POV-Ray: Newsgroups: povray.general: Media and Photons

POV-Ray : Newsgroups : povray.general : Media and Photons		Server Time 5 Aug 2024 18:22:02 EDT (-0400)

From: Don Barron
Subject: Media and Photons
Date: 1 Aug 2002 16:15:09
Message: <web.3d4995f2bab79a0926e17e30@news.povray.org>

I've tried unsuccessfully to make scenes containing a lens focussing a point
light source show the rays in a scattering medium.  Does anyone have a
worked example in a pov file to help?

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From: Christopher James Huff
Subject: Re: Media and Photons
Date: 1 Aug 2002 18:04:19
Message: <chrishuff-6157AC.16552701082002@netplex.aussie.org>

In article <web.3d4995f2bab79a0926e17e30@news.povray.org>,
 "Don Barron" <ani### [at] ukonlinecouk> wrote:

> I've tried unsuccessfully to make scenes containing a lens focussing a point
> light source show the rays in a scattering medium.  Does anyone have a
> worked example in a pov file to help?

Look at the sample scene "optics.pov". It's in the "advanced" category.

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/

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From: Peter Popov
Subject: Re: Media and Photons
Date: 2 Aug 2002 01:12:46
Message: <l35kku8f2cv8sp1nmnug7ti84bjp14620h@4ax.com>

On Thu,  1 Aug 2002 16:12:08 EDT, "Don Barron" <ani### [at] ukonlinecouk>
wrote:

>I've tried unsuccessfully to make scenes containing a lens focussing a point
>light source show the rays in a scattering medium.  Does anyone have a
>worked example in a pov file to help?

How would you calculate the focal distance of the lens? I know it is
possible, but I don't know how.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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From: Tony LaVigne
Subject: Re: Media and Photons
Date: 3 Aug 2002 10:50:04
Message: <web.3d4bed07c99addae88d4e3910@news.povray.org>

Peter Popov wrote:
>On Thu,  1 Aug 2002 16:12:08 EDT, "Don Barron" <ani### [at] ukonlinecouk>
>wrote:
>
>>I've tried unsuccessfully to make scenes containing a lens focussing a point
>>light source show the rays in a scattering medium.  Does anyone have a
>>worked example in a pov file to help?
>
>How would you calculate the focal distance of the lens? I know it is
>possible, but I don't know how.
>
>
>Peter Popov ICQ : 15002700
>Personal e-mail : pet### [at] vipbg
>TAG      e-mail : pet### [at] tagpovrayorg
>

If the thickness of the lens is thin, I think the equation is
1/f = (n-1)*(1/r1+1/r2)
implying
f=1/{(n-1)*(1/r1+1/r2)}
where f is the focal length, r1 and r2 are the radii (sp?) of the spheres.
Tony

ton### [at] xenomechanicscom

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