"Warp" <war### [at] tagpovrayorg> wrote in message 
news:472460ad@news.povray.org...
> Paul Bourke <pau### [at] uwaeduau> wrote:
>> A stereoscopic camera for PovRay.
>>    http://local.wasp.uwa.edu.au/~pbourke/modelling_rendering/stereopov/
>
>  I don't completely understand
> http://local.wasp.uwa.edu.au/~pbourke/modelling_rendering/stereopov/offaxis.gif
>
>  The two arrows on the "eyes" are completely parallel, as if indicating
> that the "eyes" are looking at infinity.

Naturally, the eyes can look at many different point pairs in the picture. 
The points where the arrowed directions hit the plane is just one such pair, 
and this particular one would indeed have infinite distance.

However, I think the arrowed lines are more meant to show off that the image 
planes for the two eyes are in fact identical, which could not have been 
achieved using a standard perspective camera, unless you used a matrix to 
skew the camera. Any perspective image has only one point that is 
undistorted in the sense that a sphere looks like a circle and not like an 
ellipse. Normally, in standard perspective POV-Ray camera that is not 
skewed, this point is in the centre of the image. However, as illustrated in 
the above diagram, the images for the left and right eyes have this 
undistorted point to the left and to the right of the centre of the image 
respectively. This makes it possible for the two projection planes to be 
parallel (and even be identical in this case).

> However, the fields of view would indicate that the "eyes" are actually 
> looking
> at the center of the projection plane.

I don't think it indicates that.

>  The example image at the bottom of the page also confuses me.
<snipped>

You seem to have figured it out yourself. :)

Rune

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