If the scans not overlap it means You have Problems In
1- Calibration panel
2- Less No. of Scans
3- In my case my Trigger object and camera frame...If camera frame not get the trigger object at the right time , my scan will differ in Pixels..
4- I forget
I have also problem in my calibration panel... My calibration grid is visible in Left side whereas the Right top side its invisible ( To check theses take one scan of calibration panel and see the calibration grid on it)... This is the reason some of my scan were not 100% overlapped However I am getting good accuracy though..
Ideally, Your scans must overlap each other..Great Number of scan will give good results..but will consume more of CPU... I did 8 scans and then merge each next scan with previous one so that my final scan overlap with the first one...
My settings were 800 Poisson and 1 Smooth...