Create Rebar From Curves in Python

ikhsan.pc · April 23, 2024, 9:21am

I’m trying to learn how to create nodes, from python, following the references to posts that were previously made, why the error?

import sys
import clr
clr.AddReference('RevitAPI')
import Autodesk
from Autodesk.Revit.DB import *
from Autodesk.Revit.DB.Structure import*

from System.Collections.Generic import IList, List

clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager

clr.AddReference('RevitNodes')
import Revit
clr.ImportExtensions(Revit.GeometryConversion)

doc = DocumentManager.Instance.CurrentDBDocument

# dynamo curves as input
curves = UnwrapElement(IN[0])
rebar_style = UnwrapElement(IN[1])
rebar_bar_type = UnwrapElement(IN[2])
start_hook_type = UnwrapElement(IN[3])
end_hook_type = UnwrapElement(IN[4])
start_hook_orientation = IN[5]
end_hook_orientation = IN[6]
host_element = UnwrapElement(IN[7])
vector = IN[8]

def CreateRebarFromCurve(curves, rebar_style, rebar_bar_type, start_hook_type, end_hook_type, start_hook_orientation, end_hook_orientation, host_element, vector):
    rebars = []
    TransactionManager.Instance.EnsureInTransaction(doc)
    for c, v in zip(curves, vector):
        curv = List[Curve]()
        curv.Add(c.ToRevitType())
        rebar = Rebar.CreateFromCurves(doc, rebar_style, rebar_bar_type, start_hook_type, end_hook_type, host_element, v.ToRevitType(), curv, start_hook_orientation, end_hook_orientation, True, False)
        rebars.append(rebar)
    TransactionManager.Instance.TransactionTaskDone()
    return rebars

OUT = CreateRebarFromCurve(curves, rebar_style, rebar_bar_type, start_hook_type, end_hook_type, start_hook_orientation, end_hook_orientation, host_element, vector)

c.poupin · April 23, 2024, 5:25pm

Hi

the error indicates that you are trying to iterate on a non-iterable object

Check that curves and vector are input lists of the same size

or

just use a for-loop (instead zip() )on the curves object and use vector (type conversion to be done) directly in the Rebar.CreateFromCurves() method.

Mike.Buttery · April 24, 2024, 8:23am

A few notes

You may find the curve elements do not need to be converted as they have been unwrapped
If you have single value for an element you can use them globally (just as you have used the doc variable) rather than pass them into the function so that your function only needs the variable to process
If possible do all your conversions in one place either in the function or as they are established
Convert a dynamo Vector with ToXyz() method
I’m pretty sure you can create the rebars using one list of curves if all the other items are static instead of one by one
As @c.poupin noted - is there a purpose for the zip
More information on the inputs (i.e. the whole graph) would assist understanding what the code is working with
You may have to unwrap the rebar hook orientation inputs

ikhsan.pc · April 26, 2024, 3:13am

I’ve checked the list curve, right

rebar Python.dyn.rvt (7.5 MB)

Rebar Python.dyn (27.0 KB)

christian.stan · April 26, 2024, 4:30am

Good morning
you are missing:
import System
in your code
Sincerely
christian.stan

c.poupin · April 26, 2024, 7:19am

Hi,

you must analyze the error message, in this example there is a problem with several object types passed as arguments that do not match with the Revit API.

here the fixed code

import sys
import clr
import System
clr.AddReference('RevitAPI')
import Autodesk
from Autodesk.Revit.DB import *
from Autodesk.Revit.DB.Structure import *

from System.Collections.Generic import IList, List

clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager

clr.AddReference('RevitNodes')
import Revit
clr.ImportExtensions(Revit.GeometryConversion)

