Here's some information from a tech note in Supportnet that was recently published: MG242346
When performing an inductance extraction if you encounter these errors below:
Error: Net Information could not be built
Error: The inputs for the inductance engine could not be properly built
The Errors cited could be caused by a missing return path.
Look for a missing return path warning in your log file.
The warning notice appears as follows:
Warning: "No Return paths could be found" for inductance extraction.
If there are any nets that are specified as the nets to be used as return paths for inductance extraction, make sure that you include proper texting for all such nets in the layout file as well.
If you specify POWER and GROUND nets as the nets to be used as return paths in your SVRF rule file using these statements:
PEX POWER LAYOUT vdd!
PEX GROUND LAYOUT vss!
Make sure you have these exact same named POWER and GROUND nets in your layout file.
The lack of a defined return path will result in the above mentioned Warning and Errors.