Attribute:

ZONE [-] (element wise) (zone number, horizontal or vertical model)

Zones with anisotropic material properties. can be defined within the model mesh. The relevant elements are assigned to different zones by utilizing the ZONE data type. The material data (K-values and associated angles) must be defined for each zone code. The material data (MATE) attribute is mandatory when using the zone codes (ZONE). If only isotropic K-values with uniform anisotropy are utilized in the model, the zone code number does not need to be defined. When defining a zone number, an integer value greater than zero is required