The Research Of 3D Modeling Method Of Tree

Natural Scenery Emulation is a subdiscipline of Computer Graphics which has attracted many scientists to research in recent years. The goal of Natural Scenery Emulation is to reappear appearance of irregular objects in nature, such as topographical features, hassock, tree, coast, cloud and so on. Among these topics, the research of 3D modeling method of tree and other plants is the most popular. There are many papers about the subject in publish, these papers put forward lots of good ideas to solve the problem. This article, we will summarize general outline of two classical methods, L-system and IFS, and some variant manners derived from the classical methods.Both L-system and IFS are purely based on Fractal. The merit of these methods is that they have fewer parameters and have a beautiful mathematical style. The demerit of these methods is that the shapes generated are not so much vivid, it is hard to conceive the result through the parameters, and the result is too sensitive reliable on the parameters.The shapes of tree have typical feature of fractal and randomness, which were influenced by their genes and circumstances. This article put forward a Dynamic Force System (DFS), which include mass, force, velocity and fractal distributing of amount of energy. DFS use a group of parameters to describe various 3D models of tree. This paper has also provided the algorithm of DFS.3D modeling method and algorithm of tree put forward by this article combine the nature structure of Fractal with a dynamic force system. This is different from other method and is a special creative idea.The algorithm presented by this article has been developed by VBA built-in AUTOCAD. The result shows that this method is not only adequate, but also very effective.The most advantage of this method is that it is easily to control Fractal structure of tree shape through the force, include inner force and outer force. We can see that tree shapes in nature are various, but basic shape is similar. The modeling method of tree shape should remain the basic shape, and also should have variability based on basic shape. The Fractal mechanism can undertake the basic shape. Traditional Method achieve variability through random process. If we look into variable shapes of tree carefully, we can easily find the fact that although local variability is completely random, the integration commonly has a tendency. So it is difficult to purely userandom process in modeling 3D tree. The solution is adoption the notion of force, which can easily solve the problem. Our method introduces the notion of inner force and outer force, inner force control the basic shape, and outer force control the whole tendency.The defect of our method is that it has many feature parameters and control parameters, and the time complexity and space complexity should be optimized.