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Bullet 2.75 released: GPU, SPH fluids, overall improvements

Posted: Thu Sep 10, 2009 2:29 pm
by bullet_team
Bullet 2.75 is available for download now (SVN revision 1754)

Some features:
  • Smoothed Particle Hydrodynamics (SPH) fluids preview, thanks to Rama Hoetzlein for contributing this under the ZLib license! See Bullet/Extras/sph. The SPH fluids will be integrated into Bullet with two-way interaction, similar to cloth/soft body simulation.
  • GPU physics kernels preview, in preparation for Bullet 3.x. Right now mainly CPU version, you can enable CUDA version manually. The OpenCL version is available in a separate branch. See Bullet/Demos/Gpu2/3dDemo
  • 2D physics demo, with 2D and 3D object interaction, see Bullet/Demos/Box2dDemo
  • New constraints: btHinge2Constraint,btUniversalConstraint,btGeneric6DofSpringConstraint, thanks to Roman Ponomarev
  • Use ALT+Left/Middle/Right Mouse button+mouse motion for Maya-style camera navigation
  • Re-enabled split impulse constraint solver option, to avoid adding momentum due to penetration recovery (includes SIMD support)
  • Removed first argument 'localInertiaTensor, from btMultiSphereShape. Update your code by remove the first argument: it calculates its local inertia from its aabb now.
  • Increased performance by disabling motion state synchronization for static/inactive objects.
    Use btDiscreteDynamicsWorld::setSynchronizeAllMotionStates(true); for backwards compatiblity.
  • Improvements in Soft Body simulation: added tetrahedral volumetric demos, allow for per-triangle/per-tetrahedron collision (pass 0 in generateClusters), increased stability for cluster collision, improved performance of bending constraint generation.
  • Added pre-tick callback option, called at the start of each internal simulation substep.
  • Added optimized capsule-capsule collider, useful for ragdolls.
  • many bug fixes
Thanks everyone for the contributions and patches and other feedback!

Remaining open issues will be addressed in upcoming versions.

Re: Bullet 2.75 released: GPU, SPH fluids, overall improvements

Posted: Fri Sep 11, 2009 7:46 pm
by Erwin Coumans
Missed one version tag in CMakeList.txt, re-uploaded a new Bullet 2.75 version from SVN revision 1758.

It contains one more change:

[*] Disabled optimization in btCollisionWorld::updateAabbs by default (only update active objects). Re-enable it using world->setForceUpdateAllAabbs(false);

Thanks for the feedback,

Re: Bullet 2.75 released: GPU, SPH fluids, overall improvements

Posted: Fri Sep 18, 2009 12:10 am
by Erwin Coumans
There is a minor update to Bullet 2.75, revision 1776
  • fixes some reported build system issues
  • adds generic 2d collision support for arbitrary convex shapes using btConvex2dShape generic. See screenshot below from updated Bullet/Demos/Box2dDemo
  • fix minor degeneracy issue with btGjkPairDetector