Research On Collision Detection Of Tree Swaying In Wind

With the development of computer graphics, the simulation of natural landscapes becomes a hot point of research due to the demands in movie making and game developing. Tree is one kind of important parts of the natural landscape. Simulating tree requires not only a drawing of its static status but also a sense of reality in its movement. Collision detection is occurred in the simulation process of tree swaying in the wind. This thesis mainly studies collision detection problems and following collision responses in simulating the tree motioning in the wind.This thesis discusses on collision problems in the simulation process of tree swaying. The collision problems are divided into five situations according to the different position of touch points. They are: collision between branches, collision between branches and ground, collision between leaves, collision between leaves and ground, and collision between branches and leaves. Collision conditions are deduced respectively to all kinds of situations and a collision detection algorithm based on diversity geometric figure is proposed. A comparative experiment is done to evaluate the proposed algorithm and OBB (Oriented Bounding Box) algorithm. The results show that the proposed algorithm performs better than OBB algorithm with higher accurate rate and executing efficiency. After dealing with collision detection problems, collision response is studied in this thesis. With the force analysis of collided models and theorem of impulse of a system of particles, the movement trajectory of objects after colliding is calculated. Experiments show that the addition of effective collision response can make the animation process tend to be more authenticity.A simulation process of tree swaying in the wind is implemented in Visual C++ using OpenGL. The reality of scene is further enhanced by using the proposed algorithm.