Eikonal Rendering: Efficient Light Transport in Refractive Objects

May 25, 2007 at 9:28 pm (Papers)


From ACM SIGGRAPH 2007, “Eikonal Rendering: Efficient Light Transport in Refractive Objects by Ivo Ihrke, Gernot Ziegler, Art Tevs, Christian Theobalt (Max-Planck-Institut für Informatik), Marcus Magnor (Technische Universität Braunschweig), Hans-Peter Seidel (Max-Planck-Institut für Informatik).

The idea: When light propagates through material, it bends and scatters based on the properties (refractive indices, scattering, extinction, etc.) throughout. To properly render an object as participating media (not just surface shading as in a BRDF), you have to use an expensive simulation such as photon mapping, in order to capture all of the correct behavior. This paper takes the route of precomputing how the light bends and scatters into a volume and evaluating this information at runtime. The authors compute the wavefront of the light advancing through the material by solving a simplified form of the Eikonal equation. I haven’t exactly followed how these simplifications are made.. partly because I haven’t totally absorbed the paper yet and partly because my diff eq knowledge is a bit limited. But it appears that are able to compute this volume much faster than any GPU computation of the regular eikonal (Won-Ki Jeong has done some interesting work in this area) that I’ve seen so far. The only drawback to this approach is that it takes a few seconds to recompute this light propagation whenever you move the light. Oh well.. it’s going to be a couple of years before this light propagation can be modeled in real-time.

figure of ray bending

Project page w/paper.


1 Comment

  1. Art Tevs said,


    I am one of the authors of this paper. If you are interested in the detailed version of this approach, then you could take a look into my master thesis. In this thesis I explain this paper in detail. Also the derivation of the rendering equations is explained in more or less understandable way 🙂
    I am currently in the finishing phase, so in couple of weeks the thesis will be online on my homepage.

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