Correction factor for tool tip determination

The grid fineness for determining the actual contour from the envelope sections is generally adjusted to the tooth size (module).  If problems still arise when determining the actual contour, the grid fineness can be further adjusted using the scaling factor f_cuts.

Note: If points cannot be found at the start or end of the contour, the grid size should be reduced (f_cuts < 1.0). If no valid contour can be found, the grid size should be increased (f_cuts > 1.0).