Search found 178 matches

by gjaegy
Tue Nov 14, 2023 4:13 pm
Forum: General Bullet Physics Support and Feedback
Topic: Constraints between kinematic and dynamic rigid bodies
Replies: 8
Views: 80503

Re: Constraints between kinematic and dynamic rigid bodies

I've played with the masses a lot, and no, this didn't really fixed the instability/wobbling issue (but I guess it had an impact on the gap).

So I'll keep my existing solution for now ;)
by gjaegy
Tue Nov 14, 2023 7:30 am
Forum: General Bullet Physics Support and Feedback
Topic: Constraints between kinematic and dynamic rigid bodies
Replies: 8
Views: 80503

Re: Constraints between kinematic and dynamic rigid bodies

I see... :/ I just had a look at the code. Actually, the current implementation of btDiscreteDynamicsWorld::synchronizeSingleMotionState() starts with the following line: if (body->getMotionState() && !body->isStaticOrKinematicObject()) That means, kinematic objects are not updated in that c...
by gjaegy
Mon Nov 13, 2023 8:14 pm
Forum: General Bullet Physics Support and Feedback
Topic: Constraints between kinematic and dynamic rigid bodies
Replies: 8
Views: 80503

Re: Constraints between kinematic and dynamic rigid bodies

It isn't that we would be calling btDiscreteDynamicsWorld::synchronizeKinematicMotionsStates() before stepping the simulation. Rather, we would just be swapping the order of sub-parts that happen during the step. I got that point, didn't express myself very well. So, shouldn't that swapped order be...
by gjaegy
Mon Nov 13, 2023 8:01 am
Forum: General Bullet Physics Support and Feedback
Topic: Constraints between kinematic and dynamic rigid bodies
Replies: 8
Views: 80503

Re: Constraints between kinematic and dynamic rigid bodies

Hi drleviathan, Thanks a lot for your answer, I appreciate it. Actually, I had to deliver so managed to find a solution by basically getting rid of the constraint between the kinematic object and the first (top) chain element. I'm now updating the position/orientation of the first chain manually, in...
by gjaegy
Wed Oct 18, 2023 8:30 am
Forum: General Bullet Physics Support and Feedback
Topic: Constraints between kinematic and dynamic rigid bodies
Replies: 8
Views: 80503

Constraints between kinematic and dynamic rigid bodies

Hi, I'm facing an issue with a chain of dynamic rigid bodies, linked together with 6DOFSpring2 constraints, and linked to a kinematic rigid body using the same constraint type. I've spent days trying to solve it, unsuccessfully, so I thought I would ask for some help :/ When the dynamic object (the ...
by gjaegy
Thu Aug 10, 2023 10:10 am
Forum: General Bullet Physics Support and Feedback
Topic: btMultiBodyDynamicsWorld and soft bodies
Replies: 0
Views: 168233

btMultiBodyDynamicsWorld and soft bodies

Hi, This might sound like a stupid question... In the case one decides to use the btMultiBodyDynamicsWorld class, I assume it is not possible to use soft bodies anymore, is that correct ? Also, I assume it's not possible to use multibodies along with btSoftRigidDynamicsWorld, meaning multibodies and...
by gjaegy
Thu Feb 23, 2023 7:53 am
Forum: General Bullet Physics Support and Feedback
Topic: issue with softbody vs. custom concave shape
Replies: 1
Views: 29800

issue with softbody vs. custom concave shape

Hi, I'm encountering an issue with Bullet internals, and I'm not sure what the best way to resolve it. Basically, the issue is related to the collision between a rope (softbody) and a terrain, for which I've derived a class from btConcaveShape, overriding processAllTriangles() etc. This derived clas...
by gjaegy
Wed Jan 04, 2023 12:51 pm
Forum: General Bullet Physics Support and Feedback
Topic: compound shape / dynamic AABB tree question
Replies: 1
Views: 19462

compound shape / dynamic AABB tree question

Hi, This might sound like a terrible question, but I'm not fully sure of the answer. The compound shape constructor has a "enableDynamicAabbTree" parameter. That tree is used to accelerate early rejection. In the case all shapes added to a compound shape are static (i.e. not moving), does ...
by gjaegy
Wed Aug 01, 2018 8:40 am
Forum: General Bullet Physics Support and Feedback
Topic: btHeightfieldTerrainShape going nuts
Replies: 8
Views: 28528

Re: btHeightfieldTerrainShape going nuts

Modifying the normal indeed improves the situation significantly. I still have some rare jittering cases, no idea why really. But it's acceptable.

Looking at the implementation of btAdjustInternalEdgeContacts(), it seems there is a little bit of additional work being done there :/
by gjaegy
Wed Aug 01, 2018 7:47 am
Forum: General Bullet Physics Support and Feedback
Topic: btHeightfieldTerrainShape going nuts
Replies: 8
Views: 28528

Re: btHeightfieldTerrainShape going nuts

I'll have a try, thanks !
by gjaegy
Tue Jul 31, 2018 1:54 pm
Forum: General Bullet Physics Support and Feedback
Topic: btHeightfieldTerrainShape going nuts
Replies: 8
Views: 28528

Re: btHeightfieldTerrainShape going nuts

Hi Danny,

some time later :) May I ask you, how have you managed to modify the contact point normal manually ? I couldn't find how to achieve that...
by gjaegy
Tue Jul 31, 2018 1:26 pm
Forum: General Bullet Physics Support and Feedback
Topic: btConcaveShape and internal edges
Replies: 0
Views: 6771

btConcaveShape and internal edges

Hi, I am currently struggling trying to avoid collision being detected between a convex hull decomposition shape and my terrain (custom shape derived from btConcaveShape). The issue is pretty intense when using small triangles, as seen in that video: https://youtu.be/MWw1ywZUsrI When using bigger tr...
by gjaegy
Wed May 31, 2017 7:16 am
Forum: General Bullet Physics Support and Feedback
Topic: btBvhTriangleMeshShape and streamed 3D models
Replies: 4
Views: 13237

Re: btBvhTriangleMeshShape and streamed 3D models

good news, I should admit I am quite reluctent on depending on a file format we don't have control over...

thanks for your answer !!
by gjaegy
Wed May 31, 2017 7:15 am
Forum: General Bullet Physics Support and Feedback
Topic: btBvhTriangleMeshShape + instances
Replies: 2
Views: 8863

Re: btBvhTriangleMeshShape + instances

OK great, I also discover the scaled bvh, which perfectly suits our needs since we have some random scaling variation of instances.

Thanks for your answer !
by gjaegy
Tue May 30, 2017 9:52 am
Forum: General Bullet Physics Support and Feedback
Topic: Strategies for Dealing with Large, Complex Terrain
Replies: 16
Views: 36265

Re: Strategies for Dealing with Large, Complex Terrain

The video is looking good, have you finally based your solution on the suggested btConcaveShape-derived class option ?