What do black and white stand for in specular, ambient occlusion and specular occlusion maps?

CHWT

I am super confused, what black and white stand for in [specular, ambient occlusion and specular occlusion] these maps seem to be different among artists (and even among different DO characters). Can anyone tell me if an area that is shiny should be shown as black or white in the specular, ambient occlusion and specular occlusion maps?

Richard Haseltine

Please put your question in the post body and the title

Black will be 0% and white 100%, which will then be multiplied with the directly set values. So if the Glossy Strength iss et to 50% then white will be 100% of 50%, which is 50%, mid grey will be 50% of 50%, which is 25%, and black will be 0% of 50%, which is 0%.

plasma_ring

The reason you might be seeing different map layouts for effects like shine is that some artists control them with maps that specify where they are, and some control them with maps that specify where they aren't. A map in a weight channel (which adds shine) may have white where the shine is because it's saying "put shine here," and a map in the roughness channel (which reduces shine) will have black there because it's saying "don't put roughness here."

CHWT

plasma_ring said:

The reason you might be seeing different map layouts for effects like shine is that some artists control them with maps that specify where they are, and some control them with maps that specify where they aren't. A map in a weight channel (which adds shine) may have white where the shine is because it's saying "put shine here," and a map in the roughness channel (which reduces shine) will have black there because it's saying "don't put roughness here."

Hmmmmm I think I will use the palm lines of G9 as example. They are white on the specular occlusion and roughness maps of the G9 Starter Essentials, but the palm lines on the specular and ambient occlusion maps of a certain artist are grey/dark grey. To me the palm lines should not be shiny when rendered.

So back to my question: should areas that are shiny be shown as black or white on the specular, ambient occlusion and specular occlusion maps? I want to know the correct DS definition.

Sorry I am quite confused as even the same type of map is not standardized across different artists.

plasma_ring

 

CHWT said:

plasma_ring said:

The reason you might be seeing different map layouts for effects like shine is that some artists control them with maps that specify where they are, and some control them with maps that specify where they aren't. A map in a weight channel (which adds shine) may have white where the shine is because it's saying "put shine here," and a map in the roughness channel (which reduces shine) will have black there because it's saying "don't put roughness here."

Hmmmmm I think I will use the palm lines of G9 as example. They are white on the specular occlusion and roughness maps of the G9 Starter Essentials, but the palm lines on the specular and ambient occlusion maps of a certain artist are grey/dark grey. To me the palm lines should not be shiny when rendered.

So back to my question: should areas that are shiny be shown as black or white on the specular, ambient occlusion and specular occlusion maps? I want to know the correct DS definition.

Sorry I am quite confused as even the same type of map is not standardized across different artists.

Substance Painter is pretty close to standard, and by default the AO maps it creates have occlusion defined by black areas, so if you used one to control shine weight the white areas would be shiny. I'm actually setting up a character's horns like that right now, so I have an example handy (you may have to look at these full size to see what the difference is):

The first one that's mostly white is how the map is created in Substance Painter, where the black areas correspond to cavities on the model. The second one I just inverted in Photoshop, but you can see how it adds reflective detail to the cavities and removes them from the ridges.

Then, this is what happens when you put the first map in the Dual Lobe Specular Reflectivity slot and the second map in the Specular Lobe 1 Roughness slot:

In the reflectivity slot, white is telling the object where to be as shiny as possible. In the roughness slot, white is telling it where to not be shiny at all. Looking at the G9 Starter Essentials map you mentioned, it's in the roughness slot, so the white lines should be removing shine.

CHWT

plasma_ring said:

 

CHWT said:

plasma_ring said:

The reason you might be seeing different map layouts for effects like shine is that some artists control them with maps that specify where they are, and some control them with maps that specify where they aren't. A map in a weight channel (which adds shine) may have white where the shine is because it's saying "put shine here," and a map in the roughness channel (which reduces shine) will have black there because it's saying "don't put roughness here."

Hmmmmm I think I will use the palm lines of G9 as example. They are white on the specular occlusion and roughness maps of the G9 Starter Essentials, but the palm lines on the specular and ambient occlusion maps of a certain artist are grey/dark grey. To me the palm lines should not be shiny when rendered.

So back to my question: should areas that are shiny be shown as black or white on the specular, ambient occlusion and specular occlusion maps? I want to know the correct DS definition.

