A method of constructing a micromechanical device by additive manufacturing for characterizing strength of a low dimensional material sample, the method including: a) deriving a three-dimensional representation arranged to represent a said micromechanical device with reference to at least one physical characteristic of a said low dimensional material sample; b) transforming the three-dimensional representation into a plurality of two-dimensional representations arranged to individually represent a portion of the three-dimensional representation; and c) forming the micromechanical device from a fluid medium arranged to transform its physical state by stereolithography apparatus in response to a manipulated illumination exposed thereto, whereby a said low dimensional material sample is loaded onto the formed micromechanical device.