What you need to do is, in the plan, make the two side roofs
triangular in shape and the main roof polygonal to approximate
the final shape of the three roofs. Then ,with the roof tool NOT selected,
select the polygonal shaped roof and command click on the edge
of the triangular roof that you want to form a hip ridge with
the corresponding edge of the polygonal roof.
Then select the triangular roof and command click on the edge of the polygonal roof
that you want to form a hip ridge with the triangular roof.
This completes the mitering of the two roofs.
Do the same operation on the edges of the other triangular roof
edge and the other edge of the polygonal roof and your done.
Please see attached image.
Peter Devlin
