How does the collision works for fondation pieces in building mode? For a floor decoration, I understand that the decoration "drops" to the ground (of the world map). If you build it, and try to put a new one, the new one "collides" with the first, so it goes on top. (Well, I guess it's not really the collision? If it was, we could put a chair under a table. So it's more a bounding box, a min max of x, y and z?) How does it works for a fondation piece? It can go through the ground. Are there two collisions in the nif (one for the top, one for the sides), and the second is deactivated during building, or is it a different node in the nif? Thanks!