A freestanding micrometer and method for determining the diameter of a cylindrical body, including measuring variations in diameter along a longitudinal length thereof, such as a roll used in the production of metal and paper sheet products. In one embodiment, data that defines the constraint and a set of spacing parameters that indicate how to space objects across the constraint are received. The resin 14 is pushed toward the outside of the generated gas bubbles 30 by the growth thereof and self-assembled between the connecting terminals 11 and the electrode terminals 12.