Rehearse motion capture for the target rig.

Editorial analysis

Rehearsal begins with the destination

The performer is not acting for an abstract skeleton. They are acting for a character with particular limb lengths, clothing, props, camera crops and expression limits. Before capture, screen a rough retarget on the destination rig. Mark where hands reach, feet plant, shoulders compress, garments intersect and the silhouette loses the intended attitude.

A small character carrying an oversized bag may need a wider real-world hand path than the performer expects. A long-limbed model may turn a casual reach into an elbow collision. Rehearsal should solve those visible problems before the team records an hour of technically clean but editorially unusable motion.

Source record

Know what retargeting can and cannot align

Unreal's current IK Rig documentation says retargeting chains transfer motion between skeletons that may differ in bone count, names and orientation. It requires chains on source and target, defines a pelvis for proportional root motion, and supports IK goals for contact. It also recommends matching retarget poses when reference poses differ, such as A-pose and T-pose.

The Skeleton documentation says its compatible-skeleton route expects nearly identical hierarchies, naming and similar proportions, while radically different structures should use IK Rig Retargeting. Neither page says an automatic mapping guarantees a production-ready performance. The editor exposes preview and output warnings because review remains necessary.

Evidence: Epic Games / Unreal Engine Documentation [s1] · Epic Games / Unreal Engine Documentation [s2]

Practical application

Record a calibration slate

At the start of each session, capture neutral stance, source reference pose, target reference pose approximation, slow head turns, shoulder rolls, finger spread, heel-toe steps, a squat, a seated pose and each recurring prop grip. Say the take, performer, rig and prop aloud or put them on a visible slate. Keep this clip with the retargeter version.

Then retarget the slate before the dramatic take. Check pelvis height, foot sliding, knee direction, shoulder volume, wrist rotation and head scale. If the target has nonhuman appendages, write which controls are performed, procedurally driven or animated later. “Fixed in post” needs an owner and estimated step, not a shrug.

Practical application

Rehearse contacts as beats

Break a product pickup into approach, first contact, weight transfer, hold, presentation and release. Capture a half-second settle at each edit-safe beat. For a chair, mark the real seat height that produces the target's intended contact. For a table, tape the target hand plane. This gives the animator usable anchors when proportions diverge.

Worked example: the character presents a bottle. The first take looks natural on the performer but the target fingers enter the label. The team rotates the grip, shifts the elbow out and holds the presentation two beats longer. The second take reduces cleanup because the rehearsal changed the performance, not because the retargeter became smarter.

Editorial analysis

Approve motion after the final camera

A wide diagnostic view reveals sliding and intersections; the delivery crop reveals whether the motion reads. Review both with final frame rate, camera and major wardrobe. Log defects by timecode and category, then decide whether to recapture, adjust the retarget pose, add IK, or hand-animate. Keep the untouched capture and the exported target animation separate.

Approve a representative set before scaling: locomotion, seated dialogue, prop contact and the character's largest gesture. The useful metric is accepted seconds after retarget and cleanup, not captured minutes.