Integrating environmental concerns as well as other constrains (cost, quality, etc.) in the design process, requires to organize the process as a system. Specific software for each design expertise are created to embrace new demands and are supporting the design activity in such complexity that the interoperability between software is crucial. The approach presented in this paper proposes a specific organization of the design process composed of local and global activities. The article focuses on the importance of modeling the data input and output exchanged between activities. It points out the necessity to define rules of transformation that are needed to link models together. The system modeled allows an infinite number of interactions and notably the integration of environmental concerns. This paper illustrates the method by studying a part of the design process of a simple product in a DTE approach. This case study involves software of material choice, CAD, LCA and focuses on transformation rules needed to give interoperable models. The results of the case study finally bring designers to adopt a new design of the product, which reduces initial environmental impacts.