@Fiesta ah yes it was as I thought, you needed to be connecting the family instance to the Python script, not Element.ElementType. My example in the original post was using Element.ElementType because I was associating Type parameters. Regardless, the script has been revised after another user modified it to accept lists of elements, which revealed a potential for mismatching of the parameter lists. So included in the .dyn attached is the new and improved version of the Python script, which can also be found here: Associate family parameter in a family
Fiesta_18_03_23_Forum_associate.dyn (15.5 KB)