The Technology Of Real-Time Rendering Realistic Trees

Environment simulation technology has been one of the hot and difficult topics in the virtual reality, computer graphics, computer games, etc. As one part of the natural scenes, trees are an essential part of the environment simulation system. Modeling and rendering realistic real-time trees has important practical value in the filed of three-dimensional games, digital entertainment, film and television special effects, urban planning and virtual campus. So, it is important to research the technology of modeling and rendering realistic trees.The goal of this article is to achieve a realistic three-dimensional tree model. Also, we research and exploration the key of modeling and rendering technology. The main contents and conclusions are as follows:1) To solve the problem of wasting time in model trees in the three-dimensional scene, we proposed the method of modeling and rendering trees based on adjusted parameters. First of all, we divided tree models into three parts:trunk, branch and leaf. Secondly, we build a multi-branching tree topology; this could store the dates of trunk and branches nodes. Then, add the data of leaf information to this multi-branching tree topology. The tree model could be adjusted by the parameters. We use iterative method to generate fractal tree trunks, branches and leaves. Finally, we traverse this topology and draw trees.2) In order to judging by the sample trees in nature, modeling and rendering complex tree models, fulfill the realistic needs in simulation system, we proposed a method based on a simple tree picture. First of all, calculate the coordinates of vanishing points base on three orthogonal groups of parallel lines in the picture. Secondly, calculate the focal distance and internal reference by the coordinates of vanishing point. Then, user interaction to obtain the image plane trees topology. Finally, add small twigs and leaves and draw trees.3) In order to meet the requirements of authenticity and real-time when draw the shadows of trees, we proposed a method to use Alpha approach to draw the shadow of the trees. First of all, we use the method of modeling and rendering trees based on adjusted parameter; then, we use the hybrid approach draw another tree with gray, and paste it on the ground, so that we can simulate the shadow of trees. We use this method modeling and rendering trees and shadows.4) To prove the effective of our method in the passage, we designed the modeling and rendering tree system.