_run(self, unit):
+        unit.set_active_unit("unit").should_be_called()
+        unit.import_unit_attributes("unit").should_be_called()
+        subject.enable_editing_unit(unit, unit="unit")
+
+
+class TestDisableEditingUnit:
+    def test_run(self, unit):
+        unit.clear_active_unit().should_be_called()
+        subject.disable_editing_unit(unit)
+
+
+class TestEditUnit:
+    def test_editing_monetary_units(self, ifc, unit):
+        unit.export_unit_attributes().should_be_called().will_return("attributes")
+        unit.get_unit_class("unit").should_be_called().will_return("IfcMonetaryUnit")
+        ifc.run("unit.edit_monetary_unit", unit="unit", attributes="attributes").should_be_called()
+        unit.import_units().should_be_called()
+        unit.clear_active_unit().should_be_called()
+        subject.edit_unit(ifc, unit, unit="unit")
+
+    def test_editing_derived_units(self, ifc, unit):
+        unit.export_unit_attributes().should_be_called().will_return("attributes")
+        unit.get_unit_class("unit").should_be_called().will_return("IfcDerivedUnit")
+        ifc.run("unit.edit_derived_unit", unit="unit", attributes="attributes").should_be_called()
+        unit.import_units().should_be_called()
+        unit.clear_active_unit().should_be_called()
+        subject.edit_unit(ifc, unit, unit="unit")
+
+    def test_editing_named_units(self, ifc, unit):
+        unit.export_unit_attributes().should_be_called().will_return("attributes")
+        unit.get_unit_class("unit").should_be_called().will_return("IfcNamedUnit")
+        ifc.run("unit.edit_named_unit", unit="unit", attributes="attributes").should_be_called()
+        unit.import_units().should_be_called()
+        unit.clear_active_unit().should_be_called()
+        subject.edit_unit(ifc, unit, unit="unit")

src/blenderbim/test/tool/test_unit.py

@@ -0,0 +1,315 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import bpy
+import ifcopenshell
+import blenderbim.core.tool
+import blenderbim.tool as tool
+from test.bim.bootstrap import NewFile
+from blenderbim.tool.unit import Unit as subject
+
+
+class TestImplementsTool(NewFile):
+    def test_run(self):
+        assert isinstance(subject(), blenderbim.core.tool.Unit)
+
+
+class TestClearActiveUnit(NewFile):
+    def test_run(self):
+        bpy.context.scene.BIMUnitProperties.active_unit_id = 1
+        subject.clear_active_unit()
+        assert bpy.context.scene.BIMUnitProperties.active_unit_id == 0
+
+
+class TestDisableEditingUnits(NewFile):
+    def test_run(self):
+        bpy.context.scene.BIMUnitProperties.is_editing = True
+        subject.disable_editing_units()
+        assert bpy.context.scene.BIMUnitProperties.is_editing == False
+
+
+class TestEnableEditingUnits(NewFile):
+    def test_run(self):
+        bpy.context.scene.BIMUnitProperties.is_editing = False
+        subject.enable_editing_units()
+        assert bpy.context.scene.BIMUnitProperties.is_editing == True
+
+
+class TestExportUnitAttributes(NewFile):
+    def test_exporting_derived_units(self):
+        TestImportUnitAttributes().test_importing_derived_units()
+        assert subject.export_unit_attributes() == {
+            "UnitType": "ANGULARVELOCITYUNIT",
+            "UserDefinedType": "UserDefinedType",
+        }
+
+    def test_exporting_monetary_units(self):
+        TestImportUnitAttributes().test_importing_monetary_units()
+        assert subject.export_unit_attributes() == {"Currency": "Currency"}
+
+    def test_exporting_monetary_units_ifc2x3(self):
+        TestImportUnitAttributes().test_importing_monetary_units_ifc2x3()
+        assert subject.export_unit_attributes() == {"Currency": "USD"}
+
+    def test_exporting_context_dependent_units(self):
+        TestImportUnitAttributes().test_importing_context_dependent_units()
+        assert subject.export_unit_attributes() == {
+            "UnitType": "ABSORBEDDOSEUNIT",
+            "Name": "Name",
+            "Dimensions": [1, 2, 3, 4, 5, 6, 7],
+        }
+
+    def test_exporting_conversion_based_units(self):
+        TestImportUnitAttributes().test_importing_conversion_based_units()
+        assert subject.export_unit_attributes() == {
+            "UnitType": "ABSORBEDDOSEUNIT",
+            "Name": "Name",
+            "Dimensions": [1, 2, 3, 4, 5, 6, 7],
+        }
+
