This shader simulates a metallic surface.
Ka is the coefficient to the ambient function.
Ks is the coefficient to the specular function.
rgh is the exponent to the specular function.
OPAC is the surface opacity.
SURF is the surface color.
NN can be used to add a bump pattern or texture.

This must be a float.  The default is 1.0.
Coefficient to the ambient function, controls the intensity 
of the color returned from the ambient function.

This must be a float.  The default is 1.0.
Coefficient to the specular function, controls the intensity 
of the highlight returned from the specular function.

This must be a float.  The default is 0.05.
Roughness is the exponent to the specular function.
It controls the rate to the falloff for the highlight.

This must be a color.  The default is WHITE.
This is the surface opacity color.
Transparent is black; completely solid is white.

This must be a color.  The default is GOLD.
This is the surface color.

This must be a normal.  The default is the surface normal, N.
This affects the normal for purposes color shading.

This shader simulates a metallic surface.
This the returned surface opacity.

This shader simulates a metallic surface.
This the returned surface color.