Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!mit-eddie!bu-cs!halleys!applix!scott
From: scott@applix.UUCP (Scott Evernden)
Newsgroups: comp.sys.amiga,comp.graphics
Subject: Re: Amgia World Ray-tracing article...
Message-ID: <448@applix.UUCP>
Date: Fri, 24-Apr-87 10:09:29 EST
Article-I.D.: applix.448
Posted: Fri Apr 24 10:09:29 1987
Date-Received: Sat, 25-Apr-87 20:45:38 EST
References: <629@puff.WISC.EDU>
Reply-To: scott@applix.UUCP (Scott Evernden)
Distribution: comp
Organization: APPLiX Inc., Westboro MA
Lines: 40
Xref: mnetor comp.sys.amiga:4034 comp.graphics:543

In article <629@puff.WISC.EDU> upl@puff.WISC.EDU (Future Unix Gurus) writes:
> The other statement I found particularly objectionable was his statement that
> "we now have the ray tracing time down to an hour. Considering professional
> systems running on Crays...take 2or 3 minutes, our Amiga isn't doing
> badly". Maybe not, but he forgets to mention that when doing animation, which
> was a major thrust of his article, the time for a single frame gets multiplied
> many times over, and thus time delays do as well. Using my pocket calculator,
> and figuring the 24fps of standard film, I get a 14400 hours of
> continous calculation for a ten minute film, or about 2 YEARS of continous
> calculation!!!!

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.  It is true, frames from that film regularly contain
several thousand objects.  I think if you do any amount of investigating, you
will find that the CG folks are quite used to tying up their machines in this
fashion.

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.

Now, certainly it must be clear that DBW_Render, and the other program used to
generate "Juggler" would benefit VASTLY if a 68881 was around?  (V1.2 AmigaDOS
and Manx C 3.4a support it, too.)

The first Mandelbrot generators I saw on my Amiga would take almost 2 minutes
to plot the entire set.  But recently, a PD demo copy of MANDFXP would do the
same set (presumeably using the same arithmetic) in about 5 seconds!!  Doesn't
this suggest that one could invest some effort in improving the math used and
realize some radical improvements?

In short, I'm completely confident that within a year's time, some
enterprising folks will do exactly what has been doubted here, and that is to
get a couple of Amigas, with 68881s maybe, produce some marvelous ray-traced
animations, and blow away the crowds at SIGGRAPH.

-scott