Toolbar / Icon:
Add-on:  QCAD Professional
Menu: Dimension > Datum
Shortcut: D, T
Commands: datum | dt


Creates a special type of leader typically used to attach a datum identifier symbol to an edge or surface in a mechanical drawing.


  1. Click the start point of the datum leader. That's the point that indicates which feature the datum refers to.
  2. Set the location of the next edge of the leader line.
  3. Set the other edges of the leader line and click the right mouse button or press the Escape key to finish.