Research On Path Planning Of Virtual Human In Virtual Environment

Virtual human path planning is defined to plan a shortest motion path for a virtual human to pass all the obstacles safely and collision-free in a virtual environment with obstacles. As a part of virtual animation technologies, the path planning of virtual human has a wide range of applications in games, movies and virtual reality. There are three aspects need to be considered in path planning, the planning method, the expression of environment and the implementation of the planning results. Meanwhile, the path planning must involve people motion simulation in the three-dimensional environment. Not only the human skeleton modeling, but also the human body walking simulation have to be considered.This research work is composed with three main sections, the virtual environment modeling techniques, the path planning based on an improved artificial potential field algorithm in two-dimensional environment and the path planning based on OSG in three-dimensional environment.Virtual environment modeling is the basis for virtual human path planning. No matter which path planning method is used, the virtual human has to know its own locations and the positions of obstacles. In this paper, the traditional grid method is used to construct the two-dimensional environment; the SketchUp based modeling method is used to construct the three-dimensional environment, which makes it easier to construct a three-dimensional scene and accelerate the speed of completion of the entire scene.For path planning in a two-dimensional environment, the two issues of the artificial potential field method are chiefly analyzed, which are the goal non-reachable with obstacles nearby and the local minimum problem. An improved repulsive force field function is used to solve the goal non-reachable problem and a temporary target point based method is proposed to solve the local minimum problem. VC++ based experiment simulations show that the method is feasible and effective.For path planning in a three-dimensional environment, this paper study on the key technologies which will be adopted in three-dimensional environment, including the key-frame path animation, the walk cycle of virtual human and the OSG based human skeleton animation. Then all the technologies are applied to the virtual emergency response training system, which achieves the evacuation route planning during the drill and proves the feasibility and effectiveness of the algorithm.