Colloquy Cycle on Thursday, July 22, 2004 - 15:00

Over the past years, impostors and image based simplification have been proposed to replace complex geometry with simpler meshes and appropriate replacement textures. Along this path, the Billboard Clouds approach approximates the global shape of an objects with a small set of planes and uses semi-transparent textures to capture finer details such as silouhettes for example. The problem is cast as a geometric cover, where a minimal set of planes is searched to intersect "regions of validity" of the model's faces. In view-independent billboard clouds (where the BC simplification must be usable for any viewpoint), those regions are defined by spheres around the vertices indicating the maximum displacement allowed during simplification. In view-independent cases (where the BC simplification is to be used for a given viewcell), the definition of the validity region involves an accurate computation of the reprojection error. In this talk, we will briefly present the view-independent billboard clouds and will then introduce our recent results on their extension to the view-dependent case.