Hello everyone,

Can anyone give some hints on how they go about creating realistic-looking
textures? I'd like to do something like rusty steel peeping out beneath
cracked weathered paint - without using an image-map (am I mad?). Obviously
I'm going to need some form of layered texture. But where does one start?
How do you choose the right colours?

Thanks
PrinceofGonville (www.wis.co.uk/justin)
keeper of
dmoz.org/Computers/Software/Graphics/3D/Animation_and_Design_Tools/POV_Ray/

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princeofgonville wrote:
> 
> Hello everyone,
> 
> Can anyone give some hints on how they go about creating realistic-looking
> textures? I'd like to do something like rusty steel peeping out beneath
> cracked weathered paint - without using an image-map (am I mad?). Obviously
> I'm going to need some form of layered texture. But where does one start?
> How do you choose the right colours?
> 
> Thanks
> PrinceofGonville (www.wis.co.uk/justin)

I use Trial and Error (TM).

For something like that - check the include files to find something like
the rust texture - I'm pretty sure there is one.  Then use a bozo
pattern over it, with transparent gaps to let it shine through.  

Er- shine isn't quite the right word for rust, is it.

-- 
Tom A.
"Archie!  You are headstrong.  I am imperious.  It's a miracle 
we get along as well as we do." - Nero Wolf
Deja mail is gone.  Look for me at raugost at yahoo . com

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"princeofgonville" <nomail@nomail> wrote in message
news:web.3dde6891452754514cc4564a0@news.povray.org...
: Hello everyone,
:
: Can anyone give some hints on how they go about creating realistic-looking
: textures? I'd like to do something like rusty steel peeping out beneath
: cracked weathered paint - without using an image-map (am I mad?). Obviously
: I'm going to need some form of layered texture. But where does one start?
: How do you choose the right colours?
: Thanks
: PrinceofGonville (www.wis.co.uk/justin)

Check out one of the IRTC entries from Feb 2001:

http://www.irtc.org/ftp/pub/stills/2001-02-28/cbwor.zip

This picture was recommended to me when I needed
to do the same. My code is now kind-of dedicated so
it's not as useful as the code by Christophe Bouffartigue.
Greate picture too, check it out...
=Bob=

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> I use Trial and Error (TM).

I use the related Moray/Pov process of Tweak and Render (TM)

:)

Jamie.

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princeofgonville wrote:

>Can anyone give some hints on how they go about creating realistic-looking
>textures? I'd like to do something like rusty steel peeping out beneath
>cracked weathered paint - without using an image-map (am I mad?). Obviously
>I'm going to need some form of layered texture. But where does one start?
>How do you choose the right colours?

"texture_map" gives you the most power for showing different
textures "on top" of each other. Here's a rusty pipe texture
that shows the technique you can start with; it's scaled for
a 0.5 unit diameter pipe. If you come up with some good ones,
share them with us!

-Mark Slone


#local IronPigment =
  pigment {
    wrinkles
    color_map {
      [0.0 rgb <0.05, 0.10, 0.15>]
      [0.7 rgb <0.10, 0.15, 0.20>]
      [1.0 rgb <0.15, 0.20, 0.30>]
               }
    scale 5
            }

#local IronTexture =
  texture {
    pigment { IronPigment }
    normal { granite 0.1  scale 2.0}
    finish { roughness  0.015  specular .5 }
           }

#local RustPigment =
  pigment {
    granite
    color_map {
      [ 0.0 rgb <0.8, 0.3, 0.1> ]
      [ 0.4 rgb <0.2, 0.1, 0.0> ]
      [ 0.6 rgb <0.2, 0.1, 0.0> ]
      [ 1.0 rgb <0.6, 0.1, 0.0> ]
               }
    scale .5
    turbulence 1
           }

#local RustTexture =
  texture {
    pigment { RustPigment }
    normal { wrinkles  scale 2 }
           }

#local RustyIronTexture =
  texture {
    bozo
    texture_map {
      [ 0.0 RustTexture ]
      [ 0.2 RustTexture ]  //  Rust
      [ 0.6 IronTexture ]  //  Iron
      [ 1.0 IronTexture ]
                 }
    warp { turbulence 1  omega .6  lambda 4 }
    scale <1,2,1>
           }

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in news:web.3dde6891452754514cc4564a0@news.povray.org princeofgonville
wrote: 

> I'm going to need some form of layered texture. But where does one
> start? How do you choose the right colours?
> 

A general approach, used a lot in printing:

Determine the general color of your texture, use that, without any 
pattern, as the first layer in your layered texture. 

Next layer contains the biggest parts of a pattern, the general 
structure. It will be partly transparent, the color of it will have the 
opposite "warmth/coolness" of the first layer. So if your first layer is 
a warm gray, with a "lot" of red, the second layer will have more blue 
in it.

This way you stack layer after layer, warm cool warm cool etc. Every 
layer adds finer detail to the texture.

Since all layers but the first are more or less transparent, you can 
control the general color impression by only changing the color of the 
first layer.

Ingo

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>princeofgonville wrote:
>
>>Can anyone give some hints on how they go about creating realistic-looking
>>textures? I'd like to do something like rusty steel peeping out beneath
>>cracked weathered paint - without using an image-map (am I mad?). Obviously
>>I'm going to need some form of layered texture. But where does one start?
>>How do you choose the right colours?

On re-reading your post I see you're more interested in how to choose
the colors. To choose the colors, I load an image of my target into
photoshop and pick off several colors and then mix them together in
a texture, usually using wrinkles or granite, and then play around
with the various control values (scale, turbulence, etc.).

I also try to find textures in other people's work, here or at
www.irtc.org, to start with. I haven't had much luck with textures
in the include directory or libraries, but here's one with pictures:
http://texlib.povray.org/textures.html

Later,
Mark Slone

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