Arnold Complex Fresnel Shader in Maya

PetSto

Hello, I want ask you on how to create correct way complex fresnel for Arnold. Let for example, we want create complex fresnel for gold material. First we create SamplerInfo and ( RemapColor or 3xRemapValue ) and aiStandart Shader. Facing ratio in SamplerInfo is inverted, 0° is white 90° is black, then we need invert it with Reverse node. Connect all nodes together, as is on image.




RemapVaule is created for each RGB wavelenght as is on website refractiveindex.info, where brezier curve going from left to right (full reflection).




I use more simple way with mel script from renderblog that you can download from https://www.creativecrash.com/maya/script/cusrom-fresnel-tool,




but RemapVaule/Color brezier curve is inverted, where goes from left(full reflection) to right, then we dont need Reverse node for SamplerInfo - Facing ratio.




Then setup aiStandart shader, turn off fresnel, diffuse weight to 0, specular weight to 1.



But my material doesn't look like as gold.



I have few a questions.

1. RemapColor/Value need Gamma Correction (RGB 0.4545) ?
2. What I'm doing wrong ?

musashidan

What values did you input to the fresnel script? The RGB values are very sensitive(at least in Max/Vray)
Slight changes in value can greatly influence the result.
You shouldn't need to mess about with inverse gamma(.4545) if you're set up for a LWF.

PetSto

I did some tests and you have right, the RGB values are very sensitive to the end result. Regarding the gamma correction you have right too. On the website refractiveindex.info all values are linear and Arnold expects at default state all his input values are linear, then we do not need an inverse gamma.