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DRAFT A.I.MEMO 					            JULY 1973


                OCCULT  -  A HIDDEN LINE ELIMINATOR.

                          Bruce G. Baumgart


ABSTRACT:

	OCCULT marks the faces, edges and vertices  of  a  polyhedron
scene  as  either  visible  or hidden with respect to a camera model.
Edges that were at first partially visible are split into  pieces  so
that each piece is either fully visible or fully hidden.

Like Warnock's algorithm, OCCULT has two parts: a recursive outer
part  that splits an image until there are only  afew
edges in it or it has become too small; the inner part is the real hidden line
eliminator.
The inner part of OCCULT is based on the idea of comparing each  edge
with  all  the other edges and hiding as much as possible when a pair
of intersecting edges is discovered.