Tor Olav Kristensen wrote:
> 
> You can give the periodic interval as an argument to the
> macro. This makes it easy to study the periodicity when
> the interval is set small.

For most purposes the noise generator should have a periodicity as large 
as possible.

> Do you know where the 'far areas' are and how the functions
> typically degenerates ?

try rendering:

camera {
   orthographic
   location <0,0,1>
   look_at  <0,0,0>
   right 1*x
   up 1*y
}

box {
   <-0.5, -0.5, 0>, <0.5, 0.5, 0>
   texture {
     pigment {
       bozo
       color_map {
         [0.0 color rgb 0.0 ]
         [1.0 color rgb 1.0 ]
       }
       scale 0.01
       translate 3e7*x
     }
     finish {
       ambient 1.0
       diffuse 0.0
     }
   }
}


>  > 2) performance.  This is quite impossible to conclude from an
> 
>> SDL version.
> 
> 
> Why is that ?
> 
> The macro can produce noise functions that behave simlar
> to f_noise3d()

But much slower.  The noise generator is quite critical for the render 
speed in a lot of scenes.  That's why the Windows version of POV-Ray 
contains a special hand optimized version of the noise function.

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 01 May. 2004 _____./\/^>_*_<^\/\.______

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