COMPRESSING ASPECT GRAPHS

Visibility Processing

In large architecture models or urban environments (ie. cities), building facades often times cause a lot of occlusion. Using the idea of linearized aspect graphs above, further compression of the aspect graph can be made by using these facades and bounding volumes of a spatial data structure (eg. octree, k-d tree, bsp) as input.

	PRECOMPUTATION
	--------------
	1. Find all "large" facades in the database.
	2. Build a spatial data structure.
	3. Build an aspect graph using only bounding volumes of the data structure and large facades as input.

	RUN-TIME
	--------
	..same algorithm as above..

Further reductions in the number of planes can be made by using the notion of separating and supporting planes.