Hi,

because it is so common to not have a roughness map handy in many a texture set, I've just been thinking along the lines of some simple node formula to

basically do what is done in this video: https://www.youtube.com/watch?v=plEgIp1LW2w .

In rough terms, the principle is one node to switch the diffuse map to greyscale, one node to invert that and then another node to play with the contrast of the resulting inverted greyscale map. The result is then a roughness map.

Now I have Ken's "Go Physical" script as a time-saver and it is a great help BUT, it is no solution for the issue of not having a proper roughness map. It's simple "maths function" node method is possibly just a touch too simple to really satisfy me.

So what I have in mind is:

Diffuse > "RGB to BW Node" > "invert" > "contrast node" = "extremely satisfying roughness-map replacement"