Hi:
There has to be enough samples, and not too many.. The ball meshing takes one number , the diamter of the ball, what it does is rotate a ball of that diameter across the points, and when it rests on 3 points, it makes an edge of a triangle. Usually, 1 - 4 mm is the right setting for it, but you may have th edecimate the cloud some to get it to remove enough points to allow it to work.. no secret to it.. just a lot of playing around..
Art