Create Atoms after Reading data

Hi
I am trying to create atoms in a specified region of the simulation box after reading the data file.
Suppose that I have an amorphous system with a simulation box of 150x150x100 stored in a data file.
After reading the data file I change the simulation box to

change_box all z final 0 200 units box

after doing this I define a simple cubic lattice with command

lattice sc 4.0

then I define a spherical region with

region sph sphere 75 75 150 30 units box

finally I want to fill this region with atoms with this command:

create_atoms 1 region sph

with this command I expect lammps to create atoms within the defined spherical region with simple cubic lattice and atom type 1.
However it gives only this:

created 0 atoms

What am I missing?
Is it possible to create atoms after simulation box is defined via read data command?

dundar.

Hi
I am trying to create atoms in a specified region of the simulation box after reading the data file.
Suppose that I have an amorphous system with a simulation box of 150x150x100 stored in a data file.
After reading the data file I change the simulation box to

change_box all z final 0 200 units box

after doing this I define a simple cubic lattice with command

lattice sc 4.0

then I define a spherical region with

region sph sphere 75 75 150 30 units box

finally I want to fill this region with atoms with this command:

create_atoms 1 region sph

with this command I expect lammps to create atoms within the defined spherical region with simple cubic lattice and atom type 1.
However it gives only this:

created 0 atoms

What am I missing?
Is it possible to create atoms after simulation box is defined via read data command?

yes. but the atoms have to be inside the region *and* the box. so
please check your box dimensions in the data file or adjust the box
dimensions as needed with change_box.

axel.