Search found 807 matches

by drleviathan
Fri Aug 12, 2022 1:56 pm
Forum: General Bullet Physics Support and Feedback
Topic: Any better documentation?
Replies: 2
Views: 80

Re: Any better documentation?

According to the ammo.js github README there exists an IRC channel for discussion: Discussion takes place on IRC at #emscripten on Mozilla's server (irc.mozilla.org) You might be able to get help there. Since javascript must be downloaded before the page is fully working it is common practice to sho...
by drleviathan
Sat Aug 06, 2022 2:32 pm
Forum: General Bullet Physics Support and Feedback
Topic: Detecting collisions with btHeightfieldTerrainShape
Replies: 4
Views: 213

Re: Detecting collisions with btHeightfieldTerrainShape

Yes, if you want to prevent the collisions in the first place you would need to look ahead, with ray-trace or some other mechanism. If you're running several hundred at once then the ray-trace seems like the cheapest approach. Rumor has it the btHeightfieldTerrainShape can get expensive if you make ...
by drleviathan
Fri Aug 05, 2022 10:41 pm
Forum: General Bullet Physics Support and Feedback
Topic: Detecting collisions with btHeightfieldTerrainShape
Replies: 4
Views: 213

Re: Detecting collisions with btHeightfieldTerrainShape

The way collision works in Bullet is... The "broad-phase" provides collision candidates (e.g. pairs bodies with overlapping bounding boxes) to the "narrow-phase" which computes the details (contact manifold) of the collision. Your problem is... you are tapping into the output of ...
by drleviathan
Mon Jul 25, 2022 3:36 pm
Forum: General Bullet Physics Support and Feedback
Topic: VR compilation error
Replies: 3
Views: 310

Re: VR compilation error

AFAICT it does indeed expect four arguments: B3_SHARED_API int b3PhysicsParamSetGravity(b3SharedMemoryCommandHandle commandHandle, double gravx, double gravy, double gravz); Check its declaration in the header to make sure: examples/SharedMemory/PhysicsClientC_API.h What version of the repository is...
by drleviathan
Thu Jul 21, 2022 3:11 pm
Forum: General Bullet Physics Support and Feedback
Topic: Rendering Issues when importing urdf linked to .obj
Replies: 1
Views: 163

Re: Rendering Issues when importing urdf linked to .obj

You might want to try asking in the python-specific forum. This is the support thread for underlying C++ library.
by drleviathan
Thu Jul 21, 2022 3:10 pm
Forum: General Bullet Physics Support and Feedback
Topic: Rendering Only Specific Objects in Camera
Replies: 1
Views: 124

Re: Rendering Only Specific Objects in Camera

You might want to try asking in the python-specific forum. This is the support thread for underlying C++ library.
by drleviathan
Wed Jun 29, 2022 2:54 am
Forum: General Bullet Physics Support and Feedback
Topic: Skeletal Animation
Replies: 1
Views: 458

Re: Skeletal Animation

Here are some scenarios of increasing complexity: (1) Kinematic character always collides like a capsule (or some other simple shape) regardless of their animation state. (2) Dynamic character always collides like a capsule (or some other simple shape) regardless of their animation state. (3) Charac...
by drleviathan
Mon May 30, 2022 3:38 pm
Forum: General Bullet Physics Support and Feedback
Topic: wrong collide result
Replies: 1
Views: 434

Re: wrong collide result

You're probably experiencing the collision margin of some convex-convex shape collisions. There is an old video on YouTube that illustrates margin.
by drleviathan
Tue May 10, 2022 4:30 pm
Forum: General Bullet Physics Support and Feedback
Topic: Max number of elements?
Replies: 1
Views: 926

Re: Max number of elements?

There is not enough information to answer your question. You will just have to try it to find out. Here are some questions about things that would affect the answer: Are all the elements dynamic? Or are some of them static or kinematic? Are all of the elements rigid bodies? Or will you be needing so...
by drleviathan
Thu May 05, 2022 3:13 pm
Forum: General Bullet Physics Support and Feedback
Topic: How to know if a body is colliding
Replies: 1
Views: 878

Re: How to know if a body is colliding

One way to do it is to scan all of the contact manifolds after each step. So something like this: void updateContactMap(btCollisionDispatcher* collision_dispatcher) { int num_manifolds = collision_dispatcher->getNumManifolds(); for (int i = 0; i < num_manifolds; ++i) { btPersistentManifold* contact_...
by drleviathan
Thu May 05, 2022 2:59 pm
Forum: General Bullet Physics Support and Feedback
Topic: Jitter when a btBoxShape moves against a btConvexHullShape.
Replies: 2
Views: 945

Re: Jitter when a btBoxShape moves against a btConvexHullShape.

Make the conveyor kinematic instead of static, give it a non-zero velocity but don't change its position. Then dynamic objects that touch it will pick up the non-zero velocity from the collision and will move along.
by drleviathan
Thu Apr 28, 2022 3:28 pm
Forum: General Bullet Physics Support and Feedback
Topic: Static `btConvexHullShape` Not Participating in Collisions
Replies: 2
Views: 813

Re: Static `btConvexHullShape` Not Participating in Collisions

btConvexHullShape does work, so I would expect something else is wrong. Does the object properly collide when you supply it with a different shape but leave all other code unchanged?
by drleviathan
Sat Apr 23, 2022 4:41 pm
Forum: General Bullet Physics Support and Feedback
Topic: How to remove vehicle/rigidbody from dynamics worlds without deleting memory
Replies: 3
Views: 959

Re: How to remove vehicle/rigidbody from dynamics worlds without deleting memory

Yes, if you remove a body from the dynamics world then it will not collide. There are ways to leave a body in the dynamics world while disabling all or selective collisions. One way to do this is to assign each object to one or more collision groups and to specify which groups it collides with. This...
by drleviathan
Tue Apr 19, 2022 3:44 pm
Forum: General Bullet Physics Support and Feedback
Topic: How to create a homing missile?
Replies: 7
Views: 4895

Re: How to create a homing missile?

I forgot to mention some other ideas: (5) As hinted at in (3) where I mentioned fins + atmospheric substrate... if you provide a stronger coupling between the missile's forward direction and its linear velocity, such that when it changes direction it also tends to re-orient the existing velocity to ...
by drleviathan
Mon Apr 18, 2022 8:17 pm
Forum: General Bullet Physics Support and Feedback
Topic: How to create a homing missile?
Replies: 7
Views: 4895

Re: How to create a homing missile?

I have a few ideas for making a homing missile smarter: (1) Reduce the value of EXPONENTIAL_TIMESCALE . This will make the missile orient toward its intended target faster. However, this just effectively reduces the orbit radius of the problem you're seeing and it makes the homing behavior more aggr...