Bi-axial and Uni-axial geogrids In FLAC 3D

@itascan
Hello everyone, How are we supposed to differentiate bi-axial geogrid from Uni-axial geogrid while assigning the properties in FLAC 3D. The properties will be different but how does FLAC incorporate axes for these two types?

Is it related to the surface co-ordinate system and if yes, please provide some concepts and guidelines for the same.