Real-Time Physics Simulation Forum

I don't have any good ideas about how one might dig into the internals of the btDbvt broadphase to feed your AI, however it is possible to use a btPairCachingGhostObject to help optimize tracking of nearby objects. The normal scenario goes something like this: You have a Character who needs to know ...

Bullet will deactivate moving bodies when both velocities are below some thresholds for > 2 seconds. The default thresholds are hard coded magic numbers: linearSleepingThreshold = 0.8 m/sec angularSleepingThreshold = 1.0 rad/sec With those defaults it is possible for slowly tumbling objects, or even...

Hrm... True, there is an #ifdef BATCH_RAYCASTER inside examples/Heightfield/HeightfieldExample.cpp however I don't see any evidence it actually works... in Bullet 2.88 because it relies on a gBatchRaycaster being a valid pointer but there is no code that actually declares or sets it. AFAICT: if you ...

By "batched" which one of these do you mean:? (1) "One raycast against the whole (batched) world of objects" (2) "A batch of raycasts against the whole world of objects" Item (1) does exist as a feature of the BulletPhysics API. Item (2) does not. Item (1) is done through btCollisionWorld::rayTest()...

Your problems are mysterious but they don't sound like problems with Bullet per-se. For example consider this bit of code: objectChaserBus = new btCollisionObject; objectChaserBus->setCollisionShape(chaserbusShape); std::cout<<"OBJ BUS "<<objectChaserBus->getCollisionShape()<<std::endl; // Prints 0 ...

speed = deltaDistance / deltaTime = meters /second acceleration = deltaSpeed / deltaTime = meters / second^2 There is no RigidBody::getLinearAcceleration() method in the API. There is a RigidBody::getGravity() method which would provide the free-fall acceleration sans collisions. To measure the tru...

I don't know how to do what you asked off the top of my head. It sounds... possible, but complicated. There are many different varieties of "Euler angles" and you'd have to define exactly what you mean. For example... are the axes of your Y, then Z, then X rotations in the world-frame or the object ...

btFixedConstraints should work ok until you get interconnected pieces with a large number of joints. As the constraint number grows the whole collection gets "soft" and the constraints will not be fully satisfied. The collection will appear to "sag" under collisions (and gravity, if you have it). Th...

Speed is the magnitude of velocity --> compute the length of the btVector3.

(1) Your Bullet libraries (LinearMath, specifically) must be compiled with: -DBT_ENABLE_PROFILE This may mean you need to compile the libs from source and add that option. (2) You wouldn't want to dumpAll() every step because that would make your simulation much slower than it already is, and would...

If you actually follow through with the CProfileManager stuff then you would get an idea as to where the bottlenecks are and how much time is spent in the various steps of the simulation. This would help you solve your problem, and also help you determine if you are actually fixing it with any worka...

Here are some ideas that occur to me: Assuming your tube is closed and a small ball will not fall out once it is placed inside... (1) Place a ball randomly (with some quantization) and let it fall. If it falls out the bottom of your simulation after a certain amount of time then conclude it was not ...

In this other thread you mention your Bullet simulation slows or blocks when you "increase the number of small balls". What you failed to mention in that thread, but what appears to be the case in this one, you are running those small balls inside a concave mesh object. If that really is your world ...

You have #include the right header file to obtain the CProfileManager declarations.