> For the complete documentation index, see [llms.txt](https://swatplus.gitbook.io/io-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://swatplus.gitbook.io/io-docs/introduction-1/routing-units/untitled-2/obj_id.md).

# obj\_id

The object ID of the element is a foreign key referencing the ID of the object in its [connect](/io-docs/introduction-1/simulation-settings/print.prt/object.md) file.