Hi,
I know about straight skeleton, but only seen implementations that can produce roofs with equally angled slopes. But you pushed me a bit to search slightly different
I’ve found this article about the method for roofs with various slopes, but unfortunately, I can’t do anything with it 
https://www.sciencedirect.com/science/article/pii/S0010448517301240
I will post it in the Old Town Roofs and leave this topic to the discussion about AriqShap3D.