Smooth String

Click the Smooth String tool on the String Tools toolbar (Strings | Tools | Smooth) to smooth one or more selected strings, or smooth the selected segments of a string. If no strings or segments are selected, the Selection Assistant will prompt you to select them.

Use the slider bar on the tool menu to adjust the point density for string smoothing. To smooth the segments of a string, click on the string and drag the mouse along the string to select a segment or select successive segments.

The smoothing operation will insert a regular spread of points and remove any unnecessary sharp corners. You can control the degree of smoothing by selecting a Loose or a Point Honouring option:

The Loose (Polynomial Approximation) option smooths selected strings or segments based on a smoothing tolerance that controls the length of a "moving" path used to calculate new vertices. The curve does not pass through any of the vertices of the original strings or segments, except the first and last. This is the default method.
The Loose (Spline) option uses a B-Spline to smooth the selected strings or segments. The curve does not pass through any of the vertices of the original strings or segments, except the first and last.
The Point Honouring (Bezier) option smooths the selected strings or segments by creating Bezier curves to match the input strings and segments. No tolerance is applied to the calculation.
The Point Honouring (Spline) option uses a T-Spline to smooth the selected strings or segments. The curve passes through all the vertices of the original polyline.