I made a video a while back describing an issue with the Live Link Plugin from Optitrack, where it did not scale the bones to the performer scale in UE. This seems to be fixed now and this video is an update.
Here is the OLD video showing the issue https://youtu.be/XZD-kKMW-w0?t=469
Here is a repo with a ball and stick skeletal mesh as and FBX you can use in UE to stream on to. All the bone names are Optitrack Motive bone names.
https://github.com/kromond/OptiSkelForUEScripts/tree/master/UnrealEngine/OptiTrackUESkel
#optitrack #unrealengine #unrealengine5 #performancecapture