[BUG] NK data file parsing

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enkidu
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[BUG] NK data file parsing

Post by enkidu » Wed Nov 29, 2006 5:45 am

I don't know how many people use the .nk data files that come with Indigo, but it only seems to work with the type 1 files - those where the wavelength range is expressed in electron volts. The type 2 files (micrometre wavelengths?) don't seem to work. Is this something that's going to be fixed?

In the mean time, I've written a script to convert the type 2 files to the type 1 using very simple linear interpolation - I can upload these somewhere if people are interested. I don't know how good the conversion is or if I've made any mistakes, as I don't have any experience in radiometry, so would appreciate if someone who knows more about this stuff could do a sanity check on the converted files...

Any help appreciated!

PS. does anybody know if it's possible to get the dielectrics working from their .nk data? Or can they only be controlled by the IOR and cauchy coefficients?

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psor
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Post by psor » Wed Nov 29, 2006 5:58 am

Heya enkidu!!!1 :D

wow, very cool of ya ... and the good thing is, you remembered me that I
found another parsing bug some time ago. :roll: As far as I remember right,
will check it tomorrow, the last line is not parsed at all, dunno why. And
another thing that I noticed is, some files include comments - Indigo hates
comments in those files and won't parse them at all. I would like to get my
hands on your script ... I don't know anything about exact IOR data, but at
least we can check them against the Maxwell database. :twisted: 8) :wink:

Thanx in advance for your contribution! ;o)

edit: Dielectric .nk files are not working correct, dunno why. Nick? ^^



take care
psor
"The sleeper must awaken"

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Zom-B
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Re: [BUG] NK data file parsing

Post by Zom-B » Wed Nov 29, 2006 7:17 am

enkidu wrote:... I can upload these somewhere if people are interested...
I'm one of this people ^^
polygonmanufaktur.de

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Phoenix
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Post by Phoenix » Wed May 09, 2007 1:11 am

psor wrote:Dielectric .nk files are not working correct, ...
Hi Nick,

what is the problem at all with these .nk's and do you see a chance, that they'll work sometime?
Or do you even found a solution meanwhile?

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OnoSendai
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Post by OnoSendai » Wed May 09, 2007 1:55 am

I don't allow transmission with nk data right now, I might change that in the future.

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Zom-B
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Post by Zom-B » Wed May 09, 2007 2:11 am

OnoSendai wrote:I don't allow transmission with nk data right now, I might change that in the future.
just imagine the possibility's to use NK materials for Gems... :wink:
polygonmanufaktur.de

tinman999
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Post by tinman999 » Wed May 09, 2007 3:15 am

You really need more than nk file to defined gems

nk file give you the refraction index, As far as I can tell for dielectric they only gives you the real part of the refraction index and rarely give the imaginary part which give the extinction coefficent (from that you can get the absorption coefficient). The absorption is usually defined separately in the form of absorbance spectrum which is very simliar to nk file but for absorption

You also need Birefringence and Polarization

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zsouthboy
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Post by zsouthboy » Wed May 09, 2007 6:39 am

Is there a format that defines materials completely physically correctly, then? (I assume used for high-end scientific data)

I'm still a huge fan of .nk files though - no guesswork needed for perfect gold, or aluminum, or whatever? Are you farking kidding me? Great!

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Phoenix
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Post by Phoenix » Wed May 09, 2007 6:59 pm

ZomB wrote:just imagine the possibility's to use NK materials for Gems... :wink:
Take a look at this:
Image
From here: http://www.maxwellrender.com/forum/view ... p?p=157406

tinman999
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Post by tinman999 » Wed May 09, 2007 10:37 pm

Look like it's measure in nanometre :D

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