Bullet 3D Game Multiphysics Library provides state of the art
collision detection, soft body and rigid body dynamics.

* Modular extendible C++ design with hot-swap of most components
* Optimized back-ends with multi-threaded support for Playstation 3
Cell SPU and other platforms
* Discrete and continuous collision detection (CCD)
* Swept collision queries
* Ray casting with custom collision filtering
* Generic convex support (using GJK), capsule, cylinder, cone, sphere,
box and non-convex triangle meshes.
* Rigid body dynamics including constraint solvers, generic
constraints, ragdolls, hinge, ball-socket
* Support for constraint limits and motors
* Soft body support including cloth, rope and deformable
* Bullet is integrated into Blender 3D and provides a Maya Plugin
* Supports import and export into COLLADA 1.4 Physics format
* Support for dynamic deformation of non-convex triangle meshes, by
refitting the acceleration structures

The Library is free for commercial use and open source
under the ZLib License.