# Differences between "Region......units lattice" and "Region......units box"

Hi, Guys,

I am a little confused about “region” command as following:

1.units lj

lattice fcc 2

region A block 0 2 0 2 0 2 units box

What does the “box” units means ?

Hi, Guys,

I am a little confused about "region" command as following:

1.units lj

lattice fcc 2

region A block 0 2 0 2 0 2 units box

What does the "box" units means ?

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2. units lj

lattice fcc 2

region B block 0 2 0 2 0 2 units lattice

Does the "lattice" units means the region is:" 0 2a 0 2a 0 2a", where a is
lattice constant? ?

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what are the differences between above 2 "units"?

what happened to reading the documentation beyond
the header segment with the syntax description?
the manual explains the difference. if you don't understand

in case you cannot find it, below is a copy.

axel.

The units keyword determines the meaning of the distance units used to
define the region for any argument above listed as having distance
units. It also affects the scaling of the velocity vector specfied
with the vel keyword, the amplitude vector specified with the wiggle
keyword, and the rotation point specified with the rotate keyword,
since they each involve a distance metric.

A box value selects standard distance units as defined by the units
command, e.g. Angstroms for units = real or metal. A lattice value
means the distance units are in lattice spacings. The lattice command
must have been previously used to define the lattice spacings which
are used as follows:

For style block, the lattice spacing in dimension x is applied to xlo
and xhi, similarly the spacings in dimensions y,z are applied to
ylo/yhi and zlo/zhi.
For style cone, the lattice spacing in argument dim is applied to lo
and hi. The spacings in the two radial dimensions are applied to c1
and c2. The two cone radii are scaled by the lattice spacing in the
dimension corresponding to c1.
For style cylinder, the lattice spacing in argument dim is applied to
lo and hi. The spacings in the two radial dimensions are applied to c1
and c2. The cylinder radius is scaled by the lattice spacing in the
dimension corresponding to c1.
For style plane, the lattice spacing in dimension x is applied to px
and nx, similarly the spacings in dimensions y,z are applied to py/ny
and pz/nz.
For style prism, the lattice spacing in dimension x is applied to xlo
and xhi, similarly for ylo/yhi and zlo/zhi. The lattice spacing in
dimension x is applied to xy and xz, and the spacing in dimension y to
yz.
For style sphere, the lattice spacing in dimensions x,y,z are applied
to the sphere center x,y,z. The spacing in dimension x is applied to