From: Axel Kohlmeyer (
Date: Fri Apr 04 2014 - 06:36:30 CDT

hi marcela,

only very few file format plugins for VMD support reading velocities
and even less support writing (as far as i can tell the HOOMD plugin
and the TNG plugin). for the rest you would have to copy the
velocities to coordinates and save them as coordinates.

the molfile API has no facility at this moment to write two files in
parallel, as it would be required in the case of a DCD file, so the
only option to extract the velocities would be to copy them to
coordinates (if needed in a new "molecule") via Tcl script and then
write them out as coordinates. of course that has the downside that
you now have the "CORD" magic string in the header that identifies the
file as a file containing coordinates.


On Thu, Apr 3, 2014 at 8:31 PM, Marcela Madrid <> wrote:
> hi
> How do I write velocities into a dcd file (or any other format) with VMD?
> I am loading a trajectory in Desmond format, and I do not see the option
> to write velDCD, I only seem successful in writing coordinates.
> Thanks so much!
> Marcela

Dr. Axel Kohlmeyer
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.