Bob Hughes wrote:
> 
> Boy, was I ever wrong about trying to use 'waves'. Anyway this here will
> make a "starter" for you hopefully. Looked fair enough to me.
> Follow the instructions okay and your all set to see this right. Two
> step rendering involved.

 I personaly would have used a gradient pattern with a perturbed
sine wave function added to the turbulence modifier. The addition
of a second transpearent gradient in top of the first with a a much
smaller scale gives the small upclose ripples seen on sand dunes
and the first pattern is for the dunes themselves. A gradiant y
pattern on a z plane using tubulence like this:

pigment { gradient y
  turbulence<0.1,0.3,0.1>
    turbulence<-0.1,-0.3,-0.1>
    Color_map { ....

The dual positive and negative turbulence modifiers give a nice looking
snake like drift to a normaly straight line and that is similar to how
sand dunes look as view from a high place. As Bob illustrated the use
of normals will add the randomness to the surface lending the
final objects surface some much needed realism.


-- 
Ken Tyler

mailto://tylereng@pacbell.net

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