Re: Portals vs Links

Linas Vepstas ([email protected])
Thu, 11 May 1995 11:27:02 -0500


Hi,

> Going through an enclosed doorway will take you to a fresh level, and you will
> only see the last level through the doorway. With this type of link, you could
> walk around that doorway and still stay in the same level; only when you move
> through it would you be taken to another level.

I guess I can't quite tell if you are making an artistic comment, or a
technical comment. Certainly today, you can draw a large rectangle (doorway),
and use WWWAnchor so that when clicked on, you get to the other side. I guess
that in the back of my mind, I always assumed that the place you came from (the
geomterical data) would still "be there" (i.e. still be in your browser). Thus,
you could dolly/pan/zoom around with your camera, and lo& behold, the old place was still
there, back behind the door.

Now, I have to admit, in my mind the spec was rather vague about this; I also have
to admit I haven't read the latest spec.

As to "wide open spaces", I beleive the "correct" way of doing these is to WWWInline
whatever you want to put into these spaces, and to surround the WWWInline with
level-of-detail constructs, so that if the object is very far away (small), you
don't inline anything, you merely draw a small-- ah triangle, whatever.
By not inlining, you save the network traffic.

Again, my last feeling about the spec was that it was rather vague about how the
level-of-detail construct worked.

I beleive that before any work on vrml 2.0 starts, someone
should put together a cookbook of how-to examples
-- doorways through which you can walk through, and back again,
(with a different vrml page on each side of the dooor),
-- doorways through which you can only walk through, and never back again,

-- doorways where you walk through once, but when you try to go back, you end up in a
different place,
-- aDoorways that "close" (have a rectangle drawn, so that door looks
closed"),
-- archways (doorways with out a "door", but different sites on each side of the
arch; astanding on one side of the arch, you can see the other;)
-- an open-plan city, where buildings materialize/pick up detail when you get close
to them, (where each "building" is on a separate vrml page) etc.
-- A room ("museum") where objects don't become detailed until you "touch"
them (click on them) (again, each object should be a separatevrml page t
that is brought in with wwwinline and/or with wwwanchor).
-- Another kind of portal chamber where clicking on an object takes you
to an entirely different place, with no traces of the old place to be found/seen
anywhere.
-- How about an example where clicking on one object "matrializes" a second
object next to it? (i.e. clicking on one object trigger a wwwanchor, which pulls in the
second objects, displaced by a few "inches". )

I think all of this is more or less possible today, with the
spec the way it is; however, going through this excercise might find weaknesses
in the way people think wwwInline & WWWAnchor work. It may well show up "bugs"
(umm features?) in the browsers(s).

(I cna only say I wish I was in a position to do this. I'm not).

--linas

P.S. sorry for my smelling ^H^H^H^H^H^H spelling. My terminal program is kinda broke
today. which is making editng is really hard.

Sincerely,
Linas Vepstas

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<a href="http://w3.austin.ibm.com/~linas">
Linas Vepstas Graphics Architecture
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11400 Burnet Road External Phone: 1-(512)-838-1116
Austin TX 78756-9260 mail: [email protected] </a>
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