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PROJECTION
PROJECTION:
The figure or view formed by joining, in correct sequence, the points at which these lines meet the plane
is called the projection of the object. (It is obvious that the outlines of the shadow arc the projections of an
object).
PROJECTORS:
The lines or rays drawn from the object to the plane are called projectors.
PLANE OF PROJECTIONS:
The transparent plane on which the projections are drawn is known as plane of projectors.
TYPES OF PROJECTIONS:
1. Pictorial Projections
Perspective Projection
Isometric Projections
Oblique Projections
2. Orthographic Projections
PICTORIAL PROJECTIONS
The projection in which the description of the object is completely understood in one view is known as
Pictorial Projection. The Pictorial projections have the advantage of conveying an immediate impression of
the general shape and details of the object, but no its true dimensions or sizes.
Note:
Isometric projection gives true shape of the object, while Perspective and Oblique Projections do not.
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PERSPECTIVE PROJECTION:
Imagine that the observer looks at the object form an infinite distance. The rays will now be parallel to
each other and perpendicular in both the front surface of the object and the plane, when the observer is at a
finite distance from the object, the rays converge to the eye as in the case of Perspective Projection.
The observer looks from the front. The front surface F of the block is seen in its true shape and size.
Note:
Orthographic Projection is the standard drawing form of the industrial world. The form is unreal in that we
don not see an object as it is drawn orthographically. Pictorial drawing however has photographic realism.
PERSPECTIVE VIEW:
If any imaginary transparent plane is introduced such that the object is in between the observer and the
plane. The image obtained on the plane/screen is as shown. This is called perspective view of the object.
ISOMETRIC PROJECTION
“Iso” means „equal‟ and “metric projection” means „a projection to a reduced measure‟.
An Isometric Projection is one type of pictorial projection in which the three dimensions of a solid are not
only shown in one view, but also their dimension can be scaled from this drawing.
OBLIQUE PROJECTION
The word “oblique” means “slanting” There are three axes-vertical, horizontal and oblique. The oblique
axis, called receding axis is drawn either at 30o or 45
o. Thus an oblique drawing can be drawn directly
without resorting to projection techniques
30o 30
o
45o
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ORTHOGRAPHIC PROJECTION:
„Ortho‟ means „right-angle‟ and „Ortho-graphic‟ means „right-angled drawing.‟ When the
projections are perpendicular to the plane on which the projection is obtained, it is known as Orthographic
Projection.
Vertical Plane:
Extend the rays or projectors further to meet a Vertical (Transparent) Plane (V.P) located behind the object.
Join the points at which the projectors meet the plane, in correct sequence. The resulting view (Fv) is called
the Front View of the object which is shown in fig. (b)
Front view shown only two dimensions of the object i.e. Length (L) and Height (H). It does not show the
breadth (B). Thus one view or projection is insufficient for the complete description of the object.
Look at the object from the top. The projection of the top surface T is TH. TH is the Top View of the object.
Both T and TH are of exactly the same shape and size.
Thus TH gives the Length (L) and Breadth (B) of the block but not the Height (H).
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EXAMPLES OF ORTHOGRAPHIC PROJECTION
A cube of 1.5" rests on one of its square faces on horizontal plane with another square face being
parallel to the vertical plane. Draw its plan, front elevation and left-end view.
A cube of 1.0" sides rests on one of its square faces in horizontal plane with another square faces making
an angle of 30o with the vertical plane. Draw its plan, front elevation and left end view.
Dd
Cc
Bb
Dd
Aa
Cc
Bb
Aa
D A C B
d a c b a b d c
A B D C
45o 30
o
Aa Bb
Cc Dd
bc ad
AD BC
dc ab
AB
1.5"
DC
1.5"
1.5"
1.5"
0.5"
LEFT VIEW
FRONT VIEW
CUBE (TOP VIEW)
TOP VIEW
FRONT VIEW LEFT END VIEW
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An equilateral triangular prism of 1" sides and 3" height rests on one of its rectangular faces on horizontal plane with its axis inclined at 30o to vertical plane.
Draw its plan and front elevation
B C A
a b c
B
A
C
C A
B b
b
c
c a
a
Cc Aa
30o
Bb
FRONT VIEW
3"
½" ½"
½"
½"
3"
TOP VIEW
1"
6
A cube of 1" sides rests on one of its edges in horizontal plane with one square face making and angle
of 30o with it and another square face being parallel to vertical plane. Draw its plan, front elevation and
left end view.
30o
DACB
dacb
Bb
Aa
Dd
Cc C
D
B
A a
b
d
c
D A C B
d a c b
TOP VIEW
FRONT VIEW FRONT VIEW
45o
7
An equilateral triangular prism 1.5" sides and 2.5" height rests on one of its rectangular faces on horizontal plane with its axis perpendicular to vertical plane.
Draw its plan, front elevation and left end view.
45o 45
o
a c b
A C B BCA
bca
ACB
acb
ab AB
C c
Aa Bb ba BA
C Cc c
2.5"
60o
60o 60o
TOP VIEW
RIGHT VIEW LEFT VIEW FRONT VIEW
8
An equilateral triangular prism of 1.5" sides and 2.5" height rests on one of its edges in horizontal plane
with its axis perpendicular to vertical plane and one rectangular face making an angle of 30o with
horizontal plane. Draw its plan, front elevation, left end view.
