Re: CCL:Inside or outside of a polyhedron

From: brian ( ( at ) ) bert.chem.wsu.edu (Brian W. Beck)
Subject: Re: CCL:Inside or outside of a polyhedron
Date: Tue, 16 Apr 1996 08:35:45 -0700 (PDT)

 Alexander Golbraikh wrote:
 :
 :
 :
 : Take any ray beginning at the given point. Count the number of
 : points of intersection of this ray with polyhedron surface. If it is
 : even, then the point is outside the polyhedron, if it is odd, then inside.
 : One precaution: the ray may slide on some edges of the polyhedron.
 :
 : Best regards,
 : Alexander Golbraikh
 :
 :
        ^ /
        |/
        <     As you say, the ray may slide. The "o" point at the
 left is
        |\    outside the "polyhedron" yet passes through the
 polyhedron
        | \   surface only once if you send the ray only through the vertices
        o  \  defined by... say the Calphas of a protein.
 	-Brian
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