WIP refactoring representations to be incrementally edited. See #1222.

# Conflicts:
#	src/ifcblenderexport/blenderbim/bim/operator.py

src/ifcblenderexport/blenderbim/bim/__init__.py

@@ -133,8 +133,9 @@ if bpy is not None:
         operator.SmartClashGroup,
         operator.SelectSmartGroup,
         operator.LoadSmartGroupsForActiveClashSet,
-        operator.SwitchContext,
-        operator.RemoveContext,
+        operator.AddRepresentation,
+        operator.SwitchRepresentation,
+        operator.RemoveRepresentation,
         operator.OpenUpstream,
         operator.BIM_OT_ChangeClassificationLevel,
         operator.AddPropertySetTemplate,

src/ifcblenderexport/blenderbim/bim/export_ifc.py

@@ -1056,29 +1056,32 @@ class IfcParser:
         for context in self.ifc_export_settings.context_tree:
             for subcontext in context["subcontexts"]:
                 for target_view in subcontext["target_views"]:
-                    rep_context = self.get_obj_representation_context(obj, context["name"], subcontext["name"], target_view)
-                    if rep_context:
-                        self.append_representation_in_context(obj, rep_context, name)
+                    representation = self.get_shape_representation(obj, context["name"], subcontext["name"], target_view)
+                    if representation:
+                        self.append_representation_in_context(obj, representation, name)
 
-    def get_obj_representation_context(self, obj, context, subcontext, target_view):
-        for c in obj.BIMObjectProperties.representation_contexts:
-            if c.context == context and c.name == subcontext and c.target_view == target_view:
-                return c
-        if obj.BIMObjectProperties.representation_contexts:
+    def get_shape_representation(self, obj, context, subcontext, target_view):
+        for representation in obj.BIMObjectProperties.representations:
+            c = self.stored_file.by_id(representation.ifc_definition_id)
+            if c.ContextType == context and c.ContextIdentifier == subcontext and c.TargetView == target_view:
+                return representation
+        if obj.BIMObjectProperties.representations:
             return
-        if context == "Model" and subcontext == "Body" and target_view == "MODEL_VIEW":
-            representation_context = obj.BIMObjectProperties.representation_contexts.add()
-            representation_context.context = "Model"
-            representation_context.name = "Body"
-            representation_context.target_view = "MODEL_VIEW"
-            return representation_context
+        # TODO: reimplement - see bug #1222
+        #if context == "Model" and subcontext == "Body" and target_view == "MODEL_VIEW":
+        #    representation_context = obj.BIMObjectProperties.representation_contexts.add()
+        #    representation_context.context = "Model"
+        #    representation_context.name = "Body"
+        #    representation_context.target_view = "MODEL_VIEW"
+        #    return representation_context
 
-    def append_representation_in_context(self, obj, rep_context, name):
-        context = rep_context.context
-        subcontext = rep_context.name
-        target_view = rep_context.target_view
+    def append_representation_in_context(self, obj, shape_representation, name):
+        context_of_items = self.stored_file.by_id(shape_representation.ifc_definition_id).ContextOfItems
+        context = context_of_items.ContextType
+        subcontext = context_of_items.ContextIdentifier
+        target_view = context_of_items.TargetView
 
-        if self.ifc_export_settings.should_roundtrip_native and rep_context.ifc_definition_id:
+        if self.ifc_export_settings.should_roundtrip_native and shape_representation.ifc_definition_id:
             self.representations[
                 "{}/{}/{}/{}".format(context, subcontext, target_view, name)
             ] = self.get_representation(obj.data, obj, context, subcontext, target_view)
@@ -1087,7 +1090,6 @@ class IfcParser:
         context_prefix = "/".join([context, subcontext, target_view])
         mesh_name = "/".join([context_prefix, name])
         mesh = self.search_for_mesh_or_curve_data(mesh_name)
-        # TODO: if the search result is empty, we should check for ifc_definition_id
         if mesh:
             self.representations[mesh_name] = self.get_representation(mesh, obj, context, subcontext, target_view)
             if "Model/Box/MODEL_VIEW" in self.generated_subcontexts and context_prefix == "Model/Body/MODEL_VIEW":
@@ -1112,7 +1114,7 @@ class IfcParser:
         return data
 
