POV-Ray : Newsgroups : povray.general : Dispersion real/simulated... Server Time
5 Aug 2024 16:15:06 EDT (-0400)
  Dispersion real/simulated... (Message 1 to 3 of 3)  
From: Marc Champagne
Subject: Dispersion real/simulated...
Date: 2 Sep 2002 16:22:14
Message: <Xns927DA5F4DA8D8POVMIKA@204.213.191.226>
Hi Folks,

Since POV-Ray simulates dispersion and allows values of 1 or higher, how
does one take a real dispersion value like quartz (0.013) and apply it to
the dispersion keyword?

Is it safe to assume that dispersion 1.013 will give us a simulated 
dispersion of 0.013?

Thanks

Marc Champagne


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From: Christoph Hormann
Subject: Re: Dispersion real/simulated...
Date: 2 Sep 2002 17:08:25
Message: <3D73D349.3106ABAC@gmx.de>
Marc Champagne wrote:
> 
> Hi Folks,
> 
> Since POV-Ray simulates dispersion and allows values of 1 or higher, how
> does one take a real dispersion value like quartz (0.013) and apply it to
> the dispersion keyword?
> 
> Is it safe to assume that dispersion 1.013 will give us a simulated
> dispersion of 0.013?

Technical dispersion values are often given as the *difference* in ior
between two wavelengths while POV-Ray uses the *ratio* of ior values at
both ends of the spectrum.  Therefore your formula is approximately
correct although the wavelengths used for defining the dispersion are not
necessarily the ends of the visible spectrum.

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 13 Aug. 2002 _____./\/^>_*_<^\/\.______


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From: MIKA
Subject: Re: Dispersion real/simulated...
Date: 2 Sep 2002 18:09:05
Message: <Xns927DB811FAF87MIKAJustMeInc@204.213.191.226>
Christoph Hormann <chr### [at] gmxde> wrote in
news:3D73D349.3106ABAC@gmx.de: 

> 
> 
> Marc Champagne wrote:
>> 
>> Hi Folks,
>> 
>> Since POV-Ray simulates dispersion and allows values of 1 or higher,
>> how does one take a real dispersion value like quartz (0.013) and
>> apply it to the dispersion keyword?
>> 
>> Is it safe to assume that dispersion 1.013 will give us a simulated
>> dispersion of 0.013?
> 
> Technical dispersion values are often given as the *difference* in ior
> between two wavelengths while POV-Ray uses the *ratio* of ior values
> at both ends of the spectrum.  Therefore your formula is approximately
> correct although the wavelengths used for defining the dispersion are
> not necessarily the ends of the visible spectrum.
> 
> Christoph
> 

Then it's as close as one can get to reality without splitting atoms :)

I've been educating myslef on the art of cutting diamonds lately (for
the sole purpose of ray-tracing) and am trying to apply all know factors
into the design.

So far so good, I shall have some diamonds for sale shortly (completly
weightless, these are *rare*), I'll surely post some images in p.b.i.
for all to see. 

Thanks

Marc


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