Can you show it that the velvet shader is useful?
( The velvet shader needs to have a prominent place in the setup, otherwise it won’t count. )
I wanted to propose to check the source code, but why would I do that, I showed in screenshot how similar the velvet shader to a diffuse shader with a darkening at facing angle. This latter one is is obvious, way more than:
"micro filament shader’, and it serves a very good purpose to represent some scattering patterns of a specific orientation of each filament "
Please look (you didn’t, otherwise you wouldn’t even come to the idea to discuss this as is.) at the screenshot where I compare the real velvet shader with just a diffuse shader and layer weight. Doesn’t that look very similar? So similar that I am not scared of any scientific argument that we should use the velvet shader.
Also, the idea that velvet (or some fabrics under certain conditions) show desaturation at grazing angle is not a crazy idea: years later after my conclusion, the principled shader came into Blender with a sheen setting. And that does something that looks more where I am talking about then putting a dark spot at facing angle.
In the Blender manual I find the following about Sigma:
Variance of the normal distribution, controlling the sharpness of the peak. It can be thought of as a kind of roughness .
Let’s break that down:
Variance of the normal distrubution: In other words: facing angle
Controlling the sharpness of the peak: (very) similar to Blend as in layer weight node)
It can be thought of as a kind of roughness : The darker the spot , the rougher appears, was the idea.
I see elsewhere the velvet shader described as:
- Velvet shader: You can think of it like a Diffuse shader, but with a big dark spot in the middle
- Sigma: A sort of roughness value that controls the size of the dark spot, where higher values means the dark spot is smaller.
Let’s also break down the following:
scattering patterns of a specific orientation of each filament (expressed as sigma )
Orientation of the filament: Fibers, In velvet they are short, and pointing outwards similar to the normals we know in blender. And how light scatters in that circumstance.
So in other words you said; “The velvet shader serves a good purpose because it simulates how light scatters in fabric / velvet /”
Yep, and it does that by placing a beautiful dark spot at facing angle.
Actually quite a fun to break down so many scientific terms into nothing more than a black spot.
Isn’t it easier to say just Black Spot? And it much more clear for those who are learning Blender.
So, again, what didn’t I understand about the underneath its variables?