Projection Method | First And Third Angle Projection | Difference
Projection Methods are used to show drawing on a paper . Projection Methods has mainly two types used in Engineering Drawing :
1) First Angle Projection Method
2) Third Angle Projection Method
|Principal Projection Planes and Quadrants|
First Angle Projection
In this the object in assumed to be positioned in the first quadrant and is shown in figure.
|Example of First Angle Method|
The object is assumed to be positioned in between the projection planes and the observer. The views are obtained by projecting the images on the respective planes. Note that the right hand side view is projected on the plane placed at the left of the object. After projecting on to the respective planes, the bottom plane and left plane is unfolded on to the front view plane. i.e. the left plane is unfolded towards the left side to obtain the Right hand side view on the left side of the Front view and aligned with the Front view. The bottom plane is unfolded towards the bottom to obtain the Top view below the Front view and aligned with the Front View.
Third Angle Projection
|Example of Third Angle Method|
Difference between first- and third-angle projections
Symbol of projection
|Symbol of first and third angle method|