In most situations all master CAD documents in a CAD structure are contained in the assembly’s BOM. However, there is a valid use case where this is not true.

For example, a component in a structure will be manufactured from a standard SCEM part, such as a long tube. The component is ‘Master’, but very simple and does not require its own drawing (dimensions will be placed on the assembly drawing). Rather than putting the modified CAD part in the BOM, the SCEM part is included instead to aid purchasing and manufacturing. See the example below.

To create a BOM structure that includes the Part of CAD C instead of CAD B, we can use the ‘marked as’ attribute in the PLM. There are different properties that can be applied to this attribute which alter how Parts are shown in the parent assembly BOM. The four different options are, ‘  ‘ (default), ‘IN-BOM’, ‘Not IN-BOM’ and ‘Phantom’. For this use case we will use the ‘  ‘ (default) and ‘Not IN- BOM’ property, but you can read more about the other attributes through the link at the bottom of this ‘How-to’.

The image below shows how to alter this property in CATIA. Select the document you want to change, then open the PDM properties window by selecting the icon on the connector toolbar. From here, there is a drop-down list to select the required marked as attribute.

For our structure above, we can set CAD B to ‘Not IN-BOM’, therefore it will not be included in BOM A. CAD D is left at the default option, meaning that because it is a master document, its Part will be included in BOM A. Finally, to add Part C this must be done manually in the PLM by following the steps below, but for more information please read the FAQ linked at the bottom of this page.

1. Open the profile card of Part A. Put it into edit mode and navigate to the BOM tab at the bottom.
2. Click on the ‘Add Parts’ button.
3. A query box will be displayed, search for Part C and press ok.
4. The part will be added to the BOM table.
   It will be highlighted as manually managed. In addition, the quantity and position override boxed will be ticked as they cannot be computed from the CAD structure. The position box can be left empty, meaning it will be assigned the next available position, or a value can be provided.
5. If required, modify the quantity value. By default, it is set to 1.
6. Click done on Part A’s profile card to save the changes.

Part A’s BOM is now updated and includes the required parts. The schematic below shows the resultant BOM structure compared to the CAD structure.

It is important to note, when creating a workflow to verify the structure, Part B  must be added as a root object of the workflow, else it will not be approved and remain in preparation as a baseline.

BOM management FAQ: BOM management in CATIA / PLM