1. Method for designing a modeled object having several faces, the method assisted by a data storage medium comprising storage instructions and comprising the steps of: identifying, for each of said faces, at least another of said faces related to said face according to geometrical criteria; computing a plurality of points forming a tessellated representation of each of said faces; wherein for each of said faces; for each point of the tessellated representation of said face; determining and storing data representative of an intersection between a three-dimensional geometrical figure touching said point and another face identified as a face related to said face; computing frontiers between points according to their respectively stored data; determining zones according to the computed frontiers; and computing new faces according to the determined zones.