It would not be perfect, but assuming you are not very very obese, when it comes to things like kicking normally - you would see your feet appear and from that you could extrapolate actions... you also have things like the LiDAR and motion senses that can detect your movement around and also extrapolate that you are walking. It is also a computer, so the first time you bend forward or move around it can build a model of your body to match reality.How could full body tracking work based on cameras in the headset? What if you have a big belly or boobs, or you tilt your head back? It wouldn’t be able to see your legs.