operator to remove representation item from shape aspect

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

@@ -53,6 +53,7 @@ classes = (
     operator.EditRepresentationItemStyle,
     operator.DisableEditingRepresentationItemStyle,
     operator.UnassignRepresentationItemStyle,
+    operator.RemoveRepresentationItemFromShapeAspect,
     prop.RepresentationItem,
     prop.BIMObjectGeometryProperties,
     prop.BIMGeometryProperties,

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

@@ -1601,6 +1601,7 @@ class EnableEditingRepresentationItems(bpy.types.Operator, Operator):
                             if inverse.OfShapeAspect:
                                 shape_aspect = inverse.OfShapeAspect[0]
                                 new.shape_aspect = shape_aspect.Name
+                                new.shape_aspect_id = shape_aspect.id()
 
 
 class DisableEditingRepresentationItems(bpy.types.Operator, Operator):
@@ -1685,3 +1686,23 @@ class UnassignRepresentationItemStyle(bpy.types.Operator, Operator):
         # reload style ui
         bpy.ops.bim.disable_editing_representation_items()
         bpy.ops.bim.enable_editing_representation_items()
+
+
+class RemoveRepresentationItemFromShapeAspect(bpy.types.Operator, Operator):
+    bl_idname = "bim.remove_representation_item_from_shape_aspect"
+    bl_label = "Remove Representation Item From Shape Aspect"
+    bl_options = {"REGISTER", "UNDO"}
+
+    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)
+        shape_aspect = ifc_file.by_id(props.items[props.active_item_index].shape_aspect_id)
+
+        tool.Geometry.remove_representation_item_from_shape_aspect(representation_item, shape_aspect)
+        # reload style ui
+        bpy.ops.bim.disable_editing_representation_items()
+        bpy.ops.bim.enable_editing_representation_items()

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

@@ -62,6 +62,7 @@ class RepresentationItem(PropertyGroup):
     layer: StringProperty(name="Layer")
     ifc_definition_id: IntProperty(name="IFC Definition ID")
     shape_aspect: StringProperty(name="Shape Aspect")
+    shape_aspect_id: IntProperty(name="Shape Aspect IFC ID")
 
 
 class BIMObjectGeometryProperties(PropertyGroup):

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

@@ -215,6 +215,8 @@ class BIM_PT_representation_items(Panel):
 
         row = self.layout.row()
         row.label(text=shape_aspect or "No Shape Aspect", icon="SHAPEKEY_DATA")
+        if shape_aspect:
+            row.operator("bim.remove_representation_item_from_shape_aspect", icon="X", text="")
 
 
 class BIM_PT_connections(Panel):

src/blenderbim/blenderbim/tool/geometry.py

@@ -730,3 +730,24 @@ class Geometry(blenderbim.core.tool.Geometry):
             should_sync_changes_first=False,
             apply_openings=True,
         )
+
+    @classmethod
+    def remove_representation_item_from_shape_aspect(cls, representation_item, shape_aspect):
+        ifc_file = tool.Ifc.get()
+        # as shape aspect might have multiple representations
+        # it's easier to find it from the item
+        for inverse in ifc_file.get_inverse(representation_item):
+            if inverse.is_a("IfcShapeRepresentation") and shape_aspect in inverse.OfShapeAspect:
+                representation = inverse
+                break
+
+        # removing last item would make representation invalid
+        if len(representation.Items) == 1:
+            # removing last representation would make shape aspect invalid.
+            # remove shape aspect first otherwise remove_representation won't remove it because of the inverse
+            if len(shape_aspect.ShapeRepresentations) == 1:
+                ifc_file.remove(shape_aspect)
+            tool.Ifc.run("geometry.remove_representation", representation=representation)
+        else:
+            items = set(representation.Items) - {representation_item}
+            representation.Items = tuple(items)