Conservative visibility preprocessing for complex virtual environments

Presents an approach to visibility culling. We propose a conservative visibility preprocessing method for complex virtual environments. The proposed method deals with general 3D graphical models and invisible polygons jointly blocked by multiple occluders. The proposed method decomposes volume visibility from the predefined volume into the area visibility from rectangles surrounding predefined volume. Then, to handle the volume visibility, we solve the area visibility problem. The proposed method expresses area visibility information into 3D space and keeps it with a BSP (binary space partitioning) tree. Area visibility information is image plane information for every viewpoint within the view rectangle. To express the area visibility information in 3D space, we present a modified ghost polygon and a method for reducing dependency between axes in the view rectangle. The proposed method has been tested on several large-scale urban scenes, and has shown its effectiveness.