IK Rig Editor

Create your custom IK Rig using goals, solvers, and settings.

Choose your operating system:

Windows

macOS

Linux

The IK Rig editor is where you set up IK Rigs and retargeting for characters. With it, you can create different Solvers, adjust Bone settings, and preview your results.

This page provides an overview of this editor and how to create IK Rig Assets.

Prerequisites

Create IK Rig

To start creating IK Rigs, you must create an IK Rig Asset. To do this, click Add (+) in the Content Browser, then select Animation > IK Rig. A dialog window will open where you select the Skeletal Mesh you want to create the IK Rig for.

create ik rig

After selecting the Skeletal Mesh, the IK Rig Asset will be created. Double-click it in the Content Browser to open it.

Editor and Feature Overview

The IK Rig editor contains the following tools and options:

ik rig editor

  1. The Reset button, which resets IK Goals to their default position.

  2. Hierarchy, which displays your Bones, IK Goals, and settings.

  3. Solver Stack, which displays the IK Solvers being used on this Skeletal Mesh.

  4. Viewport, where you can select your Bones and manipulate IK Goals to preview the IK behavior.

  5. The Details panel displays properties for your selected item. Preview Scene Settings is where you can change the ambient viewport environment, such as lighting and background.

  6. The Asset Browser displays a list of Animation Sequences that you can preview along with your IK behavior to test its effects. IK Retargeting is where you specify Bone chains for use with an IK Retargeter asset if you are retargeting this character using IK Rig.

IK Goals

IK Goals are the manipulation and effector points for your IK chains, which you create in the IK Rig Editor. IK Goals are used in conjunction with Solvers to modify an incoming pose to reach the goal locations.

To create IK Goals, first select the ending Bones in the IK chain you want to create. Typically, these would be the hand or foot Bones if you are creating IK along the arms or legs.

create ik goal

Right-click the bone in the Hierarchy panel and select New IK Goal. If your IK Rig does not already have a Solver, then a dialog window will appear where you can select a Solver to associate with the new goal. For common IK setups, you can select IKRig_LimbSolver, then click OK.

new ik goal

The goal and Solver-specific settings will be created and be visible in the Viewport and Hierarchy.

ik goal

IK Goal Properties

When you select an IK Goal, you will see the following properties in the Details panel:

ik goal details

Name

Description

Goal Name

The name of the IK Goal object.

Bone Name

The name of the end Bone that the IK Goal is acting as the effector for.

Position Alpha

The translation influence that this IK Goal has on the IK chain.

position alpha

Rotation Alpha

The rotation influence that this IK Goal has on the IK chain.

rotation alpha

Preview Mode

Previews the goal in either Additive or Absolute modes. Additive is used when you want to ensure the IK behavior is relative to any incoming animation, whereas Absolute overwrites any incoming animation along the chain.

preview mode

Transforms

Contains the current transform information for the selected IK Goal.

Size Multiplier

Multiplies the size of the IK Goal relative to its base size from the viewport settings. Increase this if you have larger, non-human characters.

size multiplier

Thickness Multiplier

Multiplies the line thickness of the IK Goal relative to its base thickness from the viewport settings You may want to increase this if you have increased the Size Multiplier.

thickness multiplier

Expose Position

Exposes position pins on the IK Rig Animation Blueprint Node in order to affect the position of the IK Goal in Animation Blueprints.

Expose Rotation

Exposes rotation pins on the IK Rig Animation Blueprint Node in order to affect the rotation of the IK Goal in Animation Blueprints.

Solvers

Different IK behaviors can be added to your IK Rig, which are called Solvers. Using Solvers, you can create a wide variety of IK effects, from simple three-bone chains to full-body multi-limb IK systems.

Visit the Solvers page to learn more about the different Solvers you can add, and how to use them in your IK Rigs.

TopicIcon.png

Solvers

Use Solvers to create different kinds of IK Rig setups.

Use Solvers to create different kinds of IK Rig setups.

Viewport Settings

When nothing is selected in the IK Rig editor, the Details panel will display the following Viewport settings:

ik rig viewport settings

Name

Description

Draw Bones

Shows or hides Bones in the viewport.

Bone Size

Scales the size of Bones.

bone size

Draw Goals

Shows or hides IK Goals in the viewport.

Goal Size

The base size of IK Goals.

Goal Thickness

The base thickness of IK Goals.

IK Rig Example Setup

A common use-case for IK in Unreal Engine is to control foot alignment to uneven terrain, which requires manipulating the feet and hips of a character. The example below will walk you through setting up this IK Rig system for a humanoid character.

Create Solvers

Start by creating a new Solver. To do this, click Add New Solver in the Solver Stack panel, then add the following Solvers:

  • Set Transform.

  • Limb IK.

  • Limb IK again.

add new solver

The order in which you add the Solvers matters, because Solvers execute in sequence according to the number displayed next to their name. For this IK system, Limb IK should evaluate last.

You can drag Solvers within the Solver stack to change their order if needed.

change solver order

Create Goals

Due to the Solver types being used for this IK system, you will need to create IK Goals for each Solver. To do this, select the pelvis and feet bones, right-click them, and select New IK Goal. Goals will be created at the location of each of these bones.

create ik goal

You can optionally adjust the goals so they appear more prominently in the viewport by selecting them and editing their Size and Thickness Multiplier properties.

ik goal size

Connect Goals to Solvers

Each IK Goal must be connected to a Solver for it to correctly act as the effector for that Solver.

To do this, select both the Solver and the IK Goal, right-click the goal, and select Connect Goal to Selected Solver.

connect goal to selected solver

Repeat this action for each goal and Solver so that all your goals are connected to their respective Solvers.

connect goal to selected solver

Set Solver Root

For some Solvers, like Limb IK, you must specify both a goal and a root. The root is typically the starting Bone of the IK chain. In this example, the thigh will be the root.

To set the root for a Solver, select both the Solver and the Bone, right-click the Bone, and select Set Root Bone on Selected Solver.

set root bone on selected solver

Repeat this action for both Limb IK Solvers so that both of them have their respective thigh Bones set as the root.

set root bone on selected solver

Final Result

You can now preview your IK system in the viewport by selecting IK Goals and manipulating them. Clicking Reset restores your Goals to their initial state.

ik rig setup