[jfrancis]

Immersive reality SHOULD use spherical perspective on a spherical screen, because spherical perspective on a spherical screen looksjust like the real world, as long as you are inside the sphere.

Affected, and treeshark -- I'm curious. Can you explain to me what your preferred situation would be in, say, an art gallery full of paintings.

Paintings on the inner surface of a sphere, or inner surface of a cylinder?

Paintings with curved lines?

Big flat paintings with curved lines that you are only allowed to see through a small (but movable) window so that panning over them makes you seem to be "looking around" ?

Something as yet unspecified?

Business as usual, but with a recognition that there is extra distortion at the edges?

What's missing from the way things are now?

[treeshark]

[Affected]

Treeshark, what method did you use to generate this grid:
http://www.treeshark.com/images/Persp/Grid.jpg

I'd be very interested in a way to create such grids myself, with the line density etc. of my choosing.

[Affected]

actually jfrancis, for me this is more just a pet perversion than something of serious consequence. I like perspective. I don't like the distortion of linear perspective at higher fields of view. I'm not saying I mean to start making 180-degree panoramas, but I'd like to be able to have, say, 110 degree fields of view in paintings and have them look a bit better than with linear. As for the actual presentation of paintings, I have no objection to the old slab-on-a-wall approach. Spherical surfaces for paintings are fine for immersion but a little inconvenient in most places.

It would be interesting to do a really big painting with spherical perspective and view it from such a distance that the perspective would match the one your eyes give. It should match up even if painted on a planar surface.
(technically a small painting viewed closer up should work too but that would require very small details)

[treeshark]

affected, I rendered a gridded floor in maya but any 3d program would do it. Then I rendered a 45 degree pass in 5 degree intervals. ie: 0 degrees 5 degrees etc. I did this once with the camera horizontal and then looking downwards in 10 degree steps.
In the end I only used couple of these as the bit of the sphere verticly up and down was not useful. I then stitched these together in Photoshop. Then by flipping you can make a whole 360 or 180 or whatever. The whole thing is then duplicated and rotated 90 degrees. Which gives you your vertical vanishing points. One important factor is that if your grid is say 100 wide then your camera needs to be either 200 400 above the floor or the two grids wont line up.
Here's one section with my crude stitching visable

Play around with it you'll soon see how it works. If you use a small section you can do very nice things that do not appear to the viewer to be different but would be distorted otherwise.

[Affected]

ah, so it WAS stitched. It looked so clean to me I figured it might've been done straight out in some app. Thanks for the info and that picture!

[treeshark]

Here's an interesting link that covers much of the ground in this topic.
http://www.uni-ak.ac.at/opengeom/dld/extreme.pdf

[jfrancis]

If these shots are doctored, then somebody has the fisheye rendering thing down!

http://movies.collegehumor.com/media/movies/b-ball-e-mail.mov