Angle Snap Toggle determines the incremental rotation for a number of features, including the standard Rotate transform. As you rotate an object (or group of objects), the object moves around a given axis in the increment you set.
Angle Snap Toggle also affects Pan/Orbit camera controls, FOV and Roll camera settings, and Hotspot/Falloff spotlight angles.
(Angle Snap Toggle). When on, angle snap affects all rotational transforms.
To rotate an object an even number of degrees:
(Angle Snap Toggle) and 
rotate the object.
By default, the rotations take place in 5-degree increments.
To rotate an object a precise degree of rotation, do one of the following:
(Select And Rotate), then right-click it to display the Transform Type-In dialog. Enter the exact rotation you want.
the settings button next to Rotate to open the Transform Type-In dialog. Enter the exact rotation you want.
(Angle Snap Toggle), then on the Grid And Snap Settings dialog, click the Options tab. Set the Angle value in the General
group to the precise degree of rotation you need, then rotate the object. Rotation snaps to the angle increment you specified.
The angle increment is set on the Options panel of the Grid and Snap Settings dialog. Right-click the Angle Snap Toggle button to display the Options panel of the Grid and Snap Settings dialog. The default is 5 degrees.
