This video explains about quadrant system required to carry out projections using first angle projection. A two dimensional space is divided into four parts using two perpendicular lines. These four spaces are known as quadrants. Similarly a three dimensional space is divided into four quadrants using two perpendicular planes. These planes are describes as vertical plane (VP) and horizontal plane (HP). HP and VP intersect forming a straight line called as XY line. When a point is located x mm above HP and y mm in front of VP, it is placed in first quadrant. The projections of these points is analogous to shadow falling on the screen opposite to an object. When the light falls on the point in horizontal direction, the shadow falls on the plane opposite to it, i.e. VP. This shadow is the projection of the point in Front View (FV). When the light falls on the point in vertical direction, the shadow falls on the plane opposite to it, i.e. HP. This shadow is the projection of the point i...