对表示复杂自然物体的纹元(texel)方法进行扩展,提出时变纹元的概念,以模拟草叶、毛发等自然物体随时间而变化的真实感效果.时变纹元内存储着自然物体随时间变化的纹元数据,从而可用于构建时变三维数据场,实现物体时变效果的模拟.采用一种纹元变形算法来生成时变纹元,该算法首先将基本纹元结构转化为点模型,然后对点模型进行动态模拟来生成时变数据,再将时变的点模型数据进行转化而得到时变纹元结构.运用时变纹元方法实现了草地随时间逐渐枯萎效果的真实感模拟.为了能够模拟草地枯萎变化过程中真实的形态、材质变化,基于物理学以及

In this paper, a technique called Time-Varying Texel (TVT) is presented for simulating the withering effects of grassland. Time-Varying Texel is defined as an extension of the traditional texel structure by adding a time dimension, where the texel at different time is computed by using a Texel Deformation Technique. In this approach, a point based structure (PBS) is employed in combination with the Time-Varying Texel. Throuogh the introduction of PBS as a bridge, a Physical-biological Model can be applied to handling the deformation at the grass texel. In addition, a mingling algorithm is applied to enhance the diversity of grassland, and the LOD representation of TVT is developed for promoting efficiency. Experimental results show that the realistic grass time-varying simulation is well achieved with the proposed techniques.

Supported by the National Natural Science Foundation of China under Grant Nos.60833007, 60773030, 60973066 (国家自然科学基金); the National Basic Research Program of China under Grant No.2009CB320802 (国家重点基础研究发展计划(973)); the National High-Tech Research and Develo