Team Alice

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

Section: New Results

Scientific visualization

Participants : Luc Buatois, Matthieu Chavent, Bruno Lévy, Nicolas Ray, Bruno Vallet.

Geometry textures

Last year, we introduced geometry textures , a novel geometric representation for surfaces based on height maps. The visualization is done through a GPU ray casting algorithm applied to the whole object. At rendering time, the fine-scale details (mesostructures) are reconstructed preserving original quality. Visualizing surfaces with geometry textures allows a natural LOD behavior. This year, we explored new applications of geometry textures, and published them in [18] . We extend the application of geometry textures beyond their initial motivation (mesostructure visualization). Thus, we present three new applications: rendering of solid models, geological surfaces visualization and surface smoothing.

Visualization of CAD and industrial models

Figure 8. The powerplant model with recovered cylindrical primitives displayed with our GPU-based ray-caster.

We continued our work on the visualization of large-scale CAD models for industrial structures. In the specific case of the oil and gas industry, structures comprise a huge number of pipes. We developed techniques to recover the equations of cylinders, cones and toric sections from triangle soups, and a GPU-oriented ray-caster for high-quality and efficient rendering of these structures. We published the method in [21] . Some results are shown in Figure 8 .

Molecular visualization

Figure 9. Left: a garmicidin molecule visualized with our high-quality realtime raycaster on the GPU. Right: ambient occlusion is a global illumination effect that enhances the perception of depth (here computed for a DNA molecule in real time).

We continued our work on interactive molecule visualization. Our system visualizes the so-called MSS (Molecular Skin Surface). Our approach is based on a GPU ray-caster, that directly uses the equation of the MSS (a piecewise quadric surface), rather than discretizing it into triangles (Figure 9 -left). This year, we improved the efficiency of the algorithm and published an article in the Journal of Molecular Graphics [17] . We also implemented an efficient version of a specific global illumination effects (screen-space ambient occlusion), as shown in Figure 9 -right. This was done in the frame of the Ph.D. of Mathieu Chavent and the training period of Cécile Poisot.


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