Diffusion and Multiple Anisotropic Scattering for Global Illumination in Clouds
Stanford Linear Accelerator Ctr.
Mail Stop 26
2575 Sand Hill Road
USA 94025 Menlo Park CA
Ryo Miyazaki, Kei Iwasaki, and Tomoyuki NishitaUniversity of Tokyo
The diffusion method is a good approximation inside the dense core of a cloud, but not at the more tenuous boundary regions. Also, it breaks down in regions where the density of scattering droplets is zero. We have enhanced it by using hardware cell projection volume rendering at cloud border voxels to account for the straight line light transport across these empty regions. We have also used this hardware volume rendering at key voxels in the low-density boundary regions to account for the multiple anisotropic scattering of the environment.
Diffusion approximation, multiple anisotropic scattering, global illumination, participating media, clouds.