"Delta" and "Error" in align

[enrique]

Hi! I am new in this software, may I know what does the "Delta" and "Error" mean when using the aligning multiple clouds/mesh?
Thank you in advance

[daniel]

Delta is the displacement/vector between the referenced point and the aligned point (after registration has been performed). And the error is the corresponding 3D distance (= norm of this 3D vector).