Beta version released. Quick presets test (used same glossiness value for all materials (exl. Chromium) only for testing purpose).
Tested with V-Ray 2.x.x, 3.x.x, Corona Renderer 1.x.x, Default Scanline
Based on OSL shader code by Vlado (Chaos Group): OSL Shaders
Installation instructions included.
thanks!
I assume this is like Grant’s method of adjusting the colormap graph, but instead you can insert the exact values for RGB based off the wavelength charts?
Texmap calculate own fresnel for each wavelength. If you put texmap in the Corona material reflection color slot - don’t forget disable material fresnel calculations (enter 999) 
Hi Regimantas, is it possible to add ability to save own presets or we have to go with map / material library route?
Didn’t have much time to play with it, but i find results rather strange. But of course more tests is needed to draw some conclussions.
Any chanche to have it for max 2012?
I’d like to play with… since I’ve read the Viscorbel article…
tnx
Gaby
So… how do I use this?
If I go to that website link I only get one value for n and k, I can’t find anything that tell me the RGB parts,
also if I compare the presets values with the info in that website, they look different.
Any ideas?
Thanks.
The RGB wavelength values are taken as the median of their ranges typically. If you look up red on wikipedia for example, its range is 620-740, so the 650 value used in the map is an approximation of its average. You would then find that number for each color, and input it into the wavelength box on the refractive index page.
For example (the copper values), inputting the R value of .65 gives you an n=.27105 and k=3.6092, hence the .271 and 3.609 in the map. Inputting the same RGB wavelength values under a different material from the index pull down will give you the corresponding n and k values for that material (ie: for aluminum, R value of .65, n=1.3424, k=7.4737, which aligns with the values on the fresnel map)
These are estimated numbers of course, not exact values.
Another experiment 
I try to develop a Texmap plug-in which reproduces the effect of thin film interference on a surface.
It is based on code: http://www.gamedev.net/page/resources/_/technical/graphics-programming-and-theory/thin-film-interference-for-computer-graphics-r2962
Plugin will be free and compatible with Corona Renderer.
Thank you for the explanation, now it make sense.
Unfortunately, lower than 2013 it isn’t planned.
This looks so sexy. Can’t wait to try it! Reminds me of the good old CoronaColorMapper times:
The thin film tests look good!
Love it !
Nice Regimantas!!
Really nice things both of those!
Looking at ‘em, they got me thinking- it could probably be possible to do some similar map for translucency fraction map and of how tremendously helpful that map could be, I mean some sort of similar falloff driven map which could have some presets for imitation some real world translucency values (I know those arent’ there in reality, but…) for let’s say some plastics, leaves, marbles and other semitransparent stones - those which can be relatively easily faked without the use of sss. Plus that map could have some fresnel driven map inputs on it’s own to help imitate some of the more complex stuff, though not necessary cause one can possibly use it in the mix or coronaMix maps to make that, still it could be easier to use that way for sure. Of course some logic must be found for it to operate in the desired/predictable way + no small amount of testing might be needed too but in the end, something tells me, it could be really great )
Let me know if you want to improve this - there are some CSV values that allow you to convert between spectrum and cieRGB/XYZ/sRGB. Each of sRGB primaries actually corresponds to multiple spectral wavelengths
Really nice. Only just got round to using this now. And thanks very much.
Would it be possible to only have just the n values also. I know we can manually type this in the the Fresnel IOR but with this plugin maybe there’s a possibility to save these reusable values as a preset and for the complex metals that have different value in the RGB range which was suggested above somewhere.
So with this plugin you can save values for basic materials like polycarbonate with a Fresnel IOR (n value) of 1.5846 http://refractiveindex.info/?shelf=3d&book=plastics&page=pc this can be saved without the need to refer back to a reference.
Would be really handy to have a seperate area for basic materials and n values along with what’s there. So we could plug it into the Fresnel IOR map for the simple mat types also. Just a wee suggestion.
Again, thanks for the freebee
+1 for presets especially for repeatetive task… i dont know how plugins works.. but you can add “saveinisettings” and “getinisettings” in the code for user to load save some values…
