Rotate Around the Z Axis
Rotating a large assembly model is easier if the rotation is set around the Z axis.
 Rotating around the Z axis does not necessarily mean that the Z axis is vertical.
 Rotating around the Z axis does not necessarily mean that the Z axis is vertical.
Do as follows:
- Select  > > User Preferences > User Preferences > Drawings, Models. Drawings, Models.
- Select View.
- Select  Rotate Around Z Axis. Rotate Around Z Axis.
- Confirm by clicking OK.
- Open a model, and set it in a projection where the Z axis is vertical.
- Rotate the model.
Note: 
  - If the initial situation before rotating the model is other than, for example, an isometric projection, the Z axis will retain its orientation and will not become vertical.
