Relative movement in VR with hand controllers

[Jabberwock]

I am using VRidge with Razer Hydra for SteamVR and now I have decided to add positional tracking which is required by some games.

As I understand, there are two options: tracking the absolute movement in the physical room or providing relative input (with a treadmill, Wii Balance Board etc.).

I have experimented somewhat with the absolute tracking with somewhat positive effect (as described here: https://www.mtbs3d.com/phpbb/viewtopic. ... 45&t=22563), but I have a problem with syncing the head/body tracking with hands (which are tracked separately by Hydra). Even if I sync them reasonably well in the SteamVR initial area (i.e. the movement of the body and the movement of hands is reasonably the same), in particular games it is wildly out of sync. What could be the reason for that?

Also, I have tried relative tracking, i.e. emulating freetrack input and feeding that to VRidge. It works quite well, but then the hands are completely out of sync - they remain, of course, in starting place, as Hydra controllers do not actually move.

How can this be solved? I imagine that it would be enough to move the hands together with the head/body at the relative input and then additionally move according to Hydra input, but I have no idea how to do that... How is it solved in other relative input solutions?