Real-Time Physics Simulation Forum

It depend on your needs, if you just rebuilt your scene from scratch on reset, there must be only few issues (look out for time accumulators, random seeds, etc...) but it should be possible and efficient. related threads: http://www.bulletphysics.com/Bullet/phpBB3/viewtopic.php?f=9&t=1630&hi...

Does XenoCollide now return the correct penetration distance and not just an conservative estimate? Last time I looked at it this was the case and Gary also agreed on this on the forum. I'd like to know that too, last time i implemented it, it was an approximation, but to be fair, in most polyhedra...

I don't think EPA is that complicated, considering that it work on all class of convex shapes (that included quadratics, ie: ellipsoid/ellipsoid ). The core of the algorithm is basically an incremental convex hull builder, the current bullet implementation of EPA (btGjkEpa2.cpp) is less that 300 lin...

Vertex positions are stored in btSoftBody::Node::m_x, so: btSoftBody* body=...; const btVector* positions=&body->m_nodes[0].m_x; const int stride=sizeof(btSoftBody::Node); /* Update positions in your display mesh */ Triangle are stored in btSoftBody::Face, so you can retrieve vertex index with: ...

Bullet already provide a wide range of broad-phases implementations: - btAxisSweep3 (SAP) - btMultiSapBroadphase (multiSAP) - btDbvtBroadphase (dynamic hierarchy) Perhaps you should try existing implementations, then make sure broad-phase is actually a bottleneck. btMultiSapBroadphase especially can...

What's really important is the mass ratio between the rope and the body, so you can increase the rope mass to improve stiffness, and/or iterations, (rope are fast to solve, try 32).

Hope it help,
Nathanael.

Try increasing rope mass, masses ratio are really the weak point of the type of solver used for soft/rigid interaction.
Also, increase ...m_cfg.piterations , try 16.

I'm interested to try it myself, can you post the code?

Nat.

You need to compile/run CDTestFramework in /extras folder.
More information here: http://www.bulletphysics.com/Bullet/php ... =18&t=2178

hope it help,
Nathanael.

can you point out some links that say how it all works? Just applying (over)simplified lift and drag on a deformable model do the tricks, of course in the real world the paper is not that deformable, and its motion is mainly driven by the turbulence in the fluid, but it work well enough (run the de...

The rope you created is 50Kg and the cylinder 10Kg, not a fair match under gravity! :wink: In addition, the last parameter of ::CreateRope is 'fixed', its used to attached node to the world (bit mask, 1:first node , 2:last node). try: btSoftBody* pRope = btSoftBodyHelpers::CreateRope( pdemo->m_softB...

I'm interested in the implementation of the dynamic AABB tree, including the ability to do view frustum culling and front-to-back traversal, but I'm having real problems finding the little sucker. A search for "frustum" in CDTestFramework doesn't result in much useful info, let alone an o...

If I am right, for a (1-dimensional) elastic collision, the difference in impulse is 2(va - vb) / (1/ma+1/mb). va-vb is vr in the code, 1/(1/ma+1/mb) is c.m_c0. So I would expect a factor 2 in front of vr? What is modeled here is inelastic collisions, through in line 1027 the term 'cti.m_normal*(dp...

@bob The mesh you describe consist of 24 vertices's, btSoftBody doesn't weld anything, a cube should be made of 8 vertex, 12 triangles. soft bodies expect consistent triangle orientation, normals pointing outward (triangle ABC, normal (B-A)x(C-a) ), and duplicated vertex mean disjoint during simulat...

@bob Can you provide some code extract so that we can reproduce the problem? @Bbilz Soft bodies is still a very new feature, it will take some time before things settle in, right now too much changes occur to enable real documentations. Here some help regarding btSoftBody::Config : btSoftBody::Confi...

Is this the correct and wanted behavior or it's my fault and I'm missing some option?

Collisions handling for soft body faces / rigid body shapes are currently in active development.

Thanks.