In the wooden frame of Qing-style ancient buildings, the step distance (that is, the horizontal distance between two adjacent purlins) is generally 4D-5D, and each step of the golden ridge is 4D. Taking four purlins as an example, the method to determine the size of the jacking frame is generally: divide the purlins at both ends of the four beams into five equal parts, one for jacking frame and two for cornice frame.