5×3 painting requires a truss of about 20.4 meters, and the painting size is 5 meters wide× 3 meters high. The length of the truss to be supported is slightly larger than the painting size to ensure stability and firmness. The advertising frame and background frame supported by the back triangle need four square heads, with specifications of 20×20 and 10×20. Specifications indicate the cross-sectional dimensions of the truss, 20×20 indicates the truss outer diameter of 20cm, 10×20 indicates the truss outer diameter 10cm, and the inner diameter of 20cm.