虚拟场景中特殊效应的分形实现

【作者】 袁秋林；

【导师】 王建宇；

【作者基本信息】 南京理工大学 ， 控制理论与控制工程， 2003， 硕士

【摘要】 在快速准确地生成各种虚拟地理环境的时候，通常要模拟场景中的各种静态和动态特殊效应，其中包括云雾、水流、海面、波浪、地形、树木等，从而增强虚拟场景的真实感和实时性。而这些特殊效应从形状和状态上来说是不规则的，如果运用传统的几何学理论很难比较真实地实现这些对象，而且计算量比较大，生成速度慢。近几年来迅速发展的分形几何学和粒子系统能较好地解决不规则形态物体的仿真建模问题，可以从少量的数据生成复杂的自然景物图象，其真实感和实时性效果非常好。 在实际的模拟过程中，结合计算机图形学技术，在现有算法和技术的基础上，不断地改进，最后达到了预期的模拟效果。基于L系统以及迭代函数系统的特性提出了改进的三维树木模型双迭代生成算法来实现三维树木模型的模拟，而在三维地貌模型的模拟中，提出了改进的基于分形插值的Diamond-Square算法实现了云团、二维纹理地表、三维地形等模型。而对于上述动态对象，运用粒子系统技术以及动力学理论模拟了波浪、爆炸等模型。更多还原

【Abstract】 When we try to model a variety of virtual scenes promptly and accurately, various stationary and moving objects in them must be realized to the life such as tree, terrain, cloud, water, smoke etc. The shapes of these specific effects to be modeled are all irregular. It is difficult to model them by means of traditional geometry theories, and its computation quantity is too enormous while its modeling speed is too slow. In these years, fractal and particle system are to be developed quickly, and they are well used to model these irregular objects mentioned above. We may use them to model complicate images and come up to the expected effects through little computation quantity.In this paper, based on the existing algorithms, I expound the corresponding well-modified modeling algorithm in terms of the modeled object and achieve the expected realization effects. I apply the modified double-iterated modeling algorithm to realize the three-dimension tree model successfully based on L-system with IPS.To realize the terrain model, I expound the improved Diamond-Square algorithm in light of fractal interpolation and use it to model cloud, two-dimension texture terrain surface and three-dimension terrain. As for the moving objects, I combine particle system and kinetics to realize sea wave and blast model with flying colors.更多还原