Focused reference · Unreal Engine 5.8
System selector
| Need | Primary system | Avoid when |
|---|---|---|
| Reuse animation on another skeleton | IK Rig + IK Retargeter | Skeletons are already compatible enough for Compatible Skeletons |
| Drive a target from a live source mesh | Retarget Pose From Mesh | Offline export is simpler and runtime flexibility is unnecessary |
| Correct whole-body reach/stance | Full Body IK | A single two-bone limb solve is sufficient |
| Runtime goal-driven limbs | IK Rig node / focused IK | The change is authored and should be baked |
| Animate controls in Sequencer | Control Rig | Only a small additive bone correction is needed |
| Quick per-bone additive repair | FK Control Rig | A reusable procedural rig is required |
| Preserve planted contacts during retarget | Speed Planting after base retarget | The real fault is chain, pose, pelvis, root, or speed mismatch |
Decision gates:
- Is this transfer, procedural correction, or authoring?
- Must it remain live at runtime?
- Does it require one limb or a connected full-body response?
- Does gameplay need to drive the goal, or can the result be baked?
- Is the problem already visible before IK? If yes, fix that stage first.
Keep ownership explicit: gameplay produces targets; the animation graph consumes targets; IK solves the pose. Do not move authoritative gameplay state into a rig graph.