Hi Yenmonger,

> But the planar command can only do a single plane at a
> time - I need to do hundreds or thousands at a time.

You could try Rhino's MeshToNurb command, or Sycode's Mesh to solid converter:
http://www.sycode.com/products/mesh_to_solid/index.htm

These will convert every polygon face in the mesh into a trimmed NURBS plane - but be aware that if you have a mesh with a lot of little polygons in it where the mesh is trying to emulate a smooth surface, each little polygon will become one trimmed plane in the NURBS solid. That can end up making an extremely heavy and complex NURBS object made up of zillion little NURBS surfaces.

NURBS solids were not designed to have smooth surfaces emulated by a zillion little slivery pieces, NURBS are designed to have smooth surfaces as actual larger smooth spline surface patches.

So that kind of conversion is only very applicable to certain kinds of shapes, like meshes that are intended to be faceted objects such as blocky shapes and not meshes that are trying to be similar to a smooth surface with a lot of little polygons.

- Michael