surfacesvisible

Surfacesvisible is a term used in computer graphics to describe the set of surfaces that are visible from a particular viewpoint. While not a standardized term in major reference works, it is commonly used informally to refer to the results of visibility computations on a three-dimensional model or scene. The concept is central to efficiently rendering or analyzing 3D data by distinguishing visible surfaces from occluded ones.

In practice, surfacesvisible is determined through hidden-surface removal techniques. Common approaches include depth testing (z-buffering), which records the closest surface at each pixel and discards farther ones, and back-face culling, which discards polygons whose normals face away from the camera. More advanced methods, such as occlusion culling or portal-based visibility, aim to skip entire regions of a scene that do not contribute to the final image. In ray tracing, visibility is established by tracing rays and identifying surfaces that intersect the rays before any occluders.

Surface representations in which surfacesvisible is computed typically involve polygon meshes or triangulated surfaces, with per-surface attributes such as normals, materials, and textures. A visibility mask or boolean flag per surface can be used to store the result, enabling rendering or analysis to proceed only on visible elements.

Applications of the concept include real-time rendering, where efficiency hinges on quickly identifying visible surfaces, and preprocessing steps in modeling, visualization, and collision detection. Limitations arise from transparency, complex occluders, or dynamic scenes, requiring more sophisticated algorithms to maintain accuracy and performance.

See also: hidden surface determination, z-buffering, back-face culling, occlusion culling, ray tracing.