Velvet shader using NEW Principled BSDF Branch!

[moony]

@LemonBranny

Hello, the color in the picture is not color grading, it is the interference of light when it passes through a thin transmissive film. I suggest you to learn about the thin film shader and the interference effect of light.

I am fairly well versed on the subject.

Micro/angle dependent Roughness & Iridescence

How about a different approach. In this case - I created 3 colour ramps (R, G and B) based on this graph from the link below [image] [image] http://markkness.net/colorpy/ColorPy.html I then added them together using the layer weight node key the observed thickness as a function of viewing angle. I wonder if it might be possible to recreate the graph using a simple math function for each RGB component, rather than using colour ramps. The three RGB components appear to be based on a sine w…

I used the term colour grading - because that’s what it seems to be at first glance. It’s calculating a colour grading based on the angle between the camera and object. It’s just that the colour grading is calculated based on an approximation to real world iridescent phenomenon.

True thin film iridescence/interference depends on the position of the light source as well as the camera - which I don’t believe Cycles has access to (at least it didn’t have in the past when I was creating the node group in my link above).

As far as I can tell - the thin film effect doesn’t change with changing angle of incident light in principled V2

It’s also not a true interference model either, because cycles isn’t currently spectral. It appears to be an approximation along the lines of what I created using RGB gradients and sine waves in the link above - but probably more accurate since I was merely eyeballing, not using the underlying maths.