I am trying to add a new family type to an existing "Concrete-Rectangular-Family" family in my revit model using VB.net.
I tried many different options, It gives me this error:
A sub-transaction can only be active inside an open Transaction.
Can someone explain what I am doing wrong? I have attached the full VB codes.
Please note: I have already changed the transaction mode to Automatic! The Revit model shall include this family "Concrete-Rectangular-Family" in order for the VB routine to work.
Thanks
Mehrak