Single scattering in refractive media with triangle mesh boundaries

Bruce Walter, Shuang Zhao, Nicolas Holzschuch, Kavita Bala
2009 ACM SIGGRAPH 2009 papers on - SIGGRAPH '09  
teapot pool glass tile glass mosaic amber cuboctahedron bumpy sphere straight-line approximation Figure 1 : The bending and focusing of light in refractive media creates distinctive rich details. The top row shows single scatter surface caustics in glass and water. The bottom row shows complex volumetric refractive caustics in amber and glass. All images were generated using the method in this paper, except the bottom right which used the common straight-line approximation that neglects shadow
more » ... ay refraction. Abstract Light scattering in refractive media is an important optical phenomenon for computer graphics. While recent research has focused on multiple scattering, there has been less work on accurate solutions for single or low-order scattering. Refraction through a complex boundary allows a single external source to be visible in multiple directions internally with different strengths; these are hard to find with existing techniques. This paper presents techniques to quickly find paths that connect points inside and outside a medium while obeying the laws of refraction. We introduce: a half-vector based formulation to support the most common geometric representation, triangles with interpolated normals; hierarchical pruning to scale to triangular meshes; and, both a solver with strong accuracy guarantees, and a faster method that is empirically accurate. A GPU version achieves interactive frame rates in several examples.
doi:10.1145/1576246.1531398 fatcat:fdturd24jbemlbdagrrkhvn6f4