Local and global evaluation methods for shape errors of free-form surfaces
are presented. The local evaluation methods use the changes of principal cu
rvatures between the original CAD data and actual surfaces. The global eval
uation methods use the aggregate normal vectors for the characterization of
portions of surfaces. Both methods are applied for the evaluation of sheet
metal formed by using numerical simulation data and coordinate measurement
data. (C) 1999 Elsevier Science Ltd. All rights reserved.