You can smooth noisy curve to make it properly used on surface/solid feature modeling.
To smooth curve:
Click Smooth Curve (Curve toolbar) or click Geometry, Curve, Smooth Curve .
To smooth curve, select the curves and define the tolerance. If you want to create new curve, check "Copy" option.
a. Noisy curve
b. Smooth preview c. Final result
If selected multi-curves can be merged into one edge, you can check "Group Smooth" to smooth the merged curve. To smooth curve to piecewise b-spline curve, check "Polygon Smooth". When "Polygon Simplify Only" is checked , simplification method will be applied into smoothing.