To Create an External Inheritance Feature
1. Retrieve an assembly, select a part in it, right-click, and choose Activate.
2. Select a second part in the assembly as the reference model from which geometry will be copied and click Get Data > Merge/Inheritance. The Merge/Inheritance tab opens with the reference model selected by default. You can select a different part as the reference model from the Model Tree or in the graphics window.
3. Click Merge/Inheritance to toggle between Merge mode (default) and Inheritance mode.
4. Click External.
5. Select a component or click Open and select a component. The Component Placement dialog box opens.
6. Choose Default from the Constraint Type list to place the external Inheritance feature in the default location or place it in a different location using one or more sets of constraints.
7. Click to complete the feature placement.
* 
Click Edit Placement to change placement references.
8. Use the Options and Properties subtabs to define external Inheritance feature properties.
* 
Properties options are identical to standard Inheritance features.
9. Click to complete the external Inheritance feature.