From: John Stone (
Date: Wed Mar 12 2003 - 13:45:21 CST

Hi Yongmei,
  There isn't a built-in way to do this, but if you have the vector
data in an array accessible via Tcl, you can use a Tcl trace on the
VMD trajectory frame to force VMD to redraw the vectors when the frame
updates. You can read the VMD user's guide section on Tcl callbacks
to see how that sort of thing is done, and then read about how to draw
your arrows using the "graphics draw" or simpler "draw" commands.
At some point we may have an easier way to do this, but at the moment
this is the only way to update them over time. If you just want to draw
vectors for a single timestep and don't need to animate them,
that's much easier.

  John Stone

----- Forwarded message from -----
Date: Wed, 12 Mar 2003 14:11:56 -0500
Message-Id: <>
Subject: display vectors on atoms

Can I use VMD to display the vectors (say velocity vectors) on each
atom? What should I do?

THanks for any help.


----- End forwarded message -----

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