Location of a Point

LOCATION OF A POINT

Though first angle and third angle projections are generally drawn in orthographic projections (First angle - Object in first quadrant; Third angle - Object in third quadrant), it is advised to practice the projections of point, located in all the four quadrants to get clear understanding of the projections of object, which will be helpful to draw the orthographic projections of planes and solids easily.

1. A Point in First Quadrant : 

Case (i): A point in first quadrant may have perpendicular distances x and y, from the reference planes VP and HP respectively.

Case (ii): A point in first quadrant may lie on horizontal plane, having any distance x, frrom the verticala plane. 

Case (iii): A point in first quadrant may lie on vertical plane, having any distance y, from the horizontal plane.

Case (iv): A point in first quadrant may lie on the reference axis, having zero distances from the reference planes.

Similarly these four cases may be drawn for the remaining quadrants. It is important to note that one more plane, known as Profile plane may be used as shown in fig. 11.3 if the side view of the point is also required. Hence location of the point may also be identified by its distance z, from the Profile plane.

x - Distance of the point from vertical plane 

y - Height of the point from horizontal plane 

z - Distance of the point from profile plane