fix_modify AtC mesh add_to_nodeset <id> <xmin> <xmax> <ymin> <ymax> <zmin> <zmax>
 fix_modify AtC mesh add_to_nodeset lbc -11.9 -11 -12 12 -12 12  
Command to add nodes to an already existing FE nodeset.
Coordinates are assumed to be in lattice units.
 1.6.1
 1.6.1