I'm trying to get a texture that looks something like a splash against a
verticle surface.  Ie, throwing something messy against the surface and
having it run down.  In this case, it's the effuvium from a pipe verticle
next to the wall.  So the stain needs to go out and down.

Has anyone done anything like this, and does anyone have any tips?  I've
tried a variety of methods, but nothing looks very good.

Thoughts?

Geoff

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Geoff Wedig wrote:
> 
> I'm trying to get a texture that looks something like a splash against a
> verticle surface.  Ie, throwing something messy against the surface and
> having it run down.  In this case, it's the effuvium from a pipe verticle
> next to the wall.  So the stain needs to go out and down.
> 
> Has anyone done anything like this, and does anyone have any tips?  I've
> tried a variety of methods, but nothing looks very good.
> 
> Thoughts?
> 
> Geoff

You could try Chris Huff's particle system patch, AFAIK it also allows to
make pigments from the simulated particles.  

Of course the 'running down' could be problematic, the visibility pattern
I wrote (Megapov MCP) could be used for that, but right now it's probably
not flexible enough.  

Another attempt would be to code something with blobs and maybe use blob
pattern / object pattern.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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Geoff Wedig wrote:
> 
> I'm trying to get a texture that looks something like a splash against a
> verticle surface.  Ie, throwing something messy against the surface and
> having it run down.  In this case, it's the effuvium from a pipe verticle
> next to the wall.  So the stain needs to go out and down.
> 
> Has anyone done anything like this, and does anyone have any tips?  I've
> tried a variety of methods, but nothing looks very good.
> 
> Thoughts?

Weird. I almost posted the same message earlier this week!!!

-- 
Francois Labreque | And a four year old carelessly banging on a toy
    flabreque     | piano is not only 'music', it's probably the last
        @         | moment of 'artistic purity' they'll ever enjoy
   videotron.ca   | before outside influences start corrupting their
                  | expression.    - Chris R.

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Geoff Wedig wrote in message <3ab27cfe@news.povray.org>...
>
>I'm trying to get a texture that looks something like a splash against a
>verticle surface.  Ie, throwing something messy against the surface and
>having it run down.

Try using a texture_map to get the shape right.

--
Mark

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Christoph Hormann <chr### [at] gmxde> wrote:

> You could try Chris Huff's particle system patch, AFAIK it also allows to
> make pigments from the simulated particles.  

> Of course the 'running down' could be problematic, the visibility pattern
> I wrote (Megapov MCP) could be used for that, but right now it's probably
> not flexible enough.  

> Another attempt would be to code something with blobs and maybe use blob
> pattern / object pattern.

Well, I wanted to avoid particles and such.  I've come up with something
procedural that isn't bad using Megapov's functions, and could probably be
made better with some work.

Since someone else asked, I'm posting it here.  IF anyone has any
suggestions for making it better (the point at the top bothers me)  I'd love
to hear them.

Geoff

#version unofficial Megapov 0.7;
camera
{
  location <0,20,0>
  look_at 0
}  

light_source
{
  <0,1000,0>
  1
}      

// A streaking pattern.  Standard bozo 10 times longer on the x.

#declare funct =
  function
  {
    pigment
    {
      bozo
    
      color_map
      {
        [0 rgbt 0]
        [1 rgbt 1]
      } 
      scale <10,1,1>*.1
    }
  }

// Function that takes the above and turns it into a radial pattern.

#declare pig =
pigment
{
  function { funct(sqrt(x*x+z*z), y, atan2(z,x)) }
}

// The streaks pigment is the radial pigment above, but only in the region
down at a - 45 degree
// angle.

#declare streaks = 
  pigment
  {
    radial
    pigment_map
    {
      [0 rgbt 1]
      [0.120 rgbt 1 ]
      [.13 pig ]
      [.38 pig ]
      [0.39 rgbt 1 ]
      [0.5 rgbt 1]
    }
  }

// Turn it into a function

#declare streak_func =
function
{
  pigment { streaks }
}

// Make the streak function fall faster as it gets further away by modifying
the z.

#declare falling_streaks =
pigment
{
  function { 1- streak_func(x, y, sqrt(z)*z/abs(z)) } 
}

Cause it to fade as it get further down.

#declare Fading_falling_streaks =
pigment
{
  gradient z
  pigment_map
  {
    [0 falling_streaks ]
    [.5 rgbt 0]
    [1 rgbt 0]
  }
  scale <1,1,10> 
  turbulence .3
  warp { reset_children }
}

// Experiment.  Comment out lines to see patternas it develops.

plane
{
  y, 0
  
//  texture { streaks}
//  texture { falling_streaks}
  texture { Fading_falling_streaks}

}

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