Fig. 1. Edge contour point on a vertical section line (VSL)

Fig. 2. Small chamfered arc (CA) in the point cloud data of sharp intersection areas of surfaces

Fig. 3. Relative position of the point on the middle line of the CA with the point on an edge contour line (ECL). (a) Positions of the middle line of the CA and the ECL; (b) position offset of the middle point on the CA relative to the point on the ECL

Fig. 4. Three kinds of distribution character of the practical points on the CA. (a) The large chamfered arc; (b) small and smooth chamfered arc; (c) small and jumping chamfered arc

Fig. 5. Flowchart of the parabola fitting for its vertex (PFV) method

Fig. 6. Pseudocode of recognizing the point whose accumulated normal angle is closest to the half central angle of the CA (CHCA) method

Fig. 7. Flowchart of recognizing the point whose approximate arc length is closest to the half arc length (HAL) of the CA method

Fig. 8. Tested templates and to-be-recognized ECLs. (a) Template 1; (b) template 2

Fig. 9. Meshed point cloud data of tested templates. (a) Template 1; (b) template 2

Fig. 10. Recognized points of the CHCA method

Fig. 11. Recognized points of the HAL method

Fig. 12. Compensation of the recognized middle point on the CA

Fig. 13. Recognized points of the PFV method. (a) Recognized points; (b) distance deviation of the recognized points; (c) machining error of the two zones on the template 1