Method and apparatus for producing a three-dimensional curved surface from two-dimensional curves in perpendicular planes

摘要

A method and apparatus for specifying a three-dimensional curve having steps of entering data specifying a first projection curve (CV.sub.1) and a second projection curve (CV.sub.2) is obtained when a three-dimensional curve (31a) is projected onto two adjacent planes (e.g., an XY plane and a YZ plane) in a rectangular coordinate system. The method also includes finding coordinate values (a.sub.i, b.sub.i) of an i- th (i=1, 2 . . . ) partition point P.sub.i from among partition points partitioning the first projection curve (CV.sub.1) into a number of line segments and finding coordinate values (b.sub.i,c.sub.i) of a point Q.sub. i on the second projection curve (CV.sub.2) having a coordinate value b. sub.i on a common axis (Y axis) among coordinate axes of the two adjacent planes. The three-dimensional curve (31a) is specified by a collection of points (R.sub.i) having the three-dimensional coordinate values (a.sub.i, b.sub. i, c.sub.i).