Abstract: To better simulate the three-dimensional trees and the effect of dynamic swaying, this paper proposes a way of using the Perlin noise to generate a mathematical model of the virtual wind, and using the Iterated Function Systems（IFS） to build the 3-D trees model. Then this method uses dynamical equation to calculate the amplitude of swaying trees, the rotation angle and offset size of the branches and leaves. Experimental result shows that the method can better simulate the natural form of trees and real effects of dynamic swaying.

Key words: Perlin noise, Iterated Function Systems（IFS）, wind filed, trees

摘要： 为了更好地模拟三维树木动态摇曳的效果，根据真实风场的变化规律，利用Perlin噪声技术产生虚拟风场的数学模型，采用迭代函数系统（IFS）方法构建三维树木模型，并运用动力学知识进行受力分析，计算树木的摇曳幅度以及树枝和树叶的旋转角度和偏移大小。实验结果表明，该方法能够较好地模拟自然树木的形态以及树木的真实摇曳效果。

关键词: Perlin噪声, 迭代函数系统（IFS）, 风场, 树木