> Needing to make small 3D symbols for point data, spheres in particular,
> I am using code like that in the ucar.visad package, class
> ShapeUtility.java, which creates VisADGeometryArray-s by specifiy the
> xyz locaiton of every vertex, and a normal for each vertex and face.
> See the 3d pyramids in the figure at the bottom of
> The VisADGeometryArray and the ShapeUtility code allows the
> needed feature of resizing the shape and setting a color. But making a
> sphere looks difficult, since it is not a simple
> polygon with flat faces. Has someone a solution?
In OpenGL and similar 3-D graphics libraries, smooth shapes
like spheres are constructed with large numbers of flat
triangles. The larger the number of triangles, the smoother
> Looking ahead, I need to color the sphere in panels (gores) like a
> beachball for earthquake focal mechanisms. See
> Any ideas?
You can construct a VisADTriangleArray, with different
colors for different triangles. The key is to avoid any
of the TriangleStrip classes, since they share vertices
among triangles that may not have the same colors.