Messing Around With Intersections

Not much to look at, but I’m hoping to make this into something that can be used for a roof on a house. I want to be able to define the perimeter by a series of points and have it automatically make a roof shape based on that. I tried something similar for the house body itself; it worked for simple perimeters like this one above, but more complex ones gave unexpected results, so we’ll see if I can figure out how to make it work this time.