Root Motion
Movement driven by the animation, not the controller
Definition
Root motion drives a character’s world-space position and rotation from the root bone’s baked translation in an animation clip, rather than from a separate movement controller. It is the gold standard for melee combat, climbing, and mocap-driven locomotion where the animation needs to land exactly where it should. The trade-off is responsiveness: tightly-tuned shooter movement usually drives the controller directly and discards root motion.
In production
Unreal Engine's Character Movement Component has a dedicated root motion mode where the capsule's position is driven directly by the root bone's translation baked into the Animation Sequence, which is why melee combos and climbing traversal rely on it so the character's hands land exactly on the mocap'd handhold rather than an approximated blend. Unity's Humanoid rig supports root motion through "Apply Root Motion" on the Animator component, and the Root Transform Position settings in the clip's import inspector control whether motion is baked from the original curve, the first frame, or a straight-line average. A common production bug is root motion "sliding" — where the capsule's collision extent doesn't match the mocap actor's stride, causing feet to visibly skate on turns unless a technical animator retargets or re-times the clip. For twitch-responsive genres like arena shooters, studios often bake root motion out entirely and drive movement purely through code, since waiting for root-motion-driven translation to catch up to player input reads as sluggish.
