Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!uakari.primate.wisc.edu!aplcen!uunet!mcsun!inesc!unl!unl!ray From: ray@fctunl.rccn.pt (Vitor Duarte & Sergio Duarte) Newsgroups: comp.graphics Subject: Line and Torus Intersection,Help! Message-ID: Date: 31 May 90 15:19:32 GMT Sender: news@fctunl.rccn.pt (USENET News System) Organization: Universidade Nova de Lisboa -- Lisbon, Portugal Lines: 24 I'm working in a ray-tracing project and I would like to include the torus as a primitive, my problem is that in order to find the points of intersection between a line and the torus, one has to know the roots of a 4th degree polinomial, as far as I know, there's a formula to determine this roots but it's a very nasty one, on the other hand one could use a numeric search ( binary search, etc). Does any one know which method is best? Thanks Sergio Duarte -- --- BITNET/Internet: ray@fctunl.rccn.pt +---------------------------------+ UUCP: ray@unl.uucp | Departamento de Informatica +----------------------------------+ | F.C.T. / Universidade Nova de Lisboa | +--------------------------------------------------------------------+