+    def test_exporting_conversion_based_with_offset_units(self):
+        TestImportUnitAttributes().test_importing_conversion_based_with_offset_units()
+        assert subject.export_unit_attributes() == {
+            "UnitType": "ABSORBEDDOSEUNIT",
+            "Name": "Name",
+            "Dimensions": [1, 2, 3, 4, 5, 6, 7],
+            "ConversionOffset": 1,
+        }
+
+    def test_exporting_si_units(self):
+        TestImportUnitAttributes().test_importing_si_units()
+        assert subject.export_unit_attributes() == {"UnitType": "ABSORBEDDOSEUNIT", "Prefix": "EXA", "Name": "AMPERE"}
+
+
+class TestGetSceneUnitName(NewFile):
+    def test_getting_a_metric_name(self):
+        bpy.context.scene.unit_settings.system = "METRIC"
+        assert subject.get_scene_unit_name("length") == "METRE"
+        assert subject.get_scene_unit_name("area") == "SQUARE_METRE"
+        assert subject.get_scene_unit_name("volume") == "CUBIC_METRE"
+
+    def test_getting_an_imperial_name(self):
+        bpy.context.scene.unit_settings.system = "IMPERIAL"
+        bpy.context.scene.unit_settings.length_unit = "MILES"
+        assert subject.get_scene_unit_name("length") == "mile"
+        assert subject.get_scene_unit_name("area") == "square mile"
+        assert subject.get_scene_unit_name("volume") == "cubic mile"
+        bpy.context.scene.unit_settings.length_unit = "FEET"
+        assert subject.get_scene_unit_name("length") == "foot"
+        assert subject.get_scene_unit_name("area") == "square foot"
+        assert subject.get_scene_unit_name("volume") == "cubic foot"
+        bpy.context.scene.unit_settings.length_unit = "INCHES"
+        assert subject.get_scene_unit_name("length") == "inch"
+        assert subject.get_scene_unit_name("area") == "square inch"
+        assert subject.get_scene_unit_name("volume") == "cubic inch"
+        bpy.context.scene.unit_settings.length_unit = "THOU"
+        assert subject.get_scene_unit_name("length") == "thou"
+        assert subject.get_scene_unit_name("area") == "square thou"
+        assert subject.get_scene_unit_name("volume") == "cubic thou"
+        bpy.context.scene.unit_settings.length_unit = "ADAPTIVE"
+        assert subject.get_scene_unit_name("length") == "foot"
+        assert subject.get_scene_unit_name("area") == "square foot"
+        assert subject.get_scene_unit_name("volume") == "cubic foot"
+
+    def test_getting_a_name_with_no_unit_system(self):
+        bpy.context.scene.unit_settings.system = "NONE"
+        assert subject.get_scene_unit_name("length") == "METRE"
+
+
+class TestGetSceneUnitSIPrefix:
+    def test_run(self):
+        bpy.context.scene.unit_settings.system = "METRIC"
+        bpy.context.scene.unit_settings.length_unit = "METERS"
+        assert subject.get_scene_unit_si_prefix() is None
+        bpy.context.scene.unit_settings.length_unit = "MICROMETERS"
+        assert subject.get_scene_unit_si_prefix() == "MICRO"
+        bpy.context.scene.unit_settings.length_unit = "MILLIMETERS"
+        assert subject.get_scene_unit_si_prefix() == "MILLI"
+        bpy.context.scene.unit_settings.length_unit = "CENTIMETERS"
+        assert subject.get_scene_unit_si_prefix() == "CENTI"
+        bpy.context.scene.unit_settings.length_unit = "KILOMETERS"
+        assert subject.get_scene_unit_si_prefix() == "KILO"
+        bpy.context.scene.unit_settings.length_unit = "ADAPTIVE"
+        assert subject.get_scene_unit_si_prefix() is None
+
+
+class TestGetSINameFromUnitType:
+    def test_run(self):
+        for key, value in ifcopenshell.util.unit.si_type_names.items():
+            assert subject.get_si_name_from_unit_type(key) == value
+
+
+class TestGetUnitClass:
+    def test_run(self):
+        ifc = ifcopenshell.file()
+        assert subject.get_unit_class(ifc.createIfcSIUnit()) == "IfcSIUnit"
+        assert subject.get_unit_class(ifc.createIfcNamedUnit()) == "IfcNamedUnit"
+
+
+class TestImportUnitAttributes(NewFile):
+    def test_importing_derived_units(self):
+        ifc = ifcopenshell.file()
+        unit = ifc.createIfcDerivedUnit()
+        unit.UnitType = "ANGULARVELOCITYUNIT"
+        unit.UserDefinedType = "UserDefinedType"
+        subject.import_unit_attributes(unit)
+        props = bpy.context.scene.BIMUnitProperties
+        assert props.unit_attributes.get("UnitType").enum_value == "ANGULARVELOCITYUNIT"
