42. The apparatus of claim 31, further comprising: hierarchical bounding boxes, wherein all bounding boxes which are completely inside an occluded bounding box are occluded.
42. The apparatus of claim 31, further comprising: hierarchical bounding boxes, wherein all bounding boxes which are completely inside an occluded bounding box are occluded. 43. The apparatus of claim 42, further comprising: a set of normals comprising occluder volumes for each object in a scene, wherein a set of normals comprising occluder volumes for said hierarchical bounding boxes at each group node in a tree are also maintained, wherein if a bounding box at a parent node in said tree is occluded, then all of its progeny are also occluded; and wherein if said parent is not occluded, then said progeny are checked individually.