Gets or sets the Roll of the Camera, in degrees around the view vector. 0 is no roll, 45 rolls the right side down, -45 rolls the left side down. This property applies to 3D views only.
Heading, Pitch and Roll are used to describe the viewing direction. Roll defines the angle of the camera rotating around the Y-axis.
Imagine yourself as the camera. In this case adjusting the roll would be equivalent to tilting your head.
There is currently no way to change the roll using the out of the box navigation tools.
If roll is set to anything other than 0 and you attempt to navigate in the view the roll will be set back to 0.
For most workflows in 3D roll will never be changed and remain its default value of 0.
Roll has no effect in 2D it will always be 0.