Proper workflow for glossy materials

[SergKlyosov]

Hi all,

What is the proper setup of glossy materials to achieve correct results in reflection?
Here is example, I'm rendering road and borders of it made of concrete, but even with really bright roughness map and low value of IOR it is reflecting light like glossy plastic?
Same goes for asphalt too

In Corona for example PBR worflow for non metal objects - just keep reflection white and adjust glossiness and bump
But it is not working with octane, all materials which have just white specular - look like plastic

Thank you

[paride4331]

Hi SergKlyosov,
Specular map contains the reflectance information for both metal and dielectrics (non metal) surfaces. This is a key difference in the metal/rough and spec/gloss workflows. The same rules apply. You need to use measured values for metals and most all dielectrics will fall with the 0.04 - 4% range. If there is dirt on the metal, the reflectance value needs to be lowered as well. However, you can add different values in the specular map for dielectric materials since you have control to author the map.
Roughness describes the microsurface of the object. White 1.0 is rough and black 0.0 is smooth. The microsurface if rough can cause the light rays to scatter and make the highlight appear dimmer and more broad. The same amount of light energy is reflected going out as coming into the surface. This map has the most artistic freedom. There is no wrong answers here. This map gives the asset the most character as it truly describes the surface e.g. scratches, fingerprints, smudges, grime etc.
That said, you have to edit the specular node setting, using Value instead of None.
Regards
Paride

[SergKlyosov]

Hi Paride, thank you for the answer
I've found this tutorial https://youtu.be/6OUI74DN_2E?t=876
Is it proper workflow which you have described above?

I can't reproduce it cause gradient map in max doesn't have that "complex mode" and "start" and "end" inputs
Can you please tell me how to proper setup this gradient?

Thank you

[paride4331]

Hi SergKlyosov,
just like that if you have not a specular texture.
Regards
Paride

[SergKlyosov]

Hi Paride,

Unfortunately you didn't get my point. I understand how specular is working.
The question is how to properly setup a shader where exist mix of high reflective and matte objects and have proper falloff etc
That video link which I've pasted is about that

Thank you

[paride4331]

Hi SergKlyosov,
with PBR you need specular texture map, in your screenshot the specular texture map is not there, so it's like all your shader has specular 1.
to do a simple test, connect your roughness texture map to specular slot, inverting it and working with gamma.
Regards
Paride