Prescribed Displacements
Directional input refers by default to the global coordinate system which is based on Plane1 with its origin located at the Origin of the part or assembly. Plane1 is the first plane that appears in the tree and may have a different name. You can use other reference planes or axes to specify directions.
Using Reference Planes
A reference plane defines a Cartesian coordinate system as illustrated in the figure.
Using Reference Axes
A reference axis defines a cylindrical coordinate system as illustrated in the figure. Reference axes are useful and necessary for specifying radial and tangential restraints.