Visibility preprocessing for interactive walkthroughs

The number of polygons comprising interesting architectural models is many more than can be rendered at interactive frame rates. However, due to occlusion by opaque surfaces (e.g., walls), only a small fraction of a typical model is visible from most viewpoints. We describe a method of visibility preprocessing that is efficient and effective for axis-aligned or axial architectural models. A model is subdivided into rectangular cells whose boundaries coincide with major opaque surfaces. Non-opaque portals are identified on cell boundaries, and used to form an adjacency graph connecting the cells of the subdivision. Next, the cell-to-cell visibility is computed for each cell of the subdivision, by linking pairs of cells between which unobstructed sightlines exist. During an interactive walkthrough phase, an observer with a known position and view cone moves through the model. At each frame, the cell containing the observer is identified, and the contents of potentially visible cells ...

• Type: Conference
• Year: 1991
• Where: SIGGRAPH
• Authors: Seth J. Teller, Carlo H. Séquin
• Keywords: Architectural Models, Computer Graphics, Opaque Surfaces, SIGGRAPH 1991, Visible Cells