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we have been having quite the discussion on the floor. is the IOR value in vray materials anywhere accurate to real life IOR values found in scientific tables all over the internet? for example diamond is listed in most tables as 2.42. if i input 2.42 into the IOR material of the diamond i am creating would that get me close? in the vray documentation and other information sources such as cg architect, allegorethmic website and so on we see values of IOR higher than 2.42. such as plastics should be between 2-6 metals are higher than 20. in other words i cannot find any definitive source on IOR numeric as they pertain to creation of materials. I am not looking for speculation or opinion. I am looking for actual answers from the people that developed the software. Help me Obi Won Vlado....your my only hope!
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Yes 2.42 would be correct, for values refractiveindex.info would be your best bet for most values:
https://refractiveindex.info/?shelf=...s&page=diamond
Plastics around 1.5 ish, glass 1.5 - 1.6 usually.
Metals are a different thing as they have two values to define reflection value (n and k), while non-metals/dielectrics have for most purposes only one value (n). You could use a high n value to approximate a metal roughly, but technically it won't be correct. Using a high n will bring you in roughly the same range at least if you prefer that method but it's always good to check against a proper metal shader esp for things like edge falloffs.
Have a look at the OSL shader here:
https://docs.chaosgroup.com/display/...Fresnel+shader
Or here:
http://www.rensheeren.com/blog/osl-reflector/
Here's refractiveindex' gold page for reference.
https://refractiveindex.info/?shelf=...tals&page=gold -
Also keep in mind that for metals you would technically need n and k values for the red, green and blue wavelengths. That would give you six values to set up for metals compared to one for most non-metals. This is because for most non-metal materials the k value overall and the n difference between the wavelengths is so small to be safely ignored.
I'm typing this somewhat quickly, let me know if that makes sense or not.
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