Draw a Spline

With the free-form spline tool you can draw a spline with your mouse directly within the viewport. Activate the tool in the left toolbar.

The spline color indicates its direction, from blue to white

Use your left mouse button to add a new point to the spline. Hovering over an existing point moves the point. A Right-click on the spline allows you to insert and delete points.

The spline color indicates the beginning and end of the spline. It starts from blue and changes to white.

To edit an existing spline, select it and run the free-form spline tool.

Spline Properties (Settings Window)

Build Orientation	This will be automatically set, depending on which view (top, left..) you use to build the spline. This is important for arrangement.
Closed	Will close the spline from the first to the last point.
Interpolation	Linear or cubic interpolation mode.
Invert Direction	Inverse the order of points. This also has an effect on arrangements.
Symmetric	This will create a horizontal symmetric form.