Hi Michael. I would most often perceive the average direction to be perp to the surface border (including trim boundaries). In program "R" i would find it by doing something like - dup edges, extract points, fit plane through points, select plane and then cplane to object, then extrude vertical to Cplane. Of course would be nice to do this automatically. The wavy face usually makes no difference to my perceived extrusion path.

jonah