Hello there.

My metal textures are always a little dull and boring and I wanted to ask if
there are any tips you could give me to spice them up a bit. For example, is
it possible to define a kind of reflection map? They used to help me a lot
to make realistic metals in MAX but I don't know if and how I can create
similar effects with POV. Thanks in advance!

Ansgar

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Ansgar wrote:
> Hello there.
> 
> My metal textures are always a little dull and boring and I wanted to ask if
> there are any tips you could give me to spice them up a bit. For example, is
> it possible to define a kind of reflection map? They used to help me a lot
> to make realistic metals in MAX but I don't know if and how I can create
> similar effects with POV. Thanks in advance!
> 
> Ansgar

You could take a peek at metals.inc. A lot of people don't like the 
predefined textures that come with Pov, but I'm happy with metals.inc, 
even if just as a starting point for my own textures. If nothing else, 
looking at the finishes in metals.inc will give you some hints on how 
reflections work in Pov.

You shouldn't need anything like a reflection map in Pov, since Pov is a 
genuine, honest-to-goodness raytracer. :-)

-- 
William Tracy
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You know you've been raytracing too long when you look at waterfalls, 
dust, rain, snow, etc, and think: "If only I had a fractalized, vector 
based particle-system modeler with collision detection!"

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> You shouldn't need anything like a reflection map in Pov, since Pov is a
> genuine, honest-to-goodness raytracer. :-)

Yes, I know that, but it is only an advantage when the metallic object in
question has an environment it can reflect. If the object is the only one
in the scene, though, it reflects nothing and therefore looks very plain.
That's where a reflection map would produce better results, cos in reality,
objects never exist in empty spaces and thus always reflect *something*.

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"Ansgar" <Tem### [at] gmxde> wrote in message 
news:web.4646234b9f35239cb86afba0@news.povray.org...
>> You shouldn't need anything like a reflection map in Pov, since Pov is a
>> genuine, honest-to-goodness raytracer. :-)
>
> Yes, I know that, but it is only an advantage when the metallic object in
> question has an environment it can reflect. If the object is the only one
> in the scene, though, it reflects nothing and therefore looks very plain.
> That's where a reflection map would produce better results, cos in 
> reality,
> objects never exist in empty spaces and thus always reflect *something*.

You can put in a textured background, and then use
no_image and no_shadow on it... that way it will only
be in the reflections.

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"Tim Attwood" <tim### [at] comcastnet> wrote:
> "Ansgar" <Tem### [at] gmxde> wrote in message
> news:web.4646234b9f35239cb86afba0@news.povray.org...
> >> You shouldn't need anything like a reflection map in Pov, since Pov is a
> >> genuine, honest-to-goodness raytracer. :-)
> >
> > Yes, I know that, but it is only an advantage when the metallic object in
> > question has an environment it can reflect. If the object is the only one
> > in the scene, though, it reflects nothing and therefore looks very plain.
> > That's where a reflection map would produce better results, cos in
> > reality,
> > objects never exist in empty spaces and thus always reflect *something*.
>
> You can put in a textured background, and then use
> no_image and no_shadow on it... that way it will only
> be in the reflections.

Better yet:  you could create a whole scene in pov and focus on the
reflections of it on the sphere.  Com'on, reflective spheres get old real
fast and they are only as interesting as what is reflected is.

I think povray should break out of the RSOCP stage and that doesn't come
effortlessly...

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William Tracy nous apporta ses lumieres en ce 12 / 05 / 2007 08:59:
> Ansgar wrote:
>> Hello there.
>>
>> My metal textures are always a little dull and boring and I wanted to 
>> ask if
>> there are any tips you could give me to spice them up a bit. For 
>> example, is
>> it possible to define a kind of reflection map? They used to help me a 
>> lot
>> to make realistic metals in MAX but I don't know if and how I can create
>> similar effects with POV. Thanks in advance!
>>
>> Ansgar
> 
> You could take a peek at metals.inc. A lot of people don't like the 
> predefined textures that come with Pov, but I'm happy with metals.inc, 
> even if just as a starting point for my own textures. If nothing else, 
> looking at the finishes in metals.inc will give you some hints on how 
> reflections work in Pov.
> 
> You shouldn't need anything like a reflection map in Pov, since Pov is a 
> genuine, honest-to-goodness raytracer. :-)
> 
There is a problem in metals.inc: all textures have way to much ambient. I 
edited it to remove all ambient in the finish and prefer the result.
There is noting resembling a reflection map in POV-Ray, and most ray tracers as 
they don't need that artifice.
Environment and reflection maps are mostly used in raster tracers, not ray tracers.

If you need something to reflect on your metal objects, use a large sphere with 
no_image and optionaly no_shadow if your light is outside it. Set it with 
finish{ambient 1 diffuse 0} and use some of the included sky pigment on it, or 
make your own texture.
Other things you can try:
Experiment with brilliance.
Experiment with variable reflection.
Experiment with the reflection exponent.
Experiment with falloff.
Give your object an interior with an ior in the 4 to 6 range (normal for metals) 
and use fresnel in the reflection{...} block. Works best when also using 
variable reflection.
Work with the specular/roughness and/or phong/phong_size highlight.

To make things interesting and simulate a very thin varnish coat or oily film, 
you can add iridescence by adding an irid{...} block in the finish.

-- 
Alain
-------------------------------------------------
REMEMBER: WHATEVER HAPPENS, HAPPENS FOR A REASON.

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