fix_modify AtC create_elementset <id> <xmin> <xmax> <ymin> <ymax> <zmin> <zmax>
fix_modify AtC mesh create_elementset middle -4.1 4.1 -100 100 -100 1100
Command to assign an id to a set of FE elements to be used subsequently in defining material and mesh-based operations.
Only viable for rectangular grids.
Coordinates are assumed to be in lattice units.