Fix #2599. Unassigning materials now also removes the Blender material.

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

@@ -142,26 +142,20 @@ class AssignMaterial(bpy.types.Operator, tool.Ifc.Operator):
     material_type: bpy.props.StringProperty()
 
     def _execute(self, context):
-        self.file = IfcStore.get_file()
-
-        if self.obj:
-            objects = [bpy.data.objects.get(self.obj)]
-        else:
-            objects = context.selected_objects
+        objects = [bpy.data.objects.get(self.obj)] if self.obj else context.selected_objects
         active_obj = context.active_object
         active_object_material_type = self.material_type or active_obj.BIMObjectMaterialProperties.material_type
-        active_object_material = active_obj.BIMObjectMaterialProperties.material
+        material = tool.Ifc.get().by_id(int(active_obj.BIMObjectMaterialProperties.material))
         for obj in objects:
-            element = self.file.by_id(obj.BIMObjectProperties.ifc_definition_id)
-            ifcopenshell.api.run(
-                "material.assign_material",
-                self.file,
-                **{
-                    "product": element,
-                    "type": active_object_material_type,
-                    "material": self.file.by_id(int(active_object_material)),
-                },
-            )
+            element = tool.Ifc.get_entity(obj)
+            if element:
+                ifcopenshell.api.run(
+                    "material.assign_material",
+                    tool.Ifc.get(),
+                    product=element,
+                    type=active_object_material_type,
+                    material=material,
+                )
 
 
 class UnassignMaterial(bpy.types.Operator, tool.Ifc.Operator):
@@ -171,18 +165,11 @@ class UnassignMaterial(bpy.types.Operator, tool.Ifc.Operator):
     obj: bpy.props.StringProperty()
 
     def _execute(self, context):
-        self.file = IfcStore.get_file()
-
-        if self.obj:
-            objects = [bpy.data.objects.get(self.obj)]
-        else:
-            objects = context.selected_objects
+        objects = [bpy.data.objects.get(self.obj)] if self.obj else context.selected_objects
         for obj in objects:
-            ifcopenshell.api.run(
-                "material.unassign_material",
-                self.file,
-                **{"product": self.file.by_id(obj.BIMObjectProperties.ifc_definition_id)},
-            )
+            element = tool.Ifc.get_entity(obj)
+            if element:
+                ifcopenshell.api.run("material.unassign_material", tool.Ifc.get(), product=element)
 
 
 class AddConstituent(bpy.types.Operator, tool.Ifc.Operator):

src/blenderbim/blenderbim/bim/module/model/handler.py

@@ -50,6 +50,10 @@ def load_post(*args):
             usecase, "BlenderBIM.Product.EnsureMaterialAssigned", product.ensure_material_assigned
         )
 
+    ifcopenshell.api.add_post_listener(
+        "material.unassign_material", "BlenderBIM.Product.EnsureMaterialUnassigned", product.ensure_material_unassigned
+    )
+
     ifcopenshell.api.add_post_listener(
         "material.edit_profile_usage",
         "BlenderBIM.Product.RegenerateProfileUsage",

src/blenderbim/blenderbim/bim/module/model/product.py

@@ -527,3 +527,29 @@ def ensure_material_assigned(usecase_path, ifc_file, settings):
             continue
 
         obj.data.materials.append(IfcStore.get_element(material[0].id()))
+
+
+
+def ensure_material_unassigned(usecase_path, ifc_file, settings):
+    elements = [settings["product"]]
+    if elements[0].is_a("IfcElementType"):
+        elements.extend(ifcopenshell.util.element.get_types(elements[0]))
+    for element in elements:
+        obj = tool.Ifc.get_object(element)
+        if not obj or not obj.data:
+            continue
+        element_material = ifcopenshell.util.element.get_material(element)
+        if element_material:
+            continue
+        to_remove = []
+        for i, slot in enumerate(obj.material_slots):
+            if not slot.material:
+                continue
+            material = tool.Ifc.get_entity(slot.material)
+            if material:
+                to_remove.append(i)
+        total_removed = 0
+        for i in to_remove:
+            obj.active_material_index = i - total_removed
+            bpy.ops.object.material_slot_remove({'object': obj})
+            total_removed += 1

