Search found 29 matches
- Wed Oct 03, 2012 6:23 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Upcoming Bullet 2.81 release, please test trunk version
- Replies: 7
- Views: 10888
Re: Upcoming Bullet 2.81 release, please test trunk version
Found the problem. It is one of those annoying situations where floating point math simply fails in release builds. Essentially the situation was that sphereRelPos.y == closestPoint.y in btSphereBoxCollisionAlgorythm line 122 but sphereRelPos.y - closestPoint.y is not zero, just some small float err...
- Thu Jul 12, 2012 10:31 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Glad to hear this fixes your problem, I will post the new patch. As far as stacking stability is concerned, as I explained in my recent post what we posted in the patch is a simplified version of our solution that also works with non split impulse. Our full solution was tested at length and lead to ...
- Thu Jul 12, 2012 7:26 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Hi, Not calling integrate transforms after the solve is intentional. Objects are moved in predictUnconstraintMotion and if you are doing split impulse, they are moved again in internalWritebackVelocity. The patch does currently break CCD but if you are using CCD nothing the patch attempts to fix sho...
- Thu Jul 12, 2012 5:00 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Playing a bit with the demos in the unpatched 2.80 version shows a bug similar to what you are describing. If you run the convex decomposition demo, try grabbing one of the tables off-center and lifting it. One out of every two clicks the table will rotate properly as if it was held by a point const...
- Wed Jul 11, 2012 10:54 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Those are definitely not expected behaviors. We see no such issues in our engine, but then again we still use Bullet 2.76. The two issues you describe are identical. it looks like you have no rotations allowed on your objects. An infinite inertia tensor would yield this type of behavior. However sin...
- Wed Jul 11, 2012 8:18 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Hi Erwin, I have posted a patch for the stability improvements described earlier in the thread. https://code.google.com/p/bullet/issues/detail?id=642&colspec=Modified%20ID%20Type%20Stars%20Status%20Owner%20Summary I also provided a new BasicDemo.cpp file that highlights the improvements. We spen...
- Thu Jul 05, 2012 4:45 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Thanks Erwin, will do. I'll post again here when I have it done.
- Mon Jun 04, 2012 7:58 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Hi Erwin,
I have grabbed the latest Bullet build. I can integrate my changes into it. Let me know how I should do this. Is there a specific repository I should use on Github? Or can I create my own svn branch on Google code?
Thanks for letting me know how to proceed.
I have grabbed the latest Bullet build. I can integrate my changes into it. Let me know how I should do this. Is there a specific repository I should use on Github? Or can I create my own svn branch on Google code?
Thanks for letting me know how to proceed.
- Tue May 29, 2012 6:10 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Hi Erwin,
Thanks for the reply. I will try to make a patch for the latest bullet version. Let me know what the name of the repository is on github. Otherwise I can post it on Google code. Let me know.
Thanks for the reply. I will try to make a patch for the latest bullet version. Let me know what the name of the repository is on github. Otherwise I can post it on Google code. Let me know.
- Fri May 25, 2012 11:45 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Thanks,
I didn't know what the proper process was to do this. I will definitely try doing this.
I didn't know what the proper process was to do this. I will definitely try doing this.
- Thu May 24, 2012 7:40 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
- Thu May 24, 2012 7:10 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Stability issue with btBvhTriangleMeshShape
- Replies: 6
- Views: 9905
Re: Stability issue with btBvhTriangleMeshShape
there seem to be a bunch of *Algorithm.cpp files that would need to change. Correct, that is what we did. It's not that many places to change overall. why would it try to merge a new contact point with an existing one if it is close enough Consider a sphere sitting on a plane. Would you really want...
- Thu May 24, 2012 5:37 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
Sorry about that I should have been more explicit: We have many more changes in our Bullet code than the ones discussed in this thread. I would have to post our entire Bullet folder to let people compile it directly. The files I posted are more meant to be diffed against what you have so you can int...
- Thu May 24, 2012 5:03 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Stability issue with btBvhTriangleMeshShape
- Replies: 6
- Views: 9905
Re: Stability issue with btBvhTriangleMeshShape
Hi JHoule, Here's a couple more issues we have found in the way persistent manifolds are being managed in Bullet: 1: When a new contact point is created, Bullet determines which of the 4 existing contacts to replace in order to maximize contact area. It is done through an approximation but we found ...
- Thu May 24, 2012 4:36 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Major contact stability improvement
- Replies: 57
- Views: 89171
Re: Major contact stability improvement
And the last one.
That's all the main changes for the change. If I find an easy way to post the entire bullet folder somewhere, I'll let you know.
That's all the main changes for the change. If I find an easy way to post the entire bullet folder somewhere, I'll let you know.