半透明物体漫散射效果的实时绘制与材质编辑  

Real-Time Editing and Rendering of Translucent Materials with Homogeneous Diffuse BSSRDFs

作　　者：王锐[1] Ewen Cheslack-Postava Rui Wang David Luebke 华炜[1] 彭群生[1] 鲍虎军[1] 

机构地区：[1]浙江大学CAD＆CG国家重点实验室,杭州310058 [2]Department of Computer Science, Stanford University, Palo Alto, CA 94305 USA [3]Department of Computer Science, University of Massachusetts, Amherst, MA 01003 USA [4]NVIDIA CORPORATE, Santa Clara, CA 95050 USA

出　　处：《计算机辅助设计与图形学学报》2008年第8期993-1000,共8页Journal of Computer-Aided Design & Computer Graphics

基　　金：国家自然科学基金(60633070);国家“九七三”重点基础研究发展规划项目(2002CB312101,2002CB312102)

摘　　要：半透明物体透明效果的真实感绘制是近年来研究的热点,提出一种针对半透明物体漫散射效果的实时真实感绘制与材质动态编辑方法——基于双向表面散射反射率函数(BSSRDF)的Dipole近似.通过主元分析将Dipole近似中的漫散射材质函数分解为与形状相关函数和与半透明材质相关函数的乘积形式;利用该分解表示,在预辐射传输的实时真实感绘制框架下,通过对散射传输的预计算来实现在多种光源环境下对半透明物体材质的实时编辑.此外,还提出一种对预计算辐射传输数据在空域上进行二次小波压缩的方法,利用表面点在空间分布位置的相关性,在保证绘制质量的前提下,大大压缩了数据,提升了绘制效率.实验结果表明,文中方法可以生成具有高度真实感的半透明效果并保证实时的绘制速度.A method for real-time editing and rendering of translucent materials with homogeneous diffuse bidirectional surface scattering reflectance distribution function （BSSRDF） is proposed. Based on the Dipole approximation of BSSRDF, we derive a new factoring form of the diffuse scattering function and project the geometry related factor onto a limited set of basis functions by employing principal component analysis, these geometry related parts can be pre-computed. As a huge amount of sample data for evaluating the diffuse scattering of a translucent surface will be involved, we further exploit the spatial coherence of the sample data on a parameterized spatial domain by non-linear wavelet transformation. We show realistic, real-time translucent material editing and relighting under a variety of lighting conditions, such as environment lighting and local area lights.

关 键 词：半透明材质编辑 双向表面散射反射率函数 主元分析 Dipole近似 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]