Search found 14 matches
- Wed Dec 07, 2011 5:38 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: btGeneric6DofConstraint Angular Motors/Friction
- Replies: 2
- Views: 4985
Re: btGeneric6DofConstraint Angular Motors/Friction
Ok, I've finally tracked this down to the fact that ODEs quickstep (optionally) randomly reorders non-contact constraints while Bullet's sequential impulse (optionally) randomly reorders non -contact constraints. Extending the bullet random constraint reordering code to handle non contact constraint...
- Tue Dec 06, 2011 1:23 am
- Forum: General Bullet Physics Support and Feedback
- Topic: btGeneric6DofConstraint Angular Motors/Friction
- Replies: 2
- Views: 4985
Re: btGeneric6DofConstraint Angular Motors/Friction
I've attached a hacked version of ConstraintDemo.cpp which exhibits the problem. Just fire a few cubes at the centre of the constraint array with the '.' key.
- Mon Dec 05, 2011 12:54 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: btGeneric6DofConstraint Angular Motors/Friction
- Replies: 2
- Views: 4985
btGeneric6DofConstraint Angular Motors/Friction
Hi, I'm attempting to use the btGeneric6DofConstraint to simulate a ball/point2point constraint with friction by enabling the angular motors with a target velocity of zero. The problem comes when trying to simulate a 2D grid of constrained bodies: B-B-B-B | | | | B-B-B-B | | | | B-B-B-B | | | | B-B-...
- Fri Nov 11, 2011 2:21 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Nasty bug in resolveSplitPenetrationSIMD
- Replies: 6
- Views: 5169
Re: Nasty bug in resolveSplitPenetrationSIMD
Just to add another data point, on Linux/gcc I'm seeing a decent performance boost when enabling SIMD on contact heavy sims. Also, I've achieved another decent improvement by replacing the _vmathVfDot3 method with the SSE4 _mm_dp_ps and also replacing the following construct _mm_or_ps( _mm_and_ps( m...
- Fri Nov 11, 2011 11:50 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Bullet and Namespaces
- Replies: 2
- Views: 3219
Re: Bullet and Namespaces
Hi Erwin,
thanks for the response. I investigated this further and it looks like the gcc option -fvisibility=hidden will do what I need. If I have further problems I'll definitely look into providing a patch.
Cheers,
Pete
thanks for the response. I investigated this further and it looks like the gcc option -fvisibility=hidden will do what I need. If I have further problems I'll definitely look into providing a patch.
Cheers,
Pete
- Sat Nov 05, 2011 10:21 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Bullet and Namespaces
- Replies: 2
- Views: 3219
Bullet and Namespaces
Hi Erwin, I know in the past the use of namespaces has been rejected as adding unnecessary complications for library users but I'd like to explain a use case where this is proving a problem. One of the advantages of using Bullet is being able to modify the library itself to support specific requirem...
- Fri Feb 18, 2011 3:03 pm
- Forum: Physics authoring tools, serialization, standards and related topics
- Topic: Fracture Bodies
- Replies: 1
- Views: 5422
Re: Fracture Bodies
This isn't included as part of the API, but an example implementation by Erwin is available here:
http://code.google.com/p/bullet/issues/detail?id=90
http://code.google.com/p/bullet/issues/detail?id=90
- Tue Nov 16, 2010 12:47 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Sticking contacts with btConvexHullShape
- Replies: 2
- Views: 2888
Re: Sticking contacts with btConvexHullShape
No, I'm using QuickStep in ODE.
Unfortunately my scene doesn't seem to work with dynamica (or the Serialize Demo), looks like the inertia tensor is being calculated wrong. I'll try debugging this when I get some spare time and get back to you.
Unfortunately my scene doesn't seem to work with dynamica (or the Serialize Demo), looks like the inertia tensor is being calculated wrong. I'll try debugging this when I get some spare time and get back to you.
- Mon Nov 15, 2010 10:06 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Sticking contacts with btConvexHullShape
- Replies: 2
- Views: 2888
Sticking contacts with btConvexHullShape
Hi, I'm using a voronoi cell based shatter tool to create a large amount (1000) of stacked convex shapes with btConvexHullShape as the collision geometry. I'm finding that while fairly stable for stacking, the resulting bodies have a tendency to stick together. Only a large direct collision impulse ...
- Sat Sep 25, 2010 10:58 am
- Forum: Release Announcements
- Topic: Bullet 2.77 is released! OpenCL & DX11 cloth, 3ds Max plugin
- Replies: 8
- Views: 117815
Re: Bullet 2.77 is released! OpenCL & DX11 cloth, 3ds Max pl
The OpenCL cloth demo doesn't work for me on a Mac (Nvidia 330M), the flags are displayed but nothing happens. The MiniCL version works fine.
Particles Demo seems to work ok though.
Particles Demo seems to work ok though.
- Thu Jan 08, 2009 3:49 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Occasional missed collisions in GJK (fixed)
- Replies: 2
- Views: 3656
Re: Occasional missed collisions in GJK
That patch seems to have completely fixed the problem for me Erwin, many thanks! Incidentally, I am setting the margin to 0 as well although this doesn't seem to cause an obvious problem in my tests. What sort of issues would I experience with GJK if I have a zero margin? What is the significance of...
- Wed Jan 07, 2009 5:39 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Occasional missed collisions in GJK (fixed)
- Replies: 2
- Views: 3656
Occasional missed collisions in GJK (fixed)
Hi, I'm using the GJK routine from Bullet to generate collisions between convex hulls. For my simulation, it's crucial for stability that even single collision events aren't missed. However what I'm seeing is that very occasionally, obviously penetrating shapes return no collision results. My questi...
- Mon Jan 05, 2009 6:55 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Use only narrow phase collision detection
- Replies: 2
- Views: 3809
Re: Use only narrow phase collision detection
Thanks, I've got this working now.
- Mon Dec 15, 2008 7:03 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Use only narrow phase collision detection
- Replies: 2
- Views: 3809
Use only narrow phase collision detection
Hi, I'm interested in using the narrow phase part of Bullet's collision detection separately, but am unsure how this is done. Ideally, I'd like to create two sets of btCollisionShape (of whatever type) plus corresponding btCollisionObject and collide them, returning the list of contacts. Can this be...