Roughness map?

[tehfailsafe]

I'm trying to figure out a bit how to create an image to use as the roughness map.
The specular map can work quite well going from white(1) to black(0) to change the amount of light that is "reflected", but the roughness is EXTREMELY low in number. For example, high glossy reflection is black (0) and a mildly blurry roughness is like 0.0000737.

Is there a way to express 0.0000737 with a texture map in an image?

For example, let's say I had some wood flooring that was to go outside, and it rained that morning. Some of the wood would be damp, some would be mostly dry, but other parts might have subtle puddles that would be quite "glossy" (0). For the most control I would want to just paint in photoshop the areas I want to be wetter than others. But how can I create 0.0000737 with Photoshop?

[matej]

I was also asking myself this. Artists are used to work in "linear mode", painting their textures from low (0.0), to middle (0.5), to high (1.0) intensity.

In this case when used for roughness, Octane should exponentially re-map a linearly painted texture, so that 0.001 becomes something like 0.0000001, 0.5 becomes something like 0.01, and so on... There is no other viable artist-friendly option. I'm not sure for the latest Octane version, but in previous version this was not happening.

[roeland]

For now you can:
- make sure the image doesn't contain pure black, because a roughness of 0.0 doesn't work
- set the power input on the image node to a very low value

--
Roeland

[Hastule]

This topic interested me because I too want to make specialized maps for certain things. In particular, I have heard of people who use things called "smudge","dirt" and "scratch" maps,but I have no idea what they're talking about, considering those are just nicknames that really represent the use of 1 or more real types of maps (bump,normal,opacity,etc) used to make a smudge,dirt,scratch etc appearance. I can make educated guesses as to how they are made, but I feel as though there is probably a REAL way to make those maps much more realistic than the ones I make are.

How would one go about making those 3 kinds of maps I just mentioned? I'd like to know for a project I'm working on. In particular, I would like to know how to make a fingerprint smudge effect on clear glass but nothing I try seems to ever work. I suppose this really is more of a question about what to do in Photoshop rather than Octane.


Thanks!!

[kubo]

@Hastule, in that particular case, I would do a b&w map of the fingerprint, map it on the mesh, and use it as a mix map for a mix material node, where the white would be the regular glass (specular material with 1.45 ior and high values in reflection and refraction) and the black would be the finger print which would be another specular material, with similar values but lower reflection, lower refraction and a high rougness, also I would add a small bump with that same map.