support assigning existing non-ifcmaterials materials

Example - https://imgur.com/a/KN8mQPL

Also added some description to material operators (https://imgur.com/a/eIVNEdU). Need to somehow emphasize that this UI is only for IfcMaterials and cannot be used to assign existing layer sets, profile sets, etc...

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

@@ -28,6 +28,7 @@ classes = (
     operator.AddMaterialSet,
     operator.AddProfile,
     operator.AssignMaterial,
+    operator.AssignMaterialToSelected,
     operator.AssignParameterizedProfile,
     operator.ContractMaterialCategory,
     operator.DisableEditingAssignedMaterial,

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

@@ -117,6 +117,7 @@ class AssignParameterizedProfile(bpy.types.Operator, tool.Ifc.Operator):
 class AddMaterial(bpy.types.Operator, tool.Ifc.Operator):
     bl_idname = "bim.add_material"
     bl_label = "Add Material"
+    bl_description = "Create a new IfcMaterial"
     bl_options = {"REGISTER", "UNDO"}
     name: bpy.props.StringProperty(default="Default")
     category: bpy.props.StringProperty(default="")
@@ -185,6 +186,32 @@ class RemoveMaterialSet(bpy.types.Operator, tool.Ifc.Operator):
         core.remove_material_set(tool.Ifc, tool.Material, material=tool.Ifc.get().by_id(self.material))
 
 
+class AssignMaterialToSelected(bpy.types.Operator, tool.Ifc.Operator):
+    bl_idname = "bim.assign_material_to_selected"
+    bl_label = "Assign Material To Selected"
+    bl_description = "Assign currently selected material in Materials UI to the selected objects"
+    bl_options = {"REGISTER", "UNDO"}
+    material: bpy.props.IntProperty(name="Material IFC ID")
+
+    @classmethod
+    def poll(cls, context):
+        if not context.selected_objects:
+            cls.poll_message_set("No objects selected")
+            return False
+        return True
+
+    def _execute(self, context):
+        material = tool.Ifc.get().by_id(self.material)
+        objects = tool.Blender.get_selected_objects()
+        core.assign_material(
+            tool.Ifc,
+            tool.Material,
+            material_type=tool.Material.get_active_material_type(),
+            objects=objects,
+            material=material,
+        )
+
+
 class AssignMaterial(bpy.types.Operator, tool.Ifc.Operator):
     bl_idname = "bim.assign_material"
     bl_label = "Assign Material"
@@ -192,6 +219,18 @@ class AssignMaterial(bpy.types.Operator, tool.Ifc.Operator):
     obj: bpy.props.StringProperty()
     material_type: bpy.props.StringProperty()
 
+    @classmethod
+    def description(cls, context, properties):
+        if not (material_type := properties.material_type):
+            if not (obj := context.active_object):
+                return ""
+            material_type = obj.BIMObjectMaterialProperties.material_type
+
+        description = "Assign current IfcMaterial to the selected objects"
+        if material_type != "IfcMaterial":
+            description += f" as part of a new {material_type}"
+        return description
+
     def _execute(self, context):
         objects = [bpy.data.objects.get(self.obj)] if self.obj else tool.Blender.get_selected_objects()
         core.assign_material(tool.Ifc, tool.Material, material_type=self.material_type, objects=objects)

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

@@ -143,7 +143,7 @@ class BIMMaterialProperties(PropertyGroup):
 
 class BIMObjectMaterialProperties(PropertyGroup):
     material_type: EnumProperty(items=get_object_material_type, name="Material Type")
-    material: EnumProperty(items=get_materials, name="Material")
+    material: EnumProperty(items=get_materials, name="Material", description="Currently selected IfcMaterial")
     is_editing: BoolProperty(name="Is Editing", default=False)
     material_set_usage_attributes: CollectionProperty(name="Material Set Usage Attributes", type=Attribute)
     material_set_attributes: CollectionProperty(name="Material Set Attributes", type=Attribute)

