Dual lobe specular - How does it work?

hugepatreon

Hello,

I was reading the documentation on Iray Uber Shader but I noticed it was missing a section on dual lobe specular

http://docs.daz3d.com/doku.php/public/software/dazstudio/4/referenceguide/interface/panes/surfaces/shaders/iray_uber_shader/shader_general_concepts/start

I find dual lobe is often very important in achieving realism so I was interested in how it works.

Dartanbeck

In my limited understanding, it adds an additional layer of specular highlights to the outside of the main shader that's currently set up.

So we can add wetness to an otherwise dry-looking material, for example. Of course, this all depends upon how we set it up to work.

 

I usually use mine for just that - adding a wet or sweaty sheen to characters and things.

Sometimes I already have a great 'wet look' for the character. So I'll use this to add more gloss to the clothing and other items - if that makes any sense

crosswind

If you google "what is dual lobe specular", you'll get answers from AI which is mostly correct, and also check this thread : https://www.daz3d.com/forums/discussion/386621/can-someone-explain-how-dual-lobe-specular-roughness-1-and-2-work-and-in-relation-to-ratio

In general, light litting on a surface yileds two lobes... each lobe can have the energy of its own with different specularity. Then in DS, setting Dual Lobe should be easy:

- Dual Lobe Specular Weight controls the overall weight. Dual Lobe Specular Reflectivity, as it implies, sets the reflection to what extent.
- Each lobe can have the roughness map of its own... or you can just assign one map to Dual Lobe Specular Weight slot which is also mappable.
- Then Dual Lobe Specular Ratio determines which lobe dominantly control the roughness effect, i.e. smaller value approaches Lobe 2, while bigger value approaches Lobe 1.

Finally, if using Dual Lobe layer, better turn off Glossy Layered Weight because this layer is on the top of Dual Lobe layer, so it may ruin Dual Lobe effect. But you still can use Top Coat layer to make subtle changes, no matter on human skins or other substances.

Dartanbeck

crosswind said:

If you google "what is dual lobe specular", you'll get answers from AI which is mostly correct, and also check this thread : https://www.daz3d.com/forums/discussion/386621/can-someone-explain-how-dual-lobe-specular-roughness-1-and-2-work-and-in-relation-to-ratio

In general, light litting on a surface yileds two lobes... each lobe can have the energy of its own with different specularity. Then in DS, setting Dual Lobe should be easy:

- Dual Lobe Specular Weight controls the overall weight. Dual Lobe Specular Reflectivity, as it implies, sets the reflection to what extent.
- Each lobe can have the roughness map of its own... or you can just assign one map to Dual Lobe Specular Weight slot which is also mappable.
- Then Dual Lobe Specular Ratio determines which lobe dominantly control the roughness effect, i.e. smaller value approaches Lobe 2, while bigger value approaches Lobe 1.

Finally, if using Dual Lobe layer, better turn off Glossy Layered Weight because this layer is on the top of Dual Lobe layer, so it may ruin Dual Lobe effect. But you still can use Top Coat layer to make subtle changes, no matter on human skins or other substances.

...and There's the Real Answer!!!

 Thanks Crosswind!!! :)

crosswind

Dartanbeck said:

crosswind said:

If you google "what is dual lobe specular", you'll get answers from AI which is mostly correct, and also check this thread : https://www.daz3d.com/forums/discussion/386621/can-someone-explain-how-dual-lobe-specular-roughness-1-and-2-work-and-in-relation-to-ratio

In general, light litting on a surface yileds two lobes... each lobe can have the energy of its own with different specularity. Then in DS, setting Dual Lobe should be easy:

- Dual Lobe Specular Weight controls the overall weight. Dual Lobe Specular Reflectivity, as it implies, sets the reflection to what extent.
- Each lobe can have the roughness map of its own... or you can just assign one map to Dual Lobe Specular Weight slot which is also mappable.
- Then Dual Lobe Specular Ratio determines which lobe dominantly control the roughness effect, i.e. smaller value approaches Lobe 2, while bigger value approaches Lobe 1.

Finally, if using Dual Lobe layer, better turn off Glossy Layered Weight because this layer is on the top of Dual Lobe layer, so it may ruin Dual Lobe effect. But you still can use Top Coat layer to make subtle changes, no matter on human skins or other substances.

...and There's the Real Answer!!!

 Thanks Crosswind!!! :)

No problem, bro !  

benniewoodell

crosswind said:

Finally, if using Dual Lobe layer, better turn off Glossy Layered Weight because this layer is on the top of Dual Lobe layer, so it may ruin Dual Lobe effect. But you still can use Top Coat layer to make subtle changes, no matter on human skins or other substances.

Thank you, I never knew to turn off glossy layered weight before when using dual lobe! 

crosswind

benniewoodell said:

crosswind said:

Finally, if using Dual Lobe layer, better turn off Glossy Layered Weight because this layer is on the top of Dual Lobe layer, so it may ruin Dual Lobe effect. But you still can use Top Coat layer to make subtle changes, no matter on human skins or other substances.

Thank you, I never knew to turn off glossy layered weight before when using dual lobe! 

You're welcome !