making a reflective roadsign using Substance Designer/Painter and Marmoset...

oraeles77

currently iim using rough-metal pbr.

non metal, fully black.

roughness white, with the less reflective areas a tiny bit grayer.

could Sub-surfice shading outputs or a smoothness output help? etc?

example of the sort of thing im making.

Obscura

You are looking for "iridescence". But it sounds like you are also using roughness wrong. White means fully rough. You can probably mimic this effect with a specular pbr setup too. Not as good as iridescence, but quite close. Try using a colored specular map.

oraeles77

Obscura said:

You are looking for "iridescence". But it sounds like you are also using roughness wrong. White means fully rough. You can probably mimic this effect with a specular pbr setup too. Not as good as iridescence, but quite close. Try using a colored specular map.

opps, yeah i meant black not white! so if I export a sbsar file with a 'colored specular map' it should have an effect? 

ActionDawg

Yes*

You can paint colored specular however you like and get pretty darn close to the look you want, but it won't look exactly the same as real iridescence because iridescence isn't quite the same as standard specular.

Roughness/gloss is unrelated. A surface can be relatively rough and iridescent like the reference you shared, or iridescent and almost mirror-gloss like a beetle's shell or a soap bubble. Roughness is a quality of a surface finish. Specular, albedo, etc are qualities of a material itself.

oraeles77

somedoggy said:

Yes*

You can paint colored specular however you like and get pretty darn close to the look you want, but it won't look exactly the same as real iridescence because iridescence isn't quite the same as standard specular.

Roughness/gloss is unrelated. A surface can be relatively rough and iridescent like the reference you shared, or iridescent and almost mirror-gloss like a beetle's shell or a soap bubble. Roughness is a quality of a surface finish. Specular, albedo, etc are qualities of a material itself.

well come to think of it, iridescence in physics is pretty different, thats when a metal etc has a few different colours, I was thinking of something which just just reflects a shit ton of light, for exmaple in that above image the red and the white would both be exactly the same on the smooth level, the only difference would be the specular of the white would be a bit higher.

road signs are retrofelfective, it means the light goes straight in, and and bounches little and goes straight out back towards its source, iridesence is when it bounces around a lot inside the material and looks pretty. so for retroreflective, would an IOR output or scattering or anisotropy or refraction have any use in Marmoset?

poopipe

There's nothing in Painter to emulate retroreflectivity - you need to use a specific lighting model 

oraeles77

poopipe said:

There's nothing in Painter to emulate retroreflectivity - you need to use a specific lighting model 

and what about the additional outputs in Substance Designer, do you know if any of them are compatible with marmoset?

poopipe

If marmoset has a shader that supports retroreflectivity you can produce data for it in Painter or designer.  I suspect it  doesn't as its a pretty niche requirement. 

Obscura

You could definitely write one though. There are several tutorials about Toolbags shading pipeline. Anyways, I think you should just go with a colored spec map.

Eric Chadwick

Moving your thread from Technical Talk to Marmoset, to get more targeted answers.

ActionDawg

oraeles77 said:

somedoggy said:

Yes*

You can paint colored specular however you like and get pretty darn close to the look you want, but it won't look exactly the same as real iridescence because iridescence isn't quite the same as standard specular.

Roughness/gloss is unrelated. A surface can be relatively rough and iridescent like the reference you shared, or iridescent and almost mirror-gloss like a beetle's shell or a soap bubble. Roughness is a quality of a surface finish. Specular, albedo, etc are qualities of a material itself.

well come to think of it, iridescence in physics is pretty different, thats when a metal etc has a few different colours, I was thinking of something which just just reflects a shit ton of light, for exmaple in that above image the red and the white would both be exactly the same on the smooth level, the only difference would be the specular of the white would be a bit higher.

road signs are retrofelfective, it means the light goes straight in, and and bounches little and goes straight out back towards its source, iridesence is when it bounces around a lot inside the material and looks pretty. so for retroreflective, would an IOR output or scattering or anisotropy or refraction have any use in Marmoset?

Iridescence is a general term for when the color of a surface's specular reflection appears to change with viewing angle. How it manifests physically can vary. Through thin-film interference it happens with essentially no internal bouncing, such as on bubbles and metals like bismuth which produce a thin oxide layer when exposed to air. The case you explain towards the end of your post is more like diffraction which is seen on CDs, bugs, fish, etc.

Retroreflection also isn't related to the amount of reflected light, but like you said about reflecting light right back in its source direction. These are all dielectric materials we're working with here, so adjusting IOR doesnt do the trick. In the real world it's done with a thin layer of microscopic glass beads or special patterns like the fancy diamond sheets you see around. Both will exhibit some amount of iridescence and using beads will exhibit more.


So for correctness you need a custom shader which reflects specular light back along its incoming direction instead of using the surface normal. Nothing currently has this built in.

oraeles77

somedoggy said:

oraeles77 said:

somedoggy said:

Yes*

You can paint colored specular however you like and get pretty darn close to the look you want, but it won't look exactly the same as real iridescence because iridescence isn't quite the same as standard specular.

Roughness/gloss is unrelated. A surface can be relatively rough and iridescent like the reference you shared, or iridescent and almost mirror-gloss like a beetle's shell or a soap bubble. Roughness is a quality of a surface finish. Specular, albedo, etc are qualities of a material itself.

well come to think of it, iridescence in physics is pretty different, thats when a metal etc has a few different colours, I was thinking of something which just just reflects a shit ton of light, for exmaple in that above image the red and the white would both be exactly the same on the smooth level, the only difference would be the specular of the white would be a bit higher.

road signs are retrofelfective, it means the light goes straight in, and and bounches little and goes straight out back towards its source, iridesence is when it bounces around a lot inside the material and looks pretty. so for retroreflective, would an IOR output or scattering or anisotropy or refraction have any use in Marmoset?

Iridescence is a general term for when the color of a surface's specular reflection appears to change with viewing angle. How it manifests physically can vary. Through thin-film interference it happens with essentially no internal bouncing, such as on bubbles and metals like bismuth which produce a thin oxide layer when exposed to air. The case you explain towards the end of your post is more like diffraction which is seen on CDs, bugs, fish, etc.

Retroreflection also isn't related to the amount of reflected light, but like you said about reflecting light right back in its source direction. These are all dielectric materials we're working with here, so adjusting IOR doesnt do the trick. In the real world it's done with a thin layer of microscopic glass beads or special patterns like the fancy diamond sheets you see around. Both will exhibit some amount of iridescence and using beads will exhibit more.


So for correctness you need a custom shader which reflects specular light back along its incoming direction instead of using the surface normal. Nothing currently has this built in.

ahh ok. well one can only dream then. thank you for the additional diagrams.

oraeles77

Eric Chadwick said:

Moving your thread from Technical Talk to Marmoset, to get more targeted answers.

no worries man. you good?