From: dstamp@watserv1.uwaterloo.ca (Dave Stampe-Psy+Eng)
Newsgroups: sci.virtual-worlds
Subject: Re: TECH: My standard is better than your standard. (LONG)
Date: 15 Aug 92 14:11:17 GMT
Organization: University of Waterloo
Originator: hlab@milton.u.washington.edu



dlwood@mailbox.syr.edu (David L Wood) writes:

>>11: Protected spaces--  If there's no reason for a visibility link, 
>>I think we can actually have a much looser region structure.  You might
>>even put the lab in a pup tent, or behind the call button (actually 
>>there's no need to put it anywhere in the world at all, if you seperate
>>visibility from other data links.  To call up someone on virtual TV, you
>>link their region to the window.  Not a huge extension, and moves away
>>from the rigid 3D space region idea (at least as an option) which IMHO
>>is a good idea.
>
>Sounds good, but how do you transfer your body into this "hidden"
>space? How is it addressed? Does it have a 128 bit universal
>coordinate counterpart?

No.  The "universal coordinate" only applies to regions/objects in the
world.  In effect, it is a seperate world.  You make links
(visibility, etc) by supplying a coordinate in each world, a
distance/rotation vector, and a scaling factor.  These links can
actually exist between objects in a single world, and may in fact form
the basis of region visibility relations in all cases.

For example, a set of rooms, or a windowed room, can only see certain
segments (subregions) and subsets of the set of rooms (regions) and
passage to the rooms is also restricted.  Why bother with the
coordinates of rooms you can't see?  Just specify those rooms you can
see or visit with visibility or access links to that region.  This is
highly efficient, and can support nested regions (with scaling) as
well.

>>15: Coordinate systems-- Why not scale within regions (assuming they're
>>nested) then you can translate to global coords using the scale factor.
>>No doubt on the first implementations a fixed scale will be used, but 
>>that's just because there's a lot of behind-the-scenes stuff to figure
>>out there.  The local software will not need upgrading as it should be
>>written to handle this in the first release.  Anyway, we will need better
>>than 1 mm in some regions and more than 4000 km in others.  Scaled nesting
>>lets this be done efficiently.
>
>I don't quite understand how this could be integrated into the router
>system? Again, how do you transfer your body and senses? It would be
>great to have different "pockets" of space with different coordinate
>systems, but how do you see one pocket from another? Does the router
>do the scaling around for you?

No: it supplies you with a link to the region, and sends objects in
that region's scale (??).  Then your machine selects its own arbitrary
scale and uses all the data to scale the objects to suit.  Lots of
flexibility internally, efficient externally.

>>17: Object control--  Not really clear-- does the winner get a message
>>before he can move the object?  Does the loser have the object fly out
>>of his hand?  Assume at least a 500 mS delay before answering, so that
>>the result will be visible.
>
>The winner would "see" no message, but his local software would
>receive one.  Well, the local software >could< display a message but
>that is for end-users' comfort.  The loser would probably receive a
>message, object owned by Mr. Armitage, or whatever.

What I was asking is: Can you move the object BEFORE your machine
receives the "OK" message, or do you rewind?  There could be a second
or two delay in message transmission, making the effects of the
decision very noticeable.

--------------------------------------------------------------------------
| My life is Hardware,                    |                              | 
| my destiny is Software,                 |         Dave Stampe          |
| my CPU is Wetware...                    |                              | 
| Anybody got a SDB I can borrow?         | dstamp@watserv1.uwaterloo.ca |
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Newsgroups: sci.virtual-worlds