Allow the usage of a work point to gain the GeometryIntent that is supplied to Sheet.Balloons.Add(ObjectCollection). Currently you must supply a Drawing Curve which requires user interaction. For fully automated drawings, the best option would be to use work points which are currently being used in Leader Notes, Linear Dimensions, Ordinate Dimensions, etc. Another possible option would be to supply geometry intent points and a component reference. The component reference would allow for the linking of the Inventor BOM Id to the balloon.
More info from the forum here:
https://forums.autodesk.com/t5/inventor-customization/unable-to-create-balloon-from-workpoint/m-p/86...