Real-Time Physics Simulation Forum

The broadphase keeps track of the AABBs and also overlapping AABB pairs between distinct objects that might need narrowphase collision check to compute the contact points (if any). Ignoring narrowphase costs... there is overhead in: (1) knowing all the AABBs and overlaps and (2) adding new AABBs to ...

If the kinematic objects are not active then they are not much more expensive than static. If you were to bounce a dynamic object around the kinematic objects then they would activate, but since they are being "animated" by btDefaultMotionState which does nothing, then they will be deactiv...

Let me repeat it back to you to make sure I understand: (1) You have two objects A and B connected by a constraint C . (2) You want to be able to reset the transforms of the two objects such that the constraint is satisfied (e.g. objects A and B are experiencing zero torque/force from the constraint...

When I look at the implementation of btAdjustInternalEdgeContacts() I see this: void btAdjustInternalEdgeContacts(btManifoldPoint& cp, const btCollisionObjectWrapper* colObj0Wrap, const btCollisionObjectWrapper* colObj1Wrap, int partId0, int index0, int normalAdjustFlags) { //btAssert(colObj0->g...

I wonder if your problem isn't so much bad normals as it is interpenetration? This idea because I think the interpenetration resolution code can also introduce non-physical results that might look similar to glitches from bad normals. However, with such a small substep I doubt this could be the case...

In the video description are links to python and C++ examples. Start by looking at the deformable pybullet examples in the code repository?

https://github.com/bulletphysics/bullet ... t/examples

Is it really the edge normals? The sprung constraints between the fuselage and the wheels complicate matters. A quick way to verify it is caused by edge normals would be to have the box drag on a btStaticPlaneShape . If the problem goes away that would support the edge normals theory. Meanwhile, the...

You're using pybullet but are asking the forums focused on C++ and the core Bullet libraries. You might try asking in the pybullet section . The only ideas I have are: Is the object properly activated? You say you "move the box to the edge of the platform" before starting the simulation, b...

I don't use ammo.js however after downloading the repository and scanning the codebase I learned: it appears to support set/getResitution().

My advice is to avoid applying force/torque because it is complicated and difficult to tune. This because the amount of force depends on the mass and angular inertia of your object. Setting the velocities is the right way to go: it is much easier to implement because it works independently of mass a...

Actually body->getWorldTransform() is not necessarily the best way to do it. When your render rate is NOT the same as your simulation step rate you can get aliased results from body->getWorldTransform() which can sometimes produce a visible jitter in the motion of otherwise smoothly moving objects. ...

I believe the units of force are Newtons: kg * m / sec^2 because the simulation step expects the duration to be in seconds. You can always use different units by scaling the substep duration and then tweaking your own mass and distance units accordingly. This can sometimes be handy when your world a...

Yes, the dynamic AABB tree helps, even for static compound shapes, especially for compound shapes with many child shapes. It is used in the narrowphase collision calculation to cull the number of contact point candidates. The only reason to NOT enable the dynamic AABB tree would be for a compound sh...

Yes, I think you are right: large ratios between the mass/inertia of constrained objects are contributing to the error of the constraint solution. I believe the problem still reproduces in the latest version of Bullet, but I haven't tested constraints in a while. Your example is probably using the b...

You're asking in the General Bullet Physics forum which is mostly about Bullet's core C++ library. You are more likely to get answers to your question if you ask in the PyBullet Support and Feedback forum.