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I'm trying to make a realistic gold shader. I would like to know what is the right way to match the information found on refractiveindex.info (for gold: http://refractiveindex.info/?shelf=3d&book=metals&page=gold) to my cycles shader. The page is in a section for "information for 3D artist" but I'm wondering what parts of the information can be integrated in a cycles material and where it should be plugged.

In this tutorial (in the section "Basic metallic shader" at the end) : http://www.chocofur.com/6-shadersamptextures.html is mentioned a technique for the reflection information. Even though this is a very-well written and complete tutorial, I'm not 100% sure about the accuracy of the information because the author claims that the red, blue and green curves match RGB curves (which I doubt because they are labeled as being for polarization) and in the author's example for gold, the curves to not actually match what is found on refractiveindex.info, as exemplified here :

enter image description here

I understand very few people are BOTH 3D artists and physicists, maybe explaining the difficulty of finding accurate information on the subject. As you can see, I have very little knowledge of optics myself.

Is there any other information on refractiveindex.info that I could plug in? Like wavelengths and absorption information for exact colors, for instance. Any information would be appreciated, suggestions of documentation on the subject as well.

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  • $\begingroup$ I guess you will never get the real thing in blender (or other similar tools), because they are mostly "artist's" tools, thought to be able to represent amazingly good even reality, but they aree not nature simulators... eg: "light" in blender is not specified with a defined wave spectrum, the "atmosphere" is not real (no oxygen, nitrogen, co2, argon, dust particles, other electromagnetic waves), and a "camera" has no definition of the "sensor" which could add in the result... $\endgroup$
    – m.ardito
    Oct 15, 2015 at 8:47
  • $\begingroup$ I understand that Cycles is not an optics simulator, but it is nonetheless based on physics. Otherwise we wouldn't have a fresnel node, or input values such as "index of refraction". I am not making simulation for a physics paper, I'm making a gold shader that can look convincing from every angle. $\endgroup$
    – Eranekao
    Oct 15, 2015 at 19:55
  • $\begingroup$ And Cycles can do just that: CG that is indistinguishable from reality. It's called "physically based rendering/shading", and while it may not be desirable in all 3D projects, sometimes it's what we're aiming for. An approximation nonetheless, but good enough to trick the eye, and to do this properly you must understand how light interacts with materials, which is physics. So basically I don't want to plug ALL physical information in my shader, I'm asking "which" are important visually and "how" do I integrate them. $\endgroup$
    – Eranekao
    Oct 15, 2015 at 19:57
  • $\begingroup$ Blender Guru does reallllllly good tutorials on photo realism. You could look at what he did in that Posts. $\endgroup$
    – HenrikD
    Feb 23, 2017 at 20:58
  • $\begingroup$ Here is an amazing free add-on that basically has a library of ready-made real-world PBR materials, including gold. I have used it extensively. blendernation.com/2016/12/23/pbr-materials-addon-2 $\endgroup$
    – christsdude
    Sep 17, 2017 at 2:05

2 Answers 2

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Here's a wonderful tutorial by Blender Guru for making a completely accurate metallic shader. I would follow his tutorial, and use this list of colors to set up your gold. Metal in real life has different colors on the edges facing away from you than the ones facing you, so this tutorial and data-table should describe how to set it all up. This approach may also be simpler than trying to interpret the graphs and curves you are currently having problems with. It's kind of a workaround, but I hope it helps! Cheers, Graves Broderick

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Use the Principled BSDF node. It's using a PBR shader which is a physically based rendering shader. You can enter values for the material you would like to do.

enter image description here

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