"Tim Nikias v2.0" <tim### [at] gmxde> wrote in message
news:3ed3b3b3@news.povray.org...
> Use a heightfield. Create a top-view
> on the stone, make an image of that.
> Now draw waves around the stone using
> another layer, and just export the layer
> of waves. Use that as basis for the heightfield.
> >
> > I am making a water surface. I do that with a texture on a plane. I want
> > ripples around a stone in the water. How can I make ripples only there,
> > and not in the whole sea?

Hmmmm. You could try something like what Tim said, to get an actual surface,
but no need to go into an image program when you could do it with an
isosurface (unless you want a quicker rendering time).

If all that's needed is a textured plane then the solution is very simple. A
normal_map can be used to limit the area where the ripples are located. For
a centered stone (of approx. 1 pov unit radius) it would go like this:

plane {y,0
    texture {
        pigment {rgbf 0.9}
        normal {
            spherical // only 1 pov unit radius
            normal_map {
                [0.9 ripples 0 scale 0.1] // outermost
                [1.0 ripples 1 scale 0.1] // innermost
                }
            scale 3// actual radius needed
            }
        finish {specular 1}
    }
}

Only an example though and would require plenty of change to be adjusted for
the scene, but that's the basic idea.

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