---
title: Control Rig Full-Body IK
source: https://dev.epicgames.com/documentation/en-us/unreal-engine/control-rig-full-body-ik-in-unreal-engine
version: Unreal Engine 5.8 Documentation
fetched: 2026-10-11
note: 原文摘录（英文要点），供 wiki 引用；非全文
---

# Control Rig Full-Body IK

- FBIK node in Control Rig graph; "solver method is built on a Position Based IK framework, which enables faster rig performance, per-bone settings, preferred angles, squash and stretch"; designed as procedural adjustment tool (ground alignment, arm reaching). Requires FullBodyIK plugin.
- Setup: Hierarchy > Full Body IK node connected to Forwards Solve; Root bone (hips/pelvis); Effectors per control (Bone + Transform from Get Transform).
- Bone Settings: Rotation/Position Stiffness (0 free, 1 locked); Preferred Angles (Use Preferred Angles; e.g. knee Z 45); Limits per axis Free/Limited (Min/Max)/Locked. Excluding bones recommended over fully stiff/locked settings.
- Effector: Position Alpha, Rotation Alpha, Strength Alpha, Pull Chain Alpha, Pin Rotation.
- Settings: Iterations ("Increase this value until the effectors converge... also increases the CPU cost"; stiffness, high Mass Multiplier, limits slow convergence), Mass Multiplier (0–5), Allow Stretch, Root Behavior (Pre Pull, Pin to Input, Free), Start Solve from Input Pose.