Wasn't it Dre who wrote:
>"Tek" <tek### [at] evilsuperbraincom> wrote in message
>news:4878f316$1@news.povray.org...
>> "Rob Richards" <ari### [at] btinternetcom> wrote in message
>> news:in4h74tllnc5r82ropj3sg006boujelu77@4ax.com...
>>> Wow, thats fantastic. Can I ask how the isosurface was defined ? i.e.
>>> is it a sphere - this pattern ? Or am i way off base !
>>
>> You're exactly right, sphere - pattern.
>>
>> --
>> Tek
>> http://evilsuperbrain.com
>>
>>
>
>Hmmm, there must be something I'm doing really wrong then as all I can get
>out of this is a flat textured shape, I dont get any porous effects at all!
>
>If I render it as a hightfield it also looks totally wrong :(
>
>Meh, goes back to fiddle some more...

It goes something like this:

#version 3.6;

global_settings {assumed_gamma 1.0}

camera {location  <0,0,-10> look_at <0,0,0>}

background {rgb <.8,.8,1>}

light_source {<-30, 100, -30> color rgb 0.5}
light_source {<0, 10, -30> color rgb 0.5}

#declare P = function{pigment {
 #local Curve=1/8; // small values make it look porous
 #local Omega=0.5;
 #local Lambda=2;
 #local Octaves=8;
 pigment_pattern {
  average
  pigment_map {
   #local octave=0;
   #while ( octave < Octaves )
    [pow(Omega,octave)
     pigment_pattern {
      crackle form <.9,0,0>
      scale pow(Lambda,-octave)
      colour_map {[0 rgb 1][1 rgb 0]}
     }
     poly_wave 1/Curve
    ]
    #local octave=octave+1;
   #end
  }
 }
 poly_wave Curve
 colour_map {[0 rgb 1][1 rgb 0]}
}}

#declare  S = function {x*x + y*y + z*z - 1}

isosurface {
  function { S(x,y,z) - P(x,z,y).grey*2 }
        max_gradient 70
        contained_by{sphere{0,1.5}}
        pigment {rgb 1}
  scale 3
}

I've not done any radiosity or other fancy rendering on this, so it
renders a bit faster but doesn't look as good.

Try tweaking the numbers in "grey*2" and "scale 3".

-- 
Mike Williams
Gentleman of Leisure

Post a reply to this message