# Reference designators ### Overview * Define reference designators in the mBOM * Install inventory into reference designator positions in the aBOM * aBOMs will fan out to represent the number of reference designators ### Example In the assembly below, there are 8 lidar, 8 radar, and 3 camera sub components.

To define positions for the camera click the `Add` button in the Reference Designators column as show below:

When the aBOM is generated, the reference designator will appear above the inventory selector for the camera items. Inventory can now be installed into specific positions. Note that 1 aBOM item was created for each reference designator.

Reference designators are also reflected in the trace view:

### Rules/Validations * You can not define more reference designators in the mBOM than quantity * When creating aBOM items for reference designators, each aBOM item is created for quantity 1 --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://manual.firstresonance.io/features/parts-and-trace/manufacturing-bill-of-materials-mbom/reference-designators.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.