questions for filling atoms in region

Dear lammps users,

I need to build a model containing phase interface. The whole box includes three regions which are named B2, B19 and INTERVAL. The B2 region is filled with B2 phase(bcc) atoms. The B19 region is filled with B19 phase atoms. The INTERVAL region is the interspace between B2 and B19, and it’s 2.0 Angstoms.
But after run I found the interspace is more than 2.0 Angstoms, and the B19 region losts a layer of atoms. So I doubt when creating atoms in region B19, lammps would create atoms from the starting point of the whole box ,not the B19 region. Is it right?

It's much easier if we can see a picture.
Have you tried looking at (visualizing) the system?
Can you post a picture of your system?
(And please include labels, such as "B2", "B19" etc, if possible.)

If you are using VMD, then you can select the "Mouse->Label->Bonds"
menu option to measure distance between pairs of atoms you click on.
(These distances can go in the picture too.)

README_visualize.txt (2.85 KB)

If you fill regions with atoms on a lattice, an

atom exactly on the region boundary may or
may not be created due to round-off. It’s up
to you to adjust the region boundaries to accommodate