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

@@ -67,6 +67,8 @@ class BIM_PT_materials(Panel):
                     op.material = material.ifc_definition_id
                     op = row.operator("bim.select_by_material", text="", icon="RESTRICT_SELECT_OFF")
                     op.material = material.ifc_definition_id
+                    op = row.operator("bim.assign_material_to_selected", text="", icon="BRUSH_DATA")
+                    op.material = material.ifc_definition_id
                     op = row.operator("bim.enable_editing_material", text="", icon="GREASEPENCIL")
                     op.material = material.ifc_definition_id
                     op = row.operator("bim.enable_editing_material_style", text="", icon="SHADING_RENDERED")
@@ -81,6 +83,8 @@ class BIM_PT_materials(Panel):
                 if material.ifc_definition_id:
                     op = row.operator("bim.select_by_material", text="", icon="RESTRICT_SELECT_OFF")
                     op.material = material.ifc_definition_id
+                    op = row.operator("bim.assign_material_to_selected", text="", icon="BRUSH_DATA")
+                    op.material = material.ifc_definition_id
                     row.operator("bim.remove_material_set", text="", icon="X").material = material.ifc_definition_id
 
         self.layout.template_list("BIM_UL_materials", "", self.props, "materials", self.props, "active_material_index")

src/blenderbim/blenderbim/core/material.py

@@ -99,17 +99,33 @@ def disable_editing_material(material_tool: tool.Material) -> None:
 
 
 def assign_material(
-    ifc: tool.Ifc, material_tool: tool.Material, material_type: Union[str, None], objects: list[bpy.types.Object]
+    ifc: tool.Ifc,
+    material_tool: tool.Material,
+    material_type: Union[str, None],
+    objects: list[bpy.types.Object],
+    material: Optional[ifcopenshell.entity_instance] = None,
 ) -> None:
-    material_type = material_type or material_tool.get_active_object_material()
-    material = material_tool.get_active_material()
+    """Assign material to the provided objects.
+
+    If `material_type` or `material` are not provided, the active ones from
+        Object Materials UI is used.
+    """
+    material_type = material_type or material_tool.get_object_ui_material_type()
+    material = material or material_tool.get_object_ui_active_material()
     for obj in objects:
         element = ifc.get_entity(obj)
         if not element:
             continue
+
         ifc.run("material.assign_material", products=[element], type=material_type, material=material)
         assigned_material = material_tool.get_material(element)
-        if material_tool.is_a_material_set(assigned_material):
+        assert assigned_material  # Type checker.
+
+        if material_tool.is_a_material_set(material):
+            # Ensure set is a valid IFC.
+            default_material = material_tool.get_default_material()
+            material_tool.add_material_to_set(material_set=material, material=default_material)
+        elif material_tool.is_a_material_set(assigned_material):
             material_tool.add_material_to_set(material_set=assigned_material, material=material)
 
 

src/blenderbim/blenderbim/core/tool.py

@@ -493,7 +493,7 @@ class Material:
     def enable_editing_materials(cls): pass
     def get_active_material(cls): pass
     def get_active_material_type(cls): pass
-    def get_active_object_material(cls, obj): pass
+    def get_active_object_material_type(cls, obj): pass
     def get_elements_by_material(cls, material): pass
     def get_material(cls, element, should_inherit): pass
     def get_material_attributes(cls): pass

src/blenderbim/blenderbim/tool/material.py

@@ -19,6 +19,7 @@
 from __future__ import annotations
 import bpy
 import ifcopenshell
+import ifcopenshell.api.material
 import blenderbim.core.tool
 import blenderbim.core.material
 import blenderbim.tool as tool
@@ -165,19 +166,27 @@ class Material(blenderbim.core.tool.Material):
         props.active_material_id = 0
         props.editing_material_type = ""
 
+    @classmethod
+    def get_default_material(cls) -> ifcopenshell.entity_instance:
+        """Return first found IfcMaterial in IFC file or create a new default material."""
+        ifc_file = tool.Ifc.get()
+        material = next(iter(ifc_file.by_type("IfcMaterial")), None)
+        if material:
+            return material
+        material = ifcopenshell.api.material.add_material(ifc_file, name="Default")
+        return material
+
     @classmethod
     def get_type(cls, element: ifcopenshell.entity_instance) -> Union[ifcopenshell.entity_instance, None]:
         return ifcopenshell.util.element.get_type(element)
 
     @classmethod
-    def get_active_object_material(cls) -> Union[str, None]:
+    def get_object_ui_material_type(cls) -> str:
         active_obj = bpy.context.active_object
-        if not active_obj:
-            return
         return active_obj.BIMObjectMaterialProperties.material_type
 
     @classmethod
-    def get_active_material(cls) -> ifcopenshell.entity_instance:
+    def get_object_ui_active_material(cls) -> ifcopenshell.entity_instance:
         return tool.Ifc.get().by_id(int(bpy.context.active_object.BIMObjectMaterialProperties.material))
 
     @classmethod