Always reading the HMD location even when VR SDK is set to none?

[guiglass]

Hi I have been trying to find a way of reading the HMD's position and rotation in Unity even when the current VR SDK mode is set to None. I notice that Vive trackers and controllers do still work in Unity even with no VR SDK enabled, but then the HMD object (main camera) no longer is updating it's location with the HMD tracking.

My game does not always require rending to VR, but it would be very nice if we always could read the tracked location (much like other tracked objects).

Is it possible to access the HMD location even when VR rendering is disabled?

Preferably, if the VR SDK is set to None (but SteamVR is running and the HMD is present) would it be possible for the SteamVR Unity plugin to continue to treat the HDM as enabled and tracked, maybe only the rendering be disabled, just so my game would continue to function as if the HMD is tracking normally?

I'm using Unity 2019.4.31f1 and the SteamVR Unity Plugin v2.2.0

Thank you so much for any advice.