LAMMPS has two requirements regarding simulation box

LAMMPS has two requirements regarding simulation box.
Requirement 1: The first box vector is aligned with the Cartesian X direction, and that the second vector is contained in the XY plane.
Requirement 2: The box “skewness” should not be too large, i.e. the box should not be too distorted, and the box angles should be neither too acute nor too obtuse.
I’m using atomsk to generate geometry and atom positions. Please can any one tell me how can I deal with these two requirements?

There is no need to tend these requirements at user level. The system created in atomsk can be saved as cfg file and be converted into lammps configuration file. Refer to the documentation.

Thank you so much for considering but I’m trying to deform poly-crystal material in LAMMPS. The geometry and atom positions are obtained from atomsk. When I run this in LAMMPS, every time I face the problem below.
ERROR: Lost atoms: original 1529137 current 1528953 (src/thermo.cpp:481)

To make the simulation box suitable for LAMMPS, there are some requirements that I can’t understand. Please refer to the documentation link where requirements are mentioned.

This kind of error is not likely due the system box requirements, but more likely due to bad simulation settings or force field or similar.

Thank you so much akohlmey