Search found 15 matches

by Octavius_Ace
Thu Oct 15, 2020 11:50 pm
Forum: General Bullet Physics Support and Feedback
Topic: After 15 years of people asking - Why is Bullet documentation still so very bad?
Replies: 2
Views: 398

Re: After 15 years of people asking - Why is Bullet documentation still so very bad?

Fair comment, I hadn't really considered the driving force being academic research and the implications therein. I'd assumed it was more a labour of love on the part of the primary author and others. I'm not saying it isn't both of course. It's a pity that knowledge is being repeatedly gained and lo...
by Octavius_Ace
Sat Oct 10, 2020 8:03 pm
Forum: General Bullet Physics Support and Feedback
Topic: After 15 years of people asking - Why is Bullet documentation still so very bad?
Replies: 2
Views: 398

After 15 years of people asking - Why is Bullet documentation still so very bad?

Apologies, for the deliberately provocative subject but I doubt I'm the only person to wonder this after years of usage. Bullet is 15+ years old A wiki was started, but is no longer available and seems not worthy of resurrection The user manual is good but is really an overview When people ask quest...
by Octavius_Ace
Sat Aug 25, 2018 8:49 pm
Forum: General Bullet Physics Support and Feedback
Topic: Improving collision detection/response for rag dolls
Replies: 6
Views: 4465

Re: Improving collision detection/response for rag dolls

I finally managed to fully resolve the issues described above and collision response between chains of constrained bodies, including rag dolls and BVH Tri-meshes are now error-free. The solution was two-fold, with the first step being embarrassingly obvious: 1) I was using v2.82 rather than the late...
by Octavius_Ace
Sat Aug 25, 2018 5:47 pm
Forum: General Bullet Physics Support and Feedback
Topic: Ragdoll body parts fall through ground
Replies: 4
Views: 2760

Re: Ragdoll body parts fall through ground

For anyone searching for solutions to similar trimesh / ragdoll / constraint chain penetration problems, I was able to resolve my problems fully.
I've updated my original post with an explanation:
https://pybullet.org/Bullet/phpBB3/view ... =9&t=11481
by Octavius_Ace
Wed Nov 29, 2017 9:06 pm
Forum: General Bullet Physics Support and Feedback
Topic: Collision with large terrain
Replies: 3
Views: 2387

Re: Collision with large terrain

To answer the first poster and the third: Use btBvhTriangleMeshShape for terrain that requires overhangs, tunnels etc. Trimeshes require geometry data that consists of vertices and triangle indices and are necessarily more complex input data. That said, tools like Blender export in lots of formats l...
by Octavius_Ace
Mon Nov 06, 2017 10:30 pm
Forum: General Bullet Physics Support and Feedback
Topic: Ragdoll body parts fall through ground
Replies: 4
Views: 2760

Re: Ragdoll body parts fall through ground

I have a similar unresolved problem with any simple chain of rigid bodies and bad interpenetration with bhv tri meshes. CCD has not resolved the issues and I have to increase the sub-steps too high to be a practical solution in a game engine. My assumption is that the non-solid nature of the tri mes...
by Octavius_Ace
Thu Aug 24, 2017 8:00 pm
Forum: General Bullet Physics Support and Feedback
Topic: Improving collision detection/response for rag dolls
Replies: 6
Views: 4465

Re: Improving collision detection/response for rag dolls

Long time since your question re. Setting up CCD but just in case you check back: I set up CCD as per the user manual, i.e. just call the 2 functions detailed above on a specific rigid body instance. As far as I'm aware that's all that is required. For anyone who's interested, I never resolved this ...
by Octavius_Ace
Sat Jan 14, 2017 7:34 pm
Forum: General Bullet Physics Support and Feedback
Topic: Improving collision detection/response for rag dolls
Replies: 6
Views: 4465