     def get_representation(self, mesh, obj, context, subcontext, target_view):
-        rep_context = self.get_obj_representation_context(obj, context, subcontext, target_view)
+        representation = self.get_shape_representation(obj, context, subcontext, target_view)
         return {
             "ifc": None,
             "raw": mesh,
@@ -1120,9 +1122,9 @@ class IfcParser:
             "context": context,
             "subcontext": subcontext,
             "target_view": target_view,
-            "has_ifc_definition": rep_context and rep_context.ifc_definition_id,
+            "has_ifc_definition": representation and representation.ifc_definition_id,
             "ifc_definition": mesh.BIMMeshProperties.ifc_definition if hasattr(mesh, "BIMMeshProperties") else None,
-            "ifc_definition_id": rep_context.ifc_definition_id if rep_context else 0
+            "ifc_definition_id": representation.ifc_definition_id if representation else 0
             if hasattr(mesh, "BIMMeshProperties")
             else None,
             "is_parametric": mesh.BIMMeshProperties.is_parametric if hasattr(mesh, "BIMMeshProperties") else False,
@@ -1344,8 +1346,9 @@ class IfcExporter:
         self.roundtrip_id_new_to_old = {}
 
     def export(self, selected_objects):
-        self.file = ifc.IfcStore.get_file()
-        if self.file and self.ifc_export_settings.should_export_from_memory:
+        self.stored_file = ifc.IfcStore.get_file() # See bug #1222
+        if self.stored_file and self.ifc_export_settings.should_export_from_memory:
+            self.file = self.stored_file
             return self.write_ifc_file()
         self.schema_version = self.ifc_export_settings.schema
         self.schema = ifcopenshell.ifcopenshell_wrapper.schema_by_name(self.schema_version)
@@ -2038,8 +2041,8 @@ class IfcExporter:
             # At the moment, we assume that styled items only apply to the body context.
             if representation.RepresentationIdentifier != "Body":
                 continue
-            rep_context = self.ifc_parser.get_obj_representation_context(product["raw"], "Model", "Body", "MODEL_VIEW")
-            if self.ifc_export_settings.should_roundtrip_native and rep_context and rep_context.ifc_definition_id:
+            rep = self.ifc_parser.get_shape_representation(product["raw"], "Model", "Body", "MODEL_VIEW")
+            if self.ifc_export_settings.should_roundtrip_native and rep and rep.ifc_definition_id:
                 # For native roundtripping, each slot could be a one to many relationship to items
                 for item in self.get_geometric_representation_items(representation):
                     original_id = self.roundtrip_id_new_to_old[item.id()]

src/ifcblenderexport/blenderbim/bim/import_ifc.py

@@ -773,6 +773,7 @@ class IfcImporter:
             obj = self.existing_elements[element.GlobalId]
         else:
             obj = bpy.data.objects.new(f"{element.is_a()}/{element.Name}", None)
+            obj.BIMObjectProperties.ifc_definition_id = element.id()
             self.add_element_attributes(element, obj.BIMObjectProperties)
             group_collection.objects.link(obj)
         self.groups[element.GlobalId] = {"ifc": element, "blender": obj}
@@ -809,6 +810,7 @@ class IfcImporter:
             shape = ifcopenshell.geom.create_shape(self.settings_2d, axis.AxisCurve)
             mesh = self.create_mesh(axis, shape)
             obj = bpy.data.objects.new(f"IfcGridAxis/{axis.AxisTag}", mesh)
+            obj.BIMObjectProperties.ifc_definition_id = element.id()
             obj.matrix_world = matrix_world
             self.add_element_attributes(axis, obj.BIMObjectProperties)
             grid.objects.link(obj)
@@ -843,6 +845,7 @@ class IfcImporter:
             except:
                 self.ifc_import_settings.logger.error("Failed to generate shape for %s", element)
         obj = bpy.data.objects.new(self.get_name(element), mesh)
+        obj.BIMObjectProperties.ifc_definition_id = element.id()
         self.material_creator.create(element, obj, mesh)
         self.add_element_attributes(element, obj.BIMObjectProperties)
         self.add_element_classifications(element, obj)
@@ -955,6 +958,7 @@ class IfcImporter:
             mesh = None
 
         obj = bpy.data.objects.new(self.get_name(element), mesh)
+        obj.BIMObjectProperties.ifc_definition_id = element.id()
 
