CNC codes conversion from linear and circular paths to NURBS curves

Kuan Yuan Lin, Wen Der Ueng, Jiing Yih Lai

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


A novel approach is proposed for converting NC files of G01/G02/G03 codes into NURBS curves. The NC points are first acquired from an NC file composed of lines and arcs. A segmentation algorithm based on the angles and lengths evaluated from adjacent points is then used to subdivide the entire group of points into segments. An error-bounded constrained curve fitting algorithm is implemented to fit each segment of points into a curve, maintaining the accuracy, smoothness and boundary continuity between the curves. The chord errors between the NC points and the fitted curves are controlled, which ensures the accurate recovery of NC paths. Also, a knot insertion algorithm is proposed to determine the appropriate number of control points automatically, allowing effective fitting of all segments. Several examples are presented to demonstrate the feasibility of the proposed approach.

Original languageEnglish
Pages (from-to)760-773
Number of pages14
JournalInternational Journal of Advanced Manufacturing Technology
Issue number7-8
StatePublished - Nov 2008


  • Constrained curve fitting
  • NC paths conversion
  • NURBS codes
  • Segmentation


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