Le 2023-11-29 à 09:20, Mike Miller a écrit :
> "Cousin Ricky" <rickysttATyahooDOTcom> wrote:
>> "Mike Miller" <mil### [at] gmailcom> wrote:
>>> Updated train on workbench. Added Santa hat on mannequin, ribbon/bow on train,
>>> and a few Christmas cards. Getting close on this one. May tweak the view angle a
>>> bit.
>>> Miller.
>>
>> The textures of the metal trimmings on the locomotive look milky.  I suggest
>> lowering the diffuse and ambient values in the finish.
> 
> Thanks...I'll take a look at that.
> Usually, a metallic finish should have an ambient of zero, or a very 
small value for a very dull surface.
Then, a diffuse should be less than 0.3. 0.3 for the dullest finish, 
down to zero for the very shiny.
Use reflection with the metallic attribute.
The finishes in metals.inc and golds.inc are totally wrong. They have 
insane ambient values. They where made to look good in an empty scene 
with nothing but black to reflect.


If the metal is to have a varnish coat, add a second mostly to fully 
transparent pigment layer above the metallic one. Add an interior 
statement for the IOR : interior{ ior 1.5 } And use the fresnel 
attribute : reflection{ 1 fresnel }.

That way, at high angle, you'll see almost only the metallic surface, 
but, at grazing angles, you get the fresnel reflection dominating.
Tried that and compared with actual metals, brass actually, coated with 
a varnish, and the result matched my physical samples.

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