On the functions of the Autocad three-dimensional object in teaching the mechanical graphing

The mechanical graphing is a fundamental course in the engineering course,which contains both the theory knowledge and the stronger practicality.The key difficulty for teaching is to help the students maintain the enough perceptual cognition,by introducing the drawing of the Autocad three-dimensional object,and to make the students observe visually and perceptually all kinds of flexible figures,in order to realize the real integration of theory and practice that is from the drawing to the figure and from the figure to the drawing.