Adaptive Grid-based Virtual Garment Simulation Technology

In the past decades, cloth simulation has become more and more important in research areas of computer graphics. With the rapid development of the Internet, on-line shopping and on-line games have put great demands on cloth simulation. Although much research has already been done, fast and realistic cloth simulation still remains a challenge. The paper analyses the basic steps of cloth simulation, develops a new collision detection and response method based on k-DOPs and proposes an improved local adaptive refinement and merging method based on triangle grid. The paper is a summarization of the virtual cloth simulation system. Follows are the main work and innovations of the paper.1. The paper first proposes an improved mass-spring model based on the survey of cloth modeling methods, by which the simulation of cloth is formulated unifiedly. The dynamic system of modeling and simulation is derived and solved using time-differentiate method, with given composition and expression of internal and external forces in the formulation. To overcome the serious weakness representing cloth properties simply of previous model, the improved mass-spring model considers mechanical properties of cloth such as stretching, shearing and bending with different stiffness of spring, which can improve the realistic effect.2. This paper then gives some typical methods of collision detection and response, presents a method for collision detection suitable for cloth simulation, which is based on the k-DOPs hierarchical bounding volumes method. The efficiency of the original detection method is improved by adapted techniques for updating bounding volumes and hierarchies. Using oriented k-DOPs inflation turns the usual overlap test into proximity detection. Meanwhile the efficiency of self-collision detection is improved by taking advantages of the surface curvature criterion.3. To balance the simulation computational cost and the flexible nature of cloth objects, the paper presents a method for dynamic adaptation of triangular meshes suitable for cloth simulation, which using a bottom-up approach for mesh refinement. The hierarchy is constructed in runtime, which does not require pre-computation and storage of multi-resolution hierarchy. Local mesh refinement and simplification are triggered by curvature-induced criterion. The performances of gap and boundary have been improved.