Author Topic: another metal/roughness to gloss/spec question...!  (Read 5608 times)

Hi
I'm using modo and of course try to render my maps from SP in gloss/spec... Not sure why but I get random results. Sometimes my exported specular map is in color (looks like a pale version of my diffuse map). Sometimes it is grayscale. I try to make a fabric material with no specularity. In SP, my roughness map is pure withe and no metal channel of course... When I export, I get a gloss map pure black (ok I think) and a gray spec map (??). Is it normal? In modo, I put gloss map on roughness and spec map on specular amount... Is it ok? Then I get a material that is not at all what I want... specular spots...!
I also did a material for a head mesh just like in the tutorial (great tutorials by the way). Cannot get near the result for specularity and gloss/roughness in modo...
Any help for me?
Thanks a lot
Great software Allegorithmic!!! Very pleasant to use!

Hi
I'm using modo and of course try to render my maps from SP in gloss/spec... Not sure why but I get random results. Sometimes my exported specular map is in color (looks like a pale version of my diffuse map). Sometimes it is grayscale. I try to make a fabric material with no specularity. In SP, my roughness map is pure withe and no metal channel of course... When I export, I get a gloss map pure black (ok I think) and a gray spec map (??). Is it normal? In modo, I put gloss map on roughness and spec map on specular amount... Is it ok? Then I get a material that is not at all what I want... specular spots...!
I also did a material for a head mesh just like in the tutorial (great tutorials by the way). Cannot get near the result for specularity and gloss/roughness in modo...
Any help for me?
Thanks a lot
Great software Allegorithmic!!! Very pleasant to use!

Hi,

Sometimes my exported specular map is in color (looks like a pale version of my diffuse map). Sometimes it is grayscale.

In the spec/gloss workflow, you will have both metal and non-metal reflectance values. Non-metal values will always be greyscale and rather low as most common dielectric materials will reflect 4%. When the specular contains color, it is in reference to metal. Metal has a much higher reflectance value 60-100% and can be tinted. 

In SP, my roughness map is pure withe and no metal channel of course... When I export, I get a gloss map pure black (ok I think) and a gray spec map (??). Is it normal?

A roughness map of pure white would be the surface is completely rough. The gloss map is the same data, but its inverted. With roughness. 0.0 (black) = smooth and 1.0 (white) rough. With glossiness, its the invert 0.0 (black) rough and 1.0 (white) smooth.

In modo, I put gloss map on roughness and spec map on specular amount... Is it ok? Then I get a material that is not at all what I want... specular spots...!

There is a good thread on the foundry forum for Substance PBR maps and modo. This might help with the material setup.
http://community.thefoundry.co.uk/discussion/topic.aspx?f=32&t=92574&show=pbr

Diffuse amount: 100%
Conserve energy: On
Fresnel: 100%
Match specular: On

I also did a material for a head mesh just like in the tutorial (great tutorials by the way). Cannot get near the result for specularity and gloss/roughness in modo...

Thanks! I make the tutorials. Can you post your images and I can take a look.

Cheers,

Wes
Integrations Product Manager / Training
wes.mcdermott@allegorithmic.com
Twitter: The3DNinja

Hi
My gloss map of the head exported from SP is gray and rough regions are white... I think it should be black... And my spec map is uniform gray... don't know why... The result is a very specular head...! Any ideas?
Thanks

Hi
My gloss map of the head exported from SP is gray and rough regions are white... I think it should be black... And my spec map is uniform gray... don't know why... The result is a very specular head...! Any ideas?
Thanks

Hi,

Yes, it does seem that the "rough" areas in the glossiness map should be black. Gloss is invert of rough. Can you post what the toughness map export looks like?

For the specular, this grey value is correct. This spec map is referencing a dielectric material (non-metal) and it's using the 0.04 (4%) reflectance for common dielectrics. Skin is about 0.028 (linear F0 value). But this specular was derived from the metal/rough workflow where the dielectric F0 value is hardcore as 0.04.

If the skin is very shiny, it looks like the gloss map is being read as "shiny" and that is where the high spec is coming from.

Cheers,

Wes
Integrations Product Manager / Training
wes.mcdermott@allegorithmic.com
Twitter: The3DNinja

metal/rough workflow where the dielectric F0 value is hardcore as 0.04.

This made me laugh, I know its supposed to be hardcoded but 0.04 is definitely a hardcore float! :)

Ironically 2 hours ago I was just watching your older Twitch video where you showed the web site where you got this data.

Mike

Ok
Gloss map would be like this: black = rough and white = smooth.
Roughness map is the inverse: black = smooth and white = rough.
So my maps looks ok.
I'll try again.
Thanks

Should I put the gloss map in the oil roughness in the skin material in Modo? and the spec map in oil specular amount?
Thnaks

metal/rough workflow where the dielectric F0 value is hardcore as 0.04.

This made me laugh, I know its supposed to be hardcoded but 0.04 is definitely a hardcore float! :)

Ironically 2 hours ago I was just watching your older Twitch video where you showed the web site where you got this data.

Mike

Hey Mike,

Hehe. Yeah, I meant hardcoded : )  The 0.04 is in linear space.

Cheers,

Wes
Integrations Product Manager / Training
wes.mcdermott@allegorithmic.com
Twitter: The3DNinja

Should I put the gloss map in the oil roughness in the skin material in Modo? and the spec map in oil specular amount?
Thnaks

Yes, you can give that a try. The exact mapping will be different as the shaders are not the same. Modo is using a physically-based system, but its more complex than the PBR realtime shaders.

Cheers,

Wes
Integrations Product Manager / Training
wes.mcdermott@allegorithmic.com
Twitter: The3DNinja