+        assert props.unit_attributes.get("UserDefinedType").string_value == "UserDefinedType"
+
+    def test_importing_monetary_units(self):
+        ifc = ifcopenshell.file()
+        unit = ifc.createIfcMonetaryUnit()
+        unit.Currency = "Currency"
+        subject.import_unit_attributes(unit)
+        props = bpy.context.scene.BIMUnitProperties
+        assert props.unit_attributes.get("Currency").string_value == "Currency"
+
+    def test_importing_monetary_units_ifc2x3(self):
+        ifc = ifcopenshell.file(schema="IFC2X3")
+        unit = ifc.createIfcMonetaryUnit()
+        unit.Currency = "USD"
+        subject.import_unit_attributes(unit)
+        props = bpy.context.scene.BIMUnitProperties
+        assert props.unit_attributes.get("Currency").enum_value == "USD"
+
+    def test_importing_context_dependent_units(self):
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        unit = ifc.createIfcContextDependentUnit()
+        unit.UnitType = "ABSORBEDDOSEUNIT"
+        unit.Name = "Name"
+        unit.Dimensions = ifc.createIfcDimensionalExponents(1, 2, 3, 4, 5, 6, 7)
+        subject.import_unit_attributes(unit)
+        props = bpy.context.scene.BIMUnitProperties
+        assert props.unit_attributes.get("UnitType").enum_value == "ABSORBEDDOSEUNIT"
+        assert props.unit_attributes.get("Name").string_value == "Name"
+        assert props.unit_attributes.get("Dimensions").string_value == "[1, 2, 3, 4, 5, 6, 7]"
+
+    def test_importing_conversion_based_units(self):
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        unit = ifc.createIfcConversionBasedUnit()
+        unit.UnitType = "ABSORBEDDOSEUNIT"
+        unit.Name = "Name"
+        unit.Dimensions = ifc.createIfcDimensionalExponents(1, 2, 3, 4, 5, 6, 7)
+        subject.import_unit_attributes(unit)
+        props = bpy.context.scene.BIMUnitProperties
+        assert props.unit_attributes.get("UnitType").enum_value == "ABSORBEDDOSEUNIT"
+        assert props.unit_attributes.get("Name").string_value == "Name"
+        assert props.unit_attributes.get("Dimensions").string_value == "[1, 2, 3, 4, 5, 6, 7]"
+
+    def test_importing_conversion_based_with_offset_units(self):
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        unit = ifc.createIfcConversionBasedUnitWithOffset()
+        unit.UnitType = "ABSORBEDDOSEUNIT"
+        unit.Name = "Name"
+        unit.Dimensions = ifc.createIfcDimensionalExponents(1, 2, 3, 4, 5, 6, 7)
+        unit.ConversionOffset = 1
+        subject.import_unit_attributes(unit)
+        props = bpy.context.scene.BIMUnitProperties
+        assert props.unit_attributes.get("UnitType").enum_value == "ABSORBEDDOSEUNIT"
+        assert props.unit_attributes.get("Name").string_value == "Name"
+        assert props.unit_attributes.get("Dimensions").string_value == "[1, 2, 3, 4, 5, 6, 7]"
+        assert props.unit_attributes.get("ConversionOffset").float_value == 1
+
+    def test_importing_si_units(self):
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        unit = ifc.createIfcSIUnit()
+        unit.UnitType = "ABSORBEDDOSEUNIT"
+        unit.Prefix = "EXA"
+        unit.Name = "AMPERE"
+        subject.import_unit_attributes(unit)
+        props = bpy.context.scene.BIMUnitProperties
+        assert props.unit_attributes.get("UnitType").enum_value == "ABSORBEDDOSEUNIT"
+        assert props.unit_attributes.get("Prefix").enum_value == "EXA"
+        assert props.unit_attributes.get("Name").enum_value == "AMPERE"
+        assert props.unit_attributes.get("Dimensions") is None
+
+
+class TestImportUnits(NewFile):
+    def test_importing_multiple_units(self):
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        unit1 = ifc.createIfcDerivedUnit(UnitType="ANGULARVELOCITYUNIT")
+        unit2 = ifc.createIfcMonetaryUnit(Currency="Currency")
+        unit3 = ifc.createIfcContextDependentUnit(Name="Name", UnitType="ABSORBEDDOSEUNIT")
+        unit4 = ifc.createIfcConversionBasedUnit(Name="Name", UnitType="ABSORBEDDOSEUNIT")
+        unit5 = ifc.createIfcSIUnit(Name="AMPERE", Prefix="MILLI", UnitType="ABSORBEDDOSEUNIT")
+        unit6 = ifc.createIfcSIUnit(Name="CUBIC_METRE", Prefix="CENTI", UnitType="ABSORBEDDOSEUNIT")
+        ifc.createIfcUnitAssignment(Units=[unit2])
+        subject.import_units()
