variable height extrusion or trim or...

 From:  bisenberger
4771.1 
Hi,
I have a surface that I want to extrude or trim (or something) to a variable height. The image indicates a surface and a curve of varying height. Is there a way to extrude the surface (or trim the extrude) so that it's height matches the height of the curve.



It looks like offsetting the curve comes close to doing what I need, but with the shape of the curve the offset becomes disjointed.
Bill

EDITED: 7 Dec 2011 by BISENBERGER