Xref: utzoo comp.graphics:16672 sci.math.num-analysis:1668
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!motcsd!silma!reddy
From: reddy@silma.com (Reddy)
Newsgroups: comp.graphics,sci.math.num-analysis
Subject: Degenerate surfaces
Message-ID: <1991Mar18.213610.18736@silma.com>
Date: 18 Mar 91 21:36:10 GMT
Reply-To: reddy@.UUCP ()
Distribution: usa
Organization: Silma, Inc. Cupertino CA
Lines: 13


Does anybody out there know a better way to approximate partial derivatives
(specifically normal - du X dv) on parametric surface S(u,v) at a degenerate point. At
the degenerate point S(u0,v0) either du=0 or dv=0 or du=dv=0.

You could offset parameter u0 or v0 by small value (epsilon) and evaluate the surface,
but that is not what I want.

Any references would be appreciated.

Thanks
        Reddy
        e_mail - reddy@silma.com