Rotate Tools
There are six different Rotate tools: Rotate Front -45, Rotate Front +45, Rotate Side -45, Rotate Side +45, Rotate Top -45 and Rotate Top +45.
The tools will rotate the selected objects and/or groups by 45 degree increments in the selected view.
Here's how it works: You first select the objects you wish rotated, then identify the view you wish them rotated within and press the corresponding button. The objects will be rotated by 45 degrees either clockwise (+) or counterclockwise (-).
You can look closely at the icons for the Rotate buttons to see how a rotation will be applied. The blue square is representative of the quad-view viewports, and the arrow shows which direction the rotation will take place in the respective view.