The modular lightweight design attempts to reconcile the partially conflicting goals between modularization and lightweight design in order to establish a harmonized modular hybrid design. This requires a close exchange of the resulting development data between the two areas. In this contribution a concept for an interface for the data exchange between system models and FEM models is presented and successfully implemented in the Cameo Systems Modeler and applied to examples from the aircraft cabin. With the interface the homogenization step of modular lightweight design can be performed.