Why the 2nd and 4th angle projection system are not used to draw engineering drawings?
Table of Contents
- 1 Why the 2nd and 4th angle projection system are not used to draw engineering drawings?
- 2 Why is first angle projection preferred over third angle projection in most of the countries?
- 3 Why third angle projection is not used in India?
- 4 What’s the difference between first and third angle projection?
- 5 Does the UK use first or third angle projection?
Why the 2nd and 4th angle projection system are not used to draw engineering drawings?
Overlapping projection views create confusion in the drawing. Therefore the 2nd angle projection system is not used to draw engineering drawings. Therefore fourth angle projection is also not used. To sum up, Because of the overlapping of front and top views 2nd and 4th angle projections are not used.
Why we use only 1st and 3rd angle projection?
We consider that horizontal plane rotates in clockwise direction after having projection on it. that’s why we use 1st angle and 3rd angle projection. because only in this two quadrants we will get the both views after clockwise rotation of horizontal plane.
Why is first angle projection preferred over third angle projection in most of the countries?
Any one type of representation can be followed. But internationally, presently first angle projection is preferred, the reason might be in first angle projection the object is directly visible but in third angle projection visualize through transparent planes.
Does America use first or third angle projection?
The two orthogonal projection methods used internationally are first angle projection and third angle projection. Third angle projection (figure 1.2) is used mainly in The United States and Canada whilst first angle projection (figure 1.1) is used mainly throughout Europe and the rest of the world.
Why third angle projection is not used in India?
The object is placed behind the vertical planes and bottom of the horizontal plane. Third angle projection is widely used in the United States….Difference between First Angle Projection and Third Angle Projection :
| SR.NO | First Angle Projection | Third Angle Projection |
|---|---|---|
| 8 | It is widely used in Europe, India, Canada. | It is widely used in United State and Australia. |
What is difference between true shape of section and apparent shape of section?
Sectional view : The projection of the section along with the remaining portion of the object is called a Sectional View. Projection on the other plane is called apparent section. 2. True shape of the section : Projection of the section on a plane parallel to the section plane will show the true shape of the section.
What’s the difference between first and third angle projection?
To get the first angle projection, the object is placed in the first quadrant meaning it’s placed between the plane of projection and the observer. For the third angle projection, the object is placed below and behind the viewing planes meaning the plane of projection is between the observer and the object.
When the projectors are parallel to each other and also perpendicular to the plane?
Explanation: In orthographic projection, the projectors are parallel to each other and also perpendicular to the plane but in oblique projection, the projectors are inclined to the plane of projection and projectors are parallel to each other.
Does the UK use first or third angle projection?
Since World War 2 where the UK sent engineering drawing to the US for manufacture the UK has adopted 3rd Angle projection as the general standard. The US, Canada, Japan and Australia are the only other regions that typically use 3rd Angle projection as standard.
Which angle projection is used in USA?
Third angle projection
Third angle projection is widely used in the United States. The projection planes come between the object and observer. The plane of projection is taken as transparent in 3rd angle projection.