[DrPizza]

HoloLens is a derivative of Kinect. Kinect 1 (with the Xbox 360) was structured light. Kinect 2 (with the Xbox One) is time-of-flight. I'm not sure which tech the HoloLens uses (I don't think Microsoft has specified one way or another, and I didn't have an IR camera to look to see if it was emitting a pattern), but I'm assuming it's based on the newer tech, because my understanding is that time-of-flight systems can much better handle having multiple devices scanning the same space. HoloLens handled this situation very well; I've seen at least 8 devices all scanning the same area without getting confused.

It's all driven by the unit, btw; no need for markers or external illumination.

[josephpmay]

Don't quote me on this, but I believe I've read that it is structured light. From my experience time of flight cameras are excellent at things like body detection and terrible at things like SLAM. (I have no idea why and could be wrong... it's been awhile since I've looked at the literature)

[the_rosentotter]

It seems like the environment scanning could be a better alternative to the array of external sensors the Vive uses to demarcate its play area. Certainly would be more elegant.