In addition to adding, deleting, or moving nodes, there are several Edit Tool features unique to splines and Bezier curves.
Splines are created by specifying either a series of fit points (points through which the spline passes) or control points (guide points). For either type of spline, you can view and move both types of points.
It is easier to understand the types of points when the spline is displayed with its frame. Open the spline's Properties to the Curves page and check Show Frame.
A knot is basically a control point. You can add knots to increase the editing detail of a spline. A node is a point through which the spline will pass (fit point).
Bezier curve use weighted nodes to control the curvature at each node point.
You can control how each node controls the curvature by selecting a node, and right clicking to open the local menu. In the local menu there are three options for controlling the curvature of a node.
Equal Curvature at point — This is the default. When selected, adjusting one of the green control handles causes the paired handle to change an equal distance, but the handles remain locked to a common control line. This option makes the curve smooth and equal on both sides of the node.
Nonequal Curvature at point — When this option is selected, adjusting one of the green control handles does not affect the distance of the paired handle, but the nodes remain locked to a common control line. This option makes the curve smooth but unequal on either side of the node.
Nonsmooth at point — When this option is selected, adjusting one of the green control handles does not affect the the paired handle at all, the nodes have separate control lines. This this option allows you to make a sharp point in the curve.
Note: These controls will have no effect if the "keep Curve Smooth" option is turned off in the curve properties. Curve Properties.
The effect of selecting a different curvature only appears after you begin moving an affected handle.
You can use the Selection tool functions to edit nodes by turning on the Selection Mode. Selection mode is available from the local menu or from the Inspector bar.
While in this mode you can select multiple nodes and move them, rotate them, and scale their collective size just as you would any other object using the selector.
Note: The selector type (2D or 3D) that will be used in Edit tool is dependant upon the type that is current for the selector.