We got buildings that are a single sphere in France like la Géode
→ Yes, when you suppose that we are dealing with a sphere section.
Is it not an ellipsoid? Could be. We have ellipsoidsas well.
The : http://fr.wikipedia.org/wiki/La_G%C3%A9ode could be ( of course, if we use my proposal ) tagged as: geodesic_dome=triangulated and triangle:number=6433
Well I should really finish writing of this proposal.
After thinking about spherical buildings, I thing we should allowed it only for nodes. Tags could look like this (Only example):
building:part=yes
shape=sphere
height=5 <= height of sphere center
radius=5 <= radius of sphere
Otherwise people start using this tag for non circular building outline and I don’t have idea how to render spherical shape at building with this outline.
You can test nodes with sphere shape tag in kendzi3d v216 but remember that is only preview how it could work.