   Biggest piece of cloth that can be simulated?
  Ok, I realise there could be a range of answers to this be an answer ever to the right order of magnitude would help :-DSo, if we have a piece of cloth modelled by some kind of mass-spring system what is the largest number of masses which can be simulated in real time? Assuming no fancy hardware acceleration and a reasonably fast processor (say 3GHz). The cloth simulation will be stand alone and not in a game so no extra processor overheads.Perhaps it depends on the simulation method used? I'm looking to do a few million points. Is that feasible?Thanks,David   
  A few millions? Are you serious? How did you get such a high number?Cinema quality pieces of cloth usually have no more than 7000-10000 particles,and even then, it takes several seconds to compute a frame.Since one of the biggest bottlenecks is collision detection (especially self-collision), the computation time can be drastically reduced if you cheat in that area. Using all sorts of computational tricks, sparse matrices and approximations can boost the performance even higher.For example, using a relatively fast force computation scheme and implicit integration, we are able to simulate a "cloth-like" object with several thousands of particles and handle collisions in real-time. (no self-collision at this point though).;  Hmmm... that's not so good. I'll give you more info on my problem. It's actually in the medical field. I will be given a CT scan of a patient and from this I will build a 3D model of some organl, the colon is a good example as it is basically a tube. I estimate such a model would have a million polygons (and hence a million vertices). Something like this:http://www-radiology.uchicago.edu/krl/images/5_3.gifI would like to cut this tube from one end to the other and unroll it, while at the same time preserving any lumps on the surface. I thought that after cutting it I could treat it as a piece of cloth and allow a doctor to virtually move it around.But like I said, maybe a million vetices. Incidently a mass-stick system would probably do, this is presumably easier than a mass-spring system? or maybe not?Any other thoughts?;  There is very little reason to have a polygon smaller than a pixel.  I suggest you have a LOD scheme and allow areas very close to the camera to be done in higher detail.  I would also suggest doing the cutting and moving around on a low LOD and then interpolating the differences over the intermediate vertices.The model you showed there looked like tens of thousands of polygons at most, which is significantly different from millions . . .   ;Quote:Original post by esuvsI would like to cut this tube from one end to the other and unroll it, while at the same time preserving any lumps on the surface. I thought that after cutting it I could treat it as a piece of cloth and allow a doctor to virtually move it around.What do you mean by move it? Why do you need cloth-like simulation if you only intend to move it? And mainly, what exactly is the purpose of this procedure?   ;  The physical model can be at a significantly lower resolution than the rendered one. Then attach (with weights) each rendered vertex to one or more physical vertices - like skinning a character skeleton.   ;  Can you accurately model the colon as a tube with such thin walls? Would you not need to model the flexibility etc. from having thick walls?So you want to unroll it so it can be examined virtually - is that the deal?For medical stuff can you not access some better hardware? It sounds like something you could use the GPU for; otherwise some kind of CPU-cluster (like a network doing distributed processing) might be applicable.   