This article is for V2 and V1 3D scanners.
Some objects are too symmetrical for the software to correctly align them, for example a ball. Every area on the ball looks like every other area. MFStudio will not be able to correctly identify the same areas on two different scans of a ball - all areas are geometrically the same.
One solution is to use tack, plasticine or anything that can create a prominent geometric marker on your object, making it easier for the MFStudio software to correctly align the scans. Then after aligning, use the brush tool to remove those points. Note that the marker should be large. If 99% of the points form the same shape, and 1% of the points are from a small piece of plasticine stuck on the side as a marker, MFStudio will use the 99% of points, effectively ignoring the marker.
Another method to capture symmetrical objects is to mount them on something that will all the scanner to scan more surface area of the object. For a ball, placing it on a stand so that the bottom of the ball is supported by a few thin legs, will allow the scanner to capture further around the underside.