...
The geometry needs to be symmetrical
The boundary conditions need to be symmetrical
The loads have to be applied only on a half/quarter/eighth of the part. They will be automatically mirrored and considered through the symmetry planes.
Attention: The loads are only allowed to be applied in the positive coordinate direction (positive coordinate half/quarter/octant)
Gravity loads normal to the symmetry plane will cancel each other out
The displacement constraints are allowed to be applied on a volume/cell that goes beyond the symmetry plane to the other coordinate half/quarter/octant unlike loads (only possible with manual interference and the Command Line Option)
The geometry needs to be located in the global coordinate origin or a local coordinate system has to be created on which the symmetry can relate to
...