I now have the basic system in place and working for the rafter roofs but if you look closely you can see there is still some refinement necessary. The example shown is two gable rafter roofs that are connected, with the trimming of the primary roof limited to only framing, cladding, gutters and soffit/fascia. Note that the insulation, gypsum, rafters and sheathing is not trimmed on the primary roof:
alt text
alt text
alt text
The tricky part with the refinement is how best to generate the cutting solid to subtract away the unwanted portions of the roof(s). Currently the way I am doing it is using the hidden roof primitive and the roof outline. I basically take the roof outline, extrude it vertically down and then union this solid with the roof primitive above. The resulting solid is then used to subtract against the geometry of any attached roofs. This seems to work reasonably well in most cases but as you can see with the soffit and fascia (and the gutters) there is some overlapping and other minor complications. The insulation also gets a little carved out in places but it is mostly acceptable.
alt text
alt text
alt text
Thoughts or suggestions?