Abstract: A new discrete representation approach and an interactive editing method for three-dimensional shoe pattern curves generated on triangular meshes of shoe last model are presented. The selection areas of shoe last surface are flattened by utilizing the improved energy model. The topological relation between three-dimensional upper surfaces and two-dimensional flattened upper surfaces is established in the process of flattening. And the real-time association for shoe pattern curves in three-dimensional and two-dimensional flattened spaces is obtained by using the topological relation mentioned. For the convenience of other programs calling, two-dimensional shoe pattern curves generated are represented by cubic non-uniform B-spline and outputted in the DXF format. Numerical results show that the proposed method has advantages of good interaction and real-time intuition, and the method can meet the requirement of real-time interactive design for shoe pattern based on shoe last.

Key words: computer aided design, shoe pattern interactive design, surface flatten, curve mapping