Having a significant impact on the design of many products and industrial systems, such as the subdivision of a ship, the layout of facilities in a plant or further still the assembly of parts of a mechanism, layout design optimization is at the heart of scientific issues. The design of an optimal layout solution is a critical and complex task due to the increasing demands of designers working on varied projects. This paper proposes an integrated approach to solving layout optimization problems, from the needs expressed by the designer to the creation of an ideal solution. This generic and interactive method is based on a design process divided into four steps: the description, formulation, and solving of the problem, and the final decision. This process is based on a multiobjective modular optimization strategy that combines a genetic algorithm with local optimization modules. The method described in this paper is interactive because the designer participates in all processs steps. For example, in the final decision step, the approach includes an inno- vative exploration tool in order to let the designer choose an optimal solution according to his perceptions. The global method is applied to an industrial problem which deals with the search for an optimal layout of facilities in a shelter. Actually, this paper also presents an innovative software which ma- terializes the integrated optimization method presented in this paper. This tool includes the different steps of the optimization method and integrates the multiobjective solving of layout optimization problems.