1. A system comprising: an electron beam directed toward a three-dimensional object with one tilting angle and at least two azimuth angles, wherein the at least two azimuth angles are applied to the three-dimensional object subsequently, and the three-dimensional object is not part of the system; a detector configured to receive a plurality of scanning electron microscope (SEM) images from the three-dimensional object; and a processor configured to calculate a height and a sidewall edge of the three-dimensional object based upon the SEM images.