I have never known how to resolve this situation. You have a second story dormer drawn manually. The walls for the room below do not extend as far as where the main and dormer roofs intersect. In an exterior camera view, there is a triangular gap. Now, if I add a wall section to close in that gap, and do "roof cuts wall at bottom", and indicate a room divider for the lower wall type, it shows accurately on the camera view, and also on an interior camera view, but on the floor plan, the wall still shows up. I've attached a picture. In the past, I've just extended the wall to close the gap when I'm doing exterior views, then pulled it back for the floor plans, but that's a royal pain. Any ideas?