"Shay" <sah### [at] simcopartscom> wrote in message
news:3da2e72a$1@news.povray.org...
>
> I think that we could help you more if you gave a more specific
description
> of your problem. What exactly are you trying to do and with what data? How
> will you be generating the points and how many of them will there be?
>
> There are a few easy ways to do this slowly with a few points, but doing
so
> with a large number of points will be complex.
>
> You can get a better effect than you got from the blobs by using the
crackle
> pattern. This may be all you need.


Alrighty...  Here's the short version:

We have momentum collision data from an experiment we've run that shows
charge-transfer (single electron capture) from a projectile ion onto an
ionized (recoil) target.  The recoil ion longitudinal momentum distribution
is what we wish to plot - and we have the data in the form of xyz
coordinates.  Usually, we're talking about roughly thousands of points to
plot.  Some will be more.  Our current commercial software allows us to plot
this in a 2D manner, with various colors representing high/low momentum
distribution.

But it looks pretty crummy for any sort of publication.  So, we're looking
at using POV-Ray to plot the data.  We can easily plot each of the
coordinate points as spheres, and we get a discontinuous distribution
scattered around.  This turns out to be somewhat difficult to read.

So, we want to represent the data in the form of an interpolated mesh, which
we can apply a general gradient pigment showing various density information.
Again, we have the xyz data points, and now we just need a simple way to
convert them into a mesh of some sort.

I've tried finding algorithms that will do this, but quickly got in over my
head with references to various interpolative methods - the methods make
sense mathematically, but... well, I stink at programming.

So that's the short version.  I've posted related questions to the group in
the past, but no one had any grand ideas, either.  And hence, my 'new'
question.  If I can find a way to take a black pigment, and identify a
singly point on the xy plane to represent the position of my xyz information
(z being represented by a gray/white pigment color), then I can create a
bitmap to apply to a heightfield (I think).  At least, this seems to make
sense in my mind.

I started out playing with bezier patches, etc. but we need the mesh to pass
through our data points (or close to it), and so treating our data as
control points yielded strange results.  Blobs were an idea, but I couldn't
seem to find a consistent way of setting the parameters.

Hope this helps clarify where I'm headed.  Thanks, Shay, for your interest.

- How

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