Great strides have been made in computer animation and special effects. In some cases, synthetic or virtual actors have been integrated into live action films. This raises the need to accurately model and render clothing. In addition, increases in automation in the garment industry create a need for more sophisticated design and manufacturing techniques, which in turn require research in cloth modeling. This investigation will bring a more rigorous basis for cloth modeling to computer graphics, and will have the added benefit of being of interest to the garment industry.
This research will create a cohesive environment for designing fabrics for garments through a two-stage system. The first stage will determine the essential properties of cloth from its underlying structure and then the second stage will use a tailored model of the specific fabric to realistically simulate the dynamic behavior of a garment. The first stage, the micro-model, will simulate the deformation of the yarns in a small section of cloth and will analyze the results of subjecting the sample to various loading conditions. The relations describing the deformation behavior of cloth as a continuum will then be used in the second stage, the macro-model, to animate a full garment. The first stage micro-model will be more general than the specific setups currently used in textile research. In particular, the proposed model will consider yarns with arbitrary yarn paths that have twist and sliding contacts with friction. Empirical evidence and observation of woven fabrics have shown that the latter two features have a substantial role in the overall look and behavior of cloth, but neither has been considered in any previous work in textiles or computer graphics for modeling yarns in fabrics. A related issue is how to deal with the contacts, since the yarns will be in close proximity almost everywhere, contributing to traction forces. The second stage will simulate fabric using the revamped model based on the results of the first stage. The main focus will be on the constitutive equations and incorporating coupled nonlinear behavior. Features such as permanent wrinkles will be added in a later pass. Additional enhancements include local reflectance, transparency, and wind resistance as a function of the local strain. The actual relations would be derived during the first stage but then used during rendering or computation of external forces in this macro-model simulation.
