While high-end headsets like the Rift and Vive use external sensors for positional tracking, the Windows VR headsets use a fully ‘inside-out’ solution which eliminates the need for external trackers and simplifies setup, but certainly makes hand-tracking more challenging. While the Windows VR headsets are often criticized for the precision of their hand-tracking, I was surprised to find how well they hold up in practice even with a fast paced, highly active game like Beat Saber (2018).
All of the Windows VR headsets use a pair of cameras on the front of the headset for positional head tracking, and generally that’s considered top notch. The same cameras are also used to look for glowing LEDs on the Windows VR motion controllers to determine their position. However, when the user’s hand leaves the field of view of the camera, the system can only make rough guesses about the position of the controllers, and when they come back into view, it needs to quickly correct their position.
Certainly there are edge cases where this sort of occlusion issue makes the Windows VR controllers sub-par compared to tracking systems with external sensors, but in practice they actually hold up quite well.
When it comes to Beat Saber, the game is nearly a worst-case scenario for the Windows VR controllers. Users move their hands quickly, constantly, and often outside of the field of view of the tracking cameras, frequently crossing arms and causing additional occlusion. When I set out to see how the Windows VR controller tracking held up in Beat Saber, I expected they might be ok for lower difficulties, but never thought they’d cut it for Expert, the most difficult setting on the game. After using a Lenovo Explorer with Windows motion controllers to beat the game’s hardest song (Balearic Pumping) on Expert, I was pleasantly surprised:
To be clear, I was playing the song here exactly as I would have with other controllers, overhead arm flails and all. And while I was a few notes short of a perfect combo, I didn’t feel like any of the missed notes were the fault of the tracking.
More so than the tracking performance, the things that detracted most from playing the game at a high level with the Windows VR motion controllers was the mushy haptics and the ergonomics of the controller. The haptics felt like they weren’t triggering right, which reduced the feedback from the game telling me when I landed a cut correctly. Meanwhile, the poor ergonomics of the handle didn’t sit in my hand as well as the Rift or Vive controllers. I ended up scooting my hand downward and avoiding the trigger entirely in order to find the grip that felt like it offered me the best control.
Speaking with Beat Saber creator Jan “Split” Ilavsky, I learned that while the game’s hit detection model does include a bit of an assist, it’s identical across all input devices.
He told me that he spent a few days tweaking the hit detection model to get it to feel just right, and the game actually uses two bounding boxes for hit detection: one that’s larger than the actual cube on screen, and one that’s smaller. The larger box is only eligible for ‘good’ cuts, while the inner box can see a ‘good’ cut or a ‘bad’ cut; the end result, Ilavsky says, is a reduction in the frequency of ‘why did I miss?’ moments compared to using a model which relies on the actual geometry of the cube.
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Check out our Early Access review of Beat Saber, something we dubbed a ‘VR rhythm game for budding Jedi Knights.’