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Chris Huff wrote:
> In article <3890E367.572DF8C2@mindspring.com>, ric### [at] geocities com
> wrote:
>
> > I was modeling a glass bottle I keep on my desk a few days ago and
> > realized that there was one aspect of it that I have been unable to
> > produce in POV: the different densities of the glass. Hopefully you
> > will know what I am talking about. The bottle that I have is not of
> > consistent thickness, so the refraction is not uniform. Short of
> > modeling the thing out of blobs, does anyone know how to simulate the
> > different densities of the glass? Or possibly add a feaure that will
> > add ior_map abilities or something like that -- kinda like a color map
> > only with ior values if there isn't already a way to do this. Thanks.
>
> The cause of the waviness isn't different ior's to the glass, it is the
> varying thickness(which is different from the density). Try using a
> normal on the glass, something like a squashed bozo will make a ripply
> effect:
> normal {bozo 0.1 scale < 1, 0.15, 1>}
> POV currently does not have a way to calculate variable refraction,
> since that would require sampling the ray in several steps through the
> object or tracing curved rays. Someone might write a patch to do this
> someday, but none currently exist. And it would be the wrong solution to
> this problem anyway.
But a right solution for another problem.
I was looking at a test tube in my Chem lab yesterday, and noticed the
ribbons of variable refraction streaming through the liquid.
It would also be nice to simulate heat lines, and mirages in the desert...
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