Exchanging Motions between Characters in Unreal Engine

Refer to the Skeleton Structures Relations between CC and UE Characters section for more information before starting exporting CC characters to UE. With this method, the character can exchange body motions (facial expressions excluded) with UE characters without applying Auto Control Rig.

Importing and Inspecting CC characters

  1. Follow the steps in the Exporting Characters to Unreal Engine section, import a CC character to Unreal Engine.

    You can open the Skeleton asset to view the bone structure and bind pose of the character.
  2. From the Preview Animation drop-down list, you can preview motions imported from Character Creator.

Exchanging Motions between CC and UE Characters

There are essentially two main ways to exchange motions between Character Creator and Unreal Engine, Utilizing Retarget Manager for same skeleton retargeting and IK Retargeter for different skeleton retargeting.

ClosedUtilizing Retargeter Manager for Same Skeleton Retargeting

This method works best when the characters share similar bone structures. It works for both character with UE 4 and UE 5 bone structures. However choosing the correct skeleton for retargeting in step three is essential for this method.

  1. In the skeleton preview window, go to the top of the toolbar and click to open the Retarget Manager button.
  2. Click the Add Skeleton button in the Retargeting Manager.
  3. Select a compatible skeleton from the pop-up list. In this case, SK_Mannequin.

    The skeleton will be added in the Manage Compatible Skeletons list.

    Note that you can even add other characters that share the same bone structures.
  4. Open the Preview Animation drop-down list again, there will be several new motions added in the list, which come along with the UE5 Mannequin skeleton selected in the previous step.

    Click on some of the new motions for previewing the motion result.
  5. Optionally view the skeleton tree and activate the Show Retargeting Options checkbox to inspect how each bone is retargeted by Character Creator and iClone Auto Setup Plugin.
ClosedIK Retargeter for Different Skeleton Retargeting

If you want to exchange motions between characters with different skeleton structures, then you can apply this method by using the IK Retargeter.

  1. In the Content Drawer, you will find an IK Rig and an IK Retargeter that are auto-created by Auto Setup when the character is imported.
  2. Open the IK Retargeter, in the Details panel, you will see the Source and Target settings.

    By default, the source and target are set to the IK rig of current character. You only need to assign the source and target characters you want and Auto Setup will process the rest procedures.
  3. Move the target character, with green handles, slightly aside for better observation (the left side is the source character).
  4. Change the source to metahuman or any character with a different skeleton (make sure it has an IK rig assigned).

    As you can see the source character at the left is replaced with the new one.
  5. From the Asset Browser, select an animation from the source character.

    The source character's animation will be transferred to the target character.
    Note that you can deactivate the Debug Draw to hide the green handles on the target character.
  6. Click the Export Selected Animations button on top of the Asset Browser to save the motion for the target character.
  7. Choose a folder for store the animation.
  8. Apply the character from the Content Drawer to the scene.
  9. Create a new sequence and add the CC HD character from the Outliner into the sequence.
  10. Click the + sign of the Animation track, you will see the available motions that are retargeted. Pick either one to add it into the animation track.
  11. Playback to view the result.
ClosedNote:
  • This method works for CC character with UE Skeleton structure. However, the result may vary due to the bind pose.
  • By changing the Source and Target characters, you can then freely exchange the motions from UE to CC or from CC to UE characters.