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From: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Newsgroups: comp.sys.amiga,comp.graphics
Subject: Re: Amgia World Ray-tracing article...
Message-ID: <2948@well.UUCP>
Date: Sun, 26-Apr-87 03:11:50 EDT
Article-I.D.: well.2948
Posted: Sun Apr 26 03:11:50 1987
Date-Received: Sun, 26-Apr-87 23:20:14 EDT
References: <629@puff.WISC.EDU> <448@applix.UUCP>
Reply-To: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Distribution: comp
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 45
Summary: DEC must be using Cray CPU's
Xref: mnetor comp.sys.amiga:4111 comp.graphics:551

In article <448@applix.UUCP> scott@applix.UUCP (Scott Evernden) writes:
>Why is 1 hour of CPU time per ray-traced frame regarded as untenable for film
>making?
>
>The animation "Andre and Wally B." was produced on a VAX11/780, and the time
>per frame was 1-2 hours.

	Wrongo.  As I understand it, the story goes like this:

	The software that computed Andre and Wally B. was indeed written on
a VAX-11/780 (named 'dagobah' I believe).  One fine day, they fired up the
software to compute one particularly messy frame.  They came back 24 hours
later to find that the picture was 1/3 finished.

	"This isn't good," thought one of the programmers, and through some
fast talking and just plain being nice, they managed to borrow a Cray XMP-48
from Cray Research.  Even the power of a Cray didn't create real-time
response.  It still needed 1-2 hours per frame.  Cray said it was Pixar's
fault for not vectorizing their code.

	Pixar now uses their own hardware for stuff.  I am pretty sure that
Luxo Jr. was computed with Pixar imaging systems.

>An Amiga is roughly equivalent in power to an 11/750, and I know that 750s
>(being the most popular of VAXen) have been used to do this sort of thing,
>as well.
>
	If it makes you feel any better, I understand that the Genesis Demo
from Star Trek II: The Wrath of Mr. Rork was computed on a VAX-11/7?0 with
rather respectable speed.

	My information comes from people I know inside Pixar.  I'll see if I
can't get an official response out of them.

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