When you insert a component from a Content Center Library family either with the command Place from Content Center or with Frame Generator you want that the Part Number field is empty.
In order to do that,
- Copy the family in a Read/Write library
- Select the family you have copied, right-click, Family Table.
- In the Family Table, select the Part Number column, right-click, Column Properties.
- In the Column Property dialog set the Expression Column field to “=”
- Publish the changes.
After that, inserting a member of that family either with the command Place from Content Center or with Frame Generator you will get an empty Part Number field.
Note. If you have modified a Structural Shape family as described above and you generate the members with Frame Generator, you need to select the box "Get Frame Member's Part Number from Content Center" in the Insert dialog for getting the empty Part Number for the frames.
By the way, the box is checked by default.
For more information about this option you can read this post.