APS Live Link
Blueprint Setup
Right click on the SkeletalMesh of the Mannequin and selecte:
Create > New Anim Blueprint
2. Give the new Blueprint a name you prefer (eg. "live_link"):
3. Finally double click on the "live_link" Animation Blueprint we just created to open the Blueprint editor.
Node Configuration
Adding the APS Live-Link pose receiver node to the Animation Blueprint
Add the AvatarPoseReceiver node to the body's AnimGraph:
📝 For Metahumans be sure to select the correct skeletal mesh, since some Metahumans include multiple medium, short and tall variants.
Locate the Animation Blueprint for the Body skeletal mesh.
Click on the body's SkeletalMesh referenced in the actual Metahuman's Blueprint, then from SkeletalMesh find the referenced AnaimationBlueprint.
Add the live-link node to the AnimationBlueprint referenced by the Metahuman Blueprint:
That's it! The Blueprint is now setup and ready for live link!
There are some additional parameters that should be noted before moving on. In cases where the mocap avatar rigs do not exactly match their target rigs in UE there are some added retargeting options that allows users to correct offsets by enabling real-time re-targeting.
Realtime Retargeting
Realtime retargeter to fix stretch from skeleton mismatch.
When clicking on the AvatarPoseReceiver node there are additional parameters. These are mostly for retargeting the mocap armature to the target armature in UE. If the mocap armature rig differs from the target rig then enabling retargeting may be necessary to fix any offses.
Reltime-retarting calculates the difference between two avatars and applies a offset automatically.
If using a mocap avatar in APS that is not exactly the same proportions as the target avatar or Metahuman this can result in stretching of the torso or neck. To solve this try using the real-time retargeter by enabling all of the "Location" toggles for the Spine, or disable the toggle for "Can Update Lengths".
If using a mocap avatar in APS that is not exactly the same proportions as the target avatar or Metahuman this can result in stretching of the torso or neck. To solve this try using the real-time retargeter by enabling all of the "Location" toggles for the Spine, or disable the toggle for "Can Update Lengths".
APS live link includes bone length information (eg. spine and arm stretch) this sometimes can cause avatars to stretch if the a mocap avatar's skeleton differs from the target UE skeleton.
In most cases disabling "Can Update Lengths" checkbox will resolve the issue.
📝Note for retargeting, if a avatar appears to be slouching try also enabling the "Rotation" checkboxes for the spine.
Update Lengths checkbox should be Unchecked for most avatars.
Compile the blueprint and save the scene. Everything should be ready to start live link!
Summary:
Created a new Anim Blueprint for the avatar.
Added the AvatarPoseReceiver and connected it to the output pose.
Enabled (optional) re targeting.
🍎 Now we're ready to start VR, load the mocap avatar and sync motion capture from APS and UE over the network!