I’d suggest using the thin film shader found here, and some map to drive change between min and max thickness (which will provide for some more random color variations.).
If you pipe the map into the refraction channel, ensure you also let it use reflColor as alpha output, or it’ll come out black.(You’ll know when you’ll get there).
Alternatively, you can pipe it into the fog color (with the alpha mapped as well).
A very quick play with this.
Based on some random tweaks to the shader here…https://docs.chaosgroup.com/display/…in+Film+Shader
EDIT: LeLle beat me to it 
Interesting, I’ve never even noticed that shader in there.. haha! Thanks for the tips guys!
It was never meant to be used creatively, but rather to mimic known films by their thickness and IoRs.
How would it have to change to become more user friendly, you’d say?
Here’s a resource that might be helpful in understanding what’s going on and help predict what you’re getting out of the shader. Also I think this shader is actually built into Vray in the plugin textures, at least it has been in the Maya nightlies for a long while now.
A preview of the color gradient created between the min and max thickness values would make it a lot more artist friendly. That or viewport support.
That being said, at that point you should probably just use a fresnel/falloff to drive a regular gradient ramp, that’s how I always do it. I don’t see the point of using the thin film shader for the inconvenience of having to guess instead of just picking the colors I want.
I think i agree with the analysis. Knowing the gradient without knowing the normals and view direction may prove too little, while if one was to be too explicit in driving the behaviour, one may as well resort to simpler approaches.
I’d think IPR would be the most helpful (it was for my simple setup above), these days.
also, yeah, i totally forgot to use the pluginNode. Old dog, new tricks, and all that. XD
To be fair the documentation doesn’t even mention it which is why I wasn’t entirely sure if it was only in the nightlies still. The Complex Fresnel Shader page has a helpful reminder that its functionality is now native in Vray.
I appreciate the notes everyone! I’ll post my results when completed. Such a great community!
https://www.sigershop.eu/free-3ds-max-plugins/sigertexmaps-thinfilm/
this here is by far the best implementation.
Good find, thanks 
Nice idea that of the addition of CC controls.
I wonder if it’d work on our side nesting the OSL map into a CC one…
edit: ahah, he copy/pasted our whole help section. ^^
Siger Studio has created a plugin that achieves this also.
Is this also available for MaYa ?
Indeed.
It should be called “VRayPluginNode” or something along the lines.
It’s created from the “create > V-Ray > create texture from V-Ray plugin” menu (again, this is a bit of a fuzzy match. sorry for this, have currently no Maya installed.)
hi @lele , I just discovered that there was a thinfilm map in the VRayPluginNodeTex, any chance to have it work in Vray GPU ?
I was playing these days with the OSL you can find here OSL Shaders but unfotunatly the thickness slot didn’t work on GPU.
Hey, sorry for the late reply. I have inquired, will let you know as soon as i do.
Ok, so OSL seems to work fine for me under GPU, thickness included.
Could it be that the texture you were using for the thickness wasn’t supported by GPU?
The attached image is the result of the sample files, with the noise mapped to thickness, and noise size reduced to 5, from 15.
The nightly is from a few days ago, but support for this hasn’t been touched in a while, so it ought to work for you too.
If, however, there are specific things which really don’t work with OSL, the GPU team could evaluate making a CPP version as well, but it’d take some time.
Hi @lele ,
you’re right it is working while doing a production render, however it seems that the thickness slot it is not working in GPU IPR mode, that’s why I thought it was not working correctly.
I’m still thinking that a GPU version of the ThinFilm directly integrated inside VRay (VRayPluginNodeTex or inside the VRayMtl) would be a better solution, here is why.
I usually experience a lot more crashes when using OSL, so I really use OSL when it’s my last solution.
Inside the VRayPlugginNodeTex ThinFilm there are some very nice color correction settings that are not included in the OSL, I suppose that they are more optimized than placing a Color Correct node after the OSL.
Another situation I discovered lately because of the actual pandemic, I had to work at home on a project on my personal computer and send the files to the office to make the renders on the renderfarm.
I was missing a Complex Fresnel OSL file (OSL Shaders) at work, and they where not showing up inside the asset tracking of 3dsmax, so impossible to relink the map, I had to go through manually dozens of shaders of the scene and search for the .osl, and the settings where also lost when I had to reload the osl. It was a huge waste of time.
By the way while writing this message I’m discovering that there is a VRayPluginNodeTex ComplexFresnel…
, does it work in GPU ?
I’m totally aware that this situation doesn’t apply to everybody but I really feel that having all the tools directly inside VRay is a more efficient way of working and can limit many problems.
So I would be super happy if the GPU Team can find the time to make it work.
