Hello Everyone,
I am trying to flatten this sheet metal part. I am able to use the flatten feature on "Piece 1" & "Piece 2" but when I flatten "Piece 3" it shows an error message "This part contains features that cannot be unbent". Can Anyone help me fix this problem.
I am attaching the Part file of the model along with my expected result
-Thanks In Advance.

Edu ​​​​​​​SOLIDWORKS ​​​​​​​