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From: robert@texas.asd.sgi.com (Robert Skinner)
Newsgroups: comp.graphics
Subject: Re: renderman
Message-ID: <1991Jan16.235903.16144@odin.corp.sgi.com>
Date: 16 Jan 91 23:59:03 GMT
References: <1992@m1.cs.man.ac.uk> <2490@motcsd.csd.mot.com> <1991Jan7.143225.10246@pyro.ei.dupont.com> <240@coplex.UUCP> <2528@motcsd.csd.mot.com> <1991Jan12.033252.27767@odin.corp.sgi.com> <1991Jan15.213216.14138@nthropy.uucp>
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In article <1991Jan15.213216.14138@nthropy.uucp>, kelvin@nthropy.uucp
(Kelvin Thompson) writes:
|> In article <1991Jan12.033252.27767@odin.corp.sgi.com> robert@sgi.com writes:
|> >
|> >Renderman is a scene *specification* interface.
|> >It is independent of and separate from the actual rendering algorithm.
|> 
|> Actually, Pixar wants to have it both ways.  They call it a "Scene
|> Description Interface," but they own the trademark on the name and
|> have total, arbitrary control over use of the name.
|> 

Kelvin points out some valid points about how Pixar owns and controls
the way the name "RenderMan" is used.  I wasn't aware of this.

|> >Anyone may implement any kind of renderer that complies with the
|> >Renderman inteface: realtime, scanline, ray tracer, or crayons.  
|> 
|> Maybe not.  You have to obtain written permission from Pixar to 
|> market such a product.  On the one hand they say that anybody
|> can obtain such a written license.  But they also say:
|> 
|>    "Anyone that creates a computer program that includes any of
|>    the procedure calls from RenderMan...may refer to the program
|>    as 'using' or 'compatible with' the RenderMan interface, IF
|>    THAT STATEMENT IS ACCURATE."  [my caps; some paraphrasing]
|> 
|> Seems to me that last phrase gives Pixar room to yank permission
|> if you don't have a complete implementation.

Again, Kelvin is correct.  As some of my coworkers have pointed, the
way Pixar is now interpreting "compatible", excludes all but the most 
complete implementations.

|> 
|> Sounds like the good folk at Pixar have been spending too much time
|> in the company of lawyers.  (Wasn't it just a couple of months ago
|> that somesuch person as A.R. Smith got caught complaining that
|> "software patents and copyrights are stifling innovation" at the
|> same time that Pixar was locking up the patent on jitter sampling?)

Yes, sad, but true.  My posting reflected my understanding of the
*spirit* of RenderMan when it was defining.  In fact, Pat Hanrahan
compares it directly with PostScript, a "page specification language".
Its too bad that noble intentions get warped when viewed through the
corporate money-glasses.

I should hope that this doesn't deter others from implementing public
domain renderers and ray tracers that use RenderMan as input.  That
would seem like an ideal way to make all of our scene descriptions
portable, and would go a long way toward helping us compare the
relative merits of various renders.

|> 
|> -- 
|> -- Kelvin Thompson, Nth Graphics, Ltd.
|>    kelvin@nth.com   nthropy!kelvin@cs.utexas.edu

Robert Skinner
robert@sgi.com

     An overheard conversation:

	"Mach was the greatest intellectual fraud in the last ten years."

	"What about X?"

	"I said `intellectual' "