During my demo, I was able to freely walk around the room, and the prototype Rift was able to display a grid when I approached a boundary (again, like SteamVR and the Vive). I asked whether or not the Rift's playable space would scale depending on room size and was told that it would. So if you have a larger room, the boundary would expand, and vice versa. With the HTC Vive, there is a pre-defined limitation on how large a space you're able to use (Valve has said in the past that it could be possible to add more base stations, but SteamVR does not currently support more than two). I asked if using Santa Cruz in a football field would allow me to walk the full distance and was reluctantly told yes.