A rectangular prism of 1.5" width, 2" length and 1.5" height rests on one of its edges in horizontal plane
with its axis perpendicular to vertical plane. Draw its plan, front elevation.
ABC
abc
AB C
c ab
Cc
B
C
A
c
b
a
30o
Bb
Aa
LEFT VIEW
1.5"
TOP VIEW
FRONT VIEW
45o
2.5"
1.5"
1.5"
2"
TOP VIEW
FRONT VIEW
9
A rectangular prism of 1.5" width and 2" length rests on one of its edges in horizontal plane with its axis
perpendicular to vertical plane and one length making an angle of 30o with V.P. Draw its plan, front
elevation.
A rectangular prism of 1.5" width and 2" length rests on one of its edges in horizontal plane with its axis
perpendicular to vertical plane and one rectangular face making an angle of 30o with H.P. Draw its plan,
front elevation.
30o
30o
1.5"
TOP VIEW
FRONT VIEW
1.5"
TOP VIEW
FRONT VIEW
1.5"
1.5"
10
A regular pentagonal prism of 1.5" sides and 2.5” heights rest on horizontal plane with its axis perpendicular of vertical plane. Draw its top view, front view and
right view.
Regular Pentagonal Prism
C′
B′ B
C
D D′
BB′ AA′
DD′
CC′ EE′
E′ A′ D′ B′ C′
E A D B C
45o
2.5"
1.5"
TOP VIEW
FRONT VIEW RIGHT VIEW
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A hexagonal prism of 1" sides and 2” heights rest on horizontal plane with its axis perpendicular of vertical plane. Draw its top view, front view and right view.
REGULAR HEXAGONAL PRISM
F′ A′E′ D′B′ C′
F AE DB C′
BB′ AA′
FF′ CC′
DD′ EE′
B
D
C C′
B′
D′
FRONT VIEW
2"
2"
1"
RIGHT VIEW
TOP VIEW
12
A hexagonal prism of 1" sides and 2" heights rests vertically on its base on horizontal plane and its one
edge of base is parallel to vertical plane. Draw top view and front view.
A hexagonal prism of 1" inch sides and 2" inch heights rests vertically on its base on horizontal plane
and its one edge of base makes an angle of 30o with vertical plane. Draw top view and front view.
F′F′
A′A′
B′B′
C′C′ E′E′
D′D′
F′ E′ B′C′ A′D′
AD BC FE
C′ B′D′ A′ C′
F′
BD AE C F
FRONT VIEW
2"
30o
TOP VIEW
1"
TOP VIEW
FRONT VIEW
13
A hexagonal prism of 1" sides and 2" heights rests vertically on its base on horizontal plane and its one edge of the base makes an angle of 75o with vertical
plane. Draw top view, front view and left view.
1"
Ff
Ee
Dd
Cc
Bb
Aa
Ee
Cc
Dd
Bb
Ff
a f b e c d
A F B E C D B C A D F E
b c a d f e
45o 75
o
2"
Aa
FRONT VIEW LEFT VIEW
TOP VIEW
14
A square pyramid of base 2" sides and vertical height 2" rests vertically on its base on horizontal plane and its one edge of axis/base is parallel to vertical plane.
Draw top view, front view and left view.
O
BC
AD
BC AD
O
C B
D A
CD BA
O
TOP VIEW
FRONT VIEW
SQUARE PYRAMID
2"
2"
LEFT VIEW
45o
15
A square pyramid of base 2" sides and vertical height 2" rests vertically on its base on horizontal plane with one edge of the base making an angle of 30o with
the vertical plane. Draw its top view, front view and left view.
C
D
O
B
A
C D B A
B
C
D
A
D C A B
O O
45o 30o
2"
SQUARE PYRAMID TOP VIEW
O
FRONT VIEW LEFT VIEW
16
A hexagonal pyramid of base 1" sides and vertical height 2" rests vertically on its base on H.P and its one edge of base is parallel to V.P. Draw top view or plan,
front elevation.
F
60o
E
C
D
A B
O
FRONT VIEW FRONT VIEW
TOP VIEW
2"
1"
HEXAGONAL PYRAMID
17
A cone of 1.5" base diameter and 2" vertical height rests on edge of its base on horizontal plane with the base making an angle of 60o with horizontal plane
and its axis parallel to vertical plane. Draw its plan, front elevation.
A
HE
DC
GF
F
C
E
A
H
B
G
D
H G
F E
A
C
D
B
60o
O
O
O
GF HE
DC B A
FRONT VIEW
2"
1.5"
TOP VIEW
18
A cylinder of 1.5" diameter and 3" length rests on edge of its end on H.P with the end making an angle of 30o with H.P and its axis parallel to V.P. Draw its
plan, front elevation.
G
FRONT VIEW
TOP VIEW
2"
1.5"
Hh Gg
Ff Ee
Aa
Cc
Dd
Bb
a he dc gf b
A HE DC GF B
e
c
f
b
g
d
h
a B
F
C
E
H
D
A
gf
dc
b
he
A
HE
DC
GF
a
B
30o
19
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