Some of the features include:
- Featherstone Articulated btMultiBody, with two-way interaction with regular btRigidBody. See Bullet/Demos/FeatherstoneMultiBodyDemo. Thanks to Stephen Thompson for the initial Featherstone implementation, and Martin Felis and Jakub Stepien for the discussion and information.
- New MLCP constraint solver interface for higher quality direct solvers. Dantzig (by Russel Smith OpenDE), PATH and Projected Gauss Seidel Mixed Linear Complementarity solvers, with fallback to the original Bullet sequential impulse solver. In a nutshell, direct MLCP solvers are useful when higher quality simulation is needed, for example in robotics. The performance is less than the PGS/SI solver, but it usually convergence faster to a good solution. See src/BulletDynamics/MLCPSolvers and Bullet/Demos/ForkLiftDemo for an example.
- New btFixedConstraint as alternative to a btGeneric6DofConstraint with all DOFs locked. See Demos/VoronoiFractureDemo
- Various bug fixes, related to force feedback and friction. Improved performance between btCompoundShape
using the new btCompoundCompoundCollisionAlgorithm. See the commit log at https://code.google.com/p/bullet/source/list
Thanks everyone for the contributions and feedback!