While attempting to add End Fill objects in a drawing, it was discovered that the objects are not exposed or supported by the API.
Please consider adding support to create, edit, and delete End Fill objects.

In the example above, overlapping round bar required tack welds. There are no corners, so some kind of work point will likely be required for the geometry intent, along with control of method, size, and orientation.
Here is link to the thread initially asking how to make End Fills with the API:
https://forums.autodesk.com/t5/inventor-programming-forum/automation-for-end-fill-symbols/m-p/139322...
I welcome your votes.
Regards,
Jerry