Element.Curves of Duct Fittings is empty

Could you tell me why Element.Curves is empty?

Hi @Hieudang96as,

Only the ducts are curves. Fittings are not curves.
What do you want to do ?

I am new to revit and dynamo and if I ask any stupid question please dont mind. Thank you very much.

You’re welcome.
Don’t hesitate to ask for help if you hit a wall.
You can mark the topic as solved.