Predicting the Drape of Woven Cloth Using Interactive Particles
David E. Breen Donald H. House
Michael J. Wonzy
Cloth Simulation• Cloth can be represented as spatially couple particles
• Particles represent the crossing points of the warp and weft threads
• Energy equations are then used to simulate interactions between the particles
Energy Equations
• Four basic mechanical interactions occur at the crossing points: thread collisions, thread stretching, bending, and trellising.
Urepel - artificial force of repulsion helping prevent thread collision
Ustrech - energy of tensile strain between particle and four neighbors
Ubend - energy due to threads bending out of local plane of cloth
Utrellis - energy due to bending around a thread crossing in the plane
Ugrav - potential energy due to gravity as a function of height
Repelling and Stretching
The stretching and repelling functions are both functions of the distance to other particles in the cloth. The repelling function is a sum of S for all particles in the cloth while the stretching functions is a sum of R for its four connected neighbors.
Bending and Trellising
The B energy is a function of the angle between three particles along a weft or warp thread. The bending energy is a summation of the B for the eight nearest neighbors.
The T energy is a function of the angle formed between a particle and its two neighbors as it moves away from equilibrium. The trellis energy is a summation of T for the particles four nearest neighbors.
Three Phase Process
First Phase: Calculate the dynamics of each particle as if it were falling freely under gravity in a viscous medium.
Second Phase: Perform energy minimization to enforce interparticle constraints.
Third Phase: Corrects the velocity of the particles to account for the second phase.
Different Cloth
Problem: Different types of cloth behave differently due to the different materials and weaves.
Kawabata Evaluation System
• Standard set of fabric measuring equipment to measure the bending, shearing, tensile, compressibility, and surface roughness of a specific fabric.
• Generates plots of force as a function of measured geometric deformation.
• Energy equations for the type of cloth are derived from the empirical data.
Other Cloth Simulations
Maria Huang, Bradley D. Nelson
http://graphics.stanford.edu/courses/cs348b-competition/cs348b-99/