Parent index for each joint in BodyJointReferenceArray order.
-1 means "root" (no parent). Used to convert world-space XR poses to
local-space transforms suitable for skeleton bones.
Hierarchy follows the WebXR Body Tracking specification and standard
humanoid anatomy.
Parent index for each joint in BodyJointReferenceArray order. -1 means "root" (no parent). Used to convert world-space XR poses to local-space transforms suitable for skeleton bones.
Hierarchy follows the WebXR Body Tracking specification and standard humanoid anatomy.