I think you have modify the sketch lines/boudary for the ceiling. and just add another rectangle/boudary for opening required for stiar. you will get the result.
A "Shaft Opening" element will cut not only the floors, but also any ceilings and roofs it intersects.
You can sketch the shaft opening to match your stair layout.
Log into access your profile, ask and answer questions, share ideas and more. Haven't signed up yet? Register