what actually happens when you raise or lower a grading group. is it only raising or lowering by the amount you specify.
i guess what i'm trying to figure out is what it actually changes, i.e. if you start with a feature line and grade to the bottom of a pond and create an infill, you can compute volume, correct?
then if you raise or lower the group, what happens, does the infill go with it?
i'm just a little confused.
thanks