[lammps-users] i want put fixed walls.

in one simulation i want put the axis x and y fixed.

someone know how i can make it?

my simulation are atom style molecular type and use
pair_coeff sw.

if i put boundary f f m the simulation fail becouse
some atoms go out of simulation box.

thank you for all.

The doc page for the boundary command is pretty clear
about what the different options mean. If you don't
want a periodic system you probabably want 's' for shrink-wrapped
if you are losing atoms.