PolyCurve.ByJoinedCurve - Not Working in Python Node

Hi All,

I am trying to join curves which are coming out of the Room.CoreBoundary in a python node. When I do it as a code block it works fine but once I write similar code in a python node it gives me the following error:

Warning: IronPythonEvaluator.EvaluateIronPythonScript operation failed.
Traceback (most recent call last):
File “”, line 14, in
TypeError: Error in IEnumeratorOfTWrapper.Current. Could not cast: Autodesk.DesignScript.Geometry.Curve in IronPython.Runtime.List

I’m assuming there is something simple that I am missing here. If anyone can point me in the right direction I would really appreciate it.

*Disclaimer, I need this to work within the python script as this is only a portion of my true goal. The remaining more extensive code has been cut out as

I have identified this as what is creating the issues here.

Use a tuple instead of a list

Hi Thomas,

Thanks for that quick response. I tried that but unfortunately that didn’t change anything.

Looks like a rank issue then, just index your lines variable:


Thank you Thomas! That indeed did work. Could I ask just so that I may understand for future reference how did you understand that from the error code?

The Curve[ ][ ] is in reference to the output data structure, in this case the double square brackets means a 2D array (aka a list of lists). The same is true for inputs.

Hence, in your for loop, your lines variable is a 2D array but Curve.ByJoinedCurves() requires a 1D array. If you index the lines it will get the first sub-list in the array which satisfies the input for ByJoinedCurves(). The first sublist from a room boundary array is always its outermost profile - any other sublist will be an interior boundary created by a column or any other room bounding element within the room. Hence, if you never have such conditions or if its unimportant, you can safely get the first index this array - like what I’ve done - and that’s the maximum extents of your room.

So going back to your question then…just a bit of guess work as the exception is telling - although a bit cryptically - that there is a problem with your list and now you know its the data structure that is triggering the problem.

I really appreciate that extremely detailed and thorough explanation. Thank you for taking the time to help me!