Dan Johnson wrote:

> But if you use a parabola and a point light to make a parallel light, only the
> light that bounces off the parabola is parallel, you have to block the rest of
> the light somehow.

conical spotlight

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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David Fontaine wrote:

> Dan Johnson wrote:
>
> > But if you use a parabola and a point light to make a parallel light, only the
> > light that bounces off the parabola is parallel, you have to block the rest of
> > the light somehow.
>
> conical spotlight
>
> --
> David Fontaine  <dav### [at] faricynet>  ICQ 55354965
> My raytracing gallery:  http://davidf.faricy.net/

Looked in documentation don't see it.  Unless you mean the spotlight source, but
that has an umbra, and penumbra.  I don't know how to make that light source act
like a perfect cone light.

Dan Johnson

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Dan Johnson wrote:
> 
> Looked in documentation don't see it.  Unless you mean the spotlight source, but
> that has an umbra, and penumbra.  I don't know how to make that light source act
> like a perfect cone light.
> 

The penumbra can be eliminated by setting the "falloff" and "radius" parameters
to an equal value. This should give what I'd call a "perfect cone light".
I'm not sure what you mean by it having an umbra. Obviously it will cast
shadows.

-- 
Margus Ramst

Personal e-mail: mar### [at] peakeduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg
Home page http://www.hot.ee/margusrt

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