Duplicating wall using python but getting an error Autodesk.Revit.Exceptions.InvalidOperationException: The parameter is read-only

ScantoBim · July 17, 2023, 9:58am

I am trying to duplicate the wall of 6 feet and create a new wall of 10 feet but i am getting this error in revit2020, please see the code and error:

Error:- Autodesk.Revit.Exceptions.InvalidOperationException: The parameter is read-only.

Code:-

import Autodesk
from Autodesk.Revit.DB import FilteredElementCollector, BuiltInParameter, BuiltInCategory, Line, Wall, XYZ, Transaction

doc = __revit__.ActiveUIDocument.Document

# Prompt user for wall height with input validation
while True:
    wall_height_input = input("Enter the height of the wall in feet: ")
    try:
        wall_height = float(wall_height_input)
        break
    except ValueError:
        print("Invalid input. Please enter a valid numeric value.")

levels = FilteredElementCollector(doc).OfCategory(
    BuiltInCategory.OST_Levels).WhereElementIsNotElementType().ToElements()
walls = FilteredElementCollector(doc).OfCategory(BuiltInCategory.OST_Walls).WhereElementIsElementType().ToElements()

# Find the wall type with 6 feet thickness
wall_type_6_feet = None
for wall in walls:
    name = wall.get_Parameter(BuiltInParameter.SYMBOL_NAME_PARAM).AsString()
    if name == '6 feet':
        wall_type_6_feet = wall
        break

if wall_type_6_feet is None:
    print("Wall type with 6 feet thickness not found. Aborting.")
else:
    # Find the level with elevation 1'
    level_1 = None
    for level in levels:
        elevation = level.get_Parameter(BuiltInParameter.LEVEL_ELEV).AsDouble()
        if elevation == 304.8 / 304.8:
            level_1 = level
            break

    if level_1 is None:
        print("Level with elevation 1' not found. Aborting.")
    else:
        p_1 = XYZ(0, 0, level_1.Elevation)
        p_2 = XYZ(50, 0, level_1.Elevation)
        line_1 = Line.CreateBound(p_1, p_2)
        lines = [line_1]

        t = Transaction(doc, 'Create Wall')
        t.Start()

        # Duplicate the wall type and change its thickness to 10 feet within the transaction
        wall_type_10_feet = wall_type_6_feet.Duplicate("10 feet")
        wall_type_10_feet.get_Parameter(BuiltInParameter.WALL_ATTR_WIDTH_PARAM).Set(
            10.0 / 304.8)  # Convert 10 feet to Revit's unit (304.8)

        for line in lines:
            # Create the wall with the specified height and 10 feet thickness
            wall_1 = Wall.Create(doc, line, wall_type_10_feet.Id, level_1.Id, wall_height / 304.8, 0, False, True)

        t.Commit()

Jean-Marc · July 17, 2023, 10:44am

Hi,
The whole error stack trace would be useful as it usually indicates the line of the error

ScantoBim · July 17, 2023, 11:14am

Hi @Jean-Marc ,

Thanks, I am getting pop-up, please see

Blockquote

IronPython Traceback:
Traceback (most recent call last):
File “D:\MyExtensions\Rvtcad.extension\Rvtcad.tab\Line.panel\ttest.pushbutton\ttest_script.py”, line 51, in
Exception: The parameter is read-only.

Script Executor Traceback:
Autodesk.Revit.Exceptions.InvalidOperationException: The parameter is read-only.
at Autodesk.Revit.DB.Parameter.Set(Double value)
at Microsoft.Scripting.Interpreter.FuncCallInstruction3.Run(InterpretedFrame frame) at Microsoft.Scripting.Interpreter.Interpreter.Run(InterpretedFrame frame) at Microsoft.Scripting.Interpreter.LightLambda.Run4[T0,T1,T2,T3,TRet](T0 arg0, T1 arg1, T2 arg2, T3 arg3) at System.Dynamic.UpdateDelegates.UpdateAndExecute3[T0,T1,T2,TRet](CallSite site, T0 arg0, T1 arg1, T2 arg2) at Microsoft.Scripting.Interpreter.DynamicInstruction4.Run(InterpretedFrame frame)
at Microsoft.Scripting.Interpreter.Interpreter.Run(InterpretedFrame frame)
at Microsoft.Scripting.Interpreter.LightLambda.Run2[T0,T1,TRet](T0 arg0, T1 arg1)
at IronPython.Compiler.PythonScriptCode.RunWorker(CodeContext ctx)
at PyRevitLabs.PyRevit.Runtime.IronPythonEngine.Execute(ScriptRuntime& runtime)

Jean-Marc · July 17, 2023, 11:23am

To start with, check what the wall_type_10_feet is:

add on line 50:

print(wall_type_10_feet)
print(type(wall_type_10_feet))

ScantoBim · July 17, 2023, 11:56am

wall_type_10_feet is a variable that represents a wall type with a thickness of 10 feet. Is it wrong?

Jean-Marc · July 17, 2023, 12:14pm

Ok,

a walltype has a thickness but it is read only. A walltype is by definition a compound structure

You need to use GetCompoundStructure to get its composition GetCompoundStructure()
then pick the layer you want to modify the thickness
then change the thickness of that layer.