src/blenderbim/test/bim/feature/material.feature

@@ -89,7 +89,7 @@ Scenario: Unassign material - single material
     And I set "active_object.BIMObjectMaterialProperties.material_type" to "IfcMaterial"
     And I press "bim.assign_material"
     When I press "bim.unassign_material"
-    Then nothing happens
+    Then the object "IfcWall/Cube" does not have the material "Default"
 
 Scenario: Enable editing assigned material - single material
     Given an empty IFC project
@@ -132,10 +132,6 @@ Scenario: Edit assigned material - single material
 
 Scenario: Assign material - material layer set
     Given an empty IFC project
-    And I add a cube
-    And the object "Cube" is selected
-    And I set "scene.BIMRootProperties.ifc_class" to "IfcWall"
-    And I press "bim.assign_class"
     And I add an empty
     And the object "Empty" is selected
     And I set "scene.BIMRootProperties.ifc_product" to "IfcElementType"
@@ -144,14 +140,10 @@ Scenario: Assign material - material layer set
     And I press "bim.add_material(obj='')"
     When I set "active_object.BIMObjectMaterialProperties.material_type" to "IfcMaterialLayerSet"
     And I press "bim.assign_material"
-    Then nothing happens
+    Then the object "IfcWallType/Empty" does not have the material "Default"
 
 Scenario: Unassign material - material layer set
     Given an empty IFC project
-    And I add a cube
-    And the object "Cube" is selected
-    And I set "scene.BIMRootProperties.ifc_class" to "IfcWall"
-    And I press "bim.assign_class"
     And I add an empty
     And the object "Empty" is selected
     And I set "scene.BIMRootProperties.ifc_product" to "IfcElementType"
@@ -219,10 +211,6 @@ Scenario: Edit assigned material - material layer set
 
 Scenario: Assign material - material profile set
     Given an empty IFC project
-    And I add a cube
-    And the object "Cube" is selected
-    And I set "scene.BIMRootProperties.ifc_class" to "IfcWall"
-    And I press "bim.assign_class"
     And I add an empty
     And the object "Empty" is selected
     And I set "scene.BIMRootProperties.ifc_product" to "IfcElementType"
@@ -231,14 +219,10 @@ Scenario: Assign material - material profile set
     And I press "bim.add_material(obj='')"
     When I set "active_object.BIMObjectMaterialProperties.material_type" to "IfcMaterialProfileSet"
     And I press "bim.assign_material"
-    Then nothing happens
+    Then the object "IfcWallType/Empty" does not have the material "Default"
 
 Scenario: Unassign material - material profile set
     Given an empty IFC project
-    And I add a cube
-    And the object "Cube" is selected
-    And I set "scene.BIMRootProperties.ifc_class" to "IfcWall"
-    And I press "bim.assign_class"
     And I add an empty
     And the object "Empty" is selected
     And I set "scene.BIMRootProperties.ifc_product" to "IfcElementType"

src/blenderbim/test/bim/test_feature.py

@@ -498,6 +498,11 @@ def the_object_name_has_the_material_material(name, material):
     assert material in [ms.material.name for ms in the_object_name_exists(name).material_slots]
 
 
+@then(parsers.parse('the object "{name}" does not have the material "{material}"'))
+def the_object_name_does_not_have_the_material_material(name, material):
+    assert material not in [ms.material.name for ms in the_object_name_exists(name).material_slots]
+
+
 @then(parsers.parse('the object "{name}" is in the collection "{collection}"'))
 def the_object_name_is_in_the_collection_collection(name, collection):
     assert collection in [c.name for c in the_object_name_exists(name).users_collection]