"gadoid" <hansen at tkgate.org> wrote in message 
news:web.46e07a2dc3c951274e9a00c00@news.povray.org...
>
> Hmmm.  It seems to me to be more of a refraction-like effect, and changing
> "crackle" to anything else does not change the way it renders.  I've 
> placed
> an image at http://www.tkgate.org/povray/electrons.png (this is a test 
> shot
> for a larger scene) that has the problem in it.   When you look through 
> the
> clear portion of the "electrons", you can see that the  waves seem shifted
> as though the sphere had an 'ior' in it.
>

Well I've tried a whole load of things and I'm still not able to see exactly 
what's causing it.
I don't think it's refraction because the background (e.g. the checkered 
plane) is not distorted in any way.

I've done a small animation, rotating the sphere and it looks like clouds of 
darkness and extra brightness are passing over the surface of the sphere as 
it rotates, though the clouds don't seem to be rotating with the sphere. 
When the sphere is above the checkered plane it starts as transparent at 0 
degrees, becomes most perturbed at 90 degrees and becomes clear again at 180 
degrees of rotation.

When the sphere is embedded halfway into a checkered plane the outer shell 
goes transparent at 0 and 180 degrees still, but at 180 degrees the normals 
from the part of the surface of the plane within the sphere appear reversed. 
ie the ones that have only passed through the front surface of the sphere. 
Indeed, if at 180 degrees the normal values are reversed each time the ray 
passes through the surface of the sphere, it would explain why the rays 
passing through both the front and back surfaces appear normal.

I'm not sure if any of this helps, but I thought I'd share my findings 
before switching off for the night.

Regards,
Chris B.

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