Once assembled in Houdini, you can animate your character with APEX. You can also import/export animation with Unreal Engine (including MetaHuman Animator).
Preparing for Animation
After assembling your character using the MetaHuman Character Rig SOP, you can prepare it for animation with the APEX animation context;
[APEX Animation Graph.png]
Create an APEX Scene Add Character SOP. Connect the output of the MetaHuman Character Rig SOP to the second input.
Create an APEX Scene Animate SOP. Connect the output from the APEX Scene Add Character SOP (created in the previous step) to the input.
Select the APEX Scene Animate SOP, turn on the display flag and click on Animate in the left toolbar.
You can then begin to animate the character using the Faceboard and body rig controls.
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Importing Animation
Animation in the FBX format can be imported using the MetaHuman Face Animation Import or MetaHuman Body Animation Import nodes.
Body Animation
To import body animation, create a new MetaHuman Body Animation Import node and connect it to the "Scene" stream of the APEX Scene Add Character node.
In the parameters, select the APEX character and path to the FBX file containing the body animation.
Finally, connect the "Scene" stream of the MetaHuman Body Animation Import node to the APEX Scene Animate, and the animation will be applied to the character.
Compatible body animation can be exported from an Animation Sequence asset in Unreal Engine 5.6 or later.
Using Sequencer, bake the Body track for the character to an Animation Sequence, exporting only transforms. Export an FBX file from the new Animation Sequence asset as normal.
Faceboard Animation
To import faceboard animation, create a new MetaHuman Face Animation Import node and connect it to the "Scene" stream of the APEX Scene Add Character node.
In the parameters, select the APEX character and path to the FBX file containing the faceboard animation.
Finally, connect the "Scene" stream of the MetaHuman Face Animation Import node to the APEX Scene Animate, and the animation will be applied to the character.
Compatible faceboard animation can be exported from the Faceboard Control Rig in Unreal Engine 5.6 or later.
In Sequencer, select Export Control Rig FBX from the right-click context menu on the faceboard control rig track for the character. When exporting faceboard animation to FBX it is important to select the "MetaHuman Controls Mapping" option.
Exporting Animation
Animation can be exported in FBX using the MetaHuman Face Animation Export or MetaHuman Body Animation Export nodes.
Body Animation
To export body animation, create a new MetaHuman Body Animation Export node and connect it to the "Scene" stream of the APEX Scene Animate node.
In the parameters, select the APEX character and path to the FBX file to export to. Click "Save to Disk" to export animation.
The exported body animation can be imported onto a MetaHuman character in Unreal Engine.
Import the FBX into the Content Browser of your project, selecting the metahuman_base_skel as the Skeleton in the FBX import options. Open the new asset at select your MetaHuman character’s body mesh in the Retarget Source Asset parameter. In Sequencer, create a new track animation track from this asset.
Faceboard Animation
To export faceboard animation, create a new MetaHuman Face Animation Export node and connect it to the "Scene" stream of the APEX Scene Animate node.
In the parameters, select the APEX character and path to the FBX file to export to. Click "Save to Disk" to export animation.
The exported faceboard animation can be imported onto the Faceboard Control Rig of a MetaHuman character in Unreal Engine.
In Sequencer, select Import Control Rig FBX from the right-click context menu on the faceboard control rig track for the character. When importing face animation it is important to select the "MetaHuman Controls Mapping" option.