Editing Ray casting (section)

== In–Out Ray Classification ==

[[File:Ray in binary solid construction.jpg|thumb|left|Ray in binary solid construction]]
This figure shows an example of the binary operators in a composition tree using “+” and “−” where a single ray is evaluated.

The ray casting procedure starts at the top of the solid composition tree, recursively descends to the bottom, classifies the ray with respect to the primitive solids, and then returns up the tree combining the classifications of the left and right subtrees.

This figure illustrates the combining of the left and right classifications for all three binary operators.
[[File:Operations on ray results.jpg|thumb|center|The three binary operations: union (+), intersection (&), and difference (−)]]