PNA used finite-element analysis to reduce the free-form shapes to single curves. Gehry refined the shapes, based on PNA rules, so that more than 90% of the surface has a single curvature. This was accomplished by slight segmentation at the panel joints, says Budd.
�We did the work zone by zone and face by face,� says Budd. �It was an iterative process,� adds Bowers.