About Assembly Orientation
An assembly appears in a default view orientation when it is first created and any time it is retrieved (provided it was saved in default orientation). You can change the default orientation of your model or create new orientations using the Orient tab in the View Manager dialog box.
Using the commands in the Orientation group on the View tab you can perform the following actions:
Return to the default orientation.
Return to the previous orientation.
Refit the model to the screen so that you can view the entire model.
Reorient the model.