I have a house model using archimesh rooms,windows, etc. When I render in blender the window is transparent as it should be. In sketchfab the window displays as a box and no matter what texture/opacity, etc I try I can’t see through the window. It appears that sketchfab is displaying the hole cutter for the windows. If I hide the window group, hole, window before I import to sketchfab I can see the hole, but can’t put a glass material over the hole. It involves a lot of extra work to hide the window and the result isn’t very good.