ValquirPacheco · July 17, 2023, 12:18pm

Hey, to add to the discussion, this week I have been messing with Walls so maybe I can try to help out. Like @Jean-Marc said, you cant change that parameter, the opposite with the Commentary parameter for example.

Eric Frits did some cool stuff to change material type, explained here. Here is his source code. Finally, about width change here. a sample of what i did to change the width, from what i understand, it is necessary change the core structure width.

        Wallbase = doc.GetElement(ElementId(1740))   # Generic Family 200mm
        newwalltype = Wallbase.Duplicate("PM 1.00")
        newwalltypeID = newwalltype.Id.ToString()
        cs = newwalltype.GetCompoundStructure()
        i = cs.GetFirstCoreLayerIndex()
        cs.SetLayerWidth(i, 1000/304.8) 
        cs.SetMaterialId(i, ElementId(1250))        # Define specific Material as Armed concrete
        newwalltype.SetCompoundStructure(cs)

Of course, a lot can be refined, much hard coded etc, me myself am not sure i understand it completely but i hope it helps out !

Any corrections feel free community, I am always wanting to learn something new

ScantoBim · July 17, 2023, 12:35pm

Hi @Jean-Marc Thank you very much. I really appreciate your knowledge and valuable time. :). It is working very well. i am happy to be part of your community

Many Thank.

ScantoBim · July 17, 2023, 12:47pm

@Jean-Marc I found, this code is only creating a 10 feet wall name, but inside the thickness of the 10 feet wall is 6’. it seems like this is duplicating the name not changing the thickness.

please see attached image

here is the updated code:

import Autodesk
from Autodesk.Revit.DB import FilteredElementCollector, BuiltInParameter, BuiltInCategory, Line, Wall, XYZ, Transaction

doc = __revit__.ActiveUIDocument.Document

# Prompt user for wall height with input validation
while True:
    wall_height_input = input("Enter the height of the wall in feet: ")
    try:
        wall_height = float(wall_height_input)
        break
    except ValueError:
        print("Invalid input. Please enter a valid numeric value.")

levels = FilteredElementCollector(doc).OfCategory(BuiltInCategory.OST_Levels).WhereElementIsNotElementType().ToElements()
walls = FilteredElementCollector(doc).OfCategory(BuiltInCategory.OST_Walls).WhereElementIsElementType().ToElements()

# Find the wall type with 6 feet thickness
wall_type_6_feet = None
for wall in walls:
    name = wall.get_Parameter(BuiltInParameter.SYMBOL_NAME_PARAM).AsString()
    if name == '6 feet':
        wall_type_6_feet = wall
        break

if wall_type_6_feet is None:
    print("Wall type with 6 feet thickness not found. Aborting.")
else:
    # Find the level with elevation 1'
    level_1 = None
    for level in levels:
        elevation = level.get_Parameter(BuiltInParameter.LEVEL_ELEV).AsDouble()
        if elevation == 304.8 / 304.8:
            level_1 = level
            break

    if level_1 is None:
        print("Level with elevation 1' not found. Aborting.")
    else:
        p_1 = XYZ(0, 0, level_1.Elevation)
        p_2 = XYZ(50, 0, level_1.Elevation)
        line_1 = Line.CreateBound(p_1, p_2)
        lines = [line_1]

        t = Transaction(doc, 'Create Wall')
        t.Start()

        # Duplicate the wall type and modify the thickness of a specific layer
        wall_type_10_feet = wall_type_6_feet.Duplicate("10 feet")
        compound_structure = wall_type_10_feet.GetCompoundStructure()
        layer_index = 0  # Index of the layer to modify (0 being the outermost layer)
        new_thickness = 10.0 / 304.8  # New thickness in Revit's unit (304.8)

        # Change the thickness of the selected layer
        compound_structure.SetLayerWidth(layer_index, new_thickness)

        for line in lines:
            # Create the wall with the specified height and modified thickness
            wall_1 = Wall.Create(doc, line, wall_type_10_feet.Id, level_1.Id, wall_height / 304.8, 0, False, True)

        t.Commit()

Jean-Marc · July 17, 2023, 4:25pm

simple sample code for a 10’ wall
Note:I am comparing the source wall type to a french name: “Mur 1”

from pyrevit import revit, DB, forms
doc = revit.doc
with revit.Transaction('duplicate Wall'):
    wt = DB.FilteredElementCollector(doc).OfClass(DB.WallType).ToElements()
    for w in wt:
        if w.get_Parameter(DB.BuiltInParameter.SYMBOL_NAME_PARAM).AsString() == 'Mur 1':
            wall_type_8_feet = w
    wall_type_10_feet = wall_type_8_feet.Duplicate("10 feet")
    compound_structure = wall_type_10_feet.GetCompoundStructure()
    layer_index = compound_structure.GetFirstCoreLayerIndex()
    new_thickness = 10
    compound_structure.SetLayerWidth(layer_index, new_thickness)
    wall_type_10_feet.SetCompoundStructure(compound_structure)

Jean-Marc · July 17, 2023, 4:26pm

you forgot to set the compound layer structure after assigning the layer thickness

ScantoBim · July 18, 2023, 7:24pm

Thanks @Jean-Marc. Its working very well.