"Killroy Quartermaine" <iam### [at] yahoocom> wrote:
> So I was thinking about modelling a fresnel lens using CSG, and I have two
> questions.
>
> 1. Is there any reason why a fresnel lens wouldn't actually work in POVRay?
>
> 2. Because of the way they're built, what I need is torii, except instead of
> round, I need them to be diamond-shaped. like, uh, for the second value of
> "round". Is there any way to do this without going beyond the realm of
> primitives? I'm not comfortable enough with light and finishes and whatnot to
> get into making any kind of complex base shapes yet.

You could take a bunch of spheres, chop them into the requisite bits, and then
put them all into a single union. This is the basic idea behind a fresnel lens,
if I read the Wikipedia article correctly. You would basically be simulating (or
re-enacting) the actual construction process behind the earliest lenses.

I don't think you want torii, as the horizontal curvature would be too great.
Well, none of the graphics in the WP article show torical lenses, just cleverly
assmbled spherical sections.

As for the rest, I can't say as I've never tried to simulate optics in POV-Ray.

-Mike

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