6. chapter 5 (isometric view)
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CE 100: CIVIL ENGINEERING DRAWING
Shaika Sharkia Lecturer, Department of Civil Engineering
University of Asia Pacific (UAP), Dhaka
ISOMETRIC PROJECTION
CHAPTER – 5
“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.
ISOMETRIC PROJECTION
REGULAR HEXAGON
R
30o 45o
120o
120o
120o
B
D
C
H
E
F
G
A
1
1
1
2
30o 30o
Isometric Axes: AD, AE & AB
Isometric Lines: EH, BF etc.
Non-isometric Lines: DB
Isometric Planes: ADHE & 1 (in Fig. 1)
Non-isometric Planes: Plane 2 (in Fig. 2)
Fig. 1
Fig. 2
ISOMETRIC SCALE
Isometric Length = 0.81 × Actual Length
D
90o
B
C
0
1
2
3
3
2
1
0
45o 30o
A
AC
AB
2
1 = cos 45o =
AD
AB
2
3 = cos 30o =
= AC
AB
AD
AB
2
1
2
3
AC
AB×
AB
AD =
2
1×
3
2
AC
AD =
3
2 = 0.81
AD = 0.81 × AC
Draw the isometric projection of a rectangular prism of base 50 mm × 10 mm
and height 75 mm, when it rests with its base on H.P and one its of
rectangular faces is parallel to V.P
75 mm
DA CB
da cb
FRONT VIEW
50 mm
Aa Bb
Cc Dd
40 mm
TOP VIEW
3
2 1
1
2
3
Y
Z
R
X
45o 30o
a
b
c
d
A
B
C
D
30o 30o 30o 30o
Difference between Isometric Projection & Isometric View
Isometric View Isometric Projection
Drawn to actual scale Drawn to isometric scale
When lines are drawn parallel to
isometric axes, the true lengths
are laid off.
When lines are drawn parallel to isometric
axes, the lengths are foreshortened to 0.81
time the actual lengths.
ORTHOGRAPHIC
PROJECTION
ISOMETRIC
PROJECTION ISOMETRIC
VIEW
B
D
C
H
E
F
G
A
B
D
C
H
E
F
G
A
B
E F
A
Front View
D A
H E
Left View
B C
F G
Right View
D C
A B
Top View
C
H G
D
Back View
B
D
C
H
E
F
G
A
B
E F
A
Right View
D A
H E
Front View
B C
F G
Back View
D
C
A
B
Top View
C
H G
D
Left View
TO PREPARE ISOMETRIC VIEW
Box Method
Co-ordinate or Offset Method
Offset Method
Four-centre method
BOX METHOD
The isometric projection of solids like cube, square and
rectangular prisms are drawn directly when their edges
are parallel to the three isometric axes. The isometric
projection of all other types of prisms and cylinders are
drawn by enclosing them in a rectangular box. This
method is called