WIP port object material assignment with 3 new features. See message. See #1222.

* Full support for editing IfcMaterialList added
 * The reusability of material set relationships are now roundtripped
 * UI is sensitive to IFC schema version and adapts intelligently

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

@@ -0,0 +1,54 @@
+import bpy
+import blenderbim.bim.schema # refactor
+from blenderbim.bim.module.material.data import Data
+from blenderbim.bim.ifc import IfcStore
+from blenderbim.bim.prop import StrProperty, Attribute
+from bpy.types import PropertyGroup
+from bpy.props import (
+    PointerProperty,
+    StringProperty,
+    EnumProperty,
+    BoolProperty,
+    IntProperty,
+    FloatProperty,
+    FloatVectorProperty,
+    CollectionProperty,
+)
+
+materials_enum = []
+materialtypes_enum = []
+
+
+def getMaterials(self, context):
+    global materials_enum
+    if len(materials_enum) == 0 and IfcStore.get_file():
+        materials_enum.clear()
+        materials_enum = [(str(m_id), m["Name"], "") for m_id, m in Data.materials.items()]
+    return materials_enum
+
+
+def getMaterialTypes(self, context):
+    global materialtypes_enum
+    if len(materialtypes_enum) == 0 and IfcStore.get_file():
+        material_types = [
+            "IfcMaterial",
+            "IfcMaterialConstituentSet",
+            "IfcMaterialLayerSet",
+            "IfcMaterialProfileSet",
+            "IfcMaterialList",
+        ]
+        if IfcStore.get_file().schema == "IFC2X3":
+            material_types = ["IfcMaterial", "IfcMaterialLayerSet", "IfcMaterialList"]
+        materialtypes_enum.clear()
+        materialtypes_enum = [(m, m, "") for m in material_types]
+    return materialtypes_enum
+
+
+class BIMObjectMaterialProperties(PropertyGroup):
+    material_type: EnumProperty(items=getMaterialTypes, name="Material Type")
+    material: EnumProperty(items=getMaterials, name="Material")
+    is_editing: BoolProperty(name="Is Editing", default=False)
+    material_set_attributes: CollectionProperty(name="Material Set Attributes", type=Attribute)
+    active_material_set_item_id: IntProperty(name="Active Material Set ID")
+    material_set_item_attributes: CollectionProperty(name="Material Set Item Attributes", type=Attribute)
+    material_set_item_material: EnumProperty(items=getMaterials, name="Material")