1. A method for producing a representation of a mold for forming an appliance for a living body, the method comprising: causing a processor circuit to display a representation of a surface of the mold, said surface being defined by an input plurality of points stored in said processor circuit and representing a shape of the mold; receiving user input identifying a plurality of points representing a line corresponding to an intended edge of the appliance on said representation of said surface; receiving user input of a desired outward flare of the shape of said surface along said line, the outward flare having a variation along said line and being operable to provide relief between the edge of the appliance and the living body; causing said processor circuit to: identify regions extending away from said line along said surface on opposite sides of said line; determine points in said input plurality of points that fall within said regions; adjust at least one coordinate of points that fall within said regions to outwardly flare the shape of said surface along said line in accordance with said user input to produce a modified surface representation; and store said modified surface representation in a computer memory to produce a modified representation of the mold.