Sweep Bend
This is how to do a closet flange in FreeCAD? https://www.xsim.info/articles/FreeCAD/en-US/HowTo/Create-a-solid-with-sweeping.html
This is how to do a closet flange in FreeCAD? https://www.xsim.info/articles/FreeCAD/en-US/HowTo/Create-a-solid-with-sweeping.html