Orthographic Projection (First Angle and Third Angle)

Orthographic projection has two forms: first angle and third angle; we shall discuss both. Traditionally, British industry has used first angle while the United States of America and, more recently, the continental countries used the third angle system. There is no doubt that British industry is rapidly changing to the third angle system and, although this will take some years to complete, third angle will eventually be the national and international standard of orthographic projection.