We made a video taking a technical look at Fantastic Contraption's companion cameras, to optimize the experience for those not actually in Virtual Reality. We really want to make the game as comfortable as possible for the observers, and I'll explain some tricks we figured out during our experiments with OpenVR and the SteamVR plugin for Unity.
Here's our Companion Camera Switcher, if you want to take a look at the source code there. Here's the Camera Smoothing Script. It's prototype code, excuse the mess ;)