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The Full Body IK modifier solves IK for all four limbs — both arms and both legs — in a single pass. It is functionally equivalent to using four separate Two Bone IK modifiers, but consolidates them into one entry in the Procedural Animation Settings list. Because all limb chains share one modifier, you can control their combined influence through a single set of Weight Overrides.

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Properties

Each limb (left arm, right arm, left leg, right leg) exposes the same group of parameters:
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KRigElement
The terminal bone of the limb chain — the hand for arms, the foot for legs. This bone will be driven to the Target position and rotation.
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KRigElement
The IK target bone that defines where the Tip should reach. This is typically an IK proxy bone such as IK hand_r or IK foot_l that you drive procedurally upstream in the modifier stack.
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KRigElement
The hint (pole) bone that controls the bend direction of the limb. Use the elbow bone or a dedicated elbow hint for arms, and the knee bone or knee hint for legs.
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float
default:"1"
Per-limb IK influence, from 0 (no IK applied) to 1 (full IK). Use this to blend individual limbs in or out independently — for example, keeping arm IK active while disabling leg IK during a jump.
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float
default:"1"
Controls how strongly the Pole Target pulls the elbow or knee in its direction. Reduce this value if the hint bone is in an awkward position and produces unwanted limb orientation.

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Compared to Two Bone IK

Use Full Body IK when you want one Weight Override to affect the whole body simultaneously — for example, blending all IK off during a ragdoll transition. Use individual Two Bone IK modifiers when each limb needs separate override chains.

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Use Cases

  • Full-body interaction poses — reach for ledges, grab handles, or brace against walls with all four limbs reacting together.
  • Unified IK weight control — drive a single override to smoothly enable or disable all limb IK at once, such as entering or exiting a vehicle.
  • Simplified modifier stacks — keep the Procedural Animation Settings list shorter and easier to read when detailed per-limb customisation is not needed.

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Setup Guide

1

Create IK proxy bones

Add empty GameObjects beneath the character root to serve as IK target bones for each limb (for example, IK hand_l, IK hand_r, IK foot_l, IK foot_r). These are the bones you will assign to the Target fields.
2

Copy real poses to IK targets

Add Copy Bone modifiers before Full Body IK in the stack to initialise each IK target with the animated hand or foot pose. This caches the base animation, letting subsequent modifiers alter the target position while the original pose is preserved.
3

Add Full Body IK

Add the Full Body IK modifier after your Copy Bone entries. Assign each Tip, Target, and Pole Target bone for all four limbs.
4

Tune per-limb weights

Adjust the Weight and Pole Weight values per limb. Add Weight Overrides at the modifier level to drive the combined influence from gameplay logic such as a grounded flag or an interaction state.