"Kenneth" <kdw### [at] earthlinknet> wrote in message 
news:web.4bde94823d08c812ae92d9930@news.povray.org...
>
> (I'm curious about the gas-giant planet's appearance; really HUGE objects 
> that
> are far off in the distance show a sort of visual 'compression'. There's 
> really
> nothing that we see on earth that would be similar, of course, so it's 
> hard to
> visualize. But the 'effect' would, I think, be the same as if you 
> squashed-down
> your textured planet in z. (Squashing it in-line with the camera.) OR, 
> placed it
> WAY off into space while increasing its size accordingly. The only similar
> example I can think of is the planet Saturn, when it's viewed NOT edge-on
> through a telescope. It's an experiment I've been meaning to try in 
> POV-Ray, but
> haven't gotten around to.)

The only squashing effect I'm aware of is when viewing through a telescope, 
which is the same flattening effect you get with a zoom lens, this image has 
a non-zoomed field of view so you wouldn't see squashing.

The squashing is because the more you zoom in, the narrower your field of 
view, the closer to parallel the edges of your view become, so the less 
perspective you have in the image. With a wide field of view objects further 
away get a lot more perspective, so get smaller quicker, a zoomed lens keeps 
things much more similar sizes.

The planet in my image is placed by positioning it relative to the camera, 
then moving it away and scaling it up as you suggest (in fact the camera is 
at <0,0,0> so I just scale the planet). However this does not alter the 
appearance of the planet, any ray traced toward it will still hit the same 
part, and it won't appear any more flattened (because it is physically 
bigger by the same amount that it's been pushed away).

You know, it's probably easier to just show you. Here's a simple scene, the 
second image shows the same scene viewed from 5x further away, with a camera 
zoomed in appropriately.

-- 
Tek
http://evilsuperbrain.com

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