Quite pleased: I added native #thinfilminterference in an absorbing layer on top of a conductor to #blender3d. I went through the math of https://hal.science/hal-01518344/document, and added terms dealing with absorption in the film. Slightly trickier than I thought, but it works. The 5.0 alpha branch dealing with dielectrics was great as a starting point!

The render shows the result with nodes on the left and the native implementation on the right. If you look carefully there's a slight color shift.
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#b3d

A fair question is, does it matter? It depends. For some looks you're better off with a dielectric film (it renders faster). But when it does matter, there's no denying the absorption is required for the right look.

Example: copper with a layer of CuO, where the layer doesn't have absorption. Compare with the image in the first post of this thread (repeated here), where realistic absorption is added.

Now I need a real Dev to fix my baby C++ code😅
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#blender3d #b3d #thinfilminterference

The method in the paper yields #iridescence that resolves to a plain reflection for thicker films, like in daily life. My nodes suffer from spectral aliasing, which means the colors keep cycling no matter the film thickness.

Now, we can have absorbing films while keeping the look and behavior of thick films. The render shows the nodes on the left and the native behavior on the right. The native behavior more accurately reflects the real-world experience.
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#blender3d #thinfilminterference

Quite pleased: I added native #thinfilminterference in an absorbing layer on top of a conductor to #blender3d. I went through the math of https://hal.science/hal-01518344/document, and added terms dealing with absorption in the film. Slightly trickier than I thought, but it works. The 5.0 alpha branch dealing with dielectrics was great as a starting point!

The render shows the result with nodes on the left and the native implementation on the right. If you look carefully there's a slight color shift.
1/3
#b3d