HI @Anonymous,
I exploded the lines you already had connected and then ran OVERKILL to remove duplicate lines. Now when I use join I can select the desired lines and they connect just fine. However, you will see there are limitations to Join by the image:
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So, I wonder if you would consider using 3D solids to make this geometry instead which would let you use UNION?
They are fairly easy to work with and would give you better visibility and control I think.
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I made a quick video that shows how you can use a closed polyline to define your beam and then Presspull it into the proper thickness.
I hope this helps.
Please select the Accept as Solution button if my post solves your issue or answers your question.
John Vellek
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