1. A method of computer aided design of a product comprising a set of objects, said method comprising a step of: identifying constraints linking objects of said set of objects, each of said constraints being oriented from a first object to a second object so as to ensure, upon solving the constraints, that the first object is not moved provided that all other of said constraints are solved; if an impossibility of solving said constraints is detected, testing whether said constraints can be solved upon modifying one oriented constraint amongst said constraints; returning a suggestion for modifying said one oriented constraint including displaying the suggestion to a user; and modifying said one oriented constraint upon user action; wherein the step of modifying comprises transforming said one oriented constraint into a non-oriented constraint.