Easy good enough roofs with one checkbox

[whengreg]

Yesterday, I tried to add a roof to my home by just adding sloped walls, and having a room with a ceiling. This wouldn't give an overhang, but it's close, and it's really easy to create.

However, this doesn't work for a rather annoying reason; ceilings are only visible from below. From outside it's just a bunch of walls giving the skeleton of a roof, with no actual roof.

Therefore, the checkbox I want is "ceiling is visible from above". All this would do is add polygons to the top side of the ceiling, which would allow the easy creation of arbitrary roof shapes.

[YGYL]

To help you come up with a temporary solution.
Set a floor color for this room area, then export the OBJ. then import the OBJ, Invert the back and front faces when importing. Place it in the same location.
Then customize the object, turn off the floor display, and change the texture of the ceiling
Finish