# Bezier Spline¶

This entity is specified by at least two on-curve points, and an off-curve control point at each end (so two off-curve points total). If only two on-curve points are present, then this is a Bezier cubic section, and the four points are exactly the Bezier control points.

If more on-curve points are present, then it is a second derivative continuous (C2) interpolating spline, composed of multiple Bezier cubic segments. This is a useful type of curve, because it has a smooth appearance everywhere, even where the sections join.

To create the Bezier cubic spline:

- Choose .
- Left-click one endpoint of the cubic segment.
- Release the mouse button. The other endpoint of the cubic segment is now being dragged.
- To add more on-curve points, left click with the mouse.
- To finish the curve, right-click, or press
`Esc`

.

The two control points are intially placed on the straight line between the endpoints; this means that the cubic originally appears as a straight line. Drag the control points to produce the desired curve.

To create a closed curve (technically, a ‘periodic spline’):

- Start by creating the curve as usual, left-clicking to create additional on-curve points (see above).
- Hover the mouse over the first point in the curve, and left-click. The curve will be converted to a periodic spline, which will be C2 continuous everywhere, including at that first point.