Metal materials - Refl glossiness

[Umro]

Hello! I have a question about metal materials.When I want to make a scratched metal surface (for example) I usually use reflection glossines maps and I place them in output map to control the glossiness.Now recently I had some problems that took me for hours to solve and I wasn't happy with the solving method because it took me one day to make a metal surface as I would like it to be.The problem was that when the sun from HDRI or Corona Sun hits the metal surface directly than the glossiness map acts almost like diffuse color and makes metal look like bad photoshop.But in the shades the reflection acts normally.I noticed this happening in vray too in my office.If anyone has an answer for that I would be grateful.But back to the topic, I found out about vray next metalness option in vray mtl that works very nice with roughness GGX BRDF and roughness maps and gives fine results.In attachments you will see two metal materials one made with vray and one with corona.The slightly darker exposed one is with vray.Now in corona I tried to remake the metalness option by using the roughness map as anisotropy rotation and it is not what I am looking for.By using relf gloss I got worse results using the same maps as used in vray.If anyone can explain how to get this "metalness" effect or point me to a right tutorial it would be much help for me and I would be very grateful for it.P.S. I am talking about older and dusty looking metals with scratches and as you can see in vray image with that high reflections in the scratches.

[burnin]

From what I'm seeing you only need to play with texture map value & contrast or gamma, overall intensity to get the desired look.

[Umro]

I will try to play with the texture in photoshop and see what happens

[sprayer]

Share shader settings. looks like you have different setup, metal looking needs higher IOR. Also you have blue light in scene. Did you tired to convert vray material via script?

[romullus]

Metals needs good enviroment to really shine. Even best metal material will look like crap in solid white enviroment.

[Umro]

I dont want to have a shiny metal so my Fresnel should not go so high as usual.I want a dirty old schratched metal that lies down in your shack for a year.As for the lighting comment..yes you are right.But I wanted to get the same result as in vray with the same moslty bad lighting.

Here I have managed to get a similar result as with vray metalness option.I realised that with metalness and ggx roughness in vray you actually gives you inverted glossiness and the metalness option automatically cranks your Fresnel up a little.First I made a vray material with glossiness in my office to match the one with metalness and roughness.So I inverted the refl gloss map in output map and played with contrast and brightness of the map to get the approximately same result.Than I converted that in corona at home and here is my result.One thing that I don't quite understand is that how does the brdf ggx tail falloff in vray convert in corona? I mean what option in corona replaces it? I think that corona reflection replaces it because when I set up reflection to 0.6 instead of 1.0 in corona I got the similar result as in vray ggx tail falloff.Correct me if I am wrong.

Thank you all for your opinions, you have helped me to get to this result.

[Avan]

For the moment corona has only the PBR option checkbox (that is better for setup i mean) which slightly changes material behaviour to archieve good glossiness look. You don have to think about any other conversion options from VRAY. Just some play with map output (contrast, etc). Dont overcomplicate things)

One more thing i want to mention - you can archieve better metal using almost nonexistence diffuse (that is the rule for metalic surfaces) (in some cases it is possiple to add slight dark tone in it) and turn off fresnel (999) with ComplexFresnel plug-in in reflection colour.

[Umro]

Thanks for the advice

[maru]

You should be able to get almost identical metal materials with Corona and Vray.
As already mentioned, the basic rule for metal materials is setting diffuse level to 0 (unless the metal is supposed to be dusty or covered with something non-metallic). Then adjust Fresnel IOR and glossiness, and you are done. :)
I am also attaching a screenshots showing a simple setup allowing you to easily fine-tune the glossiness of your material. Just use it with IR.

[John.McWaters]

You should be able to get almost identical metal materials with Corona and Vray.
As already mentioned, the basic rule for metal materials is setting diffuse level to 0 (unless the metal is supposed to be dusty or covered with something non-metallic). Then adjust Fresnel IOR and glossiness, and you are done. :)
I am also attaching a screenshots showing a simple setup allowing you to easily fine-tune the glossiness of your material. Just use it with IR.

I see that some metal materials have a falloff map plugged into reflection color. Is that still necessary with PBR mode enabled?

[Umro]

You should be able to get almost identical metal materials with Corona and Vray.
As already mentioned, the basic rule for metal materials is setting diffuse level to 0 (unless the metal is supposed to be dusty or covered with something non-metallic). Then adjust Fresnel IOR and glossiness, and you are done. :)
I am also attaching a screenshots showing a simple setup allowing you to easily fine-tune the glossiness of your material. Just use it with IR.

Thank you for your example,never looked at making glossines maps in that way.Very helpful :)