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From: frerichs@ux1.cso.uiuc.edu (David J Frerichs)
Newsgroups: sci.virtual-worlds
Subject: Re: We need a new language
Message-ID: <15638@milton.u.washington.edu>
Date: 1 Feb 91 18:22:57 GMT
References: <15594@milton.u.washington.edu>
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Organization: University of Illinois at Urbana
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In article <15594@milton.u.washington.edu> pete_leaback@cix.compulink.co.uk (Pet
er Leaback) writes:

[things wiped out]
>A VR system has to display a frame at 50 or 60 Hz or else one tends to
>get sick. If one standardises the object destription and rendering, each
[things abolished]

Have you used a VR sytem before...?  No VR system in existence has a frame
rate that high. (if there is, I will be quite impressed.) 
This is not a exact figure, but the VPL system only has
a frame rate of about 8Hz per eye (I have heard it is lower that that even).
Systems I have used have rates higher than that (no numbers allowed) but
still they don't come close to 60Hz (I hope that you are talking about
the frame rates of both eyes, not just one.)
Your statement that one tends to get sick at a low frame rate is false
(IMHO). Please forgive my forwardness if you have experienced this sickness
first hand.  Low frame rates only make for choppy movement, not flickering.
It just means that the frame stays in the buffer longer.  When you are
doing computer animation, you don't just flash a picture and take it
away, you hold a picture up til the next one is ready.  High frame rate
means smoother motion, not less flicker (flicker has to do with the display
hardware frequency).
I think that alot of people in the newsgroup have been making statements
that they think sound good at the time but aren't supported by any facts,
not a good practice if we are to get to the root of some of the problems
that face our industry.  If you are going to make wide statements about
tech, do your homework, or make sure you say that this is your opinion,
not a solid fact.

[dfRERICHS
 University of Illinois, Urbana         Designing VR systems that work...
 Dept. of Computer Engineering          Networked VR.
 IEEE/SigGraph                            _    _    _
 frerichs@ux1.cso.uiuc.edu              _/_\__/_\__/_\_
 frerichs@well.sf.ca.us                  \_/  \_/  \_/                     ]