This is so amazing that only the positions and orientations of the Quest VR headset and its two controllers were used to estimate leg movement and position. There are no tracking bars placed on the legs and no external cameras used for this great system. Meta Research Scientist Alexander Winkler He shared several videos on Twitter with links to the scientific paper on arXiv and a YouTube video in more detail.
In a scientific sense, this is known as motion tracking from sparse sensors and ML is particularly adept at extracting meaningful information from very little, if there are enough dependencies between what is known and what is not known. Since we swing our arms for balance when walking and running, arm movement is a good indicator of what the legs are usually doing. Combined with head tilt and orientation, the ML system can predict most human movements with extreme accuracy.
More traditional methods of limb tracking rely on additional devices, such as reflective tags placed on your legs and torso that are identified by external cameras, or radio-signaling bands worn at various locations on your legs to transmit position and movement data.
While these methods work, they are usually sold as accessories that cost more and are not well supported in most apps and games. If the Meta can achieve such good results with the Quest 2 headset, the developers will likely build body tracking into their games and apps.
Despite these significant developments, Meta Reality Labs acknowledges that more work needs to be done. If you move fast enough, the ML model fails to correctly identify your position. It is difficult for the computer to appreciate unusual situations, and if the virtual environment has obstacles that do not exist in reality, the movement will not match. The overall effect seems to be very good, and it would be nice to be able to see a whole body instead of a floating torso when chatting with friends in VR.
We hope this technology will be ready for launch soon. With an announcement of the Meta Quest Pro headset expected in just a few weeks, the timing for the full-body avatars looks perfect. Meta Quest Pro can track eye movement and facial expressions, providing a greatly enhanced sense of presence for your friends, family, and co-workers in the near future.