A method for creating, from a first axisymmetrical surface, a second surface belonging to a sub-system of a complex system, in which the second surface observes at least one constraint, is disclosed. The method includes: modeling the first axisymmetrical surface, while observing the constraints with at least one parameter, the modeling step including a sub-step for discretizing the first axisymmetrical surface in several points, the parameter being a coordinate of one of these points in a reference system associated with at least one portion of this sub-system, and a sub-step for reconstructing the first axisymmetrical surface from the at least one point and from the at least one constraint; modifying the at least one parameter in the reference system for modeling the second surface; and recording the second surface in a memory of the computer.