Search found 14 matches

by JHoule
Thu Jul 12, 2012 8:49 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

Much better! I'd say with your second patch, it does indeed work. Now, you say we might have a bug in our initialization, and that might be true, because we had to jump throw hoops since we create rigid bodies without collision shapes, and add the shape afterwards. Looking back at our code, we could...
by JHoule
Thu Jul 12, 2012 5:11 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

We've tried to isolate the cause of this... In your patched btDiscreteDynamicsWorld.cpp, you stopped calling (circa line 506): integrateTransforms(timeStep); and seem to have compensated with (circa line 981): body->setWorldTransform(body->getInterpolationWorldTransform()); We have isolated in our c...
by JHoule
Wed Jul 11, 2012 10:24 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

It looks quite promising. It is definitely much more stable, but we are a bit worried about some cases we encountered. First of all, we were are to stack 3 cubes using our application by pushing each sideways almost completely: 3cubes.png We would have assumed that each cube would have tipped, yet t...
by JHoule
Thu May 24, 2012 8:10 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

Not much difference in the end: I still get pretty much the same errors.

I think I'll wait for a full package, if you can make one available...
by JHoule
Thu May 24, 2012 8:00 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

Indeed, it does make a smaller patch (see attachment).

Still a little tricky to get to work in our environment, though... :-(

I'm gonna try with the Bullet demos...
by JHoule
Thu May 24, 2012 7:32 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

What version of Bullet are you based on?
by JHoule
Thu May 24, 2012 7:17 pm
Forum: General Bullet Physics Support and Feedback
Topic: Stability issue with btBvhTriangleMeshShape
Replies: 6
Views: 5194

Re: Stability issue with btBvhTriangleMeshShape

Laurent Coulon wrote: Consider a sphere sitting on a plane. (snip)
Yep, I see that case is better to collapse contact points.
Laurent Coulon wrote: this would be fixed if you try the suggested change from my other thread :D
Yeah, we're gonna try to get the files you gave to compile... Will keep you posted (on the other thread).
by JHoule
Thu May 24, 2012 6:22 pm
Forum: General Bullet Physics Support and Feedback
Topic: Stability issue with btBvhTriangleMeshShape
Replies: 6
Views: 5194

Re: Stability issue with btBvhTriangleMeshShape

Concerning your point 1), I think I agree with you that removing outdated contact points prior to trying to add a new one would help. Only, I peeked at the code, and found that we'd need to change all of the resultOut->refreshContactPoints() to be before the resultOut->addContactPoint(), and there s...
by JHoule
Thu May 24, 2012 5:17 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

I've create a patch file to try it out, only I am having trouble compiling. You seem to have created btVector3::s_zero static member (I assume), but haven't submitted any change to btVector3.h. I am also missing getWorldPosition(), translateWorldPosition(), CF_DISABLE_STATE_CHANGE, etc. And there ar...
by JHoule
Thu May 24, 2012 4:23 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

Can you zip them? Or, if all else fails, zip a patch file?
by JHoule
Thu May 24, 2012 1:03 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

I'm making a game with a lot of sliding pieces, and they are indeed jittering and penetrating the floor. Do you, by any chance, use btBvhTriangleMeshShape for your scene? It might not be your problem, but we've recently worked around some contact point issue that made boxes jitter on a simple floor...
by JHoule
Wed May 23, 2012 6:21 pm
Forum: General Bullet Physics Support and Feedback
Topic: Major contact stability improvement
Replies: 57
Views: 31222

Re: Major contact stability improvement

I'd be interested in trying your changes.

How high could you stack before, and how much higher can you now reach?
by JHoule
Wed May 23, 2012 5:15 pm
Forum: General Bullet Physics Support and Feedback
Topic: Stability issue with btBvhTriangleMeshShape
Replies: 6
Views: 5194

Re: Stability issue with btBvhTriangleMeshShape

We've isolated the issue further, and have written a quick fix. The problem is that when we add a fifth contact point to the persistent manifold, it will always replace one of the previous 4. Only that replacement can sometimes result in a contact point area that shrinks. Our fix is to compute the c...
by JHoule
Tue May 22, 2012 10:05 pm
Forum: General Bullet Physics Support and Feedback
Topic: Stability issue with btBvhTriangleMeshShape
Replies: 6
Views: 5194

Stability issue with btBvhTriangleMeshShape

We're using btBvhTriangleMeshShape for the static scene, but it's proving to yield stability issues (Bullet 2.80-rev2531). Take a simple scene: a box for the ground (static), and a smaller dynamic box placed on top of it. Everything is stable when using btBoxShape on both. But if we replace the stat...