Ceiling not shown in one project only

[Keet]

situation where the sloped ceiling is still useful

Probably when you make a room under the stairs.

That is a possibility I didn't think of. I would either leave the bottom of the stairs as a ceiling or create an object for it. Since I always custom create my staircases the 'ceiling' would be part of the staircase anyway. It would take to much playing with sloping walls and levels to achieve the same with a room ceiling.