I have drawn a rounded sunscoop as "roof by extrusion". The lower end is sitting on concrete slab and the higher end should have a fascia board attached. The upper end must be cut plumb & the lower end cut square. Someone suggested that I "cover" the piece hanging through the slab with a "filled region" on the appropriate section. Although it looks fine on screen, when plotted it is looks very unprofessional. There must be a better way I'm sure!!
Thanx for all the info, you are all of great help!