# Difference between first angle projection and third angle projection

First angle projection and third angle projection are two methods used in technical drawing to represent three-dimensional objects in a two-dimensional space, such as engineering and architectural drawings. The main difference between them lies in the placement of the object in relation to the views and the location of the observer.

## First Angle Projection:

First angle projection is a method commonly used in Europe and several other parts of the world. In this method, the object is placed in the first quadrant, i.e., between the observer and the plane of projection. The planes of projection are placed as if they were transparent, with the object appearing to project onto them. The views are then created by projecting lines from the object onto these planes of projection. The observer’s position is assumed to be in the first quadrant looking towards the object.

## Third Angle Projection:

Third angle projection is the method predominantly used in North America. In this approach, the object is placed in the third quadrant, i.e., behind the plane of projection. The planes of projection are positioned between the observer and the object. Views are created by projecting lines from the object onto these planes of projection. The observer is assumed to be situated in the third quadrant, looking through the planes of projection towards the object.

**To summarize:**

In first angle projection, the object is placed in front of the planes of projection, with the observer looking from the first quadrant.

In third angle projection, the object is situated behind the planes of projection, and the observer is positioned in the third quadrant.

It’s worth noting that the choice of projection method depends on regional standards and conventions. Both methods aim to represent the same object, but they differ in how the object and the observer’s position are related to the planes of projection.

Here are few more points to consider when comparing first angle projection and third angle projection:

### Symbolic Representation:

In technical drawings, the symbol used to represent each projection method is different. First angle projection is typically denoted by placing a symbol of a right-angle triangle with the right angle in the lower-left corner of the view. Third angle projection, on the other hand, is represented by a right-angle triangle with the right angle in the lower-right corner of the view.

### Position of Views:

### Orthographic Projection:

### Standard Conventions:

### Visual Perception:

Remember, while there are differences between first angle projection and third angle projection, the objective of both methods is to accurately represent the object’s shape, size, and details in a clear and standardized manner for communication and technical documentation purposes.