Vase Mode changed the name in some version before 3.5. Now you can achieve this with 2 modes: "Surface Mode" and "Spiralize Outer Contour". To turn it on do this:
- Choose the Custom setting menu on the right
- click a gear to set up what settings you want to see
- Under the header "Special Modes" you find both Surface Mode and Spiralize Outer Contour
- set the checkmarks on both
Turning on the Surface mode to Surface
and checking Spiralize Outer Contour
gets the "classic" Vase Mode.
Turning on Surface
without Spiralize Outer Contour
gets an infill-less outer perimeter
Now, the classic Vase mode will only print the single most outer perimeter of a print, so your model will have to be very limited with angles and contain no bridges - with one perimeter, you will only be able to print at best 45° angles!