-The work introduces a computational method for the optimization of aerospace preliminary designs. It was developed considering a collaborative approach to solve the sizing optimization of a structure model defined by finite element method and by a large number of subsystems. A brief introduction explains how the collaborative optimization method can be used for general structural problem and how this approach can offer many advantages to the computation analyses. Central discussion is the description of an automatic procedure defined by three deterministic optimization codes and their interface systems with the MSC.Nastran environment. They decompose the structure complexity executing an interface algorithm for FE models searching an optimized solution for the structural subsystems respecting different kinds of constraints. Furthermore, in order to show the uses of the procedure in an industrial context, two realistic applications for the minimum design are also discussed. The results show a good comparison with the commercial solvers, taking out better results in less time processing and finding new alternative design configurations.