doc = DocumentManager.Instance.CurrentDBDocument

# dynamo curves as input
curves = UnwrapElement(IN[0])
rebar_style = System.Enum.Parse(RebarStyle, IN[1])
rebar_bar_type = UnwrapElement(IN[2])
start_hook_type = UnwrapElement(IN[3])
end_hook_type = UnwrapElement(IN[4])
start_hook_orientation = System.Enum.Parse(RebarHookOrientation, IN[5])
end_hook_orientation = System.Enum.Parse(RebarHookOrientation, IN[6])
host_element = UnwrapElement(IN[7])
vector = IN[8]

def CreateRebarFromCurve(curves, rebar_style, rebar_bar_type, start_hook_type, end_hook_type, start_hook_orientation, end_hook_orientation, host_element, vector):
    rebars = []
    TransactionManager.Instance.EnsureInTransaction(doc)
    for c, v in zip(curves, vector):
        curv = List[Curve]()
        curv.Add(c.ToRevitType())
        rebar = Rebar.CreateFromCurves(doc, 
                                        rebar_style, 
                                        rebar_bar_type, 
                                        start_hook_type, 
                                        end_hook_type, 
                                        host_element, 
                                        v.ToRevitType(), 
                                        curv, 
                                        start_hook_orientation, 
                                        end_hook_orientation, 
                                        True, 
                                        False)
        rebars.append(rebar)
    TransactionManager.Instance.TransactionTaskDone()
    return rebars

OUT = CreateRebarFromCurve(curves, rebar_style, rebar_bar_type, start_hook_type, end_hook_type, start_hook_orientation, end_hook_orientation, host_element, vector)

ikhsan.pc · April 26, 2024, 8:21am

Thank you very much work

ikhsan.pc · April 26, 2024, 8:31am

It turns out that the string must be converted, yes, I think at the beginning he can read string data ,

ikhsan.pc · August 12, 2024, 11:59pm

Sorry mr, I tried again, by create a rebar curve stirrup, showing an EOF error, but I tried to make the standard rebar successful, why?

c.poupin · August 13, 2024, 4:47pm

check the end of your script, missing parenthesis or missing quotes

d.kelfkens · September 10, 2025, 5:39pm

@c.poupin Hi,

I’m using the script above you’ve fixed to model stirrupties. After running the script gives the following error: CreateRebarFromCurve TypeError: expected Curve, got CurveLoop.

Could the cause be that I’m feeding this script with rectangles (as curves). The startpoint is the same as the endpoint so that could be the CurveLoop.

c.poupin · September 11, 2025, 8:06am

Try to get the longest curve.

for curve_Loop, v in zip(curve_Loops, vector):
    max_curve = max(curve_Loop, key = lambda x : x.Length)
    curv = List[Curve]([max_curve ])

d.kelfkens · September 11, 2025, 5:55pm

This triggered a new error:
Traceback (most recent call last):
File “”, line 58, in
File “”, line 40, in CreateRebarFromCurve
TypeError: Error in IEnumeratorOfTWrapper.Current. Could not cast: Autodesk.Revit.DB.Curve in Autodesk.DesignScript.Geometry.PolyCurve

I’m still trying to find out how to post my Python script as you guys do. Feel a bit stupid now…

c.poupin · September 11, 2025, 6:05pm

@d.kelfkens
Paste your code, select it, then click this button.

d.kelfkens · September 11, 2025, 6:07pm

import sys
import clr
import System
clr.AddReference('RevitAPI')
import Autodesk
from Autodesk.Revit.DB import *
from Autodesk.Revit.DB.Structure import *

from System.Collections.Generic import IList, List

clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager

clr.AddReference('RevitNodes')
import Revit
clr.ImportExtensions(Revit.GeometryConversion)

doc = DocumentManager.Instance.CurrentDBDocument

# dynamo curves as input
curves = UnwrapElement(IN[0])
rebar_style = System.Enum.Parse(RebarStyle, IN[1])
rebar_bar_type = UnwrapElement(IN[2])
start_hook_type = UnwrapElement(IN[3])
end_hook_type = UnwrapElement(IN[4])
start_hook_orientation = System.Enum.Parse(RebarHookOrientation, IN[5])
end_hook_orientation = System.Enum.Parse(RebarHookOrientation, IN[6])
host_element = UnwrapElement(IN[7])
#vector = IN[8]
vector = UnwrapElement(IN[8])

