UV coordinates on pillars and floor working. I've tinkered with UVs for the ceiling surfaces but have not found a solution yet. There are always discontinuities. The ceiling is created with quadratic Bezier triangles.
I've tried to come up with my own parametric surface description but failed. Today I've looked up and implemented Bézier triangle. No I can sample the surface I want to have. Next I will have to do create an actual geometry out of this.
Combined the Delaunay triangulation with the Bezier curves to create the "walls" of a room. Next step will be figuring out how to create surfaces between curves.