Reallusion has expended significant efforts to create the most accurate CC-to-MetaHuman conversion pipeline, aiming to provide the best of both worlds for MetaHuman and Character Creator. Nevertheless, differences may still persist due to variations in structure and the mechanics of animation between the two systems.

• MetaHumans have limited support for body shapes, resulting in differences in neck thickness, body size, or height when converting CC characters to MetaHumans.

• Wearing CC Smart Hair on MetaHumans is not possible at this time, as the highest LOD of MetaHumans are limited to Groom Hair.

• Currently, MetaHumans have their own outfit system and cannot wear conformable CC outfits.

• The CC head is optimized for real-time performance at 4,000 polygons in an effort to support subdivision levels for the Unreal Engine. The native highest LOD for the MetaHuman head has 80,000 polygons, allowing for improved mesh-level definition in certain facial expressions, particularly around the eyes. This may result in noticeable differences in some cases.

• After the MetaHuman conversion, facial expressions are controlled by MetaHumans' facial control curves, potentially resulting in subtle differences in expression nuances.

Check below for detailed explanations for issues and how to fix them.

1) MetaHumans can not adopt CC textures

Once you have imported a head into Unreal using CC's Export Head feature and before using Auto Setup to apply the CC textures, make sure to Save All, otherwise the deployment will fail with an error message.

2) Failure to LiveLink facial expressions from iClone to MetaHumans

For standard procedure, please make sure you have watched the‘iClone MetaHuman LiveLink Update for UE5 | Unreal Live Link Plug-in Tutorial’.

This usually happens when you are creating a new Unreal project, or migrating an existing project from Unreal 5 to Unreal 5.1 (old to new version).

Please follow the steps of the tutorial in proper order: 

1. First add a MetaHuman to the Unreal project.

2. Copy the corresponding files to the UE project. 

This is because the Face Anim blueprint used by Live Link MetaHuman must come from the iClone MetaHuman kit in order to successfully establish a link. Otherwise, if the MetaHuman Face Anim blueprint was added after the iClone MetaHuman kit was duplicated, then the blueprint will be replaced.

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3) Important alerts for the iClone MetaHuman Live Link kit

1. Mapping Rules

The mapping rules of the expression morphs for this version have been updated. However, the data that drive facial animation are different between the two systems, causing performances to vary with results that won’t be identical (just like the prior version). 

• Facial animations in MetaHumans are driven by 700+ head bones and 600+ morphs.MetaHuman Specifications.

• Facial animations in Character Creator are driven by 140+ morphs.

Note: Some expressions are not mapped to MetaHuman because the corresponding morphs do not exist (see the image below).

Face Key > Nose_Tip_L(R)

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Face Key > MouthMove > Mouth_CloseFace Key > MouthMove > Mouth_ContractFace Key > Jaw > Jaw_Down

Face Key > Head > Head_L

Face Key > Head > Head_R

Face Key > Head > Forward

Face Key > Head > Backward

Face Key > Tongue > Tongue_ExtendJust like in iClone 7, any facial expression morph slider that exceeds 100 or has a negative number will be ignored when transferred to an Unreal MetaHuman. Make sure to keep the sliders at 100 for the ones you want to maximize (see thevideo).

2. Different Appearances

Some wrinkle patterns will look different between a CC avatar and MetaHuman. 

• The MetaHuman "Mouth_Up" morph does not have wrinkles for the chin.

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• When "Brow Raise" and "Brow Drop" are both activated, CC will use another wrinkle pattern. That is, instead of stacking the wrinkle patterns like it is done in MetaHuman, CC will use "Wrinkle Set 3" instead.

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3. The exclusive features of Character Creator and iClone

There are some unique features only available for iClone and Character Creator which are lacking for Metahumans.

• MetaHumans do not support Flow Maps. Seesitefor details.

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• MetaHumans do not respond to the Wrinkle Constraint System. Seesitefor details.

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• MetaHumans won’t respond to Rate of Appearance. Seesitefor details.

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