RailwayRouteOptimization/scripts/Draw/Dimension/DimRotated/doc/DimRotated_proc_en.html

<ol>
  <li>Enter the angle of the dimension in the options toolbar.</li>
  <li>Set the first extension line endpoint with the mouse or enter a
  coordinate in the command line.</li>
  <li>Set the second extension line endpoint.</li>
  <li>Set the position of the dimension line.</li>
</ol>