This paper presents a methodological procedure for optimization assistance in general and for the optimal design of electrical machines in particular. This approach tries to address the multiple weaknesses presented by "classical" direct optimization techniques. In particular, the tools implemented by this methodology offer the opportunity to understand more finely, typically through 2D graphical representations, the complexity of the optimization design problems. This work is an attempt to find an intermediate configuration between the pure optimization approach and the one based solely on modeling. The application of this approach is illustrated by the presentation of the main steps of the optimal design of a Permanent Magnet Synchronous Machine.