Path: utzoo!utgpu!water!watmath!clyde!att!rutgers!ucsd!ucbvax!decwrl!sun!pitstop!sundc!seismo!uunet!mcvax!ukc!stl!stc!praxis!kolmogorov!johnr From: johnr@praxis.co.uk (John Richards) Newsgroups: comp.graphics Subject: Re: Algorithm or pointers to references wanted Message-ID: <2533@newton.praxis.co.uk> Date: 24 Jun 88 08:35:09 GMT References: <242@granite.dec.com> Sender: news@praxis.co.uk Reply-To: johnr@praxis.co.uk (John Richards) Organization: Praxis Systems plc, Bath, UK Lines: 18 In article <242@granite.dec.com> pjs@granite.dec.com (Philip J. Schneider) writes: > > I need an algorithm to break up a self-intersecting polygon into >a set of convex polygons. A search through some of the "standard" >references and texts has yielded several algorithms that work on >non-convex polygons, but fail if the polygon is self-intersecting as well. > Have a look at: J.Nievergelt and F.P.Preparata, "Plane-sweep algorithms for intersecting geometric figures", Communications of the ACM 25(10), pp.739-747 (1982) They describe the class of plane-sweep algorithms which work by incrementally advancing a "front" across a plane in one direction, processing as you go. Their algorithm processes self-intersecting polygons and produces non-intersecting ones, though their terminology is different. John Richards