In the first angle projection, the object is placed in the 1st quadrant. The object is positioned at the front of a vertical plane and top of the horizontal plane.
What is first angle projection?
First-angle projection: In this type of projection, the object is imagined to be in the first quadrant. Because the observer normally looks from the right side of the quadrant to obtain the front view, the objects will come in between the observer and the plane of projection.
How do you read 1st and 3rd angle drawings?
The difference between first and third angle projection is in the position of the plan, front and side views. In third angle, what you see from the right would be drawn on the right. In first angle, the view from the right would be projected through and drawn on the left.
Why don’t we use 2nd and 4th angle projection?
As per rule of projection when horizontal plane is rotated 90 degree in clockwise direction, top and front view will overlap. Overlapping projection views create confusion in the drawing. Therefore 2nd angle projection system is not used. … Therefore fourth angle projection is also not used.
How many types of projection angles are there?
There are two types of drawing in orthographic , First Angle and Third Angle. They differ only in the position of the plan, front and side views.
Different between 1st angle projection and 3rd angle projection in drawing.
|First Angle Projection||Third Angle Projection|
|the plane of projection assumed to be non transparent||the plane of projection assumed to be transparent|
How do you read a first angle drawing?
Drawing Right and Left Side View in 1st angle projection
The left plane is unfolded towards the left side. Therefore the Right Side View is projected on the left side of the front view. Whereas the left side view is projected on the right side of the front view.