A computer-implemented method for simulating behavior of a modeled object includes storing a tolerance attribute value in a memory area for a specified parameter of the modeled object, defining a set of rules representative of a plurality of assumptions of a model simulation, executing the model simulation based on the tolerance attribute, verifying an output of the model simulation with respect to a set of rules that are dependent on input and output values for which the tolerance attribute as verified, and validating the output behavior against requirements for every stage of the product lifecycle, from preliminary design to end of life.