Real-Time Physics Simulation Forum

We've integrated bullet into our web-based 3D content system called Hypercosm. Like many others, if the forums are any indication, we struggle quite a bit getting the tuning right on vehicles. I created a little utility to make that easier, and I thought I'd share. http://www.hypercosm.com/private/C...

Hi Roman. Thanks for the response. I did realize that in the absence of a second body, the constraint would use the world as the second frame of reference. I was confused about how the axes of rotation for the constraint would be affected if the body translated away from its original position - howe...

I've been experiencing the same issue. I've tried both setting the DISABLE_DEACTIVATION activation state and calling the activate() method on the rigid bodies, to no avail. I think the hinge constraint may not suffer from this problem. Anyone gotten anywhere on this?

Bump. Anybody? Bueller?

Is there a way to utilize the motor functionality of the constraints with a single body? I've tried adding a generic 6DOF constraint to a body with no partner (thus constraining it to "the world") but this results in some undesired issues with the constraint's frame of reference (which doe...

Thanks Erwin - that's helpful.

Am I correct in my understanding that you could, theoretically, emulate the behavior of most (any?) of the specialized constraints (e.g. hinge, slider, cone etc) with a properly configured 6DOF constraint? If that's so, are the other constraint types just for convenience, or are they superior in oth...

I'm working on a vehicle sim in which I need to know what surface the vehicle's wheels are touching. After some searching I found the m_groundObject member of the m_rayCastInfo of the btWheelInfo. In the vehicle's rayCast method I see that this pointer is currently being set to a dummy object: wheel...

I tried substituting the btGImpactMeshShape per this discussion: http://bulletphysics.com/Bullet/phpBB3/ ... f=9&t=3701, and at first glance at least that seems to have helped.

When static, how does the performance of the btGImpactMeshShape compare to the btBvhTriangleMeshShape?

As far as I understand, the capsule's dimensions work like: Radius = radius Height = height + radius * 2 Where height would define the height of the *cylinder* of the capsule, not the total height. But I could be wrong. That is true - I just tweaked the values of the capsules in my example enough t...

I'm working on a little billiards game in which we're using a btBvhTriangleMeshShape for the table and rails. Ever since I upgraded from 2.71 to 2.75 it seems that the balls (btSphereShapes) won't stop rolling correctly once set in motion. If any ball gets above a certain (unknown) speed it seems li...

I submitted an issue and a patch for this http://code.google.com/p/bullet/issues/detail?id=230 before the implementation of setLocalScaling for btCapsuleShape just called the method from its parent: virtual void setLocalScaling(const btVector3& scaling) { btConvexInternalShape::setLocalScaling(s...

I've noticed some odd behavior when trying to use the setLocalScaling call with the btCapsuleShape. I tweaked the BasicDemo.cpp to demonstrate - changing the boxes to capsules and setting the scaling in stead of multiplying the capsule's parameters by the SCALING factor. See line 140 of BasicDemo.cp...

Use the identity transform, to compute the local space AABB: btVector3 aabbMin; btVector3 aabbMax; body->getCollisionShape()->getAabb(btTransform::getIdentity(), aabbMin, aabbMax); This is the local AABB, in body space. Once you convert this AABB into world space, you will likely get the same AABB ...

I'd like to get a rough bounding box for any given shape in my scene. I'd like the bounding box aligned to the axes of that object's transformation rather than the world's axes. I'm trying the following: btVector3 aabbMin; btVector3 aabbMax; btTransform bodyTrans = body->getWorldTransform(); body->g...