Marching Cubes example

[PhilC]

Does anyone know of sample code showing how the marching cubes
algorithm may be implimented using Python?

Ref:- http://local.wasp.uwa.edu.au/~pbourke/geometry/polygonise/

I can set up the cubes and test to see if their vertices are inside
the isosurface.

I can produce a resulting "metaball" but definition is poor and some
faces are reversed. (but not in any pattern that I can effectivly
debug).

My particular issues are:-

1) Finding the point at which the isosurface cuts the cube being
tested. Using a mid point produces poor results.

2) Getting the resulting triangular faces to all face outwards.

I'd prefer not to get into using VTK or matlab if possible.

Thanks :)