Orientation of AnyInertiaSolid

Hello everyone,

I want to use an AnyInertiaSolid to calculate the Jmatrix, JmatrixCoM,and the center of mass (CoM) from an STL of a vertebra. The origin an orientation of the ellipsoid that represents the inertia object appears satisfactory.

Now, I would like to create a RefFrame aligned with the main axes of this ellipsoid and centered its origin (aka the sCoM)

As the sRel I want to use the sCoM. --> this is working.
Could you advise me how I can get the Arel for this RefFrame?

Best regards,
Viktoria