Wasn't it TJ Giese who wrote:
>Alain wrote:
>> TJ Giese nous apporta ses lumieres en ce 2005-10-19 14:04:
>>> I have a bunch of data living on a nonuniform mesh.
>>> Meaning, more specifically, I have an electron density that lives on a 
>>> Gauss-Laguerre radial and Lebdeev angular quadrature grid points.
>>> I would like to choose some isodensity surface and render an image of 
>>> it in povray.
>
>> A mesh don't need to corespond to a gird of any sort. If your data are 
>> already organised as a mesh, it should be relatively easy to import them 
>> into a POV Ray scene.
>
>Thank you for your reply.  I appreciate it.
>I thought it might be useful for me to clarify my terminology, because I
>might have incorrectly used the word "mesh" in my first sentence.
>
>My data is in the format
>X1, Y1, Z1, Density1
>X2, Y2, Z2, Density2
>...
>Xn, Yn, Zn, Densityn
>
>where the cartesian coordinates Xi, Yi, Zi, do NOT represent verticies
>of a triangle and are not equally spaced.

My guess is that you'd be better off performing the interpolation
required to generate data for an evenly spaced grid in an external
program and outputting it as a df3 file. 

I think it would be possible to perform the interpolation inside the POV
SDL, but it would be ridiculously slow unless the number of points in
your data is quite small.

Alternatively, it might just be possible to order your points so that
you could find a way to use the warp command to warp a uniform
rectangular grid into a Gauss-Laguerre radial and Lebdev angular
quadrature grid. I don't know enough about such particular grids to be
able to determine if that's possible.

There are probably several other possible approaches. It all depends on
how many grid points you've got, how the data should be interpolated to
determine the density value at an arbitrary non-grid point, and what you
wan the output to look like.

-- 
Mike Williams
Gentleman of Leisure

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