creating a roof with various eave and ridge heights?

[BennyAdam]

I have a design where the roof has various eave and ridge heights but I have not found a good way to realise this in Vectorworks. I have created the form of the roof as a generic solid but in sections it obviously does not show the structure as it is not a real roof but just a simple 3D-model. I also created the same form with the 3D-poly tool but I dont know if I can create a roof out of the 3D-polygon like it is possible with the normal polygon tool. I also tried to create the roof by drawing it piece by piece with the roof face tool, which worked partially but was not very accurate. I would be very greatful if someone could help me with this problem. Thanks in advance.