Upward Drift with HMD

[Plasma]

I'll try to be more specific. As it is, when the user is wearing the HMD and is moving forward, Vizard automatically propels the user in the direction they're looking. This is fine, except that when they look up or down they drift up or down.

I want the simulation to simulate walking rather than flying through the environment.

I have set up the joystick to only move forward and back and control speed, not rotation and not strafing.

I still want the user to move where they are looking, unless they are looking up or down. How do I restrict this?

Thanks!