Select an option from the Curve Editor tab > Edit panel> Curve Fitting menu to convert the selected curve segments to a specific type of curve:
- Spline Fit — Click to convert the selected segments into a spline.

Tolerance — Enter the maximum distance between the original and fitted curves. The value specified in the Curve Fitting Tolerances page of the Options dialog, accessed from Curve Editor tab > Utilities panel > Options, is available as an option on the drop-down list.
Spline selected converts this selected curve:

To this:

- Arc Fit — Click to arc fit selected segments. This smooths curves.

Tolerance — Enter the maximum distance between the original and fitted curves. The value specified in the Curve Fitting Tolerances page of the Options dialog, accessed from Curve Editor tab > Utilities panel > Options, is available as an option on the drop-down list.
Arc fit selected converts this selected curve:

To this:

- Polygonise Selected — Click to convert the selected segments to a series of straight lines.

Tolerance — Enter the maximum distance between the original and fitted curves. The value specified in the Curve Fitting Tolerances page of the Options dialog, accessed from Curve Editor tab > Utilities panel > Options, is available as an option on the drop-down list.
Polygonise selected converts this selected curve:

To this:
