What is the difference between 1st angle and 3rd angle

Question

Accepted Answer

1st angle and 3rd angle are two different methods of representing orthographic projections in engineering drawings.

1st angle projection is commonly used in Europe and Asia, where the object is imagined to be in the first quadrant (top right) of the coordinate system.
3rd angle projection is commonly used in North America, where the object is imagined to be in the third quadrant (bottom right) of the coordinate system.
In 1st angle projection, the top view is placed above the front view, while in 3rd angle projection, the top view is placed below the front view.
The symbol for 1st angle projection is a right-angled triangle with the vertex pointing towards the object, while the symbol for 3rd angle projection is a right-angled triangle with the vertex pointing away from the object.

Top Benninger AG Junior Research and Development Engineer interview questions & answers