Align clouds together

If you have not done so beforehand, in most cases you have to align all your scans in the same coordinate system based on the shape of the scanned object or based on particular points. 

It's the case, for example, with surveying targets.

For a proper alignment based on the shape (best fit), your scans must meet two criteria:

• each scan must share some overlapping areas with adjacent scans, 

• each scan should contain at least one change of shape (e.g., corner, hole and angle).

For a proper alignment based on particular points, you must have at least three common points in the two scans.