def CreateRebarFromCurve(curves, rebar_style, rebar_bar_type, start_hook_type, end_hook_type, start_hook_orientation, end_hook_orientation, host_element, vector):
    rebars = []
    TransactionManager.Instance.EnsureInTransaction(doc)
    for c, v in zip(curves, vector):
        max_curve = max(curves, key = lambda x : x.Length)
        #curv = List[Curve]()
        curv = List[Curve]([max_curve])
        curv.Add(c.ToRevitType())
        rebar = Rebar.CreateFromCurves(doc, 
                                        rebar_style, 
                                        rebar_bar_type, 
                                        start_hook_type, 
                                        end_hook_type, 
                                        host_element, 
                                        v.ToRevitType(), 
                                        curv, 
                                        start_hook_orientation, 
                                        end_hook_orientation, 
                                        True, 
                                        False)
        rebars.append(rebar)
    TransactionManager.Instance.TransactionTaskDone()
    return rebars

OUT = CreateRebarFromCurve(curves, rebar_style, rebar_bar_type, start_hook_type, end_hook_type, start_hook_orientation, end_hook_orientation, host_element, vector)

c.poupin · September 11, 2025, 6:26pm

This means that you have an object of type Dynamo PolyCurve instead of a Revit CurveLoop object as you mentioned above.

you must convert Dynamo Geometry to a Revit GeometryObject, read this

Try this (untested):

import sys
import clr
import System
clr.AddReference('RevitAPI')
import Autodesk
from Autodesk.Revit.DB import *
from Autodesk.Revit.DB.Structure import *

from System.Collections.Generic import IList, List

clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager

clr.AddReference('RevitNodes')
import Revit
clr.ImportExtensions(Revit.GeometryConversion)

doc = DocumentManager.Instance.CurrentDBDocument

# dynamo curves as input
polycurves = IN[0] # assume is a list of polycurve
rebar_style = System.Enum.Parse(RebarStyle, IN[1])
rebar_bar_type = UnwrapElement(IN[2])
start_hook_type = UnwrapElement(IN[3])
end_hook_type = UnwrapElement(IN[4])
start_hook_orientation = System.Enum.Parse(RebarHookOrientation, IN[5])
end_hook_orientation = System.Enum.Parse(RebarHookOrientation, IN[6])
host_element = UnwrapElement(IN[7])
#vector = IN[8]
vectors = IN[8]

def CreateRebarFromCurve(polycurves, rebar_style, rebar_bar_type, start_hook_type, end_hook_type, start_hook_orientation, end_hook_orientation, host_element, vector):
    rebars = []
    TransactionManager.Instance.EnsureInTransaction(doc)
    for polycurve, v in zip(polycurves, vectors):
        max_curve = max(polycurve.Curves(), key = lambda x : x.Length) # we get only the longuest curve
        curv = List[Curve]([max_curve.ToRevitType()])
        rebar = Rebar.CreateFromCurves(doc, 
                                        rebar_style, 
                                        rebar_bar_type, 
                                        start_hook_type, 
                                        end_hook_type, 
                                        host_element, 
                                        v.ToRevitType(), 
                                        curv, 
                                        start_hook_orientation, 
                                        end_hook_orientation, 
                                        True, 
                                        False)
        rebars.append(rebar)
    TransactionManager.Instance.TransactionTaskDone()
    return rebars

OUT = CreateRebarFromCurve(polycurves, rebar_style, rebar_bar_type, start_hook_type, end_hook_type, start_hook_orientation, end_hook_orientation, host_element, vector)

d.kelfkens · September 11, 2025, 7:05pm

not there yet…

d.kelfkens · September 11, 2025, 7:47pm

My input. Maybe I’m doing something wrong.

c.poupin · September 11, 2025, 7:59pm

Yes, in your case, you need to pass arguments (all input lists) to the zip function.

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