UI to remove representation items

example - https://i.imgur.com/jJDpIQP.png

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

@@ -49,6 +49,7 @@ classes = (
     operator.SwitchRepresentation,
     operator.UpdateParametricRepresentation,
     operator.UpdateRepresentation,
+    operator.RemoveRepresentationItem,
     operator.EnableEditingRepresentationItemStyle,
     operator.EditRepresentationItemStyle,
     operator.DisableEditingRepresentationItemStyle,

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

@@ -1614,6 +1614,35 @@ class DisableEditingRepresentationItems(bpy.types.Operator, Operator):
         obj.BIMGeometryProperties.is_editing = False
 
 
+class RemoveRepresentationItem(bpy.types.Operator, Operator):
+    bl_idname = "bim.remove_representation_item"
+    bl_label = "Remove Representation Item"
+    bl_options = {"REGISTER", "UNDO"}
+
+    @classmethod
+    def poll(cls, context):
+        if context.active_object is None or len(context.active_object.BIMGeometryProperties.items) <= 1:
+            cls.poll_message_set(
+                "Active object need to have more than 1 representation items to keep representation valid"
+            )
+            return False
+        return True
+
+    def _execute(self, context):
+        obj = context.active_object
+        props = obj.BIMGeometryProperties
+        ifc_file = tool.Ifc.get()
+
+        representation_item_id = props.items[props.active_item_index].ifc_definition_id
+        representation_item = ifc_file.by_id(representation_item_id)
+        tool.Geometry.remove_representation_item(representation_item)
+        tool.Geometry.reload_representation(obj)
+
+        # reload style ui
+        bpy.ops.bim.disable_editing_representation_items()
+        bpy.ops.bim.enable_editing_representation_items()
+
+
 class EnableEditingRepresentationItemStyle(bpy.types.Operator, Operator):
     bl_idname = "bim.enable_editing_representation_item_style"
     bl_label = "Enable Editing Representation Item Style"
@@ -1730,7 +1759,9 @@ class EditRepresentationItemShapeAspect(bpy.types.Operator, Operator):
             previous_shape_aspect_id = props.items[props.active_item_index].shape_aspect_id
             # will be None if item didn't had a shape aspect
             previous_shape_aspect = tool.Ifc.get_entity_by_id(previous_shape_aspect_id)
-            shape_aspect = tool.Geometry.create_shape_aspect(product_shape, active_representation, [representation_item], previous_shape_aspect)
+            shape_aspect = tool.Geometry.create_shape_aspect(
+                product_shape, active_representation, [representation_item], previous_shape_aspect
+            )
         else:
             shape_aspect = ifc_file.by_id(int(props.representation_item_shape_aspect))
             tool.Geometry.add_representation_item_to_shape_aspect([representation_item], shape_aspect)

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

@@ -496,3 +496,4 @@ class BIM_UL_representation_items(UIList):
             row.label(text=item.name, icon=icon)
             if item.layer:
                 row.label(text="", icon="STICKY_UVS_LOC")
+            row.operator("bim.remove_representation_item", icon="X", text="")

src/blenderbim/blenderbim/tool/geometry.py

@@ -732,6 +732,45 @@ class Geometry(blenderbim.core.tool.Geometry):
             apply_openings=True,
         )
 
+    @classmethod
+    def remove_representation_item(cls, representation_item):
+        # NOTE: we assume it's not the last representation item
+        # otherwise we probably would need to remove representation too
+        # NOTE: a lot of shared code with `geometry.remove_representation`
+        ifc_file = tool.Ifc.get()
+        shape_aspects = []
+
+        consider_inverses = []
+        styled_item, colour, texture, layer = None, None, None, None
+        [consider_inverses.append(styled_item := t) for t in representation_item.StyledByItem]
+        [consider_inverses.append(layer := t) for t in representation_item.LayerAssignment]
+        # IfcTessellatedFaceSet
+        [consider_inverses.append(colour := t) for t in getattr(representation_item, "HasColours", [])]
+        [consider_inverses.append(texture := t) for t in getattr(representation_item, "HasTextures", [])]
+
+        for inverse in ifc_file.get_inverse(representation_item):
+            if inverse.is_a("IfcShapeRepresentation"):
+                if inverse.OfShapeAspect:
+                    shape_aspects.append(inverse.OfShapeAspect[0])
+                else:
+                    representation = inverse
+
+        if styled_item:
+            ifc_file.remove(styled_item)
+        if layer and len(layer.Items) == 1:
+            ifc_file.remove(styled_item)
+        if colour:
+            ifcopenshell.util.element.remove_deep2(ifc_file, colour)
+        if texture:
+            ifcopenshell.util.element.remove_deep2(ifc_file, texture)
+
+        for shape_aspect in shape_aspects:
+            cls.remove_representation_items_from_shape_aspect([representation_item], shape_aspect)
+
+        representation.Items = tuple(set(representation.Items) - {representation_item})
+        also_consider = list(consider_inverses)
+        ifcopenshell.util.element.remove_deep2(ifc_file, representation_item, also_consider=also_consider)
+
     @classmethod
     def get_shape_aspects(cls, element):
         # IfcProduct
@@ -836,4 +875,3 @@ class Geometry(blenderbim.core.tool.Geometry):
         )
         shape_aspect.ShapeRepresentations = shape_aspect.ShapeRepresentations + (shape_aspect_representation,)
         return shape_aspect_representation
-