A method for modeling at least part of a non-axisymmetric surface (5) of one portion (2) of a part (1). The portion (2) is bounded by first and second extremal planes (PS, PR). The method includes processing data from a device (10), by: (a) modeling at least two basic non-axisymmetric surfaces (Sk, SI, SE) making up the surface, each of the basic surfaces (Sk, SI, SE) extending between both extremal planes (PS, PR) of the portion (S); (b) constructing at least one connection curve (CR) tangential to the first and second surfaces; (c) locally modifying the first and second basic surfaces (Sk, SI, SE) to keep to the connection curve (CR) near a discontinuity; and (d) restoring, at least part of the obtained surface (5).