This command on the Edit menu is an easy way to shift the position of all of the parts in the section so the centroid of the section is at the origin. For built-up sections, it is sometimes easier to position the parts relative to a particular edge rather than the centroid. But since axial loads are applied at the origin, it is often necessary to shift the part locations so the centroid is located at the origin. This way axial loads are applied at the centroid, and the axial eccentricity will be limited to that caused by a shift in the effective section centroid, or by eccentricities manually entered as member check parameters or analysis inputs.