From: cdshaw@cs.ualberta.ca (Chris Shaw)
Subject: Re: PHIL: 2D vs. 3D (Was Re: INDUSTRY: FLASH! "VPL . . .")
Originator: hlab@stein.u.washington.edu
Organization: University of Alberta
Date: Mon, 14 Dec 1992 06:38:41 GMT


In article <1992Dec11 rwzobel@unity.ncsu.edu (Rick Zobel) writes:
>In article <1992Dec5 marca@ncsa.uiuc.edu (Marc Andreessen) writes:
>>getting rid of the current fixation on datagloves (and stereo goggles, for
>>that matter) would be one of the best things that could happen to VR.
>>...
>>Do you expect people to wear HMDs??

Yes, if it buys you something. One of the researchers in our lab is dead
set against HMD's because they are too intrusive, and he is setting about
proving that a HMD is not needed. For his application area (3D mecanical
CAD), he may be right. This isn't to say he's in favour of 2D interaction
techniques for 3D CAD - far from it -- it's just that he doesn't feel that
interface radicalism is necessary.

I'm not sure that he's right about this in general, because I think that
there are some applications which pretty much demand the VR style, such as
building walkthrough, design evaluation, entertainment, and see-through VR
for complex assembly training tasks.

>Let me crudely re-word this...
>
>getting rid of the current fixation on graphics (and real time rendering, 
>for that matter) would be good

>The real challenges of VR lie in perceptual psychology, spatial cognition
>and computer-machine interface techniques, interfacing to Real Work

I must say that I agree in general. However, one should be careful not to
declare that one's personal niche is the entire field, and that people who
study anything else are misled. I also agree with Andreessen's point that
HMD fixation is a bad thing, and that one should study databases.

My reply to this is that ALL of these things need study. Depending on the
application, all the results may be useful. The perceptual psych angle will
be useful in designing better 3D user interfaces, and I encourage everyone
to do this type of work.

But let's not forget a few things. You can't really talk about VR (Computer
Generated Immersive Environments) without having the Real-time 3D graphics
available. All the perceptual psychology in the world ain't going to help
if you can't get the image to the user's eyes. 

And there's two ways to do immersion: Head-mounted displays, or displays on
the walls. The Air Force has been using the display on the wall style
of flight simulator for 20 years, and they want HMD technology because it
holds the promise of being cheaper.

So what I'm saying is that to some extent, the glove-and-goggle fixation is
justified, because it forms the substrate on which you can build. This in
turn rests on the assumption that the VR style is going to be very useful
for some (not all) tasks, and that there is enough money in these tasks to
warrant glove-and-goggle development, at least for the short term.

>I am effectively comparing perspective drawings, non-interactive animations 
>(video), interactive animations (Virtus Walk-Through) and CGIE's (VR 
>Walkthrough) as they relate to the understanding of architectural space. 

Can you get Virtus Walkthrough to walk as fast as the CGIE walkthrough?
How many updates/sec? What kind of things have you found? What's the real
difference?

>but unless they are used to learn from, when the technology finally
>develops, there will be nothing there worth developing....)

The mere fact that there you have noticed some leverage (I assume) in moving 
from non-immersive to immersive walkthrough is probably enough to make the
technology useful to a wide range of people. Just because it doesn't ride
your or my particular hobby-horse doesn't mean its worthless.

>Rick Zobel
>NCSU School of Design
>Architecture Department
>rick@oscar.sod.ncsu


--
Chris Shaw               University of Alberta
cdshaw@cs.UAlberta.ca    CatchPhrase: Bogus as HELL !