Co-Authored By:

Asked by: Jaber Oettl
science space and astronomyWhat is the first angle orthographic projection?
Also asked, what is the difference between first angle and third angle orthographic projection?
To get the first angle projection, the object isplaced in the first quadrant meaning it's placedbetween the plane of projection and the observer. Forthe third angle projection, the object is placed below andbehind the viewing planes meaning the plane of projection isbetween the observer and the object.
Then, what is the use of first angle projection?
First Angle Projection is commonly used inall countries other than United States. The Indian StandardInstitution (ISI) recommend the use of First AngleProjection method now in all the institutions. Third AngleProjection is commonly used in United States ofAmerica.
First of all, we use first angle andthird angle projection because it is assumed that theHorizontal plane is rotated CLOCKWISE to bring them in the sameplane (for drawing purpose) and if we use second or fourth angleprojection , then the Horizontal and vertical views willoverlap , creating confusions in their