Engineering Graphics

1. 20MEG01 Engineering Graphics
Module II
Prepared by:
M. Sundra Pandian, M.E., M.B.A.
Assistant Professor, Department of Mechanical Engineering,
Sri Ramakrishna Institute of Technology, Coimbatore - 10

2. Syllabus
Projection of Points, Lines and Plane Surfaces (Module 2)
Projection of points – Projection of straight lines (only First
angle projections) inclined to both the principal planes –
Determination of true lengths and true inclinations by rotating line
method and trapezoidal method and traces – Projection of planes
(polygonal and circular surfaces) inclined to both the principal planes
by rotating object method.

3. Introduction
A point may be situated, in space, in any one of the four
quadrants formed by the two principal planes of projection or may lie
in any one or both of them.

4. Introduction
Its projections are obtained by extending projectors
perpendicular to the planes.
x
y x y
V
P
H
P
Reference Line

5. Introduction
Its projections are obtained by extending projectors
perpendicular to the planes.
Quadrant I
Above HP &
In front of VP
Quadrant II
Above HP &
Behind VP
Quadrant III
Below HP &
Behind VP
Quadrant IV
Below HP
In front of VP
V
P
H
P

6. Introduction
A point may be situated, in space, in any one of the four
quadrants formed by the two principal planes of projection or may lie
in any one or both of them.
Its projections are obtained by extending projectors
perpendicular to the planes.
One of the planes is then rotated so that the first and third
quadrants are opened out.
The projections are shown on a flat surface in their respective
positions either above or below or in xy

7. Projections of Points
Let the point “A” be on the first quadrant at a height of ‘h’
mm from the ground or Horizontal plane, H.P and at a distance of ‘y’
mm from the wall or vertical plane or V.P.
Lets draw the projections of the point A.
It is noted that the point is in
Quadrant 1.
Drawing the perpendicular
projector to the ground from the point
A, the projectors hits the H.P. at the
point a and similarly the V.P at a’.

8. Projections of Points
Let the point “A” be on the first quadrant at a height of ‘h’
mm from the ground or Horizontal plane, H.P and at a distance of ‘y’
mm from the wall or vertical plane or V.P.
• The point will always be denoted in
lowercase letter.
• Elevation or Front view or F.V should
always be indicated with an apostrophe
( ‘ ).
• Plan or Top view or T.V should always
be indicated with the lowercase letter
without apostrophe ( ‘ ).

9. Exercise
A point A is 50 mm above the ground and 60 mm infron t
• The point will always be denoted in
lowercase letter.
• Elevation or Front view or F.V should
always be indicated with an apostrophe
( ‘ ).
• Plan or Top view or T.V should always
be indicated with the lowercase letter
without apostrophe ( ‘ ).