Curved surface drawing apparatus and curved surface drawing program

摘要

PROBLEM TO BE SOLVED: To make it possible to radius a plane and at the same time to save features of polylines present in boundaries between planes, by using long paddy field patches.SOLUTION: A curved-surface drawing apparatus comprises: a normal line vector setting unit 31 for setting, at each of the start and end points of a line segment equivalent to a polyline, a first normal line vector derived from a polygonal mesh present in one side of the polyline and a second normal line vector derived from a polygonal mesh present in the other side; an intersection line calculation unit 32 for determining, for at each of the start and end points of the line segment, an intersection line between a first tangential plane orthogonal to the first normal line vector and a second tangential plane orthogonal to the second normal line vector; and a curved line calculation unit 33 for curved-line-interpolating the line segment by using intermediate control points respectively disposed on the intersection lines in the start and end point sides and the start and end points of the line segment, and allows the disposed intermediate control points to reflect bend angles between polygonal meshes adjacent at the polyline.SELECTED DRAWING: Figure 1