Activate the rotation toolbar.
The model can be rotated by using these buttons or by dragging the orientation icon around to the desired position.
Rotate Counter clockwise (Insert key)
Rotate Up (Home key or shift+up arrow)
Rotate Clockwise (Page Up key)
Rotate Left (Delete key or shift+left arrow)
Rotate Down (End key or shift+down arrow)
Rotate Right (Page Down key or shift+right arrow)
Notes:
If the rotation toolbar is not visible it can be activated with
Tools > Rotation Toolbar
Before rotating the model you should set the desired centre of rotation