For quick links to more information, click on the options or another page.
This drawing tool is located on the Annotate tab and can be customised with the right click Format... option.
This tool can be used for placing a smooth curved line onto a drawing. It is different to an arc because it is a constant curve between several points (a spline), whereas the arc has a fixed radius.
Refer Common Controls.
For more on these common controls see discussion on the Line page.