Modeling and Estimation of Internal Friction in Cloth
Eder Miguel (URJC Madrid)
Rasmus Tamstorf (Walt Disney Animation Studios Research)
Derek Bradley (Disney Research Zurich)
Sara C. Schvartzman (URJC Madrid)
Bernhard Thomaszewski (Disney Research Zurich)
Bernd Bickel (Disney Research Zurich)
Wojciech Matusik (MIT CSAIL)
Steve Marschner (Cornell University)
Miguel Otaduy (URJC Madrid)
Several researchers have identified internal friction as the source of large hysteresis in force-deformation measurements in real cloth, yet it has not been incorporated into computer animation models of cloth. Even if the elastic parameters are chosen to fit the average of loading and unloading behaviors, given observed hysteresis as high as 50% of the average force, ignoring internal friction may induce deformation errors of up to 25% for a given load. Internal friction also plays a central role in the formation and dynamics of cloth wrinkles. We have observed that internal friction may induce the formation of ‘preferred’ wrinkles and folds.
In this project, we developed a model of internal friction based on a reparameterization of Dahl’s model, and validated that this model provides a good match to important features of cloth hysteresis even with a minimal set of parameters. We also provide novel parameter estimation procedures based on easy to acquire and sparse data. In contrast to previous work, which relies on complex force-deformation measurement systems with uniform strain, controlled deformation velocity, and dense data acquisition, the hardware used for acquisition is extremely simple.
Finally, we provide an algorithm for the efficient simulation of internal friction using implicit integration methods. We demonstrate it on cloth simulation examples that show disparate behavior with and without internal friction.