The character glides or runs in place

The character slides across the floor without its feet driving the motion, or it pumps its legs and never leaves the spot.

Checks: in-place · root-motion-speed

Why it happens

Exactly one thing should move the character horizontally: the controller, or the clip's own root motion. Both is a glide; neither is running in place. The file cannot tell you which was intended — a treadmill cycle and a travelling cycle are both valid glTF — so this symptom only becomes checkable once the project declares who owns each movement component.

What AnimSmith measures

The two synthetic cycles below are the same walk. One keeps its root under the character; the other carries the hips 1.2 m forward over the same second. The root-path figure is measured from the file, so a declared contract can be held against it.

In place: `walk.glb`	Travelling: `walk-travel.glb`

Open the interactive report to read the measured trajectory beside the finding.

What the finding looks like

Declare that gameplay owns horizontal travel and the baked 1.2 m becomes a glide:

$ animsmith --config examples/walk-travel-in-place.animsmith.toml lint examples/assets/walk-travel.glb
examples/assets/walk-travel.glb:
  error[in-place] clip 'walk_travel': declared in-place but the root travels at 1.20 m/s — the character will glide at runtime (measured 1.2000, expected 0.0000)
  coverage[bind-pose] insufficient_rotation_evidence ×1 (scopes: first_frame_rest_delta; subjects: walk_travel): only 0 usable first-frame rotation track(s); at least three are required
1 error(s), 0 warning(s), 0 note(s), 1 coverage gap(s), 0 available prediction facet(s), 0 required-unavailable prediction facet(s)   # exits 1

The same file, the same measured 1.2 m/s. Declare that the animation owns the travel and pin the speed the controller was built around, and the finding changes to a stale pin:

$ animsmith --config examples/walk-travel-root-motion.animsmith.toml lint examples/assets/walk-travel.glb
examples/assets/walk-travel.glb:
  error[root-motion-speed] clip 'walk_travel': measured root-motion speed 1.20 m/s disagrees with the declared 1.00 ± 0.10 m/s — playback scaled by this pin will slide or moonwalk (measured 1.2000, expected 1.0000)
  coverage[bind-pose] insufficient_rotation_evidence ×1 (scopes: first_frame_rest_delta; subjects: walk_travel): only 0 usable first-frame rotation track(s); at least three are required
1 error(s), 0 warning(s), 0 note(s), 1 coverage gap(s), 0 available prediction facet(s), 0 required-unavailable prediction facet(s)   # exits 1

With no declaration at all the same file is silent. The measurement is always available; the contract is what makes it a finding.

What to do

Decide ownership per component, once. XZ, Y and yaw are independent. Declare each as "gameplay" (the controller owns it) or "animation" (extracted root motion owns it), and configure the importer and controller to match.
Get the ground truth before pinning a speed. Run animsmith measure and read the measured horizontal root speed; a pin copied from a design document is the usual cause of a stale root-motion-speed.
Re-export when the file disagrees with the decision. AnimSmith does not convert root motion to in-place motion, and transform --gait-anchor refuses accumulating root translation precisely so it cannot be misused for that.

Who fixes it: gameplay decides ownership and the artist re-exports. AnimSmith reports the disagreement between the declaration and the measurement, and has no automatic movement-policy repair. The gate closes when the declaration and the measurements agree and an engine trial proves exactly one — not zero, not two — movement producer per component.

Config

[rig]
# `in-place` and `root-motion-speed` need a resolvable root; both fall back
# to the hips role when the rig has no dedicated root bone.
profile = "auto"

# A treadmill cycle: the controller owns horizontal travel.
[clips.walk_travel]
movement_owner_xz = "gameplay"

# Or a travelling cycle, pinned to the speed the controller expects:
#
# [clips.walk_travel]
# movement_owner_xz = "animation"
# speed_mps = { value = 1.2, tolerance = 0.1 }

Precise contract: movement ownership, declared speed, and the root-role fallback

Locomotion clips carry a travel contract between the asset and the runtime, and nothing inside the file can verify it alone.

Movement ownership. Declare XZ, Y, and yaw independently as "gameplay" (the entity/controller owns that component) or "animation" (extracted root motion owns it). An in-place/treadmill clip normally uses XZ gameplay ownership; a travelling root-motion clip uses XZ animation ownership. The in-place check compares only declared XZ ownership against measured horizontal root motion. Missing axes remain unspecified and are never inferred from another axis, a filename, or measured magnitude.
Declared speed drift. Runtimes scale playback by a clip's declared locomotion speed to keep foot plants locked to world velocity; a stale speed pin plays the clip visibly too fast or too slow. The root-motion-speed check compares the declared speed_mps against the measured horizontal root displacement. Use animsmith measure to obtain the ground-truth number before pinning it.

Both checks need a resolvable root: they use the rig profile's root role, falling back to the hips role when no dedicated root bone exists. That fallback matters in practice — the built-in mixamo profile resolves mixamorig:* bone names but has no root role (Mixamo rigs have no dedicated root bone), so root-motion checks on Mixamo assets judge the hips track.

The legacy in_place boolean remains an XZ-only input alias (true is gameplay, false is animation); one selector entry cannot declare both spellings. The checks' prerequisites, configuration keys and gap semantics are listed with every other check in the built-in check reference.