What is the difference between the first-angle and third-angle projection methods?

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First-angle and third-angle projection methods are two different approaches used in engineering drawings to represent a 3D object in 2D.

First-angle projection method is commonly used in Europe and Asia, where the object is imagined to be in the first quadrant and the views are projected onto the planes of projection from the object's side.
Third-angle projection method is commonly used in North America, where the object is imagined to be in the third quadrant and the views are projected onto the planes of projection from the object's side.
In first-angle projection, the top view is placed below the front view, while in third-angle projection, the top view is placed above the front view.
The symbol for first-angle projection is a square with a number '1' inside, while the symbol for third-angle projection is a square with a number '3' inside.

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