ABSTRACT

Actually, this is only the data-driven side of scene management. When people design a virtual world, a three-dimensional scene, they tend to think in ontological terms and group entities according to logical relationships rather than purely

spatial ones. Sometimes, ontological hierarchies tend to resemble spatial organizations, but not always. This can be demonstrated in the example of Figure 9.1 where the same scene-a house complex-is partitioned in an ontological manner to form a hierarchy of elements. In the architectural version of a scene organization (Figure 9.1(b)), elements are grouped according to function, material, and consistency with traditional floor plans. Obviously, the spatial organization of this scene does not facilitate culling and efficient traversal of the hierarchy for rendering but better serves the specific application in terms of clarity of entity decomposition.