You need to import the “transaction” module:
from Autodesk.Revit.DB import Transaction
But you should preferably not work with transactions this way rather using the transaction manager as described by Dimitar in this post:
This “works”
import clr
import sys
sys.path.append('C:\Program Files (x86)\IronPython 2.7\Lib')
clr.AddReference('RevitAPI')
from Autodesk.Revit.DB import *
from Autodesk.Revit.DB import Transaction
clr.AddReference("RevitNodes")
import Revit
clr.ImportExtensions(Revit.Elements)
from System.Collections.Generic import *
clr.AddReference("RevitAPIUI")
from Autodesk.Revit.UI import *
clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager
doc = DocumentManager.Instance.CurrentDBDocument
elements = IN[0]
parameters = IN[1]
values = IN[2]
output = []
if not isinstance(elements, list):
elements = [elements]
if not isinstance(parameters, list):
parameters = [parameters]
if not isinstance(values, list):
values = [values]
t = Transaction(doc, 'Name')
t.Start()
output = "Success"
t.Commit()
OUT = output
