A method for fabrication of a piece including, superposing an electrically insulating layer including a first orifice, an additional layer including a first aperture, an intermediate layer including a first hole, and a base layer surmounted by a base motif, depositing a metal layer, so that at the end of this step, the metal layer forms a shell covering electrically conductive walls of the base motif, of the first orifice, of the first aperture and of the first hole, and includes a lateral area resting on the insulating layer, dissolving the insulating layer, coating the metal or alloy layer with a volume formed by a base material of the piece, so that the volume conforms to the shapes of the metal layer.