I'm not sure if this is a bug in my CGA code or not. I am trying to create a CGA that will create buildings that are horizontal on non horizontal lots by using some of the code from Tutorial 7 for creating floors and the Alignment2 code from the Non-Horizontal lot posted previously. I managed to get everything working properly and on lots with any sort of angle the buildings generate correctly but on other lots no geometry is generated unless I move one vertex up or down on the Y axis. The amount of movement on the Y axis is minimal but as soon as the vertex is moved geometry is generated.
The picture shows building with aligned to the heightmap with one moved vertex on the left and the blank lot is all vertices aligned to the heightmap on the right.