I might not have posted on a proper group. If I should have chosen the
povray.newusers, please don't hesitate to tell me as such.
Well, since I am still not very much acquainted with the POV-ray yet, I am
not sure whether this topic is rather absurd or not.
When a calcite crystal is laid on a page of newspaper, the characters would
form double images. The refractive indices of the clacite crystal are 1.6584
and 1.4864(n0 and ne, respectively)["Optics",p.337, Hecht]
Would it be possible with some effort to simulate this phenomena for
birefringent materials in the POV-ray 3.5?
Are there any such programs to support this function other than POV?

Thank you for your interest in this regard,

Jong

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Jong wrote:
> 
> When a calcite crystal is laid on a page of newspaper, the characters would
> form double images. The refractive indices of the clacite crystal are 1.6584
> and 1.4864(n0 and ne, respectively)["Optics",p.337, Hecht]
> Would it be possible with some effort to simulate this phenomena for
> birefringent materials in the POV-ray 3.5?

That depends on the level of realism you want.  Birefringence is an effect
related to the polarization of light and a complete support for all
important effects related to polarization would require quite elementary
changes to POV-Ray.

If you however only want the optical effect of birefringent materials on
unpolarized light you could probably achieve this by a not that
complicated modification of the refraction code.  You would however
somehow have to define the orientation of the crystal, probably as a new
interior property.

> Are there any such programs to support this function other than POV?

Not that i know of.

Christoph

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

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Dear Christoph,

 I really appreciate your support.  I am relieved to know that it might be
possible when using non-polarized light source.

What I would like to do is that the raytracing( if possible photon-mapping
included) of some (several to 20) cylindrical almost-transparent objects
parallel each other, or perpendicular, on a some simple plane like a
blackboard with the non-polarized light source.

My question then is this(level of difficulty):
Do I have to write a macro or function in this case(I might have to learn
quite a lot, a month or two, though)?
 Or do I have to 'code' some source of the POV(well, I don't think I have
the ability to do so).

Thank you again,

Jong

"Christoph Hormann" <chr### [at] gmxde> wrote in message
news:3DB8FD33.E1289495@gmx.de...
>
>
> Jong wrote:
> >
> > When a calcite crystal is laid on a page of newspaper, the characters
would
> > form double images. The refractive indices of the clacite crystal are
1.6584
> > and 1.4864(n0 and ne, respectively)["Optics",p.337, Hecht]
> > Would it be possible with some effort to simulate this phenomena for
> > birefringent materials in the POV-ray 3.5?
>
> That depends on the level of realism you want.  Birefringence is an effect
> related to the polarization of light and a complete support for all
> important effects related to polarization would require quite elementary
> changes to POV-Ray.
>
> If you however only want the optical effect of birefringent materials on
> unpolarized light you could probably achieve this by a not that
> complicated modification of the refraction code.  You would however
> somehow have to define the orientation of the crystal, probably as a new
> interior property.
>
> > Are there any such programs to support this function other than POV?
>
> Not that i know of.
>
> Christoph
>
> --
> POV-Ray tutorials, IsoWood include,
> TransSkin and more: http://www.tu-bs.de/~y0013390/
> Last updated 13 Aug. 2002 _____./\/^>_*_<^\/\.______

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Jong wrote:
> 
> [...]
>  Or do I have to 'code' some source of the POV(well, I don't think I have
> the ability to do so).

You will have to, there is no way achieving this from POV-Ray scripts.

Christoph

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

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Maybe there's a simple workaround. If you calculate two images.
One with ior 1.6584 of the interior of the crystal and another
with the other ior of 1.4864. And than combine this images in photoshop 
or similar programs.

It's not fully simulation, but...

SciBorg

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In article <3DB95D60.527123F6@gmx.de>,
 Christoph Hormann <chr### [at] gmxde> wrote:

> You will have to, there is no way achieving this from POV-Ray scripts.

You could get something almost like it, with an average texture with two 
slightly different gradient normals. True simulation requires modifying 
the source code, though.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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Once again, cheers to POV-Ray TAG and supporting members.
  I myself was not able to figure how much effort should be needed to
implement the Double Refraction or birefringent material simulation.
Now, it seems to me that the simulation may well require team effort or some
sort of 2003(or 2004?) Siggraph presentation type effort.

I really appreciate your interest and suggestions.

Jong


"Christopher James Huff" <chr### [at] maccom> wrote in message
news:chr### [at] netplexaussieorg...
> In article <3DB95D60.527123F6@gmx.de>,
>  Christoph Hormann <chr### [at] gmxde> wrote:
>
> > You will have to, there is no way achieving this from POV-Ray scripts.
>
> You could get something almost like it, with an average texture with two
> slightly different gradient normals. True simulation requires modifying
> the source code, though.
>
> --
> Christopher James Huff <cja### [at] earthlinknet>
> http://home.earthlink.net/~cjameshuff/
> POV-Ray TAG: chr### [at] tagpovrayorg
> http://tag.povray.org/

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In article <3dbbbb9e$1@news.povray.org>, "Jong" <jjk### [at] mmewhaackr> 
wrote:

>   I myself was not able to figure how much effort should be needed to
> implement the Double Refraction or birefringent material simulation.
> Now, it seems to me that the simulation may well require team effort or some
> sort of 2003(or 2004?) Siggraph presentation type effort.

Just to do double refraction wouldn't require much effort at all. (the 
dispersion feature already does a kind of multiple refraction, for 
example)
Making it direction dependant would be harder, but not too bad. 
Simulating the other polarization effects would be quite difficult. The 
thing is, it is just very special-case...you aren't going to find many 
people interested in it.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

Post a reply to this message

That's right. That would be needed by some limited number of users. I guess
very small number of users in the gem-related field or ...

Thank you so much for the valuable insights and tips.

Jong

"Christopher James Huff" <chr### [at] maccom> wrote in message
news:chr### [at] netplexaussieorg...
> In article <3dbbbb9e$1@news.povray.org>, "Jong" <jjk### [at] mmewhaackr>
> wrote:
>
> >   I myself was not able to figure how much effort should be needed to
> > implement the Double Refraction or birefringent material simulation.
> > Now, it seems to me that the simulation may well require team effort or
some
> > sort of 2003(or 2004?) Siggraph presentation type effort.
>
> Just to do double refraction wouldn't require much effort at all. (the
> dispersion feature already does a kind of multiple refraction, for
> example)
> Making it direction dependant would be harder, but not too bad.
> Simulating the other polarization effects would be quite difficult. The
> thing is, it is just very special-case...you aren't going to find many
> people interested in it.
>
> --
> Christopher James Huff <cja### [at] earthlinknet>
> http://home.earthlink.net/~cjameshuff/
> POV-Ray TAG: chr### [at] tagpovrayorg
> http://tag.povray.org/

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>Just to do double refraction wouldn't require much effort at all. (the
>dispersion feature already does a kind of multiple refraction, for
>example)
>Making it direction dependant would be harder, but not too bad.
>Simulating the other polarization effects would be quite difficult. The
>thing is, it is just very special-case...you aren't going to find many
>people interested in it.

Hmmm... Polarized light might be an idea for a feature to add. I've seen
some interesting effects as a result of using polarized light; things like
sticky tape can look really beautiful when viewed using polarized light.

Maybe it could be added to POV, but as you just said, it would be too
difficult to bother with.

Rohan _e_ii

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