Visualisation problem? Or code problem?

Dear users,

I am trying to simply model falling/moving atoms in a cylinder. The modeling part seems quite easy as well as the visualisation.

But somehow, all the image I produce stay the same, the atoms do not move.
I am using the code below


# === initializing === #
units si
atom_style sphere
dimension 3
boundary f f f
newton on

pair_style gran/hooke 2.0e5 NULL 50.0 NULL 0.5 0
communicate single vel yes

# ==== Defining the region ==== #
lattice sc 0.5
region CIL cylinder y 0 0 20 0 4
region BL block -20 20 -4 4 -20 -10
region HALFCIL intersect 2 CIL BL

create_box 1 CIL
create_atoms 1 region HALFCIL

group ATOM region HALFCIL
pair_coeff * *

# ==== Fixes ==== #
fix f1 ATOM nve/sphere
fix f2 ATOM gravity 9.81 vector 0.0 -1.0 0.0

dump myDump all image 10 dump.*.jpg type type
compute 1 all erotate/sphere

# ==== Run it ==== #
run 100

I even modified the velocity and tried different gravity vectors to produce some kind of movement… but nothing works…

So, does my code lack something? Or do the images show something wrong?

I hope my question is clear and that you would be willing to help me, that would be really great!


I suggest dumping a text file with the coordinates of all atoms, then
look at the data for a few selected atoms and check if they do NOT
move or just move so little it is unnoticeable in the JPG dump.

dump myDump all atom 100 dump.atom