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Revit 2021 resolve parameter unit naming problem when loading pre 2021 family versions into revit 2021

Revit 2021 resolve parameter unit naming problem when loading pre 2021 family versions into revit 2021

The recent release of Revit 2021 has resulted in a change in the unit naming convention for some parameters.  This has no impact for updated projects but has an impact on type catalogs where these parameters with renamed units exist.  


If you try to load a previous Revit family version into a 2021 Revit project you will get an error message and the types will fail to load.  If you upgrade that same family within a previous Revit version to 2021, Revit updates the unit naming within the background automatically.


My proposal is to include the same background function that exists for updating Revit projects for updating families as part of one of the upcoming service packs.


I have not seen this yet, could you please provide some examples?  Perhaps upload some families?


I've created a free tool to update your Family Type TXT files. More info at:



@harrymattison thanks, we created a similar tool that searches through the txt files and swaps out the units, however this doesn't resolve the issue we have when trying to store the revit family files and associated txt files for multiple versions in the same database/storage.  The type catalog txt files associated to the families will over write each other as online storage sees the txt file as the exact same element and will only save the latest version.


It also means that we need to maintain duplicate versions of the same family just to incorporate the unit change.  if we were talking just a couple of families that would be ok, however we have currently in excess of 40,000 families and duplicating this because of the type catalog will become a management and maintenance problem.


My proposal above is asking for the background processing that already exists within Revit for upgrading projects automatically just be applied to earlier Revit version families with type catalogs as its essentially the same process.

Hi Jason,

Everything you mention makes a lot of sense. I doubt Autodesk will do that
since they didn't already do it when they shipped Revit 2021. Happy to help
code some of the remaining issues you mention to share with the rest of the
community if that's feasible. Let me know.


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