Descriptive Geometry ■ One can easily visualize the corresponding situation in 3D.However,it is also necessary to be able to go back and forth between 2D and 3D.That is,be able to: represent a given three dimensional situation by a series of 2D views (i.e.,orthographic views- principal and auxiliary) visualize (and derive pertinent geometric information about)the three dimensional situation from a given set of orthographic views. Shanghai Jiao Tong University 6Shanghai Jiao Tong University 6 Descriptive Geometry n One can easily visualize the corresponding situation in 3D. However, it is also necessary to be able to go back and forth between 2D and 3D. That is, be able to: n represent a given three dimensional situation by a series of 2D views (i.e., orthographic views— principal and auxiliary) n visualize (and derive pertinent geometric information about) the three dimensional situation from a given set of orthographic views