Physics Simulation Forum

A new version of Bullet physics library is available.

- Synchronized open source version with Playstation 3 SPU Optimized version (alignment, padding, etc)
- Added braking to vehicle
- Added 'angularFactor' support in cache friendly solver
- Removed warnings, and fixed minor reported bugs
- Allow local mesh deformations. User can deform the original vertices, and call 'refitPartial' by passing a AABB that encloses the deformation. Requires passing in of a more conservative AABB used for quantization, that encloses the maximum extents of potential deformations. No demo how to use this partial update yet.

Download Bullet from sourceforge
, or get a local cached copy here:
Bullet 2.50 zipfile (windows line endings)
Bullet 2.50 zipfile Bullet 2.50 .tgz file (unix line endings)

Wiki is still unavailable. Some future plans are parallelizing the collision detection and solver. One way of parallelizing the solver is to create hash cells, create a dependency array between those cells (cells are dependend iff they share at least one rigidbody), and then let several threads process cells in parallel (if they are not directly dependent). Each thread gets new cells from a global 'todo' array, and skips cells that are done or have a dependency on a cell that is busy (by another thread). This keeps the simulation deterministic (without the 'random' in constraint iterations) and it allows for arbitrary large stacks, without cache/spu local storage limitations.
- Another future extension for conservative advancement is to support time-of-impact for deforming objects. The total deformation provides an upper limit, that can be used for a conservative advancement step.
- Last but not least, a mix between hash-space and multiple sweep and prune spaces (per hash cell) should be possible. Duplicate pairs get removed as a post process (sorting the overlapping pair array, removing neightbours and doing an additional aabb check).

Enjoy,
Erwin