Visibility Processing

Last Updated February 22, 2010

Visibility Processing Questions

Identify 4 problems with the z-buffer technique
What are the two goals of an efficient visibility processing system
Compare octree subdivision with regular spatial subdivision, in particular identify the advantages of Octree over regular subdivision
How can an octree be used to determine visibility
Outline the steps used to construct a BSP tree of a scene
Outline the steps needed to extract a visibility ordering from a BSP tree
Create a BSP tree from the following faces. Process the faces in alphabetical order, each faces' label is on the faces' positive side.

In the BSP tree created above, clearly identify the location of the viewpoint. Generate a near-far ordering of faces based on the position of the viewpoint.
How do we determine which side of a plane a point is on?
Given a plane defined by a point (4,5,8) and a normal vector (0.5,0.8,0.0), determine if the point(6,8,1) is on the positive or negative side of the plane.
How does changing the direction of a camera affect the ordering produced by a BSP tree?
How are faces in the BSP tree culled against the view volume?
How are portals used?
Describe a system to identify potential occluders at build time
Describe an approach to quickly check if an object is occluded or not occluded by a face
Describe an method to accommodate moving objects without modifying the BSP tree
Outline a procedure to restore a BSP tree after a node has been removed