Please Do Share This Knowledge With Your Friends

Engineering Drawing is one of the most important subjects in Engineering. It is medium of communication for Engineers to understand design and convey their message. most of the Engineering Students are afraid of it, but If Its concepts understood correctly the Engineering Drawing/Graphics is a fun ride.

As We all know only First and Third Angle Projections are in use, But not Second And Fourth Angle projection. Why?

To Understand this we got to go to the basics. There are four quadrants.

In First angle projection the object is assumed to be placed in first quadrant that i.e on horizontal plane and in front of vertical plane, (above and below of XY Line) So the projections are obtained on HP and VP. To Draw this on Drawing there is a rule that we have to turn the Horizontal Plane to 90′ clockwise. We get the projections above and below the XY line.

In Third Angle Projections We get exactly opposite of this. But in this both it is very easy to read the drawing.

Where as in Second Angle projection We assume the object Kept on Horizontal Plane i.e, above XY Line and Behind Vertical Plane. When We Turn Horizontal Plane to 90′. The projections obtained on VP and We get overlapped Projections. And this become very difficult to read and understand the drawing. It Could also Cause and huge error in designing.

In Fourth Angle Projections We get vice-versa of second angle projection.

Hence Second And Fourth Angle Projections Are Not Used In Engineering.

If you like this information please comment and share it.

If you have any further information regarding the above topic please do comment in Comment box. Your comments will encourage us to learn more the and share more knowledge with you