It is the method comprising the steps of defining, by a user, a base mesh associated to a subdivision surface and to a corresponding predetermined mesh-to-NURBS-surface conversion algorithm, the subdivision surface representing the 3D modeled object; defining, by the user, a 2D image and a location for engraving the 2D image on the subdivision surface; and determining a NURBS surface that corresponds to applying a deformation map on the result of performing the mesh-to-NURBS-surface conversion algorithm to the base mesh, the deformation map including displacement vectors provided for positions of the result of performing the mesh-to-NURBS-surface conversion algorithm to the base mesh, the positions corresponding to the location for engraving the 2D image, the displacement vectors being computed based on corresponding pixel values of the 2D image. Such a method improves the design of a 3D modeled object.