Thank you for your answer, but what I’m trying to find out, if exist, is access through API into the default instance values of the cable tray as Revit behave through the interface. When you create a cable tray the last value will be display the next time you click on cable tray, so I assume that Revit internally has those values store.
So I created a temporary cable tray with the instance values that I want, hoping that Revit will retain this values as it does on the interface, but it doesn't using the API.
CableTray tempcable = CableTray.Create(ActiveDocument, ActiveDocument.ForEach<CableTrayType>(x => x.Name == "Branch Conduit Zone").Id,
new XYZ(0, 0, 0), new XYZ(10, 0, 0), Active.ActiveView.LevelId);
Best Regards,