RailwayRouteOptimization/scripts/Edit/Copy/doc/Copy_proc_en.html

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<ol>
  <li>Use the selection tools to prepare a selection of entities you want to
  copy to the clipboard.</li>
  <li>Choose the copy tool.</li>
</ol>
<p>The standard copy tool of QCAD acts like the copy tool of other
applications. It does not allow you to choose a reference point for your
selection but instead computes the reference point automatically at the center
of the selection. This is not always desirable as you most likely want to place
the pasted entities at a precisely defined position. For this, QCAD offers and
alternative, more CAD specific copy tool: 
<a href="../../CopyWithReference/doc/CopyWithReference_en.html">Copy with
Reference</a>.</p>
<p>The selection is now on the QCAD internal clipboard and can be pasted into
the same or a different drawing that is opened with the same running instance
of QCAD. Note that if you quit the QCAD application, the contents of the
clipboard is lost. The QCAD clipboard can only be accessed by QCAD itself. You
cannot exchange drawing entities with other applications through copy and
paste. Please use the export and import functionality of QCAD for this.</p>
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