Recreating round-tripped representations now preserves surface styles

src/ifcblenderexport/blenderbim/bim/import_ifc.py

@@ -58,7 +58,7 @@ class MaterialCreator:
             return
         self.parsed_meshes.append(self.mesh.name)
         if self.parse_representations(element):
-            self.assign_material_slots_to_faces(obj, self.mesh)
+            self.assign_material_slots_to_faces(obj)
 
     def parse_representations(self, element):
         has_parsed = False
@@ -91,22 +91,23 @@ class MaterialCreator:
             return True
 
         style = bpy.data.materials.get(style_name)
+
         if not style:
             style = bpy.data.materials.new(style_name)
+            self.parse_styled_item(styled_item, style)
 
-        self.parse_styled_item(styled_item, style)
         self.assign_style_to_mesh(style)
         item_id = self.mesh.BIMMeshProperties.ifc_item_ids.add()
         item_id.name = str(item.id())
         return True
 
-    def assign_material_slots_to_faces(self, obj, mesh):
-        if "ios_materials" not in mesh or not mesh["ios_materials"]:
+    def assign_material_slots_to_faces(self, obj):
+        if "ios_materials" not in self.mesh or not self.mesh["ios_materials"]:
             return
         if len(obj.material_slots) == 1:
             return
         material_to_slot = {}
-        for i, material in enumerate(mesh["ios_materials"]):
+        for i, material in enumerate(self.mesh["ios_materials"]):
             if material == "NULLMAT":
                 continue
             elif "surface-style-" in material:
@@ -124,9 +125,9 @@ class MaterialCreator:
                 slot_index = [self.canonicalise_material_name(s.name) for s in obj.material_slots].index(material)
             material_to_slot[i] = slot_index
 
-        if len(mesh.polygons) == len(mesh["ios_material_ids"]):
-            material_index = [(material_to_slot[mat_id] if mat_id != -1 else 0) for mat_id in mesh["ios_material_ids"]]
-            mesh.polygons.foreach_set("material_index", material_index)
+        if len(self.mesh.polygons) == len(self.mesh["ios_material_ids"]):
+            material_index = [(material_to_slot[mat_id] if mat_id != -1 else 0) for mat_id in self.mesh["ios_material_ids"]]
+            self.mesh.polygons.foreach_set("material_index", material_index)
 
     def canonicalise_material_name(self, name):
         return re.sub(r"\.[0-9]{3}$", "", name)

src/ifcblenderexport/blenderbim/bim/operator.py

@@ -4509,8 +4509,8 @@ class GetRepresentationIfcParameters(bpy.types.Operator):
 
     def execute(self, context):
         props = bpy.context.active_object.data.BIMMeshProperties
-        dummy = ifcopenshell.file.from_string(props.ifc_definition)
-        for element in dummy:
+        elements = ifc.IfcStore.get_file().traverse(ifc.IfcStore.get_file().by_id(props.ifc_definition_id))
+        for element in elements:
             if not element.is_a("IfcRepresentationItem"):
                 continue
             for i in range(0, len(element)):
@@ -4533,21 +4533,21 @@ class UpdateIfcRepresentation(bpy.types.Operator):
     def execute(self, context):
         props = bpy.context.active_object.data.BIMMeshProperties
         parameter = props.ifc_parameters[self.index]
-        dummy = ifcopenshell.file.from_string(props.ifc_definition)
-        element = dummy.by_id(parameter.step_id)[parameter.index] = parameter.value
-        props.ifc_definition = dummy.to_string()
+        element = ifc.IfcStore.get_file().by_id(parameter.step_id)[parameter.index] = parameter.value
         self.recreate_ifc_representation()
         return {"FINISHED"}
 
     def recreate_ifc_representation(self):
         props = bpy.context.active_object.data.BIMMeshProperties
-        dummy = ifcopenshell.file.from_string(props.ifc_definition)
         logger = logging.getLogger("ImportIFC")
         self.ifc_import_settings = import_ifc.IfcImportSettings.factory(bpy.context, ifc.IfcStore.path, logger)
-        element = dummy.by_id(props.ifc_definition_id)
+        element = ifc.IfcStore.get_file().by_id(props.ifc_definition_id)
         settings = ifcopenshell.geom.settings()
         shape = ifcopenshell.geom.create_shape(settings, element)
         ifc_importer = import_ifc.IfcImporter(self.ifc_import_settings)
-        ifc_importer.file = dummy
+        ifc_importer.file = ifc.IfcStore.get_file()
         mesh = ifc_importer.create_mesh(element, shape)
         bpy.context.active_object.data.user_remap(mesh)
+        ifc_importer.material_creator.mesh = mesh
+        if ifc_importer.material_creator.parse_representation(element):
+            ifc_importer.material_creator.assign_material_slots_to_faces(bpy.context.active_object)

src/ifcblenderexport/blenderbim/bim/ui.py

@@ -755,16 +755,12 @@ class BIM_PT_mesh(Panel):
 
         row = layout.row()
         row.prop(props, "geometry_type")
-        row = layout.row()
-        row.prop(props, "ifc_definition")
         layout.label(text="IFC Parameters:")
         row = layout.row()
         row.operator("bim.get_representation_ifc_parameters")
         for index, ifc_parameter in enumerate(props.ifc_parameters):
             row = layout.row(align=True)
             row.prop(ifc_parameter, "name", text="")
-            row.prop(ifc_parameter, "step_id")
-            row.prop(ifc_parameter, "index")
             row.prop(ifc_parameter, "value", text="")
             row.operator("bim.update_ifc_representation", icon="FILE_REFRESH", text="").index = index