The Curve icon on the Drawing toolbar opens a toolbar to draw Bézier curves. Bézier curves are defined by a start point and an end point, which are called "anchors". The curvature of the Bézier curve is defined by control points ("handles"). Moving a control point changes the shape of the Bézier curve.
Control points are only visible in "Edit Points" mode. Control points are represented by circles, anchor points are represented by squares. The start point is a little bit larger than the other anchor points.
Bézier curve segments and straight line segments can be joined to form more complex Bézier curves. Three different transitions can be applied to join adjacent segments:
A symmetrical anchor point has the same line curvature on either side, and two control lines that move together as a straight line.
A smooth anchor point may have different line curvatures on either side.
A corner anchor point has one or two independent control lines. Changing one side has no effect on the other side.
On the Drawing toolbar, open the Curves toolbar and select the Curve tool.
Click where you want the curve to start, and drag in the direction where you want the curve to go. The control line will indicate the direction.
Hold down Shift while you drag to restrict the direction to a 45 degree grid.
Release the mouse where the first control point should be.
Move the pointer to where you want the curve segment to end. The curve follows the pointer.
Do one of the following:
Double-click on the position of the end point to finish drawing the line.
To create a closed shape, double-click the starting point of the line.
Click and release the mouse button to add an anchor point. Move the mouse to draw the next segment.
Click and drag in any direction to add a smooth anchor point.
On the Drawing toolbar, open the Curves toolbar and select the Freeform Line tool.
Click where you want the curve to start, and keep holding the mouse button down.
Draw the freeform line as you would do with a pencil.
Release the mouse button to finish the line.