Is it possible to make a Curtain wall parallel with the ground rather than standing upright?
Yes it is possible by using the massing tool. Sketch you polyline to the desired shape, choose create form (set thickness etc), then finish mass. You can then create a curtain system by face. The mass can then either be deleted or hidden for future use. Note: if you keep the mass and revise it you can update the curtain wall automatically using the ‘update to face’ command.