New feature to unlink Blender materials and IFC materials

src/blenderbim/blenderbim/tool/__init__.py

@@ -22,6 +22,7 @@ from blenderbim.tool.collector import Collector
 from blenderbim.tool.container import Container
 from blenderbim.tool.context import Context
 from blenderbim.tool.ifc import Ifc
+from blenderbim.tool.material import Material
 from blenderbim.tool.owner import Owner
 from blenderbim.tool.style import Style
 from blenderbim.tool.surveyor import Surveyor

src/blenderbim/blenderbim/tool/material.py

@@ -0,0 +1,32 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import ifcopenshell
+import blenderbim.core.tool
+import blenderbim.tool as tool
+import blenderbim.bim.helper
+
+
+class Material(blenderbim.core.tool.Material):
+    @classmethod
+    def link(cls, material, obj):
+        obj.BIMObjectProperties.ifc_definition_id = material.id()
+
+    @classmethod
+    def unlink(self, obj):
+        obj.BIMObjectProperties.ifc_definition_id = 0