This work is a training work for the basic hand-painted expression part of industrial design hand-painted by Yixiang. The main purpose is to improve the line manuscript ability of design expression. Line is the most basic element and basic skill that constitutes hand-painted industrial design. After the line is practiced, there is no problem with the complex products and renderings. If the lines are not practiced well, all expressions will bury hidden dangers afterwards.. If you are interested in these works, you can also log on to the BILIBILI account of Yixiang Design and Art Center, which has full HD video. Yixiang Design Art Center is the first batch of industrial design education institutions in China, established in 2004. For more than ten years, a very systematic tutoring system has been accumulated, covering hand-painted tutoring, software tutoring, postgraduate entrance examination tutoring, overseas study tutoring, ability improvement and other fields. Yixiang hand-painted, IDKAOYAN industrial design postgraduate entrance examination, INDIGO design study abroad and vocational training are all very influential brands under Yixiang. If you want to obtain more high-quality hand-painted videos and industrial design learning methods, please contact WeChat public platform: Yixiang Design or WeChat 13811818414.