Curved surface fitting method, curved surface fitting device, curved surface fitting program, and computer-readable storage medium storing curved surface fitting program

A curved surface fitting device including a computer having a calculation unit, the curved surface fitting device fitting a curved surface model set in a three-dimensional space to a plurality of object points of an object to be modeled set in the three-dimensional space by causing the computer to perform free-form deformation (FFD), the calculation unit comprising:

• a control point setting unit that sets a plurality of control points of a three-dimensional shape surrounding the curved surface model;
• a deformation target point setting unit that sets, on the curved surface model, a plurality of deformation target points corresponding to the plurality of object points, the plurality of deformation target points on the curved surface model being points on the curved surface model being closest to the plurality of object points on the object, respectively;
• a movement amount determination unit that determines movement amounts of the plurality of control points, respectively, by executing a least squares method so as to minimize a total value of the movement amounts obtained by adding up squares of distances between the plurality of deformation target points and the plurality of object points corresponding to the plurality of deformation target points;
• and
• an FFD execution unit that updates the plurality of control points to new control points based on the movement amounts to deform the three-dimensional shape and fits the curved surface model to the plurality of object points of the deformed three-dimensional shape by executing the free-form deformation.