From: Davide Mercadante (
Date: Thu Jan 28 2016 - 10:30:47 CST

Dear All,

I have been reading several posts about this but I couldn’t find an answer and what I am trying is not working. I have a simulation run with GROMACS and trr or eventually gro files in which velocity information for each atom are stored. In order to do something with those in my script I want to extract these information.
I’ve found this which makes me think that may be there is no easy solution yet for this inside vmd. The "$sel get {vx vy vz}" command doesn’t seem to be working as I get a list with 0 values {0.0 0.0 0.0}. Looking at previous posts on the mailing list some other users successfully ran this command to get velocities out but I am not sure if they were using NAMD- or LAMMPS-like trajectories (not specified). Is there any other way of getting these information using VMD and gromacs trajectories?

Thank you for your time.