The projection of form and structure concerned in many books and many sets of drawing software in development at present all lack the content of oblate revolution surface and its intersection line.

• 在各种书籍中涉及的形体投影,以及目前开发、研制的各种绘图软件中,均缺少扁回转面及其截交线内容,这对于机器零件的表达是一种不足和缺憾。