Team Alice

Overall Objectives
Scientific Foundations
Application Domains
New Results
Contracts and Grants with Industry
Other Grants and Activities

Section: New Results


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

Geometry textures

Figure 9. Geometry Textures: We developed algorithms to convert a scanned mesh into a set of height fields, and algorithms to display these height fields in real-time on the GPU.

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

Figure 10. Textured models using our “material-space texturing” approach. A morphable and tileable texture is generated from the exemplars (small images) and applied onto the model using our interactive parameterization algorithm.

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.


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