Filter list of elements by parameter

I want to filter my ducts by system, but now this is my progress, and this don´t work, someone can help me?Consulta 1

Hi Josue,

I am glad to help you out! I have slightly modified your script you were missing node. Have Fun:)


Excelent… but i have a cuestion, why when someone of the elements in the model don´t have system the program don´t work. Try it, put a duct without system.

Regards Kulkul.

Josue your English is little bad :slight_smile: Never mind. Can you show a screenshot what exactly your talking about.

When one of the ducts don´t have system (the value of this parameter is “null”) the “program” not work. You know Why?

Thank you

Josue, Can you put your revit Duct file here. Just cleanup everything only show ducting.


This is the file in RVT 2016


And this is my dynamo

Prueba Calibre


Hi Josue,

I have seen your file and notice that your not assigning system type on some of the ducts that’s the reason your getting that null values. You can use “Object.IsNull” node to fix your issue or you can use lunchbox get parameter value by name also. Choice is yours :-D

Dynamo files: Prueba-Calibre Revised Prueba-Calibre Revised (LunchBox)

Duct filter

Duct filter1

thank you, you are very good for this.


i´m actually trying this script, to isolate “AREAS” from revit. The problem is that it don’t get them as I though it would do. I’ve tryed as well with “ROOMS” to check if it would able to get it too, and still don’t work. It just worked fine, after change to WALL categories… so I realized that it maybe just work with model elements.
My question is, if you know how it could work to Areas/Rooms.
Thank you!