I could use some help figuring out how to use the Extrude Surface command to create a female cavity locating piece.
I am trying to create fixture block that will locate around the extended water bottle section on my part for locating purposes. When I try to use extrude surface I can only select the flat faces and not the curved and complex geometry edges. Basically I want to create a female cavity to the the bottom extension on my part. See the attached photo of the section I need the cavity on.
Is there a different surface feature I should be using instead? Appreciate any help.