To inhabit a virtual reality, to really feel like you're there, you need to be able to look down and see your own hands moving. It's the first thing you look for when you first strap an Oculus Rift DK2 to your face and it's the first comment you make to your friends when you take the VR headset off.
Essential reading: The Wareable Watchlist - 50 gamechangers for 2015
That's why Oculus just bought Nimble VR, the company behind the successful Kickstarter project Nimble Sense, the $99 gesture control depth sensor designed to work with VR headsets. It uses an IR laser and an IR camera and has a 110 degree field of view.
The idea isn't new. So far, we've seen hackers stick Leap Motion controllers to the front of the VR headset and there's even a Leap Motion 3D Jam competition in progress right now with lots of Oculus-optimised games competing for $75,000 in prize money. But Leap Motion was designed as a desktop controller and either Oculus preferred Nimble VR's technology or Leap didn't want to make a deal.
It seems Oculus is trying to perfect its first consumer Rift to the point where the experience won't put people off VR and head mounted displays. Hiring all this talent makes sense - the Nimble VR team have been working on Nimble Sense since 2012 and have experience at Pixar and Industrial Light & Magic.
The Kickstarter project had already doubled its $62,500 target thanks to over 1000 backers but it has now been cancelled. The device was initially going to ship in June 2015 which makes it unclear whether this deal will speed up or slow down a consumer Oculus Rift release.
What is clear is the potential for this technology. The initial demos show users reaching out and grabbing virtual objects and controlling virtual UIs. In Nimble's stretch budget, they mention the possibility of a long-range camera (to 150cm away rather than the default 70cm) and customisable frame rate and shutter speed controls.
In a blog post onNimble VR's website, the three founders Rob, Chris and Kenrick said: "We'll be joining forces with Oculus, a team that is creating an entirely new platform and industry.
"Our work started off with colour gloves, evolved into markerless tracking with multiple Kinect cameras and eventually led to the development of our own tiny 3D camera, the Nimble Sense, that could be mounted on an Oculus Rift. We're excited to continue to push at the boundaries of input and user experience in VR."
Oculus actually went on a bit of a spending spree acquiring not just Nimble VR but 3D modelling company 13th Lab too. It's also just hired motion capture expert Chris Briegler. As predicted, 2015 is gearing up to be a very special year for VR indeed.