What are first angle and third angle project?

First angle and third angle projection are two methods of creating orthographic projections of 3D objects in technical drawing. In first angle projection, the object is positioned between the observer and the projection plane, resulting in the top view appearing below the front view and the right side view appearing to the left. Conversely, in third angle projection, the object is placed behind the projection plane, which positions the top view above the front view and the right side view to the right. These projection methods are standardized in different regions, with first angle commonly used in Europe and third angle prevalent in the United States.