Problem with retyping and sorting lammps datafile in VMD

Hello everyone,

I have an issue with VMD topotool.
In my case, I have a polymeric solution built by moltemplate and everything works well. In this step of simulation, I want to move one polymer chain from one side of the simulation box to another.
Simply I use topo readlammpsdata full to load my datafile in VMD, then I move the target polymer and I save it by topo writelammpsdata full.

What I get as an output is a totally retyped and re-ordered datafile in atom masses, types, and their coefficients. My coeff data is stored in a separate file and it’s difficult to re-order all the coeffs in this system.

Here is what I load in VMD:

The output of writelammpsdata without any changes in coordinates or topology:


I just wonder if there is something I’m doing wrong or if I’m missing a flag or a keyword.
Thank you in advance,

Please post questions about VMD to the vmd-l mailing list. This is off-topic here.

To make this a LAMMPS topic, why don’t you use the displace_atoms command — LAMMPS documentation ?