@Draxl_Andreas lists comprehensions is one way to loop thru your rooms:
import clr
clr.AddReference('RevitAPI')
from Autodesk.Revit.DB import *
from Autodesk.Revit.DB.Structure import *
clr.AddReference('RevitAPIUI')
from Autodesk.Revit.UI import *
clr.AddReference('System')
from System.Collections.Generic import List
clr.AddReference('RevitNodes')
import Revit
clr.ImportExtensions(Revit.GeometryConversion)
clr.ImportExtensions(Revit.Elements)
clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager
rooms = IN[0]
if isinstance(rooms,list): rooms = UnwrapElement(rooms)
else: rooms = [UnwrapElement(rooms)]
def convUnits(value):
return UnitUtils.ConvertFromInternalUnits(value, UnitTypeId.Meters)
roomsHeight = [convUnits(room.get_Parameter(BuiltInParameter.ROOM_HEIGHT).AsDouble()) for room in rooms]
roomsPerim = [convUnits(room.get_Parameter(BuiltInParameter.ROOM_PERIMETER).AsDouble()) for room in rooms]
lateralSurfs = [h*p for h, p in zip(roomsHeight, roomsPerim)]
OUT = roomsHeight, roomsPerim, lateralSurfs
