Assigning BOM Items using Bill of Materials Transfer 
Purpose
If you use bill of material (BOM) transfer to assign BOM items to a network activity, subsequent changes in the BOM are automatically updated in the network.
You can only assign reference points for items in a bill of material, not for the component in the header. You can only assign such components as
Assembly ItemsYou cannot assign BOM items to a standard network using reference points. You can however enter reference points in the data fields which have been defined for this purpose, so that when you use this standard network to create an operative network the system also copies the reference points.
During assignment using reference points, the system ignores material components that you have already manually assigned to a network activity. These material components do not appear in the list of assignments.
Prerequisites
To use BOM transfer, one of the following prerequisites must be met for the activities or the network.
Process Flow
The reference point in the BOM must agree with the reference point in the corresponding network activity.

If , prior to Release 4.6A, you defined other fields in BOM items and network activities as reference fields, you must copy these definitions in Customizing the Project system by choosing Material ® BOM transfer ® Define Fields in BOM and Activity as Reference Point.
Result
The BOM items and the activities are linked logically.
For information about how changes to BOMs affect the network, if you execute the assignment again, see
The Effects of Changes in Bills of Material and BOM Transfer.