PROJECTION OF POINTS CLASS NOTES FOR ENGINEERING
PROJECTION OF POINTS
CLASS NOTES FOR ENGINEERING
Projection of a point is the most basic. A
point can lie in any of the four quadrants
It shows the location of a light or a fan
point in a building drawing. Two points
when join forms a line. For a point, ‘A’
mark front view with small alphabet
with a dash, ‘a’ ‘. Mark Top view
by a small alphabet without a dash as ‘a’.
Fig. Four quadrants
Horizontal plane (HP) 1234 and 1456
Vertical Plane (VP) 1487 and 14910
First quadrant 1784321
Second quadrant 4781654
Third quadrant 49101654
Fourth quadrant 1234–9101
Fig. Projections of a point ‘A’ in four quadrants
Key position of points in the quadrants and their projections.
A.
Quadrant 
Position 
front view 
top view 
1^{st} 
In front of VP and above HP 
lies Above x y 
Below x y 
2nd 
Above HP and behind VP 
Above x y 
lies Above x y 
3^{rd} 
Behind VP and below HP 
Lies Below x y 
Above x y 
4th 
Below HP and in front of VP 
Below x y 
Lies Below x y 
Quadrant  Position  Front view  Top view 
1st  (i) lies in HP and distance x in front of VP
(ii) Lies in VP and distance x above HP 
(i) Lies in XY
(ii) Above XY 
(i) Below XY
(ii) In XY 
2nd  (i) Lies in HP and distance x behind VP
(ii) Lies in VP and distance x above HP 
(i)Lies in XY
(ii) Above XY 
(i) Above XY
(ii) Lies in XY 
3rd  (i) Lies in VP and distance y below HP
(ii) Lies in HP and at distance x behind VP 
(i) Below XY
(ii) Lies in XY 
(i) Lies in XY
(ii) Above XY 
4th  (i) Lies in VP and at distance y below HP
(ii) Lies in HP and distance x in front of VP 
(i) Below XY
(ii) Lies in XY 
(i) Lies in XY
(ii) Above XY 
Key features projection of points.
A.
(i) Distance of the front view is always from the HP.
(ii) Top view distance is always from the VP.

If distance is above HP, front view is above x y and vice versa.

If point is in front of VP, top view is below x y and vice versa.
Representation of front view and top view of a point
A.
(i) Mark front view by a small alphabet with a dash. For example, the front view of point H is h’.
(ii) Mark Top view by a small alphabet without a dash. The front view of point H will be h.

Mark Point by a capital alphabet as H.
Q. Types of projections mostly used in engineering drawing.
A.
Projections are orthographic and isometric. Use Orthographic projections. Use HP, VP and PP planes for orthographic projections. Projections on a plane are 2 dimensional.
Different methods of projections in use
A.
First and third angle projections are in common use.
First Angle Projection 
Third Angle Projection 
Object lies in the first quadrant. 
Here the object lies in the third quadrant. 
When object is in between the observer and the vertical plane. 
Vertical plane is in between the observer and the object. 
Front view is on the back, 
In this, front view is on the front, 
Right side view is on left and so on. 
right side view is on right and so on 
https://www.mesubjects.net/wpadmin/post.php?post=7270&action=edit Orthographic Projections
https://www.mesubjects.net/wpadmin/post.php?post=3785&action=edit Q. ANS. Projections