Le 16-01-08 22:45, Mike Horvath a écrit :
> I have a nice gold glass texture I am using for sunscreens in my space
> scene.
>
> texture
> {
>      pigment {gamma_color_adjust(<1.000, 0.875, 0.575, 0.000, 0.900>)}
>      finish
>      {
>          brilliance    2
>          diffuse        D_GoldA
>          ambient        A_GoldA
>          reflection    R_GoldA
>          metallic    M
>          specular    0.20
>          roughness    1/20
>      }
> }
>
> What would a good similar one be for copper? Thanks.
>
>
> Mike

Metellic textures should rely mostly on their reflectivity, with little 
to no diffuse and NO ambient at all.

This gives a finish similar to this:

finish{
  brilliance 2 // or more
  diffuse albedo 0.1 // or less
  ambient 0 // Anything else is unrealistic
  specular albedo Specular_Value
  roughness 0.05 // (= 1/20) or less
  metallic
  reflection{Metal_reflection metallic }
// if using uberpov, add the same roughness as specular
}

As the brilliance increase, the specular and reflection should do the 
same and roughness and diffuse should go down.

ambient must be set at zero. Editing metals.inc and gold.inc to use 
ambient 0 everywhere, in my opinion, greatly improve those textures, and 
the scenes that use them.

Adding albedo greatly improve the finish. As brilliance increase, it's 
effect become more important.

Normaly, Metal_Reflection should be a gray value. Using a colour and 
metallic will exagerate the colouring of the reflection in an 
unrealistic way, but may be used for artistic purpose or for some 
special effects if the relfection colour is different from the metal's 
pigment.

Amy metallic finish greatly depend on it's environment.



Alain

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