Sorry I am quite confused as even the same type of map is not standardized across different artists.

Substance Painter is pretty close to standard, and by default the AO maps it creates have occlusion defined by black areas, so if you used one to control shine weight the white areas would be shiny. I'm actually setting up a character's horns like that right now, so I have an example handy (you may have to look at these full size to see what the difference is):

The first one that's mostly white is how the map is created in Substance Painter, where the black areas correspond to cavities on the model. The second one I just inverted in Photoshop, but you can see how it adds reflective detail to the cavities and removes them from the ridges.

Then, this is what happens when you put the first map in the Dual Lobe Specular Reflectivity slot and the second map in the Specular Lobe 1 Roughness slot:

In the reflectivity slot, white is telling the object where to be as shiny as possible. In the roughness slot, white is telling it where to not be shiny at all. Looking at the G9 Starter Essentials map you mentioned, it's in the roughness slot, so the white lines should be removing shine.

Wow, thanks a lot for the detailed explanation!

Soooooo, if a map is used as specular / ambient occlusion / specular occlusion, white adds shine; if the same map is used as roughness map, white adds roughness i.e., reduces shine. Am I right?

plasma_ring

CHWT said:

Wow, thanks a lot for the detailed explanation!

Soooooo, if a map is used as specular / ambient occlusion / specular occlusion, white adds shine; if the same map is used as roughness map, white adds roughness i.e., reduces shine. Am I right?

I'm happy it helped! :D Yep, that's pretty much it, although someone more familiar with how ambient occlusion works in Daz could probably give you a more exact answer. The easiest way I find to think of it is that white is "yes" and black is "no," so once you learn what a channel does, white is just where the effect is active.

The main reason people set things up differently is that an effect that adds shine looks different from an effect that takes it away, and you can get some pretty interesting effects using the same maps Substance Painter uses to control things like edge wear and shadow. I want my characters to look painted rather than realistic, so I do some weird stuff with maps to create more stylized shine effects.

CHWT

plasma_ring said:

CHWT said:

Wow, thanks a lot for the detailed explanation!

Soooooo, if a map is used as specular / ambient occlusion / specular occlusion, white adds shine; if the same map is used as roughness map, white adds roughness i.e., reduces shine. Am I right?

I'm happy it helped! :D Yep, that's pretty much it, although someone more familiar with how ambient occlusion works in Daz could probably give you a more exact answer. The easiest way I find to think of it is that white is "yes" and black is "no," so once you learn what a channel does, white is just where the effect is active.

The main reason people set things up differently is that an effect that adds shine looks different from an effect that takes it away, and you can get some pretty interesting effects using the same maps Substance Painter uses to control things like edge wear and shadow. I want my characters to look painted rather than realistic, so I do some weird stuff with maps to create more stylized shine effects.

white means 'yes' and black means 'no', good tip! Thanks again!

Matt_Castle

Note that DS has a (somewhat hidden) function called the Image Editor which can be used to invert the way a map is used. This is a very useful function, but its existence can cause confusion in cases like this.

CHWT

Matt_Castle said:

Note that DS has a (somewhat hidden) function called the Image Editor which can be used to invert the way a map is used. This is a very useful function, but its existence can cause confusion in cases like this.

Never know I can do that! Could you please explain a little bit more on how to invert a map?

felis

Left click on an image and select Image Editor. And there you can select Invert.

CHWT

felis said:

Left click on an image and select Image Editor. And there you can select Invert.

Thank you!

Matt_Castle

It's a very useful feature; you can also use it to tile an individual map separately to the rest of the material (although note that none of its effects will show up in OpenGL, only in Iray), or to use the alpha from an image as a mask rather than the greyscale.

Note that none of its functions interfere with Iray's texture instancing. (Iray can normally only reuse a texture in VRAM if different channels/surfaces are using an absolutely identical texture, but the image editor's inversion/tiling/etc can be used without having to load two version of the texture).

CHWT

Matt_Castle said:

It's a very useful feature; you can also use it to tile an individual map separately to the rest of the material (although note that none of its effects will show up in OpenGL, only in Iray), or to use the alpha from an image as a mask rather than the greyscale.

Note that none of its functions interfere with Iray's texture instancing. (Iray can normally only reuse a texture in VRAM if different channels/surfaces are using an absolutely identical texture, but the image editor's inversion/tiling/etc can be used without having to load two version of the texture).

noted. Thanks a lot!