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How to import animation-only packs into Unreal Engine 5 with the current IK retargeting workflow

Import MoCap Online animation-only packs into Unreal Engine 5 and retarget them to your character using the current IK Rig and IK Retargeter workflow.

Written by Kyle Blietz

Direct Answer

If your MoCap Online pack contains animations only, the current Unreal workflow is to import the animation assets against a source skeleton, create source and target retarget rigs, build one retarget asset between them, preview the transfer, and then export retargeted animation sequences for your own character. This draft intentionally follows the current Epic documentation path rather than the older UE4-era Retarget Manager advice.

What You'll Need

  • A MoCap Online pack in the Unreal Engine or FBX Format that matches your pipeline.

  • A source skeleton that the imported animations already use.

  • A target skeletal mesh and skeleton for the character you actually want to animate.

  • Matching source and target reference poses, or a plan to correct them.

Step 1 - Confirm the source assets you are actually importing

  1. Confirm whether you downloaded the native Unreal Engine pack or an FBX source pack.

  2. If you are using a native Unreal Engine pack, bring the content into the project from the Content Browser with Content Browser > Import when importing files directly.

  3. If you are using FBX source files, import the animations against the correct source skeleton using FBX Import Options > Import Animation.

  4. Before retargeting, make sure the source animations preview correctly on the source skeleton.

Step 2 - Create the source and target retarget rigs

  1. Create one retarget rig asset for the source character with Add (+) > Animation > IK Rig > IK Rig.

  2. Create a second retarget rig asset for the target character with the same workflow.

  3. In both rig assets, set the retarget root with Set Retarget Root.

  4. In both rig assets, create retarget chains for the major limbs you need to transfer: spine, arms, legs, neck, and head. Add fingers only if you actually need finger motion in this pass.

Step 3 - Build the retarget asset and map the chains

  1. Create a retarget asset from the source rig with Add (+) > Animation > IK Retargeter.

  2. Assign the target rig inside that retarget asset.

  3. Review the source-to-target chain mapping and fix any chain that did not auto-match correctly.

  4. If source and target start from different reference poses, create or edit a retarget pose until the two characters match visually.

Step 4 - Preview before you export anything

  1. Preview one or two representative animation sequences inside the retarget asset first.

  2. Check whether the character keeps contact where you expect, whether the body orientation stays stable, and whether the clip still behaves as animation-only content instead of trying to replace the character.

  3. If the preview looks wrong, stop and fix chain mapping or retarget pose before exporting a batch.

Step 5 - Export the retargeted sequences

  1. Export only the animations that passed preview.

  2. Save them to a clean output location so the retargeted sequences are easy to identify.

  3. Test one exported sequence on the target character before wiring a larger animation set into gameplay logic.

Common Mistakes To Avoid

  • Treating an animation-only pack like a replacement character mesh.

  • Reusing outdated UE4 Retarget Manager steps instead of the current IK Rig and IK Retargeter workflow.

  • Skipping Set Retarget Root and chain setup on one side.

  • Ignoring an A-pose versus T-pose mismatch and then troubleshooting bad results later.

Escalate When

Escalate if the source animations do not preview correctly on their own source skeleton, if the target rig is non-humanoid enough that the standard chains do not describe it cleanly, or if the project expects custom gameplay logic around root motion, distance matching, or motion warping.

Current-source notes for review

  • Verified against Unreal Engine 5.7 documentation, May 2026.

  • Approved Decision-7 UI labels used in this draft: Content Browser > Import, FBX Import Options > Import Animation, Add (+) > Animation > IK Rig > IK Rig, Set Retarget Root, and Add (+) > Animation > IK Retargeter.

  • Product-format source checked against MCO - Products FORMAT records for Unreal Engine and FBX Format, plus the Canonical Product Map format availability fields.

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