Three-Dimensional Fabric Static And Dynamic Drape Simulation And Evaluation

Drape is one of the most important properties of apparel fabrics; it is directly related to textile aesthetics, which is crucial for the development and selection of textile materials in apparel industry. The draping behavior of fabrics and garments reproduced by software holds great potential for design, product development and marketing efforts in the business to business environment, and for mass customization efforts geared toward the ultimate consumer. Therefore, the technologies that provide true 3D virtual representation of fabrics and garments have attained more and more attentions in areas of textile and garment design.3D garment drape simulations are now possible due to the fast development of computer technology. However, successful software for 3D garment drape simulation cannot be implemented effectively until virtual images accurately represent reality. Draping of a garment is tremendously influenced by the fabric mechanics. Until these can be integrated into the virtual representation, 3D virtual draping will not fulfill its potential as a technology for improving business processes.Cloth modeling and simulation algorithm has been a great challenge to researchers since 1980s. Researches apply their energies aiming at developing physically based cloth models to visually reproduce the draping behavior of particular type of fabrics. However, studies with documents and current commercially availablesoftware reveal that existing cloth drape simulations are not yet sufficient for design. This is caused mainly by three factors. First, too many ideal conditions make the cloth models far from true resemblance to real fabrics that are actually more complex than a simple collection of some ideal elements. Secondly, there are always trade-offs between realism and efficiency, thus most existing techniques emphasized on one side. Third, very limited understanding has been attained on how to examine the accuracy of virtual 3D draping of fabrics.Efforts to model the complex 3D draped deformations of cloth have been conducted by two research fields: the computer animation field and the textile engineering and CAD field. Researchers in both areas have built different cloth models. Among existing physically based cloth models, the mass-spring model, which was first introduced into cloth modeling field by Breen and Provot in 1990s, has been proved a simple and powerful approach. It models the cloth with interactive particles and each particle is animated by integrating over time the force or the energy associated with it. Thus the 3D shape of draping cloth is obtained.The objective of this research is to develop methods for accurate virtual 3D draping of fabrics and apparel on a digitized 3D model of the human body considering variations in fabric mechanical properties.As one of the creative points of this research, a modified physically based mass-spring model is proposed to represent fabrics and garments. The material properties important to fabric draping, including aerial density, tensile, shear, and bending properties, are described respectively in the model. Here, the mass of eachcloth particle represents the aerial density of the fabric, and the forces of structural, shear, and bend springs serve to resist respectively the planar stretching/compression, shearing, and bending deformations of the fabric. As pure planar shear deformation never solely exists in fabric draping without being accompanied by buckling and bending deformations, the local quadrangle of the fabric always takes on the shape of 3D irregular triangular pyramid, which greatly complicates the calculation of shear force and shear angle. To handle this case, the shear deformation of the local quadrangle is described by the stretching/contracting of two spatial shear springs. Thus the 3D problem is simplified into two ID problems, which is simpler but more flexible than before.The mechanical properties of each kind of springs are derived from the stress-strain behaviors of a particular type of fabric exhibited during KES tests. Here, the stress-st...