Modeling is present throughout the design process. Nevertheless, existing studies generally cover only certain activities, and certain technical points of view: functional analysis, preliminary design, detailed design, simulation (structure, thermal, tolerancing, etc.). The purpose of this paper is to present a general overview for different types of modeling. This approach allows to describe and to formulate the assumptions made during the development of physical models for the simulation. This process allows to transform a real complex system into a simplified simulation model. This process is defined by a set of operations and is represented by a procedural scheme. The definition of simulation models is the result of this modeling process. These notions are illustrated using a simple example from the geometrical tolerancing domain with modeling by a tolerance stackup.
