A curve that fits another curve may be useful when you want to use a particular curve whose characteristics are unsuitable for subsequent operations, for example, a curve with a sharp angle.
You can use the fitted curve to maintain the shape of the desired curve while at the same time improving its problem points, for example, by eliminating sharp angles.
You can also use fitted curves to simplify curves obtained from certain operations. Thus, you can reduce the number of arcs of curves obtained from the intersections of surfaces. For example, if a curve has a large number of arcs, you can fit it over another curve that has only one arc for each convex or concave section of the curve (i.e., only one arc for each "bend" in the curve).
You can control the following parameters (remember the values you enter must comply with the fundamental relationship between control points, degree, continuity and number of arcs for a NURBS):
As soon as the curve to fit is selected, a Tangency constraints drop-down list is available, enabling you to set continuity constraints at the first, the second or both end points. Appropriate handles are displayed so as to enable you to rotate the tangents at the end points as you like.
Finally, under Advanced Options, further options are available to define the tolerances used to control the sampling:
When you define curves by fitting them to other curves, you can select multiple curves. The program adds a new curve for each curve you select, using the same data for each new curve.