From: John Eagan <76130.2225@CompuServe.COM>
Subject: Re: DESIGN: Doors between virtual worlds
Date: 10 Aug 92 15:10:26 EDT



Bob Pendleton (bobp@hal.com) writes: 

>> (quoting me, stuff deleted) ...... as part
>> of the standards for any sort of networked VR, a set of basic
>> attributes for a "world", covering things like Scale, Gravity,
>> blablabla.
>
>Too restrictive.
>
>No reason why a world has to have gravity. I should be able to define
>objects that accelerate anything within say 10 meters of the object in
>any direction the object likes. This way I can build a Mobius strip
>jogging tracks or hallways that twist all over the place while
>maintaining local "up" as perpendicular to your current location.
>
>I should be able to get rid of gravity completely and just have sticky
>walls...
>
>Virtual worlds are not models of the physical world. But they can be.

Last sentence, agreed, completely. In fact, that's one thing that I
wish was not such a sticking point in general conceptual discussions
of "what VR is and will be". VR is not necessarily a "real world"
simulation, and in fact I'd be much more interested in a virtual
environment that was _not_ a model of the "real world", for the most
part. The most interesting possibilities of VR, to me, lie in the
potential for abstract environments that have little to do with the
"Real World". That's why I suggested having a packet of attributes
sent to a user entering a "portal", to tell the machine at the users
end "what's what in _this_ World", such as what the scale is and other
parameters (is this particular World the size of a house, or is it a
"space" that's space in the astronomical sense (no ground,
astronomical dimensions, 0 gravity, etc...) The idea is, to not make
it restrictive at all, by making sure that when one enters a World,
they get the setup of that World. No gravity? Fine. Open space with a
body somewhere in it that has it's own gravity that begins to act upon
objects within a certain distance? Great, define the gravity of the
World as zero, and then make the gravity attributes of that body in
there part of the parameters for that particular object that is that
body.

The idea, which I didn't elaborate on enough, is to _not_ restrict
things, as much as possible, by making discrete Worlds, with their own
characteristics, and have those individual discrete Worlds accessible
through Rob J.'s "portals", so that the overall "Universe" would be as
I described in my earlier post, a relatively tight cluster of some
simple objects that mark where the "portals" are.

Besides opening things up greatly on a conceptual "World design"
level, this sort of approach would get us away from some of the
problems being wrestled with here, with suggestions like having
128-bit data values so you can cover anything from microscopic
dimensions to light-year distances in one humongous virtual world.
Taking the approach of discrete Worlds accessed through portals in a
Universe would be a simpler and more flexible way of doing things, I
would think, whether on a PC system or a massive internet system.

For the "low-end/desktop PC" avenue, things would be simplified by
having a Universe with a sort of matrix of objects(simple spheres,
icons, whatever) marking Worlds, and then reading in a data file for a
particular World upon entry to the associated portal marked by one of
those spheres/icons/whatever.

For a network VR system, especially on a broad scale, this approach
seems, IMHO, like the only _practical_ way of doing it. Individual
Worlds in the net (the Universe) would be analogous to internet sites,
with small markers like suggested earlier in a 3d grid/matrix,
analogous to site addresses in the current net system.

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*John Eagan                         "humans is funny critters.." *
*VR section leader                                   -me         *
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