The Collision Detection And Response Research With Physical Or Behavioral-Characteristic Simulation In Three-Dimensional Scenery

The collision detection and response is the basic research in CAD/CAM, human motion simulation, physics modeling, and virtual reality etc. It has been becoming more and more important with the development of computer simulation, virtual reality and 3D games.The collision detection and response research with physical or behavioral-characteristic simulation in three-dimensional space arises just in the environment above. It hopes through some research, to discuss the ways and method of the collision and response of object with the physical and behavioral-characteristic modeling in VR, do some foreshadowing for the extensive VR technology simulating true environment more realistically.The paper, which is based on the project of National Science Fund — Behavior-Characteristic modeling for Distributed & Interactive 3D Scenery and the project of the Development of Distributed and Interactive 3D Simulation Platform, chiefly research the technology of collision detection and response of object in 3D scenery. It mainly involves four parts: the collision detection methods of various objects, the collision determination technology of 3D models with triangulated mesh surface, the collision detection and management technology of complex 3D scene, the collision response of rigid object with physical simulation.The collision detection method: In chapter 3, according to space position relation of objects, the author combines octrees, AABBs with the object-oriented concept to form a object-oriented dynamic octrees which can quickly update to refit the dynamic scene, its leaves include not the triangles of the whole scene, but the objects with AABBs. The collision detection passes three steps. Firstly, we detect if the root boxs of the dynamic objects intersect the children boxes of the octree to determine the possible intersection spaces quickly. Secondly, by AABBs of every object in the assured spaces last step, we subdivide its potential intersection area. At last, we detect every triangle in these leaves boxes of AABBs to decide if dynamic objects collide. Itis proved by practical running that this method overcomes the limitation that traditional octrees can not keep object's geometric and physical attributes, at the same time, gives full play to the advantage of its space subdivision. It can quickly determine the current interacting objects; reach the aim of accelerating rendering of scene and reducing the times of overlapping detection between objects.In order to describe the state of objects after collided, it is not enough just to detect their intersection. Then the collision determination is adopted to determine the just time and regions when objects collide. In chapter 2, the author use space-time relativity between the moving or fixed objects in three-dimensional space and collision triangles gained by collision detection to rapidly look for contact regions of the convex objects colliding with each other. It describes the contact regions by a finite number of point contacts. Based on the topological relation of contact regions we determine the collision position, point contacts and contact normals by computing the minimum distance between points and faces, edges and edges. It also specifies the process of calculating point/face, edge/edge contact. It has been proved that by reducing the range of contact regions and simplifying the computes of contact normals, the method enhances the real-time performance of collision determination and establishes the favorable foundation for the movement simulation later.In the collision response with physical simulation in chapter 4, the author combine theory mechanics with computer, state the step and method of physical movement simulation of multi rigid bodies. To the collision response of rigid bodies, we build different mechanics models based on two contact types: collision contacts and temporary contacts. For the former we build response model by momentum and angular momentum theorem; for the latter we build dynamics model by analysing the mechanics and movement states of rigid body. T...