hI @Anonymous,
Thanks for the video. It appears that you are doing this correctly but your model doesn't seem to always give the XEDGES the cleanest lines. I was able to get it to work a couple times but not on the third or fourth tries. I tried a BO (Boundary) as well and as you can see in this image, there are several connections that are not perfect (indicated by red circles).

On my later attempts, I simply recreated the fillets and everything works fine again.
I was a little surprised when running FLATTEN that most of the geometry gets erased. Where did the original file originate?
Please select the Accept as Solution button if my post solves your issue or answers your question.
John Vellek
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