The free Havok PC version is released today, and it includes tools for Max, Maya and XSI.
http://tryhavok.intel.com/http://softwarecommunity.intel.com/isn/ ... Forum.aspxIt could provide a proper toolchain for other physics engines, including Bullet. A simple method would be using a Havok HKX loader and convert all Rigid Bodies, Collision Shapes and Constraints from a Havok World to a Bullet Dynamics World, and use the BulletColladaConverter to export to COLLADA .dae.
Someone interested to check out a path to COLLADA?
Erwin