[Sigia-l] QTVR

[Scott Paterson]

Just a qwik comment about QTVR.

QTVR provides the ability to make object movies as well as panoramas. Object
movies provide all the criteria Christopher is describing regarding the
ability of the user to manipulate their perspective. Object movies, as the
term sounds, are 3D models exported as .mov files. The interface is similar
to the panoramas in that the user clicks and drags and I think zooming is
possible. One big problem with object movies is file size. They're big
suckers. I made a super simple example(150x150px @ 1.8MB) for you here:
www.ramplab.com/proj/cube.mov

[sgp]

.
----- Original Message -----
From: "Christopher Fahey [askrom]" <askROM at graphpaper.com>
To: <Sigia-l at asis.org>
Cc: "'Listera'" <listera at rcn.com>
Sent: Wednesday, July 10, 2002 2:57 PM
Subject: RE: [Sigia-l] 3-D workflows


> Ziya wrote:
> > Do you consider QTVR 3D?
>
> I don't consider it a 3-dimensional dataset. QTVR is just a 2d image
> with fancy scroll mechanisms and fancy distortion algorithms meant to
> imitate a 3D perspective, but the data is still a "bitmap" of pixels
> with X and Y (no Z) coordinates (ignoring for now the color dimension).
>
> > How about a globe that revolves on its own axis in front of
> > you while you stay stationary?
>
> If the globe has relief mountains sticking out of it, and/or if the user
> can directly control the rotation along the X, Y, and Z axes, then yes.
> If it's just a rotating video loop, then no. The question is this: Is
> the globe a 2D map projected onto a sphere, or is it a 3D dataset like a
> CAD model.
>
> > Is the ability of the viewer to move physically and/or
> > virtually in a given
> > space relative to a specific object the sole differentiator?
>
> Yes, with a caveat: the user does not need to move their body, they
> simply need to be able to move their *perspective* on the dataset.
> Causing a 3D model of a tree to rotate is sematically the same as
> walking around the tree. The differentiator, then, is the ability to
> change perspective on the dataset.
>
> 2D images can be entirely grasped by just looking and not ever moving
> the perspective. A QTVR image can convey the same information even if it
> were just a still image of a panorama - if you think about it, the QTVR
> technology actually inhibits the user's ability to view all the
> information in the dataset! If one was able to (like the scene in blade
> runner) look *behind* the objects depicted in a QTVR image, then it
> might qualify as a 3D dataset.
>
> The viewer must be able to move and rotate their perspective in more
> than 2 dimensions: X, Y, and Z. I'm not trying to set up some kind of
> strict rule system about what is 3D and what is not - both of your
> examples are clearly intended to blur the distinction between 2D and 3D
> datasets, and hence to trip me up! I think we can agree that there is a
> significant qualitative difference between an isometric projection of a
> building that you can only look at and a scale model of a building that
> you can stick your head into and peek around the corners.
>
> -Cf
>
> [christopher eli fahey]
> art: http://www.graphpaper.com
> sci: http://www.askrom.com
> biz: http://www.behaviordesign.com
>
>
>
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