Irregular shape nesting and placing with evolutionary approach

The purpose of this paper is to propose an evolutionary method to solve a garment shape nesting and placing problem. The structure used by the evolutionary algorithm is organised into a hierarchical tree which is similar to representation used in genetic programming. The first level deals with the basic nesting operation in which a reduced `comb code´ is used. The higher level makes use of trees organised in such a way that each of them represent a strip of layout. This representation can efficiently cope with the combinatorial aspect of the shape placing. Simulations have been implemented in a Smalltalk environment. Results compared to those of tree search show that the evolutionary method is a suitable tool for finding several good solutions and deterministic search comes as a complementary tool for focusing the search on a specific region