Research On Collision Detection Of Flexible Cloth In Virtual Environment

In the past decades, cloth simulation has become more and more important in the research of computer graphics. Due to the rapid development of computer technology, today's cloth simulation can simulate cloth deformation through computer animation. But the technology still can not meet the demands of our information age, there is still lots of research work to be done in this area.The goal of this thesis is to get a stable cloth simulation method that can also meet the real time requirement. To achieve this goal, the physical and mechanical properties of real cloth were analyzed and several cloth simulation methods were compared, method based on mass-spring model was chosen. Dynamics equations of cloth simulation were established based on Newtonian mechanics and a modified strategy on variable time step of adapted Runge-Kutta method is proposed in order to trade off between accuracy and compute efficiency of cloth simulation system.One of the most important part of cloth simulation is how to deal with collision between the cloth and other rigid objects. Bounding volume hierarchy provides an effective method to resolve the complexity of algorithm in collision detection. The idea behind it is to approximate the object with a simpler bounding volume that is a little bigger than the object. In building hierarchies on object, one can obtain increasingly more accurate approximations of the object.The paper is on the basis of the collision detection of flexible cloth, we use a method which combines hierarchical region partition with AABB bounding boxes techniques to handle the prob1ems emerging in collision detection between c1oth and other objects in textile simulation. Through the simplification of the calculation on the triangles surface curve rate,we proposed a method transforming the self-collision detection among the different parts of cloth into collision detection between the cloth and its surrounding environment by recursion, it enhances the efficiency of collision detection dramatically. At the end, the paper discuss the collision detection algorithm between basic geometrical units, which comes down to point-triangle methods and deal with collision response according to mechanics principle.The simulation program was developed using Microsoft Visual C++ 6.0. OpenGL was used for 3D scene rendering and animation. The program can simulate the process of cloth descending and colliding with the ground or a sphere, real time realistic cloth deformation and collision response was achieved.