Method for creating spatially balanced bounding volume hierarchies for

Abstract

Disclosed is a method for processing an arbitrary collection of objects, forming a complex structure, into a hierarchy of bounding volumes, from a root volume bounding all objects, to sub-volumes bounding individual objects or assemblies thereof, for use as successive approximations to said objects in a computer generated display. The method includes the first step of creating a bounding volume for each of the objects. Selected bounding volumes are then processed through a combining algorithm determining whether or not, based upon a geometric relationship between the bounding volumes and the higher level, root volume, the selected bounding volumes can be combined. If it is determined that the bounding volumes can be combined, a new bounding volume is created with the combined volumes comprising sub-volumes thereof. This process systematically repeats and attempts to combine all sub-volumes. The combining algorithm preferably allows a combination if the volumes of the combination of the sub-volume is smaller than a fixed percentage of the parent volume. When a pair can combine, it is replaced by a box bounding volume that contains the pair as sub-volumes, and the process continues. In this way, a bounding volume hierarchy for all objects and assemblies within a complex structure is created.