Justin Smith wrote:
> 
> [...]
> 
> The problem is that when I make the noise large enough (either by scaling
> the #declared pigment function in the declaration, or by increasing the
> multiplier at the end of subtracting it from the base function, or both),
> it always leaves "floaters"... pieces of terrain that are not actually
> connected or are connected by very thin sections to the main object. If I
> make the noise small enough to prevent this from being noticeable, the
> general silhouette of the mountain is still a perfect paraboloid and looks
> very unnatural.

To some extend that's a general problem of isosurfaces, Mike's suggestion
avoids it, but it will have some problems and restrictions as known from
heightfields then.  To avoid the regular appearance when using not so
strong displacement you can deform the paraboloid object with a low
frequency noise function.

function { (x*x)/5000 + (y + f_noise3d(x/30, 0, z/30)*90)/90 + (z*z)/5000
}

will deform in y-direction (like what Mike suggested) so if you now apply
a displacement it will look less regular.

> [...]
> 
> Now, I have seen some great isosurface work before (particularly I remember
> an entry in the Asia IRTC that had photorealistic terrain entirely made
> with isosurfaces)...

Thanks ;-)

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 13 Aug. 2002 _____./\/^>_*_<^\/\.______

Post a reply to this message