Downsampling Scattering Parameters for Rendering Anisotropic Media

摘要

Volumetric micro-appearance models have provided remarkablyrnhigh-quality renderings, but are highly data intensive and usuallyrnrequire tens of gigabytes in storage. When an object is viewedrnfrom a distance, the highest level of detail offered by these modelsrnis usually unnecessary, but traditional linear downsampling weakensrnthe object’s intrinsic shadowing structures and can yield poorrnaccuracy. We introduce a joint optimization of single-scatteringrnalbedos and phase functions to accurately downsample heterogeneousrnand anisotropic media. Our method is built upon scaledrnphase functions, a new representation combining abledos andrn(standard) phase functions. We also show that modularity can bernexploited to greatly reduce the amortized optimization overheadrnby allowing multiple synthesized models to share one set of downsampledrnparameters. Our optimized parameters generalize wellrnto novel lighting and viewing configurations, and the resultingrndata sets offer several orders of magnitude storage savings.