Search found 24 matches

by slithEToves
Fri Aug 14, 2015 3:58 pm
Forum: General Bullet Physics Support and Feedback
Topic: Rolling box "sucked" through mesh terrain; video example!
Replies: 2
Views: 4537

Re: Rolling box "sucked" through mesh terrain; video example

I don't know if you are still having a problem with this, but there is a similar issue here with a new solution:

http://bulletphysics.org/Bullet/phpBB3/ ... f=9&t=9100
by slithEToves
Fri Aug 14, 2015 3:32 pm
Forum: General Bullet Physics Support and Feedback
Topic: btBvhTriangleMeshShape strange bug
Replies: 2
Views: 5649

Re: btBvhTriangleMeshShape strange bug

Sorry this reply is so slow in coming, but thanks for your post with such a clean example of this problem. I just updated from 2.76 to 2.82 and had the same issue, but noticed that it didn't happen if I ported your example to 2.83. Anyway, the problem is in btGjkPairDetector.cpp. If you set m_fixCon...
by slithEToves
Thu Dec 09, 2010 8:45 pm
Forum: General Bullet Physics Support and Feedback
Topic: btQuantizedBvh serialization
Replies: 2
Views: 2551

Re: btQuantizedBvh serialization

The original allocator was resized 1 larger than it needed to be, and the iteration/recursion on the tree was limited by m_curNodeIndex rather than by the array size, so the extra slot was not necessary in the serialized data.
by slithEToves
Thu Oct 28, 2010 7:23 pm
Forum: General Bullet Physics Support and Feedback
Topic: Aabb test
Replies: 2
Views: 3124

Re: Aabb test

m_clientObject is the btCollisionObject.
by slithEToves
Thu Oct 28, 2010 7:06 pm
Forum: General Bullet Physics Support and Feedback
Topic: Animating a Collision Mesh?
Replies: 1
Views: 4303

Re: Animating a Collision Mesh?

You can use a btCompoundShape to do this. Your model likely has an internal hierarchy that you may not need to preserve in the collision, however, so you can flatten it to only have a 1 level deep hierarchy in your compound. Use convex primitives, such as boxes and cylinders/capsules for the body pa...
by slithEToves
Thu Oct 28, 2010 6:56 pm
Forum: General Bullet Physics Support and Feedback
Topic: Sharing btCollisionShape with different scale
Replies: 2
Views: 4970

Re: Sharing btCollisionShape with different scale

You can use the btUniformScalingShape to accomplish this.
by slithEToves
Fri Mar 19, 2010 2:47 pm
Forum: General Bullet Physics Support and Feedback
Topic: Capsule vs Multisphere
Replies: 1
Views: 2686

Re: Capsule vs Multisphere

Multisphere is fine. It is slightly slower than Capsule, but not enough to worry about.
by slithEToves
Tue Apr 21, 2009 3:01 pm
Forum: General Bullet Physics Support and Feedback
Topic: Sphere / Box collision generates multiple contact points
Replies: 1
Views: 4720

Re: Sphere / Box collision generates multiple contact points

Bullet allows some penetration, and because of this, you can have multiple contact points. Bullet keeps up to 4 points, 3 to specify a contact triangle, and 1 that represents the deepest point of penetration. In your case, if you only want to consider 1 point, you can most likely just use the point ...
by slithEToves
Tue Apr 21, 2009 2:51 pm
Forum: General Bullet Physics Support and Feedback
Topic: Simplest possible C/D between two objects?
Replies: 7
Views: 6450

Re: Simplest possible C/D between two objects?

In addition, adding a simple AABB check before the processCollision call can make Dominik's code fairly optimal.
by slithEToves
Fri Jan 02, 2009 11:51 pm
Forum: General Bullet Physics Support and Feedback
Topic: Use only narrow phase collision detection
Replies: 2
Views: 3766

Re: Use only narrow phase collision detection

Yes, this can be done. Setup a btDefaultCollisionConfiguration, btCollisionDispatcher, and btDispatcherInfo. If you want easy object management, you can use a btCollisionWorld, but if you manage your own objects and pairings like it sounds like you are doing (using only Bullet's narrow phase), this ...
by slithEToves
Tue Aug 14, 2007 7:27 pm
Forum: General Bullet Physics Support and Feedback
Topic: Bullet Ray Cast
Replies: 10
Views: 12974

Intuitively it seemed like the correct point should have been available during the last step of the subsimplex cast, but I couldn't convince myself whether the correct point was there or not when stepping through the algorithm. I will probably switch to using the GJK cast instead as Erwin suggests, ...
by slithEToves
Tue Aug 14, 2007 5:42 pm
Forum: General Bullet Physics Support and Feedback
Topic: Bullet Ray Cast
Replies: 10
Views: 12974

The support in the motion direction would not be the correct point in general. Imagine a triangle moving in the direction of one of its vertices, with a glancing collision just at another vertex. The support would pick the wrong vertex in this case. A support that is along the returned collision nor...
by slithEToves
Tue Aug 14, 2007 5:04 pm
Forum: General Bullet Physics Support and Feedback
Topic: Bullet Ray Cast
Replies: 10
Views: 12974

This is good info. I have been running a GJKPairDetector test at the TOI location specified by the subsimplex cast to get the contact point. It returns the correct point, but it seems non-optimal to do this.
by slithEToves
Wed Aug 01, 2007 4:41 pm
Forum: General Bullet Physics Support and Feedback
Topic: Box (instead of ray) tracing?
Replies: 6
Views: 9465

I have been using this code extensively, and it works as it is supposed to with the exception of the normal direction. Other than this issue, I have tested this code against many different convex shape types and have had no issues once I fed my data to Bullet correctly. Note that this last point is ...
by slithEToves
Tue Jul 10, 2007 3:24 pm
Forum: General Bullet Physics Support and Feedback
Topic: Suggestion for higher precision velocity integration
Replies: 5
Views: 5733

Have you tried Runge-Kutta? It is usually considered the best general case numerical differential equation solver, and may work for your situation as well. Second order Runge-Kutta (RK2) is sometimes adequate, but RK4 seems to be the most often used method. Here are some links: http://mathworld.wolf...