# fix_modify AtC mesh create_elementset command

## Syntax

    fix_modify <AtC fixID> mesh create_elementset <id> <xmin> <xmax> <ymin> <ymax> <zmin> <zmax>

-   AtC fixID = ID of [fix atc](fix_atc) instance
-   mesh create_elementset = name of the AtC sub-command
-   id = id to assign to the collection of FE nodes
-   \<xmin\> \<xmax\> \<ymin\> \<ymax\> \<zmin\> \<zmax\> = coordinates
    of the bounding box that contains only the desired elements

## Examples

``` LAMMPS
fix_modify AtC mesh create_elementset middle -4.1 4.1 -100 100 -100 1100
```

## Description

Command to assign an id to a set of FE elements to be used subsequently
in defining material and mesh-based operations.

## Restrictions

Only viable for rectangular grids.

## Related AtC commands

-   [fix_modify AtC command overview](atc_fix_modify)
-   [fix_modify AtC mesh delete_elements](atc_mesh_delete_elements)
-   [fix_modify AtC mesh
    nodeset_to_elementset](atc_mesh_nodeset_to_elementset)

## Default

Coordinates are assumed to be in lattice units.