         if shape:
             m = shape.transformation.matrix.data
@@ -1760,6 +1764,7 @@ class IfcImporter:
         element = rel_aggregate.RelatingObject
 
         obj = bpy.data.objects.new("{}/{}".format(element.is_a(), element.Name), None)
+        obj.BIMObjectProperties.ifc_definition_id = element.id()
         obj.instance_type = "COLLECTION"
         obj.instance_collection = collection
         self.place_object_in_spatial_tree(element, obj)
@@ -1823,6 +1828,7 @@ class IfcImporter:
             return
 
         obj = bpy.data.objects.new(self.get_name(element), mesh)
+        obj.BIMObjectProperties.ifc_definition_id = element.id()
         self.material_creator.create(element, obj, mesh)
         obj.matrix_world = self.get_element_matrix(element, mesh_name)
         self.add_element_attributes(element, obj.BIMObjectProperties)

src/ifcblenderexport/blenderbim/bim/operator.py

@@ -10,6 +10,7 @@ import subprocess
 import ifcopenshell
 import ifcopenshell.util.selector
 import ifcopenshell.util.geolocation
+import ifcopenshell.util.element
 import ifcopenshell.util.schema
 import tempfile
 from . import export_ifc
@@ -2156,6 +2157,7 @@ class CutSection(bpy.types.Operator):
     bl_label = "Cut Section"
 
     def execute(self, context):
+        self.file = ifc.IfcStore.get_file()
         camera = bpy.context.scene.camera
         if not (camera.type == "CAMERA" and camera.data.type == "ORTHO"):
             return {"FINISHED"}
@@ -2322,11 +2324,10 @@ class CutSection(bpy.types.Operator):
             bpy.data.objects[name].hide_set(value)
 
     def does_obj_have_target_view_representation(self, obj, camera):
-        return camera.data.BIMCameraProperties.target_view in [
-            c.target_view
-            for c in obj.BIMObjectProperties.representation_contexts
-            if c.context == "Plan" and c.name == "Annotation"
-        ]
+        for representation in obj.BIMObjectProperties.representations:
+            element = self.file.by_id(representation.ifc_definition_id)
+            if ifcopenshell.util.element.is_representation_of_context(element, "Plan", "Annotation", camera.data.BIMCameraProperties.target_view):
+                return True
 
     def is_landscape(self):
         return bpy.context.scene.render.resolution_x > bpy.context.scene.render.resolution_y
@@ -2464,109 +2465,45 @@ class ActivateView(bpy.types.Operator):
         return {"FINISHED"}
 
 
-class SwitchContext(bpy.types.Operator):
-    bl_idname = "bim.switch_context"
-    bl_label = "Switch Context"
-    has_target_context: bpy.props.BoolProperty()
-    context_name: bpy.props.StringProperty()
-    subcontext_name: bpy.props.StringProperty()
-    target_view_name: bpy.props.StringProperty()
+class AddRepresentation(bpy.types.Operator):
+    bl_idname = "bim.add_representation"
+    bl_label = "Add Representation"
 
-    # Warning: This is an incredibly experimental operator. It effectively does
-    # a mini-import. A better approach will make this obsolete in the future.
     def execute(self, context):
         self.obj = bpy.context.active_object
 
+        self.file = ifc.IfcStore.get_file()
         if "/" not in self.obj.data.name:
             self.obj.data.name = ifcopenshell.guid.compress(str(uuid.uuid4()).replace("-", ""))
             self.obj.data.name = "Model/Body/MODEL_VIEW/" + self.obj.data.name
-            has_default_context = False
-            for subcontext in self.obj.BIMObjectProperties.representation_contexts:
-                if (
-                    subcontext.context == "Model"
-                    and subcontext.name == "Body"
-                    and subcontext.target_view == "MODEL_VIEW"
-                ):
-                    has_default_context = True
-                    break
-            if not has_default_context:
-                representation_context = self.obj.BIMObjectProperties.representation_contexts.add()
-                representation_context.context = "Model"
-                representation_context.name = "Body"
-                representation_context.target_view = "MODEL_VIEW"
 
         self.context = bpy.context.scene.BIMProperties.available_contexts
         self.subcontext = bpy.context.scene.BIMProperties.available_subcontexts
         self.target_view = bpy.context.scene.BIMProperties.available_target_views
 
