Real-Time Physics Simulation Forum

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/Kenny

The 7th Workshop on Virtual Reality Interaction and Physical Simulation, VRIPHYS 2010. http://vriphys2010.inrialpes.fr/ The event will take place November 11-12 in Copenhagen, Denmark. I can wholehearted recommend this event, its fun and a lot of new and novel research for interactive physical simul...

Exactly how the b-vector would influence the accuracy/iteration tradeoff for an iterative complementarity solver is a bit unclear to me. The b-vector contains the Baumgarte term and the relative velocity we like to eleminate. Take the ODE formulation for example: J*W*JT * lambda = c/dt - J*(v/dt + ...

I have heard a lot of statements in the last time about the number iterations needed to find a stable solution for stacking or articulated structures. Thanks to Erin Catto who shared a lot of information and Erwin Coumans who provides a sample implementation of this (along with his own collision li...

Erwin asked if I would like to make a few comments on this topic, so here goes.... I completely agree that the most used collision detection approach in computer games today is compounds. That is a collection of simpler geometries. It is very easy to explain to an artist how this works, and further ...

I read the paper, nice work:-) I do have a few questions/remarks: Using an event driven scheme, would the usage of sequential collision response (I got the impression when reading the paper, that this is what you use) cause problems when configurations with infinite sequences are encountered? Have y...

i'm arriving to this discussion late, and trying to understand what shock-propagation can do. kenny, my (perhaps poor) understanding is that it's akin to the multigrid method commonly used in PDEs, i.e. you form a coarser representation of the problem, solve that, then use that as a starting point ...

Isn?t that similar to what "Shock wave propagation? does when it arbitrarily sets the mass of rigid bodies to infinity based of intuition and without any mathematical or physical explanation. I am not expert but in my mind switching the mass of a body to infinity and dampening the velocity of ...

My impression is that shock propagation is not used in commercial engines. It makes for nice demos, but it creates odd behavior in real game play. Does anyone know of a commercial engine that uses shock propagation? No, and I think there is three reasons for this. Firstly, the book-keeping for find...

Solving an entire contact manifold between two bodies with a dedicated direct solver might help convergence, then you've kind of reduced the problem to one of iterating over contacts between spheres. Spheres? The mathematical model of a velocity based complementarity based formulation is for ``simu...

1) Has anybody actually written a code based on the algorithms from Baraff's paper and is it possible to take a look at some parts of it ? I think Baraff and Witkin used to have a company, where they among other things made the initial rigid body simulator used in Maya. I think it was called Coriol...

Following links are some DivX animations of my first experiments dealing with contacts & collisions (each web page has the link to the AVI and a short description - feel free to add comments) ... Hmm, maybe I was to slow to get around to read your post, but I think the links are dead by now? Th...

Yes, it is strange that no convergence results are provided. In fact I rarely see good benchmarks for new algorithms/solvers. At least for graphics I think this is very true, in my opinion engineering and applied math seem to do better, but they often don't care about real-time:-) I have discussed ...

I came across this optimization on my own, even though I have actually seen code that uses it. I missed it before because I was busy keeping my Jacobians straight, and it's usually kind of obfuscated. Going back now I've noticed it's in ODE, it's in Erin Catto's paper, it's all over! My question is...

I implemented post stabilization ...[snip]... has the advantage that the interpenetration resolvement doesn't contribute to the pesistent momentum. Persistent momentum? One thing that is not clear from the paper is if I need to rebuild the Jacobian after the position update or if I can use the same...