Thanks Harold!

You've described my problem successfully!
Alex and slime were able to solve my problem.
After reading your description?
;-)))

- Vic -

---------------------------------------------------------------

"Harold Baize" <bai### [at] itsaucsfedu> wrote in message
news:3ccb18a8@news.povray.org...
>
> Thorsten said:
> > But they are not wrong!  As soon as your eyes focus on something this is
> > precisely the effect you have.  What you are trying to generate is an
> image
> > infinitely far away, so your eyes have to look nearly parallel.
>
> That is true, our EYES see the images this way, but our brain does not.
> I don't think he is trying to generate an image at infinity, but expects
it
> to look as if it were at infinity, because he (we) can't recreate the
> viewing experience of looking at a scene close to our face. Also, it
> is convergence that is the issue, not focus. The eyes cross (converge)
> on close objects.
>
> Our eyes begin to converge from parallel at about 2m (six feet), we
> don't notice it until things are close, like 0.3m. Our perception
> adjusts for geometric distortion and other issues when we focus
> close and converge our eyes, for example we ignore the distant
> background which is out of focus and can't be stereoscopically
> fused (it is a "double image"). Minor keystone distortion is likewise
> ignored. When we view a pair of images rendered from this geometry later
> on the computer screen it is disturbing because we don't have the
> ability to ignore or compensate for the distortions because we are
> viewing it in a different context and with parallel eyes focused at a
> different depth. That is why one should always generate stereo
> pairs with parallel cameras. The issue becomes how to set the
> "stereo window" which is the virtual frame created by the edge of
> the image. I set the stereo window by trimming the left and right
> edges of the stereo pairs.
>
> > As you keep talking about viewport limits I suppose your problems
> > understanding the correct behavior come from the use of z-buffer based
> > algorithms.  It is indeed true that for those when rendering stereo
views
> the
> > viewport is commonly moved, but this is only an approximation necessary
to
> > avoid having to transform the whole scene in order to keep the rendering
> fast.
> > The image you call "bad" is actually the correct image for a stereo view
> of a
> > human eye and the "good" one a simple approximation similar to those
> commonly
> > produced by a z-buffer based stereo renderer.
>
> I know nothing of z-buffer based algorithms, but I would argue that the
> image
> Vic labeled as "good" was rendered correctly for stereo viewing, and the
> "bad" image was rendered accurately for what the eye sees, but not for
what
> the brain perceives or for stereo viewing.
>
> Harolddd
>
>

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