SP-Octrees Visualization Using Impostors

SP-Octrees (Space-Partition Octrees) allow a multiresolution representation of polyhedral objects, and have been successfully used in progressive transmission. Nonetheless, the SP-Octree is a solid modeling structure, intended to solve problems as solid intersections and point inclusion tests. At intermediate levels of the SP-Octree, the visualization is a rough approximation of the object due to the fact that grey nodes are shown as the convex hull of the part of the solid included in that node. In this paper we present an approach to use SP-Octrees for adaptative visualization, that improves the visualization of these multiresolution models by applying impostors over those planes of the hierarchical structure that belongs to the convex hull but are not part of the solid boundary (ficticious planes). By doing so, it is possible to obtain a better approximating visualization of the object, although the maximum LOD is not used. At every moment, the impostor is selected depending on the viewpoint.