تعليق رسمي
You need to include a larger area than JUST the piles you want to measure. In order to even be able to make volume measurements you will need to be able to draw the polygon for measurement around the flat surface base of it. If the volume measurement polygon leaves the area where the data is it may stall.
If you care about your 3D and elevation related products it is important to use 80% overlap and also cover some of the area around the piles.