+        props = bpy.context.scene.BIMUnitProperties
+        assert len(props.units) == 6
+
+        assert props.units[0].ifc_definition_id == unit1.id()
+        assert props.units[0].name == ""
+        assert props.units[0].is_assigned is False
+        assert props.units[0].unit_type == unit1.UnitType
+        assert props.units[0].ifc_class == unit1.is_a()
+
+        assert props.units[1].ifc_definition_id == unit2.id()
+        assert props.units[1].name == "Currency"
+        assert props.units[1].is_assigned is True
+        assert props.units[1].unit_type == "CURRENCY"
+        assert props.units[1].ifc_class == unit2.is_a()
+
+        assert props.units[2].ifc_definition_id == unit3.id()
+        assert props.units[2].name == "Name"
+        assert props.units[2].is_assigned is False
+        assert props.units[2].unit_type == unit3.UnitType
+        assert props.units[2].ifc_class == unit3.is_a()
+
+        assert props.units[3].ifc_definition_id == unit4.id()
+        assert props.units[3].name == "Name"
+        assert props.units[3].is_assigned is False
+        assert props.units[3].unit_type == unit4.UnitType
+        assert props.units[3].ifc_class == unit4.is_a()
+
+        assert props.units[4].ifc_definition_id == unit5.id()
+        assert props.units[4].name == "MILLIAMPERE"
+        assert props.units[4].is_assigned is False
+        assert props.units[4].unit_type == unit5.UnitType
+        assert props.units[4].ifc_class == unit5.is_a()
+
+        assert props.units[5].ifc_definition_id == unit6.id()
+        assert props.units[5].name == "CUBIC CENTIMETRE"
+        assert props.units[5].is_assigned is False
+        assert props.units[5].unit_type == unit6.UnitType
+        assert props.units[5].ifc_class == unit6.is_a()
+
+
+class TestIsSceneUnitMetric(NewFile):
+    def test_run(self):
+        props = bpy.context.scene.unit_settings
+        props.system = "METRIC"
+        assert subject.is_scene_unit_metric() is True
+        props.system = "IMPERIAL"
+        assert subject.is_scene_unit_metric() is False
+        props.system = "NONE"
+        assert subject.is_scene_unit_metric() is True
+
+
+class TestSetActiveUnit(NewFile):
+    def test_run(self):
+        ifc = ifcopenshell.file()
+        unit = ifc.createIfcSIUnit()
+        subject.set_active_unit(unit)
+        assert bpy.context.scene.BIMUnitProperties.active_unit_id == unit.id()

src/ifcopenshell-python/ifcopenshell/api/unit/add_conversion_based_unit.py

@@ -0,0 +1,37 @@
+import ifcopenshell
+import ifcopenshell.util.unit
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {"unit_type": "LENGTHUNIT", "name": "METRE", "prefix": None, "conversion_offset": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        if self.settings["unit_type"] == "LENGTHUNIT":
+            dimensional_exponents = self.file.createIfcDimensionalExponents(1, 0, 0, 0, 0, 0, 0)
+            si_unit = self.file.createIfcSIUnit(UnitType=self.settings["unit_type"], Name="METRE")
+        elif self.settings["unit_type"] == "AREAUNIT":
+            dimensional_exponents = self.file.createIfcDimensionalExponents(2, 0, 0, 0, 0, 0, 0)
+            si_unit = self.file.createIfcSIUnit(UnitType=self.settings["unit_type"], Name="SQUARE_METRE")
+        elif self.settings["unit_type"] == "VOLUMEUNIT":
+            dimensional_exponents = self.file.createIfcDimensionalExponents(3, 0, 0, 0, 0, 0, 0)
+            si_unit = self.file.createIfcSIUnit(UnitType=self.settings["unit_type"], Name="CUBIC_METRE")
+
+        conversion_real = ifcopenshell.util.unit.si_conversions.get(self.settings["name"], 1)
+        value_component = self.file.create_entity("IfcReal", **{"wrappedValue": conversion_real})
+        conversion_factor = self.file.createIfcMeasureWithUnit(value_component, si_unit)
+
+        if self.settings["conversion_offset"]:
+            return self.file.createIfcConversionBasedUnit(
+                dimensional_exponents,
+                self.settings["unit_type"],
+                self.settings["name"],
+                conversion_factor,
+                self.settings["conversion_offset"],
+            )
+        return self.file.createIfcConversionBasedUnit(
+            dimensional_exponents, self.settings["unit_type"], self.settings["name"], conversion_factor
+        )