From: Axel Kohlmeyer (
Date: Tue Jul 10 2007 - 15:07:16 CDT

On Tue, 10 Jul 2007, Stern, Julie wrote:

JS> Hello,

hello julie,

JS> I'm interested in displaying velocity information from a dlpoly
JS> history file. I did find on this group that I have to color by
JS> User. But I don't know a couple of things to make that work. Does
JS> anyone know if the velocity info in a dlpoly history file is in a
JS> User column? I thought its just its normal place for velocity data.

all of the current VMD trajetory reader plugins do not read the
velocitiy information, so you'll have to input that information
with some scripting on your own. also the User field is a scalar,
not a vector, so you could only display the magnitudes.

JS> How do I then access that info? Do I call it velocity by name in a
JS> tcl script? How do I point that info to the User label? I just
JS> needed a few more details, since I haven't done that before.

as for some examples on how to display additional properties via
scripting, please have a look at:

you may need a combination of some of the script fragments shown there
to get exactly what you want, but with some effort, it should be doable.

if you have not done much VMD or tcl scripting before, i recommend to
start with some of the (scripting) tutorials referenced from the VMD
home page and some tcl tutorial to get the hang of what you're doing
and then look a little close at the stuff on the CPMD-VMD page...

hope this helps,

JS> Thanks.
JS> --Julie

Axel Kohlmeyer
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
If you make something idiot-proof, the universe creates a better idiot.