-        if self.has_target_context:
-            self.context = self.context_name
-            self.subcontext = self.subcontext_name
-            self.target_view = self.target_view_name
-
         existing_mesh = self.obj.data
         existing_mesh.use_fake_user = True
-        mesh = bpy.data.meshes.get(
-            "{}/{}/{}/{}".format(self.context, self.subcontext, self.target_view, self.obj.data.name.split("/")[3])
+        mesh = self.obj.data.copy()
+        mesh.name = "{}/{}/{}/{}".format(
+            self.context, self.subcontext, self.target_view, self.obj.data.name.split("/")[3]
         )
-        if not mesh:
-            try:
-                global_id = self.obj.BIMObjectProperties.attributes.get("GlobalId").string_value
-                mesh = self.pull_mesh_from_ifc(global_id)
-            except:
-                mesh = self.obj.data.copy()
-                mesh.name = "{}/{}/{}/{}".format(
-                    self.context, self.subcontext, self.target_view, self.obj.data.name.split("/")[3]
-                )
-                has_context = False
-                for context in self.obj.BIMObjectProperties.representation_contexts:
-                    if (
-                        context.context == self.context
-                        and context.name == self.subcontext
-                        and context.target_view == self.target_view
-                    ):
-                        has_context = True
-                        break
-                if not has_context:
-                    representation_context = self.obj.BIMObjectProperties.representation_contexts.add()
-                    representation_context.context = self.context
-                    representation_context.name = self.subcontext
-                    representation_context.target_view = self.target_view
-            mesh.use_fake_user = True
+        representation = self.obj.BIMObjectProperties.representations.add()
+        representation.name = self.subcontext
+        representation.type = "Brep" if self.file.schema == "IFC2X3" else "Tessellation"
+        mesh.use_fake_user = True
         self.obj.data = mesh
+
+        # TODO: push representation
         return {"FINISHED"}
 
-    def pull_mesh_from_ifc(self, global_id):
+    def push_mesh_to_ifc(self):
         self.file = ifc.IfcStore.get_file()
         logger = logging.getLogger("ImportIFC")
         ifc_import_settings = import_ifc.IfcImportSettings.factory(bpy.context, ifc.IfcStore.path, logger)
-        element = self.file.by_id(global_id)
+        element = self.file.by_id(self.obj.BIMObjectProperties.ifc_definition_id)
         settings = ifcopenshell.geom.settings()
         settings.set(settings.INCLUDE_CURVES, True)
-        if element.is_a("IfcProduct"):
-            representations = element.Representation.Representations
-        else:
-            representations = element.RepresentationMaps
-
-        for rep in element.Representation.Representations:
-            if (
-                rep.ContextOfItems.is_a("IfcGeometricRepresentationSubContext")
-                and rep.ContextOfItems.ContextType == self.context
-                and rep.ContextOfItems.ContextIdentifier == self.subcontext
-                and rep.ContextOfItems.TargetView == self.target_view
-            ):
-                break
-            elif (
-                rep.ContextOfItems.is_a("IfcGeometricRepresentationContext")
-                and rep.ContextOfItems.ContextType == self.context
-                and rep.ContextOfItems.ContextIdentifier == self.subcontext
-            ):
-                break
-
-        if not element.is_a("IfcProduct"):
-            rep = rep.MappedRepresentation
-
-        shape = ifcopenshell.geom.create_shape(settings, rep)
+        shape = ifcopenshell.geom.create_shape(settings, self.file.by_id(self.ifc_definition_id))
         ifc_importer = import_ifc.IfcImporter(ifc_import_settings)
         ifc_importer.file = self.file
         mesh = ifc_importer.create_mesh(element, shape)
@@ -2574,37 +2511,94 @@ class SwitchContext(bpy.types.Operator):
             self.context, self.subcontext, self.target_view, self.obj.data.name.split("/")[3]
         )
         self.obj.data = mesh
-        material_creator = import_ifc.MaterialCreator(ifc_import_settings)
+        material_creator = import_ifc.MaterialCreator(ifc_import_settings, ifc_importer)
         material_creator.create(element, self.obj, mesh)
         return mesh
 
