An Algorithm for Hidden Line Elimination
The algorithm presented causes the elimination of
hidden lines in the representation of a perspective 
view of concave and convex plane-faced objects on the
picture plane.  All the edges of the objects are 
considered sequentially, and all planes which hide every
point of an edge are found.  The computing time 
increases roughly as the square of the number of edges.
 The algorithm takes advantage of a reduced number 
of concave points and automatically recognizes if only
one object with no concave points is considered. 
In this last case, the result is obtained in a much simpler way.
CACM April, 1969
Galimberti, R.
Montanari, U.
