Parameter value Problem Dynamo after fill and clear (inside Revit)

Hello, I have a parameter called “Beschreibung” if it’s never been described, dynamo returns null (which is correct) but when it’s filled in and the text is removed afterwards, it’s no longer null and that breaks my filters.

Is there a reason and a possibility that my filter can still work somehow?

If never filled out

If filled in once and later cleared

Thanks for every help

This is typical for many parameter types in Revit. Parameters will have no value (null) until they are filled out. After that, they can only be modified or cleared (empty value) but not reset to no value (null).

For string values (which can typically be cleared), this is easy enough to work around in Dynamo as you just need to make two checks instead of one. Check that the value is either null OR empty ("").

@bsJB9HQ ,

emptyness is killing me… :wink: We use so called Optionsets f.e. “ND” (not defined) or “False” “0” as values… …when everybody knows you can handle the data!