
4.2 Geometric State 247
(a) (b)
Figure 4.5 A situation where a better-fitting bounding volume leads to culling, but a worse-
fitting one does not. (a) The bounding sphere is not tight enough to induce culling.
(b) The bounding box is tight enoug h to induce culling.
On the other hand, if most of the objects are typically inside the frustum, in which
case you get the combined cost of the query and drawing, the sphere bounding vol-
umes look more attractive. Whether or not the better-fitting and more expensive
bounding volumes are beneficial depends on your specific 3D environment. To be
completely certain of which way to go, allow for different bounding