Abstract: From the aspect of geometry, this paper gives new understandings on descriptive geometry.
Combined with the demand for computerization, the theory system of descriptive geometry is
clarified. On this basis, some expressions in some textbooks of descriptive geometry are first
reframed. Then the essences of theories on projection, 2D/3D corresponding, drawing by ruler and
compass, as well as isometric drawing, shadow and perspective are revealed. Problems related to
computerize these theories are further discussed. In the end, some assumptions are proposed to the
development of descriptive geometry both in theory and in application.

Key words: geometry, graphics, descriptive geometry, projection