## Section: New Results

### Rendering

Participants : Laurent Alonso, Bruno Lévy, Nicolas Ray, Rodrigo Toledo.

#### Geometry textures

For highly-detailed geometry, triangle mesh is not the most memory-efficient representation. In the frame of his Ph.D. [Oops!] , Rodrigo Toledo developed algorithms to convert a scanned mesh into a set of height fields and to display them on the GPU [Oops!] . Figure 9 shows the different phases of the algorithm. We first use Alliez et al.'s Variational Shape Approximation [25] to partition the model, then we generate a set of overlapping charts (to minimize boundary artifacts). Finally, we iteratively subdivide the charts that cannot be projected on a plane. By analogy with “geometry images”, we call the so-constructed representation a “geometry texture”. Rodrigo Toledo obtained the best paper award for his paper [Oops!] at the SIBGRAPI conference.

#### Material-Space Texturing

The ALICE team has developed several algorithms to generate texture coordinates [6] , [9] , [8] , that have now become standards. However, texture coordinates are only one aspect of texturing. More importantly, creating the texture itself is a tedious and difficult task, that requires much user interaction. For this reason, we started a cooperation with Greg Turk's team (GeorgiaTech), leading expert in the domain of texture synthesis. We developed a new representation of texture (that we call “material space”), that can represent materials that smoothly vary over a surface. We also developed algorithms to generate a tileable texture, and an interactive parameterization method to apply those textures onto the model. The result is shown in Figure 10 . From a set of small photographs (called “exemplars”), our algorithm generates a tileable texture, with an additional “material coordinate”. This material coordinate allows continuously morphing from one material to the other.