RE: 3D SPEX

[P3D Greg Marshall <greg.marshall@xxxxxxxxxxxxxxx>]

Duane Perry wrote:
<snip>
>The instructions said to set the
>refresh rate higher (100-120Hz) so I tried to find out if my home
>system would go higher and what little documentation I had seemed
>to indicate it was already about as high as it could go.  I still
>held out high hopes for my brand new Gateway 2000 system but 
>despite spec sheets for the video card and monitor that boasted of
>refresh rates of 120 Hz and many references in the documentation
>to "increasing the refresh rate" I could find no instructions for
>doing so.  After much web browsing and several phone calls I was
>told by a Gateway tech that they did not "support" higher refresh
>rates than the standard 85 Hz.  I am glad I did not buy this 
>system from the spec sheet expecting to use these glasses.  If you
>are considering buying liquid crystal glasses, make sure you have
>the equipment and expertise to make it all work.  I am still 
>hopeful that I will be able to sit someone down at my PC someday
>and treat them to a hi-res full screen slide show of interesting
>images, possibly even some of my own.
>                                      Duane Perry

I think we'd all agree that you have to be very careful in reading
manufacturers' specs.  I've been designing display controllers
for over 15 years and guess I've seen just about every misleading
spec possible.

There are two major items to consider here:  (1) Refresh rate is 
usually limited by the monitor, which is also usually the most ex-
pensive part of the display system, so pick it carefully.  The max
refresh rate (vertical sweep rate) itself is usually not the limiting
factor unless you are using relatively low resolution.  The hori-
zontal rate max may limit the refresh rate for a given resolution.
(2) The max refresh rate will only be as high as the "weakest"
element (monitor, controller, and software).  Annoyingly, it is very
often the software that gets in the way - the programmers just
didn't put in the modes even though the hardware can support it.
(Not to bitch about programmers, they just don't have the time to
do more than the tasks defined by management).

I share your dream that someday we'll be able to show great 3D
on common display devices, but you should be aware of some
of the problems:  (1) High refresh rate and high resolution translate
pretty directly to high cost with CRTs - I don't think this can be got
around.  (2) Stereo images on CRTs exhibit ghosting due to the
long exponential decay of the phosphors.  This can be solved
very easily by changing the phosphor composition.  But will they
do it to satisfy those of us who want stereo displays?  No.  (3)
CRTs will eventually be replaced by various flat panel displays
which (guess what?) are even more problematic for stereo!

BTW, check SELL-3D for a special offer to P3D members!

Greg Marshall, Canopus


------------------------------