How do I add a new custom property to a material of an object in my Python script? In an earlier version it was possible to use
bpy.context.object.active_material.gltf_double_sided = True
but I guess in Blender 2.81a it is not supported, the script fails on this line. Unfortunately, the API documentation is very, confusing. Is there something like, e.g.
bpy.context.object.active_material.data['gltf_double_sided'] = True
(btw, the line above does not work)