Re: Gridded3DSet.isosurf() and int[][] Pol_f_Vert

Hi Bob,

> In the implementation of the isosurf() method, the construction of the
> Pol_f_Vert[] array is based on the notion that 1 vertex may be shared (or
> adjacent to) by a maximum of 8 polygons.  I'm wondering where this result
> is derived from.  In other words, why is 8 the maximum number of polygons
> shared by a vertex.  The reason I am wondering is because in our own
> implementation of Marching Cubes (taken from the Visualization Toolkit),
> as far as I can tell, I'm getting a result that says a vertex can be
> shared by up to 9 polygons.  I seem to be getting this result fairly
> consistently and I don't know, at this writing, whether or not this is a
> valid result.

In our isosurf method, a vertex lies on a cube edge so is adjacent
to at most four cubes, and there can be at most two polygons
adjacent to a vertex from one cube.

I wouldn't worry too much about it.  I'd either use our
isosurf as is, or replace it with your own.

By the way, we recently added a new method makeContour()
to ShadowType to make it easier to define new extensions
of DataRenderer with radically different approaches to

Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738