Program and method for generating approximate curve from approximate point group data

A computer-readable recording medium storing an approximate curve generation program, the approximate curve generation program being used to direct a computer to perform steps comprising:

• sectioning point group data into sections of which corresponding to each line segment of an approximate polygon shape which is generated when the point group data approximating a curve shape are obtained, and sorting the point group data close to a section boundary as valid point group data, and the point group data inside the valid point group data as invalid point group data
• selecting a second point group data to be associated with a correction curve using only the valid point group data, selecting a portion of the valid point group data and a specified number of the valid point group data before and after the portion of the valid point group data as the second point group data;
• generating a smooth correction curve passing through or close to the second point group data to be associated with the correction curve;
• moving the valid point group data and each piece of the invalid point group data surrounded by the valid point group data toward the smooth correction curve, and the moved valid point group data are defined as corrected point group data;
• generating an approximate curve passing through or close to the corrected point group data, wherein
• the approximate curve being as smooth as an original curve being generated from the point group data and provided as transfer command data in an NC program used in an NC apparatus for controlling transfer of each drive axis of a machine, the point group data being obtained by approximating the curve shape as an original transfer shape by minute line segments.

An approximate curve generation method, comprising:

• sectioning point group data into sections each of which corresponding to each line segment of an approximate polygon shape which is generated when the point group data approximating a curve shape are obtained, and sorting the point group data close to a section boundary as valid point group data, and the point group data inside the valid point group data as invalid point group data;
• and
• generating an approximate curve using only the valid point group data, said approximate curve passing through or close to the valid point group data, wherein
• the approximate curve being as smooth as an original curve being generated from the point group data and provided as transfer command data in an NC program used in an NC apparatus for controlling transfer of each drive axis of a machine, the point group data being obtained by approximating the curve shape as an original transfer shape by minute line segments.