Search found 91 matches

by hyyou
Mon Jun 10, 2019 4:13 am
Forum: General Bullet Physics Support and Feedback
Topic: How to detect collision for an animated deforming mesh?
Replies: 5
Views: 208

Re: How to detect collision for an animated deforming mesh?

What is multiple keyframed RigidBodies? You can change shape of the rabbit rigidbody (e.g. every 10 timesteps). For example, when it is jumping, two legs may be pop out a lot from the main body. ➨ create an approximate compound shape "A" When it is sitting, two legs may embed into the main body. ➨ ...
by hyyou
Wed Mar 27, 2019 11:05 am
Forum: General Bullet Physics Support and Feedback
Topic: Strange Behaviour in Release Only
Replies: 6
Views: 540

Re: Strange Behaviour in Release Only

probably uninitialized value in some fields of btTransform

In C++, a variable that is not assigned to any value will usually be = 0, but only in debug mode.
In release mode, it will usually be an ugly random value.
by hyyou
Fri Jul 20, 2018 10:58 am
Forum: General Bullet Physics Support and Feedback
Topic: Is there a lower limit for velocity in Bullet?
Replies: 4
Views: 815

Re: Is there a lower limit for velocity in Bullet?

You're welcome. XD

I call this for every body every time-step.

Code: Select all

btRigidBody->activate();
by hyyou
Thu Jul 19, 2018 3:04 pm
Forum: General Bullet Physics Support and Feedback
Topic: Is there a lower limit for velocity in Bullet?
Replies: 4
Views: 815

Re: Is there a lower limit for velocity in Bullet?

Body is automatically deactivated if its speed size is too small.
http://www.bulletphysics.org/mediawiki- ... ion_States

(I may insert some code snippet later)
by hyyou
Mon Jul 09, 2018 7:17 am
Forum: General Bullet Physics Support and Feedback
Topic: When building URDF models, which visualizer do you use?
Replies: 3
Views: 1027

Re: When building URDF models, which visualizer do you use?

I have just known URDF from your post.
After some search, I found a Blender's addon https://github.com/dfki-ric/phobos. :mrgreen:
From skimming, it looks good and its development is still active. ( but I have never used it yet )
by hyyou
Sat Jun 30, 2018 1:34 am
Forum: General Bullet Physics Support and Feedback
Topic: Using btTriangleShape objects as btCompoundShape children (C++)
Replies: 2
Views: 778

Re: Using btTriangleShape objects as btCompoundShape children (C++)

This line ...... tetrahedralShape0->addChildShape(btTransform(), triangle0); "btTransform()" <----- No initialization constructor is called! Please "setIdentity ()" before you use it. Reference: http://bulletphysics.org/Bullet/BulletFull/classbtTransform.html By the way, I don't think inheriting Bul...
by hyyou
Thu May 10, 2018 2:54 am
Forum: General Bullet Physics Support and Feedback
Topic: Detection of child shape indices in a collision for a compound shape
Replies: 6
Views: 1125

Re: Detection of child shape indices in a collision for a compound shape

^ Because of the uninitialized value, I have to remember type of the shape in my own code. Great answer, drleviathan! ... It is also consistent with what I noticed. To reply OP's email, yes, I believe query the "index" is the best way. It is probably the only way. AFAIK, Bullet's API doesn't provide...
by hyyou
Sun Apr 29, 2018 2:18 am
Forum: General Bullet Physics Support and Feedback
Topic: Minimalist game loop with tunneling
Replies: 12
Views: 2017

Re: Minimalist game loop with tunneling

I am out of idea.

I have never faced such problem for the built-in btBoxShape.
Perhaps, it is limitation of btBvhTriangleMeshShape or its margin.
(more info about margin) https://www.youtube.com/watch?v=BGAwRKPlpCw
by hyyou
Fri Apr 06, 2018 2:12 am
Forum: General Bullet Physics Support and Feedback
Topic: btBvhTriangleMeshShape tunneling
Replies: 9
Views: 1337

Re: btBvhTriangleMeshShape tunneling

I believe it is very fast, but not sure if it is too fast.

I just noticed that, at some time-steps, it looks like stack of box simulation.
Try to enable "SOLVER_RANDMIZE_ORDER". (http://bulletphysics.org/mediawiki-1.5. ... SolverInfo)

I am curious if it helps.
by hyyou
Thu Apr 05, 2018 2:08 am
Forum: General Bullet Physics Support and Feedback
Topic: btBvhTriangleMeshShape tunneling
Replies: 9
Views: 1337

Re: btBvhTriangleMeshShape tunneling

(I will avoid to repeat what drleviathan already mentioned.) Hmm... I feel that the dropping boxs move quite fast. I am curious. How much are their max speed? There is a rumor that the middle parameter of stepSimulation() should be 1. (https://stackoverflow.com/a/21273467) I didn't verify it, but I ...
by hyyou
Tue Apr 03, 2018 12:33 pm
Forum: General Bullet Physics Support and Feedback
Topic: motion state and others
Replies: 5
Views: 1250

Re: motion state and others

Thank a lot, drleviathan, for very rich answer!
I gain extra knowledge from your gravity and btConvexHullShape part.
I will follow you everywhere. XD
by hyyou
Mon Apr 02, 2018 1:57 am
Forum: General Bullet Physics Support and Feedback
Topic: motion state and others
Replies: 5
Views: 1250

Re: motion state and others

- gravity - what is the proper way of setting correct value of it? To avoid any issue, I set it as (0,0,0) and apply gravity impulse every time-step instead. btQuaternion(0.0f, 0.0f, 0.0f, 1), I read http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-17-quaternions/ btVector3(0, 0, 0) /...
by hyyou
Sat Mar 31, 2018 2:16 am
Forum: General Bullet Physics Support and Feedback
Topic: Mouse picking, rayTest
Replies: 2
Views: 651

Re: Mouse picking, rayTest

Whoo.... the code is so long. Sorry for not read it. I stuck with the same issue. Here is how I solved :- 1. Erase all Graphics code. Erase all mouse-related code. 2. Create empty world. 3. Create 1 very simple btBoxShape & 1 btRigidbody with all 1 mask at position (0,0,0). 4. Try to ray test only 1...
by hyyou
Sat Mar 24, 2018 2:06 am
Forum: General Bullet Physics Support and Feedback
Topic: Integrate simulator with Bullet
Replies: 5
Views: 675

Re: Integrate simulator with Bullet

Thank drleviathan, for the great answer!

On topic:-

OgreBullet (http://wiki.ogre3d.org/OgreBullet) is a popular example.
It aims to integrate a node-based graphic engine (Ogre) with Bullet.
OP may get some neat idea from it. I have never used it though.
by hyyou
Thu Mar 22, 2018 3:52 pm
Forum: General Bullet Physics Support and Feedback
Topic: Integrate simulator with Bullet
Replies: 5
Views: 675

Re: Integrate simulator with Bullet

I use 1 body = 1 node.
Yes, there are still a lot of (fun) work.