Additional Windchill Capabilities > Manufacturing Process Management > Transforming an eBOM into an mBOM > Implied Equivalence of Parts
  
Implied Equivalence of Parts
When parts from an upstream structure are reused in the downstream structure, the parts with similar number and view in both the structures are implied to be equivalent. Parts can be reused using the structure transformation actions, such as drag and drop, Copy and Paste, referred to as paste as is, Assemble As Is, and Duplicate without propagating.
Depending on the action performed on the parts and the hierarchy of the nodes in the upstream structure, the equivalence icons and appear for the similar parts in both the structures. For more information on the equivalence icons, see Occurrence and Equivalence Icons.
* 
Based on the settings that are configured for the preference Maintenance of Equivalent Links to Self, the equivalent links are either updated automatically or manually by end users when there is a change in the upstream structure.
The image illustrates the equivalent links to self existing for the parts in the upstream and downstream structure.