From brian |-at-| bert.chem.wsu.edu Tue Apr 16 11:47:08 1996 Received: from cheetah.it.wsu.edu for brian -8 at 8- bert.chem.wsu.edu by www.ccl.net (8.7.1/950822.1) id LAA02042; Tue, 16 Apr 1996 11:41:33 -0400 (EDT) Received: from bert.chem.wsu.edu (bert.chem.wsu.edu [134.121.43.22]) by cheetah.it.wsu.edu (8.6.13/WSUit-1.1) with SMTP id IAA25464; Tue, 16 Apr 1996 08:41:20 -0700 Received: by bert.chem.wsu.edu (AIX 3.2/UCB 5.64/4.03) id AA22114; Tue, 16 Apr 1996 08:35:45 -0700 From: brian:~at~:bert.chem.wsu.edu (Brian W. Beck) Message-Id: <9604161535.AA22114 "-at-" bert.chem.wsu.edu> Subject: Re: CCL:Inside or outside of a polyhedron To: golb%!at!%osi.lanet.lv Date: Tue, 16 Apr 1996 08:35:45 -0700 (PDT) Cc: chemistry;at;www.ccl.net In-Reply-To: from "Alexander Golbraikh" at Apr 16, 96 11:50:50 am X-Mailer: ELM [version 2.4 PL24] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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 -- ============================================================================= | .---------.| Brian W. Beck | E-mail Addresses: | |/\ | || Biochem/Biophysics | brian: at :bert.chem.wsu.edu | || \\ WSU || Washington St. Univ| brian_beck#* at *#wsu.edu | |\ - *|| 206 Fulmer | URL http://elmo.chem.wsu.edu/~brian | | | || Pullman, WA, USA | VOICE (509) 335-4083 | | \___________|| 99164-4660 | FAX (509) 335-9688 | =============================================================================