GetParameter not working. Why?




I am simply trying to copy information from one parameter into another parameter in all Window families. Namely - copy info from the “Description” into “Material”.

Any idea why this is not working?


Window Schedule











Window Parameters

Forget Dynamo for a minute…Can you type “Wood” into that parameter for any individual family instance (in other words - is that parameter of type “Text”)? Also, open the family and verify that that parameter is not mapped to another parameter or calculated using a formula.

Your image shows a schedule - are you sure the name of the column “Window Material” is actually the parameter that is being scheduled, or was the column renamed? Also, is that column a calculated value instead of a parameter?

If all of these tests still prove that is should be possible…then the Dynamo issue is worth looking into.


Ben, Thanks for your response. Everything you listed is not the issue.

If you notice, the GetParameter node is not returning any value for the “Description” parameter. This is a default parameter that comes pre-built in all Revit families.


I might Remember wrong but isn’t “description” a type parameter? In that case you will need to get the instances type before you can get the parameter value

try using element.parameters to see what parameters the instance you are operating actually has.

Nice catch Sylvester. I should have known that, but I’m an engineer and don’t bother with windows much… The issue here is that the parameter you are trying to read is a Type Parameter, and you are trying to read the parameter “Description” from a list of family instances. Instead, you should first be pulling the family types of those family instances, then doing the “GetParameter” node. Depending on whether the “Window Material” parameter is type or instance, the SetParameter procedure will be a little different as well. See image below.

Window parameter edit


This worked perfectly! Thank you very much for putting these graphs together.

So am I correct in understanding that family “Symbol” = family “Type”…?

All the various nomenclature Dynamo has for families is getting a little confusing for me.


Correct. Symbol = Type. It’s an API thing…