CA Scanline uses SimCloth3 for more than 3500 cloth simulations

May, 2003
Vlado interviews Christoph Sprenger from CA Scanline Production

Can you give us some background about yourself and your company?

"CA Scanline Production is a VFX house based in Munich (Germany), focusing on feature and TV films, where I'm lead Character Animator. Some of our projects are the dam breaching scene from "Wave of Death" which was shown in the Electronic Theatre at Siggraph 2001, the plane crash sequence also screened at Siggraph (2002) and the Academy Award 2003 winning feature film "Nowhere in Africa" where we visualized a huge flock of grasshoppers. There are other projects as well, but I guess these are the most famous and best known sequences we brought to life. You can check out our website at www.scanline.de to get a complete overview of our projects."

 

Can you tell us something about your current project?

"One of the current projects we are working on is called Hero of the Gladiators, a German TV movie, which will be broadcasted in the fall of this year. We have to visualize a huge arena with 15000 unique people, all acting differently upon complex behaviours. CA Scanline developed a proprietary software called Sheep, which generates and simulates that crowd. Since we wanted to match the need of absolute photorealism in every aspect, it was also very important for us not to use usual skinning techniques for the cloth, but to entirely simulate it. It would be impossible to keep any deadline if you simulate the 15000 unique cloth meshes on a shot-per-shot basis, as you can imagine; I guess no software is capable of doing this right now. One would also have to check every piece of cloth in a scene for its integrity. I guess this would be an endless nightmare. Thats why we decided to use presimulated data for our cloth meshes and handle them similarly to the actual motion clips of the characters themselves. Presimulated cloth data gives us a huge amount of control over the look and animation of each single cloth. Our cloth department did over 3500 cloth simulations in less than two and a half weeks with SimCloth3 and we are still not finished at this stage. The entire simulation time for those was 263 hours, calculated on our "simulation farm". We wrote a network manager and client for SimCloth3 to be able to use our renderfarm for the simulation and to have full control over the huge data streams. This helped us a lot to complete the task within time, since the local workstations were hardly used and the animators could continue their work as scheduled."

 

Why did you choose SimCloth3? Did you consider any other options for cloth simulation?

"First I have to say that I'm a big fan of freeware software, one fact that made our decisions easier from the beginning. We also tested reactor's cloth, but we weren't very happy with the control one has over the settings and especially with the fact that the wind isn't animatable. We frequently encountered integrity losses, also the simulation time was not satisfying when using more detailed meshes. Another reason for choosing SimCloth3 in the end was to have full control over the modelling process of the cloth. And finally you were so kind to give the max community another free and highly improved version of SimCloth 2.5, and it was open source. Basically that made the choice very simple and we had all aspects we wanted for this task; a fast, stable, highly customizable and `cheap´ simulation software."

 

What problems did you confront with while working on this task?

"Actually we ran into quite a lot of problems. Since we had to simulate every clip with every cloth mesh, there was no setup for all possible conditions. Some meshes had no problems with certain clips others made immense troubles with the same animation. You developed the MeshDeformer modifier to help us out here. We were able to decrease the number of losses and fails significantly due to this modifier, which deforms the collision objects so that they do not intersect. As you can imagine the most difficult parts were in the spine area, where the upperarm pushes vertices into the body and intersections can easily occur. Also of big help was the customizeable vertex subobject setting, where one can exclude vertex groups from self-collisions, collisions and intersection checks."

 

Is there anything else you would like to tell us?

Yes, the biggest thanks belong to you of course, for supporting us in this unique way!!! A big THANK YOU, for every wish you implemented and made SimCloth3 even more powerful. We are sorry that we cannot show any animated shots at this point, but we will have a Siggraph sketch this year and will hopefully show some nice imagery.

Learn more about SimCloth3 on the SimCloth home page.

 

MeshDeformer is a simple plugin that indents one mesh based on another mesh.
/Vlado