Okay, I see you made a few updates since I read your original and went off to verify my thoughts.

I guess it depends upon the number and density of the points as to how effective the filtering would be.

I was picturing something like a buckyball. If the origin was at the centre of the buckyball, then every atom (molecule??) would either be filtered in or filtered out, unless the constraining value was extremly tight.

Of course, you can move the origin, and then you'd get a greater or lesser ring of potentials, depending upon the relationship between the chosen origin and the position of the atom under test.

Or with a buckytube, you get rings, ovals, or two long parallel lines of potentials.

Then again, bucky-anything is probably a fairly rare case:)