Abstract: A system for parameterized design and unfolding of sheet metal pipes has been developed on the basis of the analysis for the computer-aided conditions and manufacturing requirements of the sheet metal industry at home and abroad. It integrates the functions of part design and unfolding, and contains all-around design objects as well as precise design results. Some critical techniques are introduced, such as modeling tragedy, the abstraction of interface curves, the mapping of the interface curves to mid-layer curved face, and interface design. At last, the examples of application are illustrated.

Key words: computer application, system for design and unfolding of sheet metal, modeling based on mid-layer, processing the thickness of plate