Computing spanning line segments in three dimensions.

P preserves the property of intersection; that is, a plane intersects P if and only if it also intersects ?. This paper gives a linear time algorithm for constructing ? for a polyhedron with N extreme vertices. If N is odd, the algorithm is optimal in yielding ? N/2?+1 spanning line segments. If N is even, it gives ( N/2)+1, which is optimal in some cases and nearly optimal in others.