A rigid motion the data do not determine, in world coordinates: a point p moves along translation + rotation x (p - about), scaled so that the moving mesh's points move by 1 (root mean square).
p
translation + rotation x (p - about)
The point the rotation turns about: the moved points' centroid.
The rmse of the other pose found along this motion, which fits as well.
The rotation part, as an axis scaled by its rate.
A rigid motion the data do not determine, in world coordinates: a point
pmoves alongtranslation + rotation x (p - about), scaled so that the moving mesh's points move by 1 (root mean square).