I need to be able to Roll the camera (rotate around the view axis) when doing walk navigation. (Think of a fighter jet doing a roll maneuver as it flies through a narrow canyon.) With WASD, I can translate forward and backward, left and right. With EQ, I can translate up and down. With the mouse, I can pitch and yaw. That covers five of the six degrees of freedom. But I can't find a way to roll. What am I missing?
(For context, I'm working inside a spherical space station. Fly navigation is useless in the confined space, and because I don't have a universal "up", I need to be able to roll as I move around the structure.)
