Conservative Visibility Determination for Architectural Scenes

In this article I present a conservative visibility determination algorithm, particularly suited for interactive walkthroughs in architectural scenes. This algorithm is able to determine which parts of the scene are visible during an interactive real-time walkthrough. The algorithm consists of an off-line part, which preprocesses the scene, and an on-line part, which determines the potentially visible faces for a given viewpoint. The algorithm uses a heuristic, which tries to maximize the number of found occluders, to guide the spatial subdivision. The faces of the cells that intersect the scene after the subdivision are used as occluders. During the interactive walkthrough, the nodes of the scene are recursively tested against a buffer that stores the occluders of drawn cells.