Data Management Capabilities > Managing Part Structures > Product Structure Explorer > Checking Out an Object > About Occurrences and Reference Designators
About Occurrences and Reference Designators
You can define multiple occurrences of any component part whose unit of measurement (Units) is each by setting the Quantity field.
You can see each individual occurrence by expanding the product structure in the left pane of and explorer or in the Uses tab in the right pane of an explorer .
You can also label a specific occurrence using a reference designator. A reference designator identifies individual occurrences of a part in the structure. For example, a motor may have two valves, one designated as the intake valve and the other as the exhaust valve. Therefore, the occurrences for the valves would be given the reference designators Intake and Exhaust. The Reference Designator column in the structure or Uses tab displays the reference designator range if the BOM view is expanded or the individual reference designator of the occurrence view is expanded.