Abstract:         Under the natural conditions，the shape of sand dunes is varied and the natural conditions of the sand dunes are very poor， and the vegetation on which they live depends is often on different states. The computer graphics and fractal geometry were used to simulate the growth of dune and vegetation. Through the function iteration system,it can achieve a single tree and forest of the morphological simulation,and also simulation the trees in the dune growth by bolding the branches. The color of trees is divided by the method of tracing the affine transformation points to achieve the color of trees changing with the season. Using computer graphics to draw flowers and the random function to replace some of the points on the trees for flowers，little flower of trees was simulated. Using the combination of different phases of the sine curve the dune is drawn and then the dune vegetation scene is simulated by combining with the trees. The external factors are used to simulate the natural shape of the dune windward slope under natural conditions. Finally,by increasing the density of dune and the number of trees to expand the area of trees the local forest scene simulation is generated.

Key words: Iterated function system,    , Tree simulation,    , Sand dune simulation,    , Graphics

摘要：         自然条件下的沙丘形状多变,自然条件恶劣的沙丘地带其赖以生存的植被常常呈现出不同状态。利用计算机图形学和分形几何技术模拟沙丘及植被的生长状况。通过函数迭代系统实现单棵树木及树林的形态模拟,对枝干进行加粗处理模拟树木在沙丘中的生长状况。采用追踪仿射变换点的方法对着色树木的树叶颜色进行划分,实现树木颜色季节性的变化。利用计算机图形学方法绘制花朵,采用随机函数对树木中的部分点用花朵替换,模拟繁花点点的林木。利用正弦曲线不同相位的组合绘制沙丘,与树木结合实现沙丘植被场景模拟,通过加入外力影响因子模拟自然条件下沙丘迎风坡上的自然形态。最后增加沙丘密度及扩大树木覆盖面积生成局部树林场景的模拟。

关键词: 迭代函数系统,   ,  树木模拟,   ,  沙丘模拟,   ,  图形学