[Python] opencv -- How to actually use cv2.estimateAffine3D to align 3d points in python?

I want to compute a similarity alignment that overlays two sets of points in correspondence (rotation, scaling, translation). OpenCV has a lovely function for doing this, estimateAffine3D(). Despite a couple of other stack overflow questions about it, noone has presented an actual example of how to use this function to do what it is advertised to do (even the function documentation is opaque). Asking and answering my own question with a code example, just to get this documented and save you some time.

Continue reading...