Mapping spine joints between SAM 3D Body and Unreal Engine (UE5)

[qianzhi-yhx]

Hi everyone,

I am working with the SAM 3D Body model and trying to map its skeleton to the Unreal Engine standard skeleton for animation/retargeting purposes.

Could anyone clarify the exact anatomical mapping for the spine joints in both systems? Specifically:
SAM 3D Body Spine Joints: Which specific anatomical vertebrae (e.g., T12, L1, etc.) do c_spine0, c_spine1, c_spine2, and c_spine3 correspond to?
Unreal Engine Spine Joints: Which anatomical vertebrae do the standard UE spine bones (spine_01, spine_02, spine_03, spine_04, spine_05) represent?
Joint Matching: Has anyone established a reliable 1:1 or interpolated mapping pair between the SAM 3D Body spine joints and the UE spine joints?

Any insights, documentation references, or retargeting tips regarding this would be greatly appreciated!

Thanks in advance for your help!