Real-Time Physics Simulation Forum

In case anyone has similar problems (I know it's a bit specific). I solved the problem by increasing the margin on the box and decreasing the collision material's damping (to near zero) in our own custom built physics engine.

Hope this helps!
All the best,
Ash

Sorry, what?

Hi Folks, I have been trying to track this problem down for a while. I am using Bullet for collision detection, but a custom physics engine written by a physics professor friend of mine. When the car is "bottoming out" on the track the collision seems to be in the wrong direction (the norm...

Wow, awesome stuff. Could you let us know a little bit about how you managed to integrate it? My current project ( http://onlineracingchampionship.com ) uses bullet for collision detection and a custom vehicle dynamics physics engine. I was considering a port to Unity3d, but I couldn't figure out ho...

Hi Folks, I have been experimenting with Intel's Inspector tool (30 day trial) which can detect memory issues such as Uninitialized Memory. I have found quite a few potential problems in my code, but I've noticed one in bullet too. It could be nothing, but I thought I should report it in any case. I...

Hi Folks,

Got it working by removing the margin and giving the cylinder proper dimensions.

All the best,
Ash

Hi Folks, I have recently updated Bullet to the latest version. I had been on a REALLY old version of bullet and it had been working fine. I am simulating cars, so I am using a btCylinderShapeZ for the wheels / a box for the car itself and a btBvhTriangleMeshShape (using tris from an Ogre3d mesh). W...

Hi Erwin,

Any noticable speedups with the SIMD? Are there any benchmarks?

Keep up the good work, thanks for an excellent library!
All the best,
Ash

Good stuff, glad it was helpful.

All the best,
Ash

Hi Folks, I'm not sure if i'm not shutting something down properly, but I am getting a small amount of memory unallocated after a run. The constructor: - btConvexConvexAlgorithm::CreateFunc::CreateFunc() { m_ownsSolvers = true; m_simplexSolver = new btVoronoiSimplexSolver(); m_pdSolver = new btGjkEp...

Hi Erwin, As long as i'm doing more or less the right thing, I think it's probably fast enough for the minute and hopefully there are some optimizations that might speed things up in the next few months. I am using the current version with btAxis3Sweep and btBvhTriangleMeshShape. I think that it is ...

Anyone else got any suggestions?

Has anyone benchmarked the difference between a lot of small collision meshes and a big one? Just wondering if it would be faster.

Thanks guys!
All the best,
Ash

PS. Making progress: - http://www.siroccoracing.com/indev/drivingLotus.avi

Hi Erwin, I have updated to the latest version and I reckon its about twice as quick. It is executing in around 0.8ms normally, but it occasionally it executes in 2-3ms. Even 0.8ms seems a little slow for a couple of boxes on a mesh, can you think of anything I could do to quicken things up a little...

Hi Erwin, Thanks for the quick response as always :) I am indeed using the btBvhTriangleMeshShape for both meshes that represent the track. The 2 meshes have 3528 tris and 10080 respectively. The 2 "cars" are merely 2 btBoxShapes, I am not using raycasts (at least not yet). I am using a sl...

Hi Folks, In my test application I have a couple of meshes representing the racing track (world geometry) in my game. I am dropping a couple of cars on there (with box collision shapes). I have profiled the collision detection and its taking quite a long time (2-3ms typically) on my 3.6Ghz dual core...