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Visualization of very complex scenes can be significantly accelerated using <italic>occlusion culling</italic>. In this paper we present a visibility preprocessing method which efficiently computes potentially visible geometry for volumetric viewing cells. We introduce novel <italic>extended projection</italic> operators, which permits efficient and(More)
Some very impressive results have been obtained in the past few years in plants and trees image synthesis. Some algorithms are largely based on the irregularity and fuzziness of the objects, and use fractals, graftals or particle systems. Others focus on the branching pattern of the trees with emphasis on morphology. Our concern here is the faithfulness of(More)
Many problems in computer graphics and computer vision require accurate global visibility information. Previous approaches have typically been complicated to implement and numerically unstable, and often too expensive in storage or computation. The Visibility Skeleton is a new powerful utility which can efficiently and accurately answer visibility queries(More)
Visibility problems are central to many computer graphics applications. The most common examples include hidden-part removal for view computation, shadow boundaries, mutual visibility of objects for lighting simulation. In this paper, we present a theoretical study of 3D visibility properties for scenes of smooth convex objects. We work in the space of(More)
We analyse some recent approaches to the global illumination problem by introducing the corresponding <i>reflection operators</i>, and we demonstrate the advantages of a two-pass method. A generalization of the system introduced by Wallace <i>et al.</i> at Siggraph '87 to integrate diffuse as well as specular effects is presented. It is based on the(More)
Quadtrees constitute a hierarchical data structure which permits fast access to multidimensional data. This paper presents the analysis of the expected cost of various types of searches in quadtrees — fully specified and partial-match queries. The data model assumes random points with independently drawn coordinate values. The analysis leads to a class of(More)