Hi All
This is Creat CableTray method from Revit API
How I can put a Fixed value to the ElementId cabletrayType,but without draw CableTray in Revit and Extract the type id from it .
You do need to create the Cable Tray family and its types before you can use the API to place it. You don’t have to place it to get its type. Just load it into the model, and then use family Types node to get the type and its ID.
I am not sure of there is a CableTray node in Dynamo at the moment, but as you can sure add one. It would be relatively easy given that it takes pretty standard inputs.