Why can not we use second angle projection method in Engineering drawing?

Answer 1

In 1st angle projection the front view will be in the top of the xy plane and the top view will be in the bottom of the xy plane

.In 3rd angle projection the top view will be in the top of the xy plane and front view will be in bottom of the xy plane. dis will give a clear view.i hope u know dis... but in 2 angle projection both the views(front and top) will be in the top of the xy plane and in 4th angle projection both the views (front and top) will be in the bottom of the xy plane... since both the views will be in one side of the xy plane, its not possible to draw... both views will merge... to get more clear view, refer any basic engineering drawing book.......

Answer 2

Third Angle Projection is the most widely used in engineering drawings, whereas First Angle Projection is also used in America and Australia.

Second and Fourth Angle Projections are not used to avoid confusion in having multiplicity of the projection usage, and also to have a standard practice in simplifying the drawing methods.

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Answer 3

The second and third quadrants are not used in engineering drawing because it produces a regurgitation of the first and third quadrants. The best way to observe this is to get two pieces of cardboard or bristol board and join them by the center producing a cross shape; this will act as the principal planes of projection. Hold a stack of coins between the second quadrant as if to mimic gravity {anything to give a cylindrical shape could be used}. On the vertical plane shine a torch light unto the coins in the direction of the vertical plane and observe the shape. the rays of light from the torch is referred to as the projectors; and the shape obtained is the front view/elevation. If this is done in the fourth quadrant