Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!sunic!liuida!isy!lysator.liu.se!zap
From: zap@lysator.liu.se (Zap Andersson)
Newsgroups: comp.graphics
Subject: Re: Renderman and trimmed surfaces
Keywords: shading,Pixar,rendering,surfaces
Message-ID: <548@lysator.liu.se>
Date: 1 Apr 91 14:41:34 GMT
References: <3667@autodesk.COM>
Sender: news@isy.liu.se (Lord of the News)
Organization: Lysator Computer Club, Linkoping University, Sweden
Lines: 40

pierre@Autodesk.COM (Pierre Malraison) writes:


>Renderman sipports a wide variety of surface types, but none of them are allowed to
>be trimmed.

First, are we discussing here the STANDARD Renderman, or a particular implem-
mentation, SUch as MacRenderman or Autodesk Photorealistic Renderman Renderer?

The STANDARD supports trim curves very well. I read from page 249 in my
issue of the "Renderman Companion":

Trim Curves

Using an optional capability defined under the RenderMan Interface, and 
application can cut out arbitrary regions of a non uniform rational
B-spline (NURB) surface. 

It then goes on to explain Trim-curves and the RiTrimCurve() interface call.

So ewhere's the problem?


>1) Has anyone come up with a reasonable way to display trimmed surfaces
>(e.g. a NURB with a hole in the midddle) in Renderman?

>2) If not, is it planned for any future revision of Renderman.
>More generally,besides CSG what about B-reps?


>-- 
>Pierre Malraison
>U.S. Snail: Autodesk ,Inc. 2320 Marinship Way,Sausalito CA 94965
>e-mail:         pierre@acad.uu.net
>Opinions expressed above purely personal.
--
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