 
-class RemoveContext(bpy.types.Operator):
-    bl_idname = "bim.remove_context"
-    bl_label = "Remove Context"
+class SwitchRepresentation(bpy.types.Operator):
+    bl_idname = "bim.switch_representation"
+    bl_label = "Switch Representation"
+    ifc_definition_id: bpy.props.IntProperty()
+
+    def execute(self, context):
+        self.obj = bpy.context.active_object
+
+        self.file = ifc.IfcStore.get_file()
+        if "/" not in self.obj.data.name:
+            self.obj.data.name = ifcopenshell.guid.compress(str(uuid.uuid4()).replace("-", ""))
+            self.obj.data.name = "Model/Body/MODEL_VIEW/" + self.obj.data.name
+
+        context_of_items = self.file.by_id(self.ifc_definition_id).ContextOfItems
+        self.context = context_of_items.ContextType
+        self.subcontext = context_of_items.ContextIdentifier
+        self.target_view = context_of_items.TargetView
+
+        existing_mesh = self.obj.data
+        existing_mesh.use_fake_user = True
+        mesh = bpy.data.meshes.get(
+            "{}/{}/{}/{}".format(self.context, self.subcontext, self.target_view, self.obj.data.name.split("/")[3])
+        )
+        if not mesh:
+            mesh = self.pull_mesh_from_ifc()
+            mesh.use_fake_user = True
+        self.obj.data = mesh
+        return {"FINISHED"}
+
+    def pull_mesh_from_ifc(self):
+        self.file = ifc.IfcStore.get_file()
+        logger = logging.getLogger("ImportIFC")
+        ifc_import_settings = import_ifc.IfcImportSettings.factory(bpy.context, ifc.IfcStore.path, logger)
+        element = self.file.by_id(self.obj.BIMObjectProperties.ifc_definition_id)
+        settings = ifcopenshell.geom.settings()
+        settings.set(settings.INCLUDE_CURVES, True)
+        shape = ifcopenshell.geom.create_shape(settings, self.file.by_id(self.ifc_definition_id))
+        ifc_importer = import_ifc.IfcImporter(ifc_import_settings)
+        ifc_importer.file = self.file
+        mesh = ifc_importer.create_mesh(element, shape)
+        mesh.name = "{}/{}/{}/{}".format(
+            self.context, self.subcontext, self.target_view, self.obj.data.name.split("/")[3]
+        )
+        self.obj.data = mesh
+        material_creator = import_ifc.MaterialCreator(ifc_import_settings, ifc_importer)
+        material_creator.create(element, self.obj, mesh)
+        return mesh
+
+
+class RemoveRepresentation(bpy.types.Operator):
+    bl_idname = "bim.remove_representation"
+    bl_label = "Remove Representation"
     index: bpy.props.IntProperty()
 
     def execute(self, context):
+        # TODO This should be refactored into a testable agnostic module. See #1222.
+        # Prep work
+        self.file = ifc.IfcStore.get_file()
         obj = bpy.context.active_object
-        data = obj.BIMObjectProperties.representation_contexts[self.index]
+        representation = obj.BIMObjectProperties.representations[self.index]
+        element = self.file.by_id(representation.ifc_definition_id)
+        c = element.ContextOfItems
 
+        # Blender work
         if "/" not in obj.data.name:
             obj.data.name = "Model/Body/MODEL_VIEW/" + obj.data.name
-
         mesh = bpy.data.meshes.get(
-            "{}/{}/{}/{}".format(data.context, data.name, data.target_view, obj.data.name.split("/")[3])
+            "{}/{}/{}/{}".format(c.ContextType, c.ContextIdentifier, c.TargetView, obj.data.name.split("/")[3])
         )
-
         if mesh:
             if obj.data == mesh:
+                # TODO we can do better than this
                 void_name = "Void/Void/Void/" + obj.data.name.split("/")[3]
                 void_mesh = bpy.data.meshes.get(void_name)
                 if not void_mesh:
                     void_mesh = bpy.data.meshes.new(void_name)
                 obj.data = void_mesh
             bpy.data.meshes.remove(mesh)
+        obj.BIMObjectProperties.representations.remove(self.index)
 
-        obj.BIMObjectProperties.representation_contexts.remove(self.index)
+        # IFC work
+        # TODO: this works as a MVP but leaves a bunch of junk in the file. See #1222.
+        self.file.remove(element)
         return {"FINISHED"}
 
