Hi Barry-H

That's what I want to do, but I don't know how. Could you do it for me in my file "Guitarra Tasman_2_A.3dm"? This is the last step I need to take to finish it.

Thanks in advance.

So ;)

Draw any line where you want an axe of rotation!

Hi Booleano.
to get the 3 hinges shown on your photo it was necessary to modify
your case profile so that it touches the hinge axis in 3 places.
Basically if you create a profile curve and the axis line you can mirror
about the axis to get the case top then rotate it about axis to get what you want.
Anyway attached is my file.
hope this helps.
Cheers
Barry