I have some simple assets, a lighthouse and a lamppost. The lighthouse supports two materials so I can light up the windows by changing that material. The lampost has similar looking lights but it doesn't support a second material. I am pretty certain I need to edit the lampost mesh and add a sub-mesh. Not that I know how to do it but I'd like to try. I played with ProBuilder a bit and while I seem to be able to edit the mesh I don't see an option for adding a sub-mesh. So is there a mesh editor, a tutorial or something that would explain how to add "glass panels" to my lampost?