 
@@ -4427,6 +4421,7 @@ class GetRepresentationIfcParameters(bpy.types.Operator):
     bl_label = "Get Representation IFC Parameters"
 
     def execute(self, context):
+        self.file = ifc.IfcStore.get_file()
         obj = bpy.context.active_object
         props = obj.data.BIMMeshProperties
         element_id = self.get_ifc_definition_id(obj)
@@ -4452,9 +4447,10 @@ class GetRepresentationIfcParameters(bpy.types.Operator):
             context, subcontext, target_view = ("Model", "Body", "MODEL_VIEW")
         else:
             context, subcontext, target_view = obj.data.name.split("/")[0:3]
-        for c in obj.BIMObjectProperties.representation_contexts:
-            if c.context == context and c.name == subcontext and c.target_view == target_view:
-                return c.ifc_definition_id or None
+        for representation in obj.BIMObjectProperties.representations:
+            element = self.file.by_id(representation.ifc_definition_id)
+            if ifcopenshell.util.element.is_representation_of_context(element, context, subcontext, target_view):
+                return representation.ifc_definition_id or None
 
 
 class BakeParametricGeometry(bpy.types.Operator):
@@ -4462,14 +4458,16 @@ class BakeParametricGeometry(bpy.types.Operator):
     bl_label = "Bake Parametric Geometry"
 
     def execute(self, context):
-        obj = bpy.context.active_object
-        if "/" not in obj.data.name:
-            context, subcontext, target_view = ("Model", "Body", "MODEL_VIEW")
-        else:
-            context, subcontext, target_view = obj.data.name.split("/")[0:3]
-        for c in obj.BIMObjectProperties.representation_contexts:
-            if c.context == context and c.name == subcontext and c.target_view == target_view:
-                c.ifc_definition_id = 0
+        # TODO rewrite, see #1222
+        # obj = bpy.context.active_object
+        # if "/" not in obj.data.name:
+        #     context, subcontext, target_view = ("Model", "Body", "MODEL_VIEW")
+        # else:
+        #     context, subcontext, target_view = obj.data.name.split("/")[0:3]
+        # for representation in obj.BIMObjectProperties.representations:
+        #     element = self.file.by_id(representation.ifc_definition_id)
+        #     if ifcopenshell.util.element.is_representation_of_context(element, context, subcontext, target_view):
+        #         representation.ifc_definition_id = 0
         return {"FINISHED"}
 
 
@@ -4479,6 +4477,7 @@ class UpdateIfcRepresentation(bpy.types.Operator):
     index: bpy.props.IntProperty()
 
     def execute(self, context):
+        self.file = ifc.IfcStore.get_file()
         props = bpy.context.active_object.data.BIMMeshProperties
         parameter = props.ifc_parameters[self.index]
         element = ifc.IfcStore.get_file().by_id(parameter.step_id)[parameter.index] = parameter.value
@@ -4505,9 +4504,10 @@ class UpdateIfcRepresentation(bpy.types.Operator):
             context, subcontext, target_view = ("Model", "Body", "MODEL_VIEW")
         else:
             context, subcontext, target_view = obj.data.name.split("/")[0:3]
-        for c in obj.BIMObjectProperties.representation_contexts:
-            if c.context == context and c.name == subcontext and c.target_view == target_view:
-                return c.ifc_definition_id or None
+        for representation in obj.BIMObjectProperties.representations:
+            c = self.file.by_id(self.ifc_definition_id).ContextOfItems
+            if c.ContextType == context and c.ContextIdentifier == subcontext and c.TargetView == target_view:
+                return representation.ifc_definition_id or None
 
 
 class BlenderClasher:

src/ifcblenderexport/blenderbim/bim/prop.py

@@ -1480,6 +1480,7 @@ class BoundaryCondition(PropertyGroup):
 
 
 class BIMObjectProperties(PropertyGroup):
+    ifc_definition_id: IntProperty(name="IFC Definition ID")
     is_reassigning_class: BoolProperty(name="Is Reassigning Class")
     global_ids: CollectionProperty(name="GlobalIds", type=GlobalId)
     attributes: CollectionProperty(name="Attributes", type=Attribute)
@@ -1544,6 +1545,7 @@ class ItemSlotMap(PropertyGroup):
 
