Search found 23 matches

by Geometrian
Mon Oct 17, 2016 2:16 am
Forum: General Bullet Physics Support and Feedback
Topic: btSoftBody Internal Forces
Replies: 1
Views: 1105

btSoftBody Internal Forces

Hi, I'm trying to get some kind of measurement of internal forces from btSoftBody. (I need to measure the stress on each link for an engineering simulation. This would also be useful for computing tension in ropes, tearing cloth, etc.) I have found a few scattered posts , but no answers. I also trie...
by Geometrian
Wed Nov 19, 2014 8:37 am
Forum: General Bullet Physics Support and Feedback
Topic: Volume of btConvexHullShape
Replies: 2
Views: 1565

Volume of btConvexHullShape

I need to calculate the volume of a "btConvexHullShape" (more accurately, I need to compute a mass, but I'll do this through a density). Short of implementing my own convex hull algorithm, what should I do? I considered making a temporary "btConvexTriangleMeshShape" and then using its "calculatePrin...
by Geometrian
Thu Mar 20, 2014 6:51 pm
Forum: General Bullet Physics Support and Feedback
Topic: Soft Body Self Collision Detection
Replies: 0
Views: 3503

Soft Body Self Collision Detection

Hi, I have found a few posts about doing various kinds of softbody collision detection with Bullet 2, but none helpful. I am specifically interested in colliding concave softbodies with themselves, with concave rigid bodies, and with other concave soft bodies. From what I've ascertained, there is so...
by Geometrian
Tue Nov 26, 2013 9:32 pm
Forum: General Bullet Physics Support and Feedback
Topic: Memory Leak from Linking
Replies: 10
Views: 5186

Re: Memory Leak from Linking

This still occurs in 2.82.

I'm fairly sure at least part of the problem is that the "static btClock gProfileClock;" declared at btQuickprof.cpp:21 allocates memory that is never freed.
by Geometrian
Thu Nov 21, 2013 11:52 pm
Forum: General Bullet Physics Support and Feedback
Topic: getPersistentManifold() Returns NULL
Replies: 1
Views: 1195

getPersistentManifold() Returns NULL

Hi, I have a compound object and I'm trying to collide it against various things. I can't seem to figure out why, but in certain situations, my code crashes since getPersistentManifold() is returning NULL. My near callback is below: void _fz_near_callback(btBroadphasePair& collisionPair, btCollision...
by Geometrian
Tue Jun 25, 2013 7:26 am
Forum: General Bullet Physics Support and Feedback
Topic: Near Callback Discard
Replies: 1
Views: 1376

Near Callback Discard

Hi, I need to be able to test whether to let two objects collide after detecting whether they would. For example, if there are two separate cubes, the instant they actually start to intersect is when I decide whether to let Bullet continue processing the collision. To this end, I have implemented a ...
by Geometrian
Sun Jun 02, 2013 9:00 pm
Forum: General Bullet Physics Support and Feedback
Topic: Box-Sphere Inaccurate Collision
Replies: 2
Views: 2338

Re: Box-Sphere Inaccurate Collision

The collision margin was exactly the problem--I had no idea it even existed!

The scene I discovered it in was a sphere of radius 10cm rolling over boxes of size 1m on a side.

Thanks!
by Geometrian
Wed May 29, 2013 4:12 am
Forum: General Bullet Physics Support and Feedback
Topic: Box-Sphere Inaccurate Collision
Replies: 2
Views: 2338

Box-Sphere Inaccurate Collision

Hi, When a box (btBoxShape) and a sphere (btSphereShape) collide, the collision is very good on faces, but inaccurate at edges/corners. My tests show that on edges, the amount of penetration relative to the size of the box can range from 0.5% to 2.0%. It seems to be independent of the time step--I t...
by Geometrian
Wed May 15, 2013 10:35 pm
Forum: General Bullet Physics Support and Feedback
Topic: Guaranteed Collision Callback
Replies: 3
Views: 2741

Guaranteed Collision Callback

Hi, I am attempting to figure out when two objects collide. What I want: Ideally, whenever a collision actually occurs , Bullet would call a callback, giving me the option to ignore the collision or allow Bullet to continue with collision response (restitution, reaction, etc.). Some things close and...
by Geometrian
Thu Apr 18, 2013 10:31 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Facilities for Physics-Based Animation
Replies: 0
Views: 2244

Facilities for Physics-Based Animation

I'm looking for a way to animate humanoid characters in a physically-based manner. I looked around a bit, but wasn't able to find anything useful in the way of a toolkit--mostly it's just technical papers on the topic. I figured I would ask the people who follow such things more closely. My requirem...
by Geometrian
Sun Apr 14, 2013 1:50 am
Forum: General Bullet Physics Support and Feedback
Topic: BT_DECLARE_ALIGNED_ALLOCATOR new Operator Overload
Replies: 4
Views: 4008

Re: BT_DECLARE_ALIGNED_ALLOCATOR new Operator Overload

Figured it out. The library indeed didn't overload "new", but it did #define it to something else, for purposes of catching memory leaks: #define DEBUG_NEW new( _NORMAL_BLOCK, __FILE__, __LINE__ ) #define new DEBUG_NEW Is it possible to keep this definition, or something similar, but still use Bulle...
by Geometrian
Sun Apr 14, 2013 12:13 am
Forum: General Bullet Physics Support and Feedback
Topic: BT_DECLARE_ALIGNED_ALLOCATOR new Operator Overload
Replies: 4
Views: 4008

Re: BT_DECLARE_ALIGNED_ALLOCATOR new Operator Overload

*Bump* I don't know why this could be happening. The other library doesn't overload new as far as I know (although it certainly uses it). The problem doesn't seem to occur if the library's header files are included after Bullet's and if no "new" allocations happen for Bullet objects in that compilat...
by Geometrian
Sun Apr 07, 2013 7:09 pm
Forum: General Bullet Physics Support and Feedback
Topic: Memory Leak from Linking
Replies: 10
Views: 5186

Re: Memory Leak from Linking

So memory leak appears after you add functionality, which is never executed? In that case, are you sure you destroy all objects you created? physics->removeRigidBody(...); delete RigidBody; delete CollisionShape; Are you sure it's not your code causing leak at all? Exactly. The code that's causing ...
by Geometrian
Sun Apr 07, 2013 4:12 am
Forum: General Bullet Physics Support and Feedback
Topic: BT_DECLARE_ALIGNED_ALLOCATOR new Operator Overload
Replies: 4
Views: 4008

BT_DECLARE_ALIGNED_ALLOCATOR new Operator Overload

Hi, When trying to use Bullet with another library (which nowhere overloads new), I get many many errors. Some selected ones are below: //... 1>c:\program files (x86)\microsoft sdks\windows\v7.0a\bullet-2.81-rev2613\src\linearmath\btvector3.h(82): error C2802: static member 'operator new' has no for...
by Geometrian
Fri Jun 08, 2012 1:12 am
Forum: General Bullet Physics Support and Feedback
Topic: btGImpactMeshShape Not Reacting to Gravity
Replies: 0
Views: 1313

btGImpactMeshShape Not Reacting to Gravity

Hi, First off, I'm trying to get concave dynamic rigid triangle meshes to collide and react properly. From scattered sources, I surmised that this can be done through ConvexDecomposition or btGImpactMeshShape. Because the ConvexDecomposition demo is, quite frankly, illegible, I'm trying btGImpactMes...