> <ffj### [at] club-internetfr> wrote:
>
> >I'd like to know if some of you have some tips to render metallic
> >textures.
> >What kind of value they give to brilliance, diffuse, ambient,.....
> >If they add normal to it.....
> >
> >I'd like to know how the others deal with it and how they build them.
>
> I am not an expert in any case but anyway see if my experience is of
> help.
>
> Pigment:
>
> A solid color :) I prefer unsaturated colors for metals but of course
> there are exceptions, such as copper or gold.
>

By unsaturated, do you mean a color like <0.2,0.2,0.2> ?

>
> Finish:
>
> I always go for a low ambient (0.05-0.2) and a diiffuse equal to
> 1-ambient (unless reflection is used), using a brilliance from 1.75 to
> 3.25, usually setting in the range 2.25-2.75.

> I also always use two
> highlights, a tight specular in the range 0.5-1 and roughness
> 0.0005-0.005 and a soft phong with half the specular's intensity and a
> phong_size in the range 20-5.

Ah maybe that's the trick I was looking for : A soft and a tight
highlights.

> With these, I use metallic 0.75-1,
> usually 0.9 or so. Reflection is also important, but I never go over
> 0.5. With MegaPOV, reflect_metallic is also very helpful, as much as
> metallic itself.

Reflect_metallic ? I am going to browse the MegaPOV help more thoroughly.
Apparently, I have missed a few interesting new features

>
> Normal:
>
> I don't usually use a normal unless I want to achieve some kind of
> anisotropy. In this case I use a very finely scaled normal (like scale
> 0.0001 - 0.001 for a unit sphere) following the direction of the
> anisotropy. For example, if a brushed aluminum Utah teapot is what
> you're after, you can give the lid a wood normal with a very high
> frequency (1000-10000) or scaled very small. As a rule og thumb that I
> use, there should be two or more complete waveforms of the normal in
> every pixel. This, of course, requires antialiasing settins akin to
> +am0.025 +am2 +r3 +j1.0 +patience=Godlike , but it is (still) the only
> way to achieve anisotropy in POV.
>
> Photons:
>
> Photons help if the object is a) reflective and b) complex. It has to
> have some way to reflect light onto itself and then photons make
> wonders for photorealism.
>
> Radiosity:
>
> I've hardly used radiosity so I can't help you any here, sorry.
>
>

Thanks for all



> Maybe you'll find some of the above applicable.
>
> Peter Popov ICQ : 15002700
> Personal e-mail : pet### [at] usanet
> TAG      e-mail : pet### [at] tagpovrayorg

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