Real-Time Physics Simulation Forum

I too would like to see spam posts cleaned up faster. benlot is a frequent and helpful participant in these forums and has my support for forum moderator role.

Bullet supports continuous collision detection (CCD). It uses a small sphere to do a sweep between the steps, and then collides the real body. A brief wiki page provides some hints on how to use it.

I'm going to have to eventually solve this same problem. I've given it a little bit of thought but have not yet started. My main idea right now is to run two distinct simulations: one for the "game level" (WorldA) and and one for the vehicle (WorldB). The vehicle body itself would be dynam...

Not enough info.

Are you writing a Bullet application in C++ directly or are you using some framework on top of Bullet? If you supply a link to your code, or provide snippets of exactly what you're doing, then it will be more likely that we can answer your questions.

There are two ways that I know of to obtain the normal of the surface under the character: (1) After every simulationStep() of the world: scan the ContactManifolds for contact between the character and other objects and harvest the collision normals from the relevant collisions. You can find example...

If someone is considering using bullet physics for a game with networked physics I'd recommend against it. I think that statement needs qualification. Bullet might not be suitable for the Deterministic Lockstep method for networked physics, but that is only one of three that Glenn Fiedler discusses...

I am wondering: What are you really trying to do? Are you trying to slave a dynamic object to a known constant position? Or are you trying to slave it to a known position that is changing? Does your object really need to be dynamic (is it even dynamic?) or can it be kinematic (moves but does not get...

I looked through the code and found some randomization happening in the constraint solver classes, however, as far as I can tell relevant behavior flags are not set by default, so the randomization feature should be bypassed. The constraint solvers are used (I think) to solve the contact points so m...

Can you make the Bullet simulation exactly the same server and client? The short answer: no, not for server-client situation where the clients may be running entirely different hardware than the server. The long answer: you should read these articles: http://gafferongames.com/networked-physics/intro...

It looks like the Aabb is actually the tight bounding box around a spinning local Obb. The implementation of btCylinderShape::getAabb() is as follows: void btCylinderShape::getAabb(const btTransform& t,btVector3& aabbMin,btVector3& aabbMax) const { btTransformAabb(getHalfExtentsWithoutMa...

d3x0r, I could probably come up with some snippets that would be helpful but it is not clear to me how the game is supposed to work: The camera view... does it look down from above at a fixed position or does it follow the ball? When tossing a ball around on a real tilt maze there are some frame of ...

btMotionState is a pure virtual class. Hence it defines an API that you must implement for your own derived class. In particular there are two methods to be implemented: virtual void getWorldTransform(btTransform& worldTrans ) const = 0; virtual void setWorldTransform(const btTransform& wor...

There is some experimental GPU acceleration code in Bullet but I have not tried it.

I don't think you need to update the transforms of the children of the btCompoundShape when making it a child of another. Instead you just set the transform of the btCompoundShape itself -- Bullet will evaluate the child transforms recursively. I have not tested this, but is how I would expect it to...

More info is required before we could speculate on what the problem is. What are the dimensions of these objects? If your objects are very small I wonder if what you're seeing is the "collision margin" effect. For more info about margins watch this video: Bullet Physics Collision Margins a...