Barrell vault and cross vault simulations (self standing)

I’ve made few physical vault models for teaching purposes, barrell and cross vault.

http://opendimension.org/images/vaults.jpg

Idea is to show how do they work, eg. how they must be built in order to stay up. Anyway, here is the model:
http://www.opendimension.org/blender_en/blends/vaults.blend

EDIT. I forgot to mention that these will collapse with 2.45. I’ve used SVN version and they should stay up fine.

Feel free to use for your own purposes.

PS. My previous arch pressure models can be found here:
http://www.opendimension.org/blender_en/arch_pressure.php