CloudCompare forum

Hello,
I'm looking for documentation to understand how the “align” tool works.
On which values is the root mean square calculated?
How does it work?

Thank you in advance.

So the documentation is here: https://www.cloudcompare.org/doc/wiki/index.php/Align

And the RMS is simply the root of the average squared distance between every pair of points (after registration).

Thank you very much.

If I understand correctly, this is a 7-parameters HELMERT transformation such that the distance between each pair of points is minimised ?

Yes, I believe we use Umeyama's algorithm to find it.

And before we were using: 'Closed-form solution of absolute orientation using unit quaternions', B.K.P. Horn, 1987.