Datum Axis
Use > 
Axis to create datum axes. You may need datum axes on your model to create a number of Creo Simulate modeling entities. For example, you can use a datum axis when designing a cyclic symmetry constraint or defining a coordinate system.
Axis to create datum axes. You may need datum axes on your model to create a number of Creo Simulate modeling entities. For example, you can use a datum axis when designing a cyclic symmetry constraint or defining a coordinate system.If your model is an assembly then the Select a Component dialog box opens. The top level assembly is selected by default and displayed in the collector. Select the component for which you want to create a datum axis. Click OK. The DATUM AXIS dialog box opens.
For more information on creating datum axes, search the Part Modeling functional area of the Creo+ Help Center.
When you create datum axes, Creo Simulate treats the axes as simulation features. Simulation features are not visible or accessible when you return to Creo+ unless you promote them.