Daren Scot Wilson wrote:
> 
> It is a bad thing that the dispersion patch has a hard-coded spectrum.  What we
> need is user-defined spectra, and then I won't ever be troubled by such
> questions.   And clever artists could then do some weird things.
> 
> Consider the average refractor telescope's objective lens, or lenses in any
> optical instrument.  Normally these are made of two kinds of glass, for example
> crown glass and flint glass, with different dispersions.  How to model this in
> povray?
> 
> Lemme work on my IRTC entry, and in march I'll figure out how to allow
> user-defined dispersions.   In the meantime I'll accept ideas, suggestions.
> 
> Later, for an encore, maybe I'll do birefringent materials and polarization...
> 

I'm implementing dispersion with photon-mapping (using your code), and I will
soon switch to some form of user-defined spectra (at least for light sources...
so you can define monochromatic yellow or green+blue yellow, for example).

-Nathan

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Daren Scot Wilson wrote:
> 
> No, actually, it's a sign that all the fundamental laws of logic, space and
> time are falling apart. The physical universe as we know will cease to exist...

Read too much of Douglas Adams, I guess? ;-)

> It is a bad thing that the dispersion patch has a hard-coded spectrum.  What we
> need is user-defined spectra, and then I won't ever be troubled by such
> questions.   And clever artists could then do some weird things.

Definitely. I'll give you some time...

> Consider the average refractor telescope's objective lens, or lenses in any
> optical instrument.  Normally these are made of two kinds of glass, for example
> crown glass and flint glass, with different dispersions.  How to model this in
> povray?

No problem, if every object can be assigned different dispersion
spectra.

> Lemme work on my IRTC entry, and in march I'll figure out how to allow
> user-defined dispersions.   In the meantime I'll accept ideas, suggestions.

Ok, ok,

> Later, for an encore, maybe I'll do birefringent materials and polarization...

Oh yeah, and please, please do coherent light, so that I can
finally model interference and laser speckle and the like,
hang on, man!!!

Markus
-- 

 Ich nicht eine Sekunde!!!" H. Heinol in Val Thorens

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Markus Becker wrote:
> 
> > Later, for an encore, maybe I'll do birefringent materials and polarization...
> 
> Oh yeah, and please, please do coherent light, so that I can
> finally model interference and laser speckle and the like,
> hang on, man!!!
> 
> Markus

Yeah ! And beam splitting, and diffraction grating experiments,
and..., and...

-- 
Ken Tyler

mailto://tylereng@pacbell.net

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Markus Becker wrote:
> 
> Daren Scot Wilson wrote:
> >
> > No, actually, it's a sign that all the fundamental laws of logic, space and
> > time are falling apart. The physical universe as we know will cease to exist...
> 
> Read too much of Douglas Adams, I guess? ;-)

No, probably just went out of the door, or looked in a newspaper... :-)

//Spider

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Daren Scot Wilson wrote:

> Later, for an encore, maybe I'll do birefringent materials and polarization...

OK, there was also a line in there for suggestions so how
does this sound...

Make something in which you can define ior with a density
map.  Maybe with ior as another media type in addition to
the emitting, absorbing, and scattering ones.  That way you
could get something that might be able to model things like
the way water looks when you disolve a sugar cube into it.

That and the coherent light source someone else mentioned
would be cool.

Cheers.

-- 
Carl Bartels, Department of Chemsitry, Mcgill University, to
reply to me,
just kill a and 5 from the email name, Montreal, QC, cAnAdA

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Spider wrote:
> 
> Markus Becker wrote:
> >
> > Daren Scot Wilson wrote:
> > >
> > > No, actually, it's a sign that all the fundamental laws of logic, space and
> > > time are falling apart. The physical universe as we know will cease to exist...
> >
> > Read too much of Douglas Adams, I guess? ;-)
> 
> No, probably just went out of the door, or looked in a newspaper... :-)

Oh, I didn't realize that you're sooo deeeep into raytracing... ;-)

Markus

-- 

 Ich nicht eine Sekunde!!!" H. Heinol in Val Thorens

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> 
> Oh, I didn't realize that you're sooo deeeep into raytracing... ;-)
Not really, I just re-coded reality in a #macro. Only problem is how to
load it. I'm sure it will work better with my "optimisations". And I
doubt anyone else will notice the difference :-)

//Spider

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Daren Scot Wilson wrote:

> Later, for an encore, maybe I'll do birefringent materials and polarization...
> 

Might as well throw in diffraction as well.
The Jones calculus ties all this up very nicely in matrix form.

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Oh yeah, polarization,  I think I'll hold off on playing with that. 
Diffraction seems to have everyone drooling for now.   And I need to read up on
photon mapping, since it looks like we'll be enjoying that soon (nudge, wake up
Nathan!)  and it may help with these other neat-o features.  


-- 
Daren Scot Wilson
dar### [at] pipelinecom 
www.newcolor.com
----
Physics is Phun

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One phenomenon that phascinates me -

When you look at a bright point light - a street lamp, or the glare of the sun
on a clean car, you see all kinds of colorful rays induced by diffraction and
refraction in the eyelashes, the edge of the eyelid and nonuniformity in the
cornea.   

Maybe someday we'll be writing

camera {
    location <...>
    look_at  <...>
    eyelashes on
    eyelid  squint 0.1
}

....??? 


-- 
Daren Scot Wilson
dar### [at] pipelinecom 
www.newcolor.com
----
"A ship in a harbor is safe, but that is not what ships are built for"
                                            -- William Shedd

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