Thanks @Quetzalcodename, it is indeed the same error I am receiving, but it does not solve the issue, as they’re using an exporter from this thread from 6 years ago (The trials and tribulations of Blender & Skeletal Meshes), which doesn’t play nice with newer versions of Blender.
For what it’s worth, I did search for solutions before posting this thread:
The suggestion in this thread (Bone size too small to create physics asset - #12 by pickersZ) don’t work either.
This one didn’t even get a reply (Bone size is too small to create physics assets)
This video makes it look simple ( Tip: Fix "The bone size is too small to create Physics Asset" [Blender2.8 to Unreal Engine4] - YouTube), but unfortunately makes no difference.
This thread suggests using Send to Unreal (Bone size too small to create physics asset? - #5 by NotSoAccurateNo1), but besides requiring python, and enabling remote code execution, it still results in skeletal meshesh that won’t let you create a physics assets because “bone size is too small”.
This thread (The bone size is too small to create Physic manually) points at the documentation, which assumes you can create a physics asset in the first place, and unfortunately I haven’t yet found another way to make the Physics Asset Editor appear.
In fact, even if I try to create a physics asset for Unreal’s manequin hand it says: “The bone size is too small to create Physics Asset ‘UE4ManequinHand’ from Skeletal Mesh ‘MannequinHand_Right’. You will have to create physics asset manually.”.