Half octagonal roof?

I did that: placed a hidden room marker in the room where the roof was pointing in. I painted the walls and floor black and put that marker in it. During gameplay I didn't see the part that has a roof in it because of that marker. You can also use skip level room markers on the top floor so the camera, during gameplay, skips that floor when you go up. It can make for nice roofing: you go from the floor where Sims live straight to the top of the roof: it skips the less pretty part so of speak. Not exactly sure how to explain it but if you play around with it, you probably see what I mean. Anyway, you're welcome and have fun. :smiley:

Edit:
Oh, before I forget: on lots with such markers you probably need the cheat RestrictBuildBuyInBuildings true/false.