How to use displacement and gloss image from POLIIGON

[bdesign]

Thanks very much, Søren. I really appreciate all your technical enlightenment.

Eric

[Will Gibbons]

The recent enlightening information from Søren concerning the non-linear relationship between gloss and roughness got me wanting to delve futher into this subject. When searching, I came across this great post from 4 years ago by DriesV: https://www.keyshot.com/forum/index.php?topic=4751.0 .
Based on his findings, I opened a new 32-bit document in Photoshop and created a custom gradient in 10% increments, entering the floating point roughness values provided. I then opened a gloss map from Poliigon (Tiles 40_GLOSS_3K) and applied a Gradient Map adjustment layer using the custom gradient, then saved out as a new file. I used this new map in the Roughness channel along with the rest of the Tiles 40 texture map set. To my eye, the resulting render is significantly improved in overall appearance and realism. I'm attaching the custom PS gradient (GlossInversion_GradientMap.grd) for any who wish to give it a try. Place it into your AppData/Roaming/Adobe/Adobe Photoshop/Presets/Gradients folder and load it into the Gradient Editor window when applying the Gradient Map adjustment layer. Thanks again to Søren and Dries for the inspiration to dig deeper into this.

Cheers,
Eric

Hi Eric, quick question. How did you arrive at those values for each stop in creating the gradient adjustment layer?

Thanks,

[bdesign]

The recent enlightening information from Søren concerning the non-linear relationship between gloss and roughness got me wanting to delve futher into this subject. When searching, I came across this great post from 4 years ago by DriesV: https://www.keyshot.com/forum/index.php?topic=4751.0 .
Based on his findings, I opened a new 32-bit document in Photoshop and created a custom gradient in 10% increments, entering the floating point roughness values provided. I then opened a gloss map from Poliigon (Tiles 40_GLOSS_3K) and applied a Gradient Map adjustment layer using the custom gradient, then saved out as a new file. I used this new map in the Roughness channel along with the rest of the Tiles 40 texture map set. To my eye, the resulting render is significantly improved in overall appearance and realism. I'm attaching the custom PS gradient (GlossInversion_GradientMap.grd) for any who wish to give it a try. Place it into your AppData/Roaming/Adobe/Adobe Photoshop/Presets/Gradients folder and load it into the Gradient Editor window when applying the Gradient Map adjustment layer. Thanks again to Søren and Dries for the inspiration to dig deeper into this.

Cheers,
Eric

Hi Eric, quick question. How did you arrive at those values for each stop in creating the gradient adjustment layer?

Thanks,

Hey Will-
In the old post by Dries that I referenced (reply #4 under this thread: https://www.keyshot.com/forum/index.php?topic=4751.0 ), he presents a chart with paint gloss values from 10%-90%, with the corresponding roughness values in orange. 0% and 100% gloss are assumed to be black and white, respectively. I used the floating point values in orange, with pure white and pure black on each end.

Eric

[Will Gibbons]

That makes sense. So, assuming those values are the ideal ones, each stop in your gradient doesn't need any tweaking, correct?

Thanks,

[bdesign]

That makes sense. So, assuming those values are the ideal ones, each stop in your gradient doesn't need any tweaking, correct?

Thanks,

Well...that's the way I look at it. This isn't a "scientifically accurate" inversion I'm sure, but I think it's close, and I'm quite happy with the results

Eric

[Will Gibbons]

That makes sense. So, assuming those values are the ideal ones, each stop in your gradient doesn't need any tweaking, correct?

Thanks,

Well...that's the way I look at it. This is in no way, of course, a scientifically accurate inversion I'm sure, but I'm pretty happy with the results

Eric

Understood. Thanks!

[bdesign]

Understood. Thanks!

Sure thing, Will

Cheers,
Eric

[Esben Oxholm]

Interesting thread, guys!
I never thought about the relationship between gloss and roughness not being linear. 

Would it be possible in some way to do the gradient conversion with the material graph directly inside KeyShot, to save the additional conversion in Photoshop? I guess not, but I keep being surprised with your solutions, Eric

[soren]

For gradient node conversion, see mtl-file posted here https://www.keyshot.com/forum/index.php?topic=13929.0

/Søren