 
 class BIMMeshProperties(PropertyGroup):
+    ifc_definition_id: IntProperty(name="IFC Definition ID")
     is_native: BoolProperty(name="Is Native", default=False)
     is_swept_solid: BoolProperty(name="Is Swept Solid")
     swept_solids: CollectionProperty(name="Swept Solids", type=SweptSolid)
@@ -1553,4 +1555,4 @@ class BIMMeshProperties(PropertyGroup):
     ifc_parameters: CollectionProperty(name="IFC Parameters", type=IfcParameter)
     active_representation_item_index: IntProperty(name="Active Representation Item Index")
     presentation_layer_index: IntProperty(name="Presentation Layer Index", default=-1)
-    ifc_item_ids: CollectionProperty(name="IFC Definition ID", type=ItemSlotMap)
+    ifc_item_ids: CollectionProperty(name="IFC Item IDs", type=ItemSlotMap)

src/ifcblenderexport/blenderbim/bim/ui.py

@@ -645,9 +645,7 @@ class BIM_PT_representations(Panel):
         row.prop(bpy.context.scene.BIMProperties, "available_contexts", text="")
         row.prop(bpy.context.scene.BIMProperties, "available_subcontexts", text="")
         row.prop(bpy.context.scene.BIMProperties, "available_target_views", text="")
-        # TODO: reimplement with incremental editing
-        # op = row.operator("bim.switch_context", icon="ADD", text="")
-        # op.has_target_context = False
+        row.operator("bim.add_representation", icon="ADD", text="")
 
         self.file = ifc.IfcStore.get_file()
         for index, representation in enumerate(props.representations):
@@ -656,16 +654,12 @@ class BIM_PT_representations(Panel):
             row.prop(representation, "type", text="")
             if not representation.ifc_definition_id:
                 continue
-            subcontext = self.file.by_id(representation.ifc_definition_id).ContextOfItems
-            if subcontext.is_a() == "IfcGeometricRepresentationContext":
+            context_of_items = self.file.by_id(representation.ifc_definition_id).ContextOfItems
+            if context_of_items.is_a() == "IfcGeometricRepresentationContext":
                 continue
-            # TODO: reimplement with incremental editing
-            # op = row.operator("bim.switch_context", icon="OUTLINER_DATA_MESH", text="")
-            # op.has_target_context = True
-            # op.context_name = subcontext.ContextType
-            # op.subcontext_name = subcontext.ContextIdentifier
-            # op.target_view_name = subcontext.TargetView
-            # row.operator("bim.remove_context", icon="X", text="").index = index
+            op = row.operator("bim.switch_representation", icon="OUTLINER_DATA_MESH", text="")
+            op.ifc_definition_id = representation.ifc_definition_id
+            row.operator("bim.remove_representation", icon="X", text="").index = index
 
 
 class BIM_PT_classification_references(Panel):

src/ifcopenshell-python/ifcopenshell/util/element.py

@@ -93,3 +93,32 @@ def replace_attribute(element, old, new):
                 if item == old:
                     new_attribute[j] = new
                     element[i] = new_attribute
+
+
+def is_representation_of_context(representation, context, subcontext=None, target_view=None):
+    if target_view is not None:
+        return (
+            representation.ContextOfItems.is_a("IfcGeometricRepresentationSubContext")
+            and representation.ContextOfItems.TargetView == target_view
+            and representation.ContextOfItems.ContextIdentifier == subcontext
+            and representation.ContextOfItems.ContextType == context
+        )
+    elif subcontext is not None:
+        return (
+            representation.ContextOfItems.is_a("IfcGeometricRepresentationSubContext")
+            and representation.ContextOfItems.ContextIdentifier == subcontext
+            and representation.ContextOfItems.ContextType == context
+        )
+    elif representation.ContextOfItems.ContextType == context:
+        return True
+
+
+def get_representation(element, context, subcontext=None, target_view=None):
+    if element.is_a("IfcProduct") and element.Representation:
+        for r in element.Representation.Representations:
+            if is_representation_of_context(r, context, subcontext, target_view):
+                return r
+    elif element.is_a("IfcTypeProduct") and element.RepresentationMaps:
+        for r in element.RepresentationMaps:
+            if is_representation_of_context(r.MappedRepresentation, context, subcontext, target_view):
+                return r.MappedRepresentation