Components/Facial-Expressions.md

@@ -27,8 +27,76 @@ Important: this component requires a mapping `PoseAsset Mapping` for according c
 
 # CC4 Characters and Metahumans
 
+Facial expressions are driven by setting morph targets and bone transforms. The morph targets are pure vertex transform snapshots, defined by the artist in DCC, used for controls like eyebrow up and down, mouth corners movements, or details like wrinkles; The bone transforms are usually used for jaw and eyeball movements.
+
+MetaHuman provides a cinematic and scalable approach to facial control. It defines a set of high-level, standardized controls (e.g., mouth stretch), then maps these controls to Animation Curves, which, in turn, drive a massive library of granular, pre-sculpted morph targets. This complex curve-to-expression mapping and inference is executed within the Control Rig. In this way, MetaHuman provides artists with intuitive, high-level control that automatically generates detailed facial expressions, using its library of morph targets without requiring the user to sculpt them individually.
+
 Since CC4, Reallusion has updated its export pipeline to UE5 to better accommodate Metahuman's design philosophy when talking about their animation pipelines in UE5, especially the curve-driven facial expressions.
 
-Facial expressions are driven by setting morph targets and bone transforms. The morph targets are pure vertex transform snapshots, defined by the artist in DCC, used for controls like eyebrow up and down, mouth corners movements, or details like wrinkles; The bone transforms are usually used for jaw and eyeball movements.
+(See ExpBoneData in the Post-ABP of your CC4 character for the exact reference)
+
+## Migrate FacialExpressionMapping from CC3 to CC4 Characters
+
+1. Duplicate an AnimationSequence asset without bone animations of your CC4 character.
+2. Add the AM_ExpMapping_cc3_to_cc4 modifier to the sequence asset
+3. Set the parameter PoseMapping to your CC3 pose asset
+![image](uploads/11dc0995de56505783b286ccb4d616f9/image.png){width=900 height=304}
+4. You can also check the naming conversion if your CC4 character has different namings for morph targets.
+![image](uploads/0d75eb1d49e61405c9d14c1614bf55e7/image.png){width=460 height=583}
+5. Click Apply All Modifiers or right-click on the modifier and Apply Modifier.
+6. The expressions will be coded into each animation frame.
+![image](uploads/f03f9b81c5c5467732c97a5561a1a988/image.png){width=900 height=341}
+7. In Content Browser, right-click on the AnimationSequence asset -> Create -> Create Pose Asset.
+![image](uploads/5cd64c96507a32c5eabd3e3330b75ec2/image.png){width=317 height=600}
+8. Copy-paste these names to PoseNames.
+| header |
+| ------ |
+|    
+1_l
+1_r
+2_l
+2_r
+4_l
+4_r
+5_l
+5_r
+6_l
+6_r
+7_l
+7_r
+9
+10
+11
+12_l
+12_r
+13
+14_l
+14_r
+15_l
+15_r
+16
+17
+18
+19
+20
+22
+23
+24
+25
+26
+27
+28
+32
+33_l
+33_r
+35
+38
+44_l
+44_r
+45_l
+45_r
+    |
+![image](uploads/a58b40fd9272d276ab1ea2867fce9427/image.png){width=468 height=600}
+9. Set the PoseAsset to be the Mapping in the FacialExpressionComponent
+
 
-MetaHuman provides a cinematic and scalable approach to facial control. It defines a set of high-level, standardized controls (e.g., mouth stretch), then maps these controls to Animation Curves, which, in turn, drive a massive library of granular, pre-sculpted morph targets. This complex curve-to-expression mapping and inference is executed within the Control Rig. In this way, MetaHuman provides artists with intuitive, high-level control that automatically generates detailed facial expressions, using its library of morph targets without requiring the user to sculpt them individually.
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