From: Juan R. Sáenz-Diez (Yuri) (jrsdm++at++acm.org)
Date: 09/03/2000 12:03:01
There are several papers explaining the topic. One that I found interesting
because it explains it but also proposes an alternate way of avoiding it
when you just cannot go to 60/60 is "Multiple Image Suppresion in a Low-Cost
Visual System" by Ronald G. Moore. I found a reprint of this in SIGGRAPH'98
Course Notes #20. Try rmoore++at++es.com . Good luck.
Regards,
Yuri.
----- Original Message -----
From: Dick Rous <dick++at++sgi.com>
To: Hui Li <huili++at++mail.sc.cninfo.net>; <info-performer++at++sgi.com>
Sent: Sunday, September 03, 2000 3:16 PM
Subject: RE: Is it because of Phase lock?
> If your framerate is less than the refresh rate of your dispay (e.g. 30
vs.
> 60 Hz.),
> the what you see are so calledmultiple images. These occur when objects
have
> a substantial angular velocity with respect to the eye. It is a visual
> "deceiption", caused
> by the snowflakes being twice rendered in the same spot, then shift to the
> next position in
> time, where again they are rendered twice.
> You will notice the same effect when your simulation moves the eyepoint
> along a road.
> Thin vertical objects alongside the road seem to "double" when the angular
> velocity increases.
> The solution is to make your framerate equal to the refresh rate. (by
> optimising your
> database or/and adding gfx hardware) .:-)
>
> Cheers,
>
> Dick.
> __________________________________________________________
> Dick Rous SGI - European Technical
> Support
> email: dick++at++sgi.com
> phone: +31-35-6423160 fax: +31-35-6423162 VNET: 955-6868
> __________________________________________________________
>
>
>
> -----Original Message-----
> From: Hui Li [mailto:huili++at++mail.sc.cninfo.net]
> Sent: 02 September 2000 15:02
> To: info-performer++at++sgi.com
> Subject: Is it because of Phase lock?
>
>
> I try to simulate snow flakes on a 2 cpu onyx2.
>
> what I do is draw the snow flakes at the draw call back. However, what i
saw
> on the screen
> the flakes becomes doubled, each flakes seems be draw twice on it's drop
> pass, when i slow
> down the speed or freeze simulation, it looks
>
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---- Por favor, acuse recibo -- Please acknowledge receipt ---- Juan R. "Yuri" Sáenz-Diez Vis-Sim & VR Consultant +34 630 815 772 jrsdm++at++acm.org
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