From: Axel Kohlmeyer (
Date: Thu Apr 27 2017 - 06:28:09 CDT

On Thu, Apr 27, 2017 at 1:40 AM, Karteek Kumar <>

> Hello Users,
> I have written coordinates and velocities of each atom in LAMMPS dump
> trajectory.
> For some reason, I am interested in writing down the velocities of few
> group of atoms.
> I have visualized the trajectory in VMD and save the trajectory with the
> selection.
> The output file contains just the coordinates, velocities are missing.

​yes, the molfile plugin for LAMMPS does not have support for writing out

> Can anyone help to write the velocities of the selection for all the
> frames?

i see two possible options and​ both require some programming:

1) you can modify the source of the lammps molfile plugin to also write out
velocities, compile and load it into VMD and then write out your LAMMPS
format file as before

2) rather than writing out your file in the standard way using the molfile
plugins, you write a custom Tcl function that writes the file with the
information you want.


> Thanks in advance.
> Thanks,
> Karteek

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