I may be compeletely wrong, because I don't have a lot of experience
with isosurfaces, but I did run into something similar.  It seems to me
that the isosurface code works "backwards" from normal POV-Ray
nomenclature. i.e. something like isosurface{y-noise3d(x,y,z)} actually
adds the height of the noise to the plane whereas
isosurface{y+noise3d(x,y,z)} subtracts the noise from the surface. 
Likewise it seems that increasing the x,y,and z values makes for smaller
noise features. e.g. noise3d(x*20,y*20,z*20) makes finer detail than
noise3d(x*3,y*3,z*3).

You may simply be running into your bounding box.  Try translating the y
component of your isosurface down a bit at see it the tops of your noise
"finish out".

Mike Wilson 

"Greg M. Johnson" wrote:
> 
> I've made a smooth landscape using an isosurface containing noise3d + y
> .  Note in the image below how some of the features are truncated: flat
> tops. I want it to be completely smooth, but have this general feel.   I
> was trying to figure out what might have been wrong with my code.  But
> then I remembered a similar thread about some of the noise-based
> pigments in povray.  Did I hear something to the effect that the pov
> designers used an unorthodox definition of the noise (something about
> the interval?) ?
> 
> The question is: which of the scenarios below are most probable:
> 1. I may acheive smoothness by fixing my code;
> 2. I will fail because these flat tops are inherent in any (correct)
> application of noise;
> 3. I will fail until a pov version comes out with a "correct"
> application of noise.
> 
>   ------------------------------------------------------------------------
>  [Image]

Post a reply to this message