Table 1. Difference between first- and third-angle projections

Either first angle projection or  third angle projection are used for engineering drawing.  Second angle projection and fourth angle projections are not used since the drawing becomes complicated. This is being  explained with illustrations in the lecture on Projections of points (lecture 18).

Symbol of projection

The type of projection obtained should be indicated symbolically in the space provided for the purpose in the title box of the drawing sheet. The symbol recommended by BIS is to draw the two sides of a frustum of a cone placed with its axis horizontal The left view is drawn.