Virtual Studio not working unless HMD connected.

I have a Vive Pre system. I have built a green screen studio and the Tracker and Camera and Virtual Camera/Unreal Engine work great together and I am very happy. I can mix virtual into my real life camera image all day.

BUT ----

I have purchased a stand alone Lighthouse 2.0 for use with the Tracker without the rest of the system. I have no use for an HMD or controllers. I have setup SteamVR using the NULL driver for the HMD.

The Tracker is connected to SteamVR, I can see it tracking in both SteamVR and OpenVR but Unreal Engine refuses to see/use the data.

Am I doing something wrong?

Getting the Tracker up and running with the full system was so simple!! It seems really strange that I can’t get it working without the HMD and controllers…


(I hope this was the right place to post… there doesn’t seem to be a virtual production forum and this seemed close enough)