This tutorial shows how to setup a Dynamic Look At Target behaviour, that can be used together with the iPhone facial tracking ( or any other facial tracking solution ).
The Blueprint logic shows how to get necessary data for both the realtime values from the iPhone via LiveLink and the Look At Target, and the use of the Dot Product that allows the realtime switching between the two values.
We’ll also use a modified ARKit Pose Asset where we remove the eyes animation curves by using the ones from the MetaHuman Blueprint.
Within the YouTube video description you’ll also find a sample project with this setup.
https://dev.epicgames.com/community/learning/tutorials/mJGj/unreal-engine-ue5-techanimtip-1-dynamic-eyes-look-at-target