Author Topic: What texture should I use and where should I connect them while using Arnold  (Read 8706 times)

Hi! I have been using Substance Painter and enjoying it.
but the thing is, it looks nice inside of Substance Painter, but when I use maya and Arnold to do render, I cannot get the same result even I use the same HDRI light.

This is the closed result I can get(in the attachment)

I use roughness as the only texture because roughness is the only thing have different value in Substance Painter
You can see how I connect the texture in maya and aiStandard Material

I have the same HDRI, But I cannot get the same result, Please tell me how to make the transfer between Substance Painter and Arnold for maya, with out an accurate way, Texture in substance Painter means NOTHING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I can't see your images so I don't know how you plugged it but :
To make it work, you should use the PBR (metal/roughness) materials from substance, and output all maps from it

if you have a non metallic material, it's easy for a quick shader :
diffuse color slot -> diffuse map (gamma corrected with a node)
diffuse weight at 1
specular weight at 1
specular color -> pure white  (gamma corrected with a node)
specular roughness -> roughness map
tick the fresnel box on and put the reflectance at normal value depending on your material (around 0.030~40)

If you have a pure metallic material
diffuse color slot >  black (you can also use a toned done diffuse map) (gamma corrected with a node)
diffuse weight at 1
specular weight at 1
specular color -> diffuse map (gamma corrected with a node)
roughness map -> specular roughness
tick the fresnel box off

with a mix of both metallic or non, i's a bit trickier

basically you need to tick fresnel on and use the metallic map to blend a value of 1 for metallic portions and your 0.035 value for the reflectance at normal value.
use a blend for the diffuse and specular color as well.

bump is as usual.

BTW, the shader computation being different in different renderers, except by building a custom realtime shader you won't have a 100% accurate preview though.

(note, those are for quick shaders that would work in most cases but not every cases and I wish arnold had a viable way to blend materials like Vray)

Well, I am afraid that is a bit of a simplification.

First off. EVERYTHING has fresnel. In metals it might not be as noticable because they tend to have a very high basereflectance (meaning in the center) to begin with, so you might not see how it gradualy gets stronger towards the edges, but trust me, even metals have fresnel.

for instance you can go here:
http://refractiveindex.info/
to see how the basereflectance is for all different kinds of metals. simply choose on the top of the site wich material you want, then scroll down to the bottom to view the fresnel curve.

Second. In arnold you rarely need gamma curves as this is handeled by the render globals. Also to mention it any gamma curve applied to white will end up beeing the same white. a gamma curve really just alteres values greater than black and smaller than white, basically leaving black and white themselves as is. So gamma correcting white is really futile.

On the topic of layering. The layered shader in maya works just fine. only thing you have to do is switch the layering to "layered texture" and it works like charm. so you can always make two shaders, one metal and one nonmetal, and layer them using the metallic map to blend them.

cheers

Guillaume

PS: here the reflectance curve of chrome. I'd say that looks quite fresnel to me.
;)

It is a simplification, I do agree, yet it does work in most cases ;)

as for the layered shader, the render times unfortunately tends to get pretty long if you rely on them too much :/
need to try again with the latest release though.

For the gamma curve, depends on your pipeline as well. At work we use the gamma nodes instead of the render settings (probably an remnant of MR and Vray workflow since we still use both of those as well)

Thanks for the precisions though, and the link is a goldmine  :D

I have the same problem roughness maps doesn't work in arnold i tried to use white and black fill maps and there wasn't any differance ... it renders like it was a white map