[lammps-users] fix freeze

Thanks Plimpton. I've tried that with fix serforce zero as follow.
#fix 1 GB setforce 0 0.0 0.0 ##
#velocity GB zero linear ##
#velocity GB zero angular ##

It can fix the orientation well. But during the NPT simulation,the position still changed.

Fix NPT changes the box size and scales the atom coords accordingly.
If you don't want this to happen, read the fix npt doc page. It describes
how to turn that off.

Steve