Research on Computer Graphics

I've come to graphics in the year 2000 or so, and up to now I've been working on the following projects: I think the most significant, and the least succesful of these works was the Voxel Based Global Illumination Method. Basically, either poeple laughed at the idea, or they got mad at me for proposing such a radical approach. In any way, I had most difficulty publishing the thing. You can find a selection of papers of papers here, here and here. I have to admit we were slow to develop an interactive GPU version of the method. But never mind. Anyway, I am happy that some people are effectively applying some of the ideas.

Voxel Global Illumination

I've proposed a Voxel method for radiosity which was published as a poster at DGCI'2002. This is a completely new approach to global illumination. Basically, when we want to render a 3D scene, we approximate the surfaces of all the objects by a voxel surface (see the topological part of my research for a theoretical study of such discrete surfaces).
Once we have a discrete scene composed of voxels, encoded in an octree data structure, we discretize both surfaces and directions in the space in the continuous diffuse illumination equation (a classical equation used in radiosity), thus obtaining a discrete equation. As in classical radiosity, this discrete equation fullfils the requirements for applying (say) the Gauss-Seidel method, so we can numerically compute a solution of the equation.

This method has been much improved and made practical by my PhD student Pierre Chatelier, who made substantial optimization (providing optimal complexity for the visibility problem) and generalized the method for general BRDF. Lukasz Piwowar is currently improving the method a lot, by providing unaliased display which enables to reduce the number of voxels dramatically, and including all source code in a comprehensive software.

The method is being developped with a parallel algorithm for cluster by my student Rita Zrour, under the joint supervision of Fabien Feschet.
Here is a recent test image (sponza atrium) :


Here are a few more images, some of which are voxel global illumination combined with local specular models:


Here are the two first images, (with only lambertian reflexion and aliased display) ever obtained by our method
(at that time, the method was very slow and nobody took it seriously. It was published as a poster):

Result of radiosity, display by z-buffer


same scene as above, other viewpoint, display by z-buffer.