Re: Improving collision detection/response for rag dolls

For anyone who is interested, implementing per rigid body CCD, has not improved the interpenetration issues I'm experiencing. I have set up CCD on each of the RBs in a 3 RB/2 hinge constraint chain, so RB + hinge + RB + hinge + RB. Each RB has a capsule as its collision shape. I have also set the sw...
by Octavius_Ace
Mon Jan 09, 2017 9:21 pm
Forum: General Bullet Physics Support and Feedback
Topic: Improving collision detection/response for rag dolls
Replies: 6
Views: 4465

Re: Improving collision detection/response for rag dolls

Thanks for taking the time to reply. It's much appreciated. The scaling advice is a good pointer, although my rigid bodies are around the 0.5 to 2 unit size, which I believe conforms to the "good practice" pointers found in the bullet manual. That said, my test landscape mesh does have comparitively...
by Octavius_Ace
Sun Jan 08, 2017 5:11 pm
Forum: General Bullet Physics Support and Feedback
Topic: Improving collision detection/response for rag dolls
Replies: 6
Views: 4465

Improving collision detection/response for rag dolls

Hi, I have skeletal mesh animation and the transition to bullet-controlled rag doll animation working and now want to improve the collision detection/response between the rag doll's rigid bodies and the static world mesh. For simple test purposes, I have a chain of 3 rigid body capsules, with 2 ball...
by Octavius_Ace
Sun Jul 24, 2016 4:45 pm
Forum: General Bullet Physics Support and Feedback
Topic: Kinematic / Character manifold collision points [SOLVED-ish]
Replies: 2
Views: 2488

Re: Kinematic / Character manifold collision points [SOLVED-

Hi, I'm not sure my resolution to this will help anyone else but as I've inadvertently managed to fix the problem, I'll detail what I did. To debug the narrow phase collision detection, I replaced the shared Bullet libs I was using (v2.8.3), with what I thought was the same version of BulletCollisio...
by Octavius_Ace
Mon Jul 18, 2016 1:50 pm
Forum: General Bullet Physics Support and Feedback
Topic: Kinematic / Character manifold collision points [SOLVED-ish]
Replies: 2
Views: 2488

Re: Kinematic / Character manifold collision points

Hi, a lot of views for this question but no responses, so I'm not sure if there's a lack of specific detail or the post is too wordy. It might help if I re-phrase and simplify the question: What could cause Bullet to report overlapping pairs with an empty manifold, when a ghost object collides with ...
by Octavius_Ace
Sun Jul 17, 2016 7:01 pm
Forum: General Bullet Physics Support and Feedback
Topic: Kinematic / Character manifold collision points [SOLVED-ish]
Replies: 2
Views: 2488

Kinematic / Character manifold collision points [SOLVED-ish]

Hi, I have a Kinematic platform (box) object and a btKinematicCharacterController object, both of which I can move around under user control. If I move the character object so it collides with the stationary platform, the "recoverFromPenetration" function in the btKinematicCharacterController class ...
by Octavius_Ace
Sun Jun 05, 2016 2:38 pm
Forum: General Bullet Physics Support and Feedback
Topic: Dynamic object transform basis not updating [SOLVED]
Replies: 2
Views: 1959

Re: Dynamic object transform basis not updating [SOLVED]

My guess is that the inertia tensors are not being properly computed. If you supply a zero inertia tensor then the object will not rotate (it behaves as if it had infinite rotational mass). Maybe look at the bottom of this forum thread . Bingo! That solved it. Thanks very much. Turned out I was set...
by Octavius_Ace
Sat Jun 04, 2016 10:56 pm
Forum: General Bullet Physics Support and Feedback
Topic: Dynamic object transform basis not updating [SOLVED]
Replies: 2
Views: 1959

Dynamic object transform basis not updating [SOLVED]

Hi, I've integrated Bullet into numerous small projects and utilised static, kinematic and dynamic objects to good effect. A recent major refactor has resulted in odd behaviour for dynamic objects and I'm hoping for suggestions on where to look for a bug in my code. Essentially my dynamic object pos...