Datum Target Areas

[ewh]

When detailing the drawings of lofted parts for a customer, I am accustomed to using datum target points to establish the GD&T framework. I have use datum target areas in the past on casting drawings, so am somewhat familiar with them.
We recently received some SCD drawing from our customer specifying datum target areas instead of points, with holes located in the center of these areas and controlled to the datums defined by the areas. Is this a legitimate use of target areas? How is such a part to be inspected? These are lofted parts, and no two areas are going to be similar.
TIA!

 

[ringman]

Thundair,

The datums can be points which, theoretically can't be measured. NOW THAT IS REALLY SMALL.

How is the tolerance of the point location controlled by the datum target? They would seem independant of one another. (This is with reference to the example in Puffstuff.)

Thanks
Ron