How to create complex curved roof

[Zebbedy]

I'm designing a building in Revit that consists of tapered rectangles, with each wall curving into a flat roof. I've made foam models of it but have no idea how to go about modelling those curves coming in from different angles.

Any help would be much appreciated!

[marmiketin]

The best way to do this would be to create a mass in the shape of the roof you want and then create a roof-by-face and select the faces of the mass which you want the roof to follow.