Part Modeling > Datum Features > Datum Curves > About Sketched Datum Curves
  
About Sketched Datum Curves
You can sketch datum curves in the same manner as any other features. Sketched curves can consist of one or more sketched segments and of one or more open or closed loops. However, using datum curves for other features is usually restricted to a single curve (which can consist of many segments) of an open or closed loop.
To sketch a datum curve in a sketch window, click Model > Sketch.