Real-Time Physics Simulation Forum

Hi, You may also be interested in the work of Stephane Redon (and collaborators) on interval-arithmetic based continuous collision detection. Also, a google-search reveals this article about bullet's CCD approach with references (at the end) to the some relevant CCD research: http://www.continuousph...

Definitely, manipulating object positions directly sounds dangerous. You can easily end up adding energy to the system and make thinks jitter or explode. From a theoretical prespective, what you are trying to do, if I understand it correctly, is adding an "ObjectOnSurface" constraint to al...

Hi BGB, I agree with you on the benefits of having a decoupled API layer and an "internal" implementation of the physics engine. That simplifies a lot user-code, engine extensibility and parallelization, in my opinion. I am currently implementing not one but two engines concurrently (not i...

Hi yfan, Handling multiple simultaneous collisions/contacts is never easy. If you're resolving collisions by projection in a Verlet+Relaxation way (based in Jakobsen's article maybe?) and you don't want to write a complex or expensive solution (like applying projections one by one and performing new...

Some years ago I came across a paper by Demetri Terzopoulos that help you: http://portal.acm.org/citation.cfm?id=202162&dl=GUIDE&coll=GUIDE&CFID=27844896&CFTOKEN=39435710 However, I doesn't seem to be freely available on the web, so I'm afraid you'll need an ACM subscription to get i...

Jackpot!

Hi, The attracting mesh in my system is a skinned mesh where each vertex attracts its corresponding particle with a user-defined coefficient [0,1] which I call "rigidity". In general I use it to control the global shape of a deformable surface/cloth or to avoid large deformations in specif...

Interesting link, thanks! The method sounds very simple... but handling such dense meshes interactively must be a challenge, specially with continuous self-collisions. I'm curious abount how well particle-based fluids will perform, I've always thought eulerian fluids to be superior for CG purposes. ...

Hi All, I've recently found this in Autodesk's website: http://area.autodesk.com/custom/?id=4547 It's completely based on particles and claims to be able to simulate "any" kind of Model: rigids, cloth, fluids... Sounds like a "Theory Of Everything" for physics based animation. Ju...

Hi, I considered the Inv inertia tensor (and inverse mass matrix) trick, but I don't think it's a general and "safe" solution... don't you end up with a singular matrix? And in any case you can't use the direct inertia tensor, because some elements would be infinity, so if the engine uses ...

In this interview about LBP: http://www.gamasutra.com/php-bin/news_index.php?story=13051 I found the following observation quite interesting: Concepting was also a large part in resolving what the company had termed their "screwdriver fights," settling, for instance, an early battle about ...

Ja, this game looks amazing... ...and even has an editor mode where you can build levels and share them (first video in the following link) http://www.gametrailers.com/gamepage.php?id=4491 The physics look great, but the gameplay and visual design make it just perfect. There also seems to be a lot o...

Hi Dirk, Baraff's paper on Partitioned Dynamics (cloth-rigid is just an example near the end) http://www.cs.cmu.edu/~baraff/papers/partition-tr.pdf About NR (outer) and GS (inner) iterations, now I start to understand what you mean... so in a cloth with only edge-stretch constraints, having 1 outer ...

Hi, I tried the modified stiffness paprameter, but didn't find it usefull. You get so small values when getting above 4 iterations that I simply allow tweaking this value independently for edge and bend constraints in a range from 0 to 2. Technical artists are quite experienced with tweaking so I do...

Hi again :) I think that the "qualitative" change of behaviour depending on timestep and number of relaxation iterations is the biggest drawback of this method, as you suggest. Too much iterations or too high fps makes constraints too rigid even if you're using SUR because it is supposed t...