Root motion vs in-place animation: which to use in Unity, Unreal and Godot

A game-ready humanoid skeleton usually has a root bone on the floor, under the hips. The root is the character’s position in the world; everything else is the pose.

• Root motion: the root bone travels during the clip. A walk moves forward about a stride per step, a turn rotates the root, a lunge carries it half a metre. The engine reads that movement and applies it to the character, so the feet and the distance covered always agree.
• In place: the root stays at the origin and the body walks on the spot, like a treadmill. Your character controller moves the character, and you match the clip’s playback speed to the movement speed.

Most projects mix the two: in-place cycles for responsive movement, root motion for the one-off moves where position matters. That is why our packs ship both. In the Unarmed Combat Animation Pack, for example, the dodges and the knockdown carry real distance in their root-motion versions, and in the Vehicle and Seated Animation Pack entering and exiting the car moves the root by 0.74 m so the character ends beside the door.

Unity handles both on a Humanoid rig. Root motion for Humanoid clips comes from the body’s centre of mass, not from a named root bone.

Root motion

1. Select the FBX, open the Rig tab and set Animation Type to Humanoid. For clip files, set Avatar Definition to Copy From Other Avatar and pick your character’s avatar.
2. In the Animation tab, tick Loop Time (and Loop Pose) for cycles. Under Root Transform Rotation and Root Transform Position (Y), tick Bake Into Pose for straight walks and runs; leave rotation unbaked for turns. Leave Root Transform Position (XZ) unbaked so the forward travel becomes root motion.
3. On the Animator component, tick Apply Root Motion.
4. If you move the character with a CharacterController or Rigidbody, add an OnAnimatorMove() method to a script on the same object and apply animator.deltaPosition yourself. When that method exists, Unity hands root motion to your script.

In place

Untick Apply Root Motion and move the character in code. Feed its speed into a blend tree parameter so the right cycle plays at the right speed.

Root motion

1. Import the clips onto your character’s skeleton. Our UE5-named FBX files are in centimetres, so import them at scale 1.
2. Open each Animation Sequence and, in Asset Details, tick Enable Root Motion. Root Motion Root Lock can stay on Ref Pose.
3. In the Animation Blueprint, open Class Defaults and set Root Motion Mode. Root Motion from Montages Only is the default; choose Root Motion from Everything if state machine clips should move the character too.
4. The Character Movement Component applies the motion. While walking or falling, the vertical part of root motion is ignored and gravity still applies.

Epic notes that root motion has a performance cost: with either mode on, the animation graph updates on the game thread instead of a worker thread. Use it where it earns its place.

In place

Leave Enable Root Motion off and let the Character Movement Component drive the character, with a Blend Space keyed on speed. If you only have root-motion clips, Force Root Lock pins the root so they play in place, though the feet will slide unless the playback speed matches.

Root motion

1. Import the GLB or FBX, open Advanced Import Settings and map the skeleton with a BoneMap using SkeletonProfileHumanoid. Our rig’s bone names match the profile, so it fills automatically.
2. On your AnimationTree (or AnimationPlayer), set Root Motion > Track to the root bone, for example %GeneralSkeleton:Root if the skeleton was made a unique node during import.
3. Each frame, read get_root_motion_position() and get_root_motion_rotation() from the tree, turn the position into a velocity, and move your CharacterBody3D with move_and_slide().

In place

Leave the root motion track empty, move the CharacterBody3D from input, and drive a BlendSpace1D or BlendSpace2D with its velocity.

Foot sliding

With in-place clips, sliding means the playback speed and the movement speed disagree. Measure the clip’s speed once: our Locomotion pack lists it for every cycle (for example 1.40 m/s for Walk and 4.00 m/s for Run), so a character moving at 2.1 m/s should play Walk at 1.5× or blend towards Jog. With root motion, sliding usually means root motion is not being applied at all, so the clip and the controller are both trying to move the character.

The character snaps back at the end of a loop

A root-motion clip is playing without root motion turned on: the mesh walks away from its capsule, then jumps back when the clip restarts. Turn on Apply Root Motion (Unity), Enable Root Motion (Unreal) or the root motion track (Godot), or use the in-place version.

Twisted wrists or palms facing the wrong way

This is a retargeting problem rather than a root motion one: the clip was authored on a skeleton whose arm bones point or roll differently. See our guide to retargeting animations in Unity, Unreal Engine 5 and Godot.

T-pose vs A-pose

The rest pose doesn’t change how root motion works, but a mismatch between the clip’s skeleton and yours makes arms float or clip into the body. Our mannequin binds in an A-pose and includes a T-pose take; the retargeting guide shows how to tell each engine which pose to compare.