where can one find these tests you did?

Nathan Kopp wrote:
> 
> "Ammar Al-Allak" <a.a### [at] ueaacuk> wrote...
> > Hi
> >
> > Fromt what I understand, wave independent scattering is not physically
> > accuarate since it doesn't take the wavelength into account, but to be
> > honest
> > I don't really understand the principal of that. (Some sort of a detailed
> > explanation would help!!)
> 
> Making it fully wave-dependent would be nearly (if not fully) impossible,
> because POV uses the RGB format to store all colors.  This means that the
> specturm is discritized into three steps - red, green, and blue.  This
> leaves very little information to be used by wavelength-dependent features.
> 
> However... scattering can be color-dependent.  Note that I say
> color-dependent and not wavelength-dependent... they are different.  Used
> properly, you can make color-dependent scattering look a whole lot like
> wavelength-dependent scattering.  For example, some work has been done using
> scattering type 4 to simulate earth's atmosphere (using scattering type 2
> for clouds within the atmosphere).  Using a bluish color for scattering,
> with an appropriate density and an extinction of 1.0 generates a nice blue
> sky.  And when the light source (sun) is rotated around this virtual earth,
> nice pink and red sunsets appear almost magically.  I did some tests a while
> back (based on someone else's original code) and it worked very well (though
> it was _very_ slow).
> 
> > I also need the precise algorithm POV Ray uses for Rayleigh scattering and
> > how it could be modified so that it becomes Wave dependent.
> 
> The source code can be downloaded from www.povray.org.  That, plus the docs,
> should be sufficient for determining the exact algorithm.
> 
> -Nathan

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