Reference Designator Identifier

Is the reference designator on a Drawing or BluePrint where the BOM is used.

Is an identifier used to refer to an instance of the  Item (part number) in manufacturing instructions, engineering drawings and/or CAD models. ReferenceDesignator is also often known as an installation point. There will be a single distinct ReferenceDesignatorID for each instance of an Item, however multiple distinct ItemIDs could have the same ReferenceDesignatorID value within a BOM, such as for alternate parts or parts selected from a test-fit-and-select processes.