System design methodology in C.A.D. programs based on the finite element method

The general structure of a Finite Element package is analysed and we show how it is possible to build an evolutive system, both highly structured and without a great problem of portability. The help of a program generator may reduce the time devoted to the construction or the adaptation of a package and may increase its reliability. Problem solving techniques are available for the optimization of the general structure of the system and the reduction of computation time. A global structure well adapted to the present needs of computer aided design using finite elements is given in an example.