SHAPE DIVISION METHOD, SHAPE DIVISION PROGRAM AND DATA PROCESSOR

PROBLEM TO BE SOLVED: To enable shape division for edge machining of a spectacle lens to be performed according to prescribed standards so as to improve accuracy and efficiency of the shape division.SOLUTION: A shape division method of dividing three dimensional shape data of a spectacle lens into a plurality of shape element data for edge machining includes steps of: acquiring a prescribed circumscribed graphic shape 55 circumscribing a projection shape 54 of the circumference of the spectacle lens by a prescribed angle while varying the relative angle between the projection shape 54 and the circumscribed graphic shape 55; extracting data on an inner region shape 56 common among all the acquired circumscribed graphic shapes 55 as outermost shape data for machining; acquiring a difference region between a shape 56 specified by the outermost shape data for machining and a projection shape 54 specified by the projection shape data of the lens circumference; and extracting shape data of the acquired difference region as shape data for penetration machining.