Online simulation technology had always been the trend in industrial development. In the early days of paper drawings, the "amount of paper used" was the most objective indicator of the complexity of a piece of equipment. Take, for example, a bicycle. 10 sheets of drawings were enough to depict all of its construction. At least 100 sheets of drawings were required for a motorcycle. As for a car, around 1,000 sheets of drawings were required. For complex equipment consisting of thousands of parts, such as tanks and aircraft, the amount of paper used may exceed 10,000 sheets.