Can someone explain how Dual Lobe Specular Roughness 1 and 2 work, and in relation to ratio?

Flortale

Edit: here's an explanation to anyone interested.

Dual Lobe Weight: This controls the strength of the specular effect (how well you can see the effect).
Reflectivity: How much it acts like a mirror, reflecting things in the scene. This is good for great wet or oiled effects.
Dual Lobe Roughness 1: Setting this value low makes things more wet looking, setting it higher spreads the specular effect out.  0.15 is good for like wet skin, while .4 or .5 is good for lotioned skin.
Dual Lobe Roughness 2: The reason there is two is because dual lobe will create a range of specular from rougheness1 to roughness 2.  You can set this one to a lower value.  

Example of roughness settings good for glossy lips
- Roughness1: 0.1
- Roughness2: 0.05

Dual lobe ratio: I have no idea what this does, but I leave it at default.  It seems the people who make DAZ core original figures also leave it at default. I'm guessing it controls which dual lobe roughness channel is more dominant.  I'm guessing that at a ratio value of 0.85 makes the roughness2 channel more dominant? Can anyone confirm? I'll eventually test it and update this post.

Flortale

Is it true that setting dual lobe weight to 1.0, uses only one of the roughness channels, while setting the weight to 0.5 uses both roughness channels? The documentation doesn't explain any of this, or maybe I missed it. Has no one figured out how dual lobe works?

rokkr

Flortale said:

Edit: here's an explanation to anyone interested.

Dual Lobe Weight: This controls the strength of the specular effect (how well you can see the effect).
Reflectivity: How much it acts like a mirror, reflecting things in the scene. This is good for great wet or oiled effects.
Dual Lobe Roughness 1: Setting this value low makes things more wet looking, setting it higher spreads the specular effect out.  0.15 is good for like wet skin, while .4 or .5 is good for lotioned skin.
Dual Lobe Roughness 2: The reason there is two is because dual lobe will create a range of specular from rougheness1 to roughness 2.  You can set this one to a lower value.  

Example of roughness settings good for glossy lips
- Roughness1: 0.1
- Roughness2: 0.05

Dual lobe ratio: I have no idea what this does, but I leave it at default.  It seems the people who make DAZ core original figures also leave it at default. I'm guessing it controls which dual lobe roughness channel is more dominant.  I'm guessing that at a ratio value of 0.85 makes the roughness2 channel more dominant? Can anyone confirm? I'll eventually test it and update this post.

I did many tests and, though in theory makes sense to distinguish weight and reflection, both controls seem to do the same thing. For instance, I did some tests with one at .25 and the other at .5 and vice-versa, and both instances seemed to produce the same render (I tested with other values too).

About the lobes 1 & 2, you're right. Though independently they are glossiness/roughness dials, it's the difference between the two that produce some interesting effects, but there also seems to be some qualitative jumps. For instance, while the first ranging from .5 to above and the second between .3 and above but with a distance of .2 from the first produce a shining effect decreasing it's intensity as the values go higher, if the value of the second lobe goes to .2 while the first it at .5 (or below) a wet effect starts to be produced. (I also inverted the values and it didn't seem to produce any difference...)

And this effect is intensified by this last dial dual lobe specular ratio: at 0, the wetness is at its maximum while when the value rises, it starts to look creamy.

All those tests I used for skin, but the logic applies to other materials.

 

 

 

Fishtales

If you use the Metallicity setting for the shader the higher the Roughness the less shine. For all surfaces that aren't Metallic I use the Specular/Glossiness setting. When using the Metallicity setting the higher the Roughness the less shine with the Glossiness setting the higher the Glossiness the more shine. I leave the Weight setting at 1.0. I use the specular Reflectivity at 0.5 and only move it up or down to increase or decrease the amount of overall shine on the surface. Lobe 1 is the inner lobe and Lobe 2 is the outer one so making Lobe 1 bright and Lobe 2 less shiny gives the Lobe effect. The Specular Ratio slider determines how much of a separation there is between the two lobes.

lilweep

ok so whats a lobe.

Edit: Nvm, V3Digitimes explains it here https://www.daz3d.com/skin-shading-essentials-tutorial