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Free download: Thin-film Interference for Cycles (GPU Compatible)


Jett writes:

After searching for a way to simulate the color changes found on lab grown bismuth crystals and dichroic glass, I eventually happened across Pruster's thin-film interference OSL shader. With the help of various literature and the OSL shader, I was able to adapt Pruster's script into a GPU compatible interference node group. Find Pruster's original news post here.

The interference group takes the complex refractive index of a substrate and up to two thin-film layers to calculate the physically-correct colors of the desired material. With it, materials such as aged copper, 'a thin-film on an arbitrary dielectric', car paint, and heated iron can be simulated correctly as seen below:

The interference group also has the option to simulate plain conductors such as gold and osmium:

And while we're at it, let's look at the golden reflections of a space helmet material and the shiny pastels of a dichroic glass material:

Only the interference node group is under the CC BY-NC-SA 4.0 license, but its output can be used for any purpose. All the materials shown here are only a small preview of what is provided in the blend file, so check it out and maybe even create your own materials with the interference node group.

Download it for free at Blend Swap or find the same file on the BlenderArtists forum.

Hope you enjoy it!


    • I've found out that if you once put something for free online, people start to sell it. It happened to me, so I understand very well why he licenses it like that. You can basically now re-create the node group with your own settings and you are free to use it for commercial things.

      • That's what GPL stands for, and there is nothing terrible in selling an open source program as long it remains open source - that's how the open source business model works.

        • Blender is licensed under GPL but when you give away a node set-up, model, material, scene, etc you can license it however you wish, including CC BY-NC-SA 4.0.

  1. "You can basically now re-create the node group with your own settings and you are free to use it for commercial things." yeah... about that...

    -You can not use this blend or its derivatives for commercial purposes.

    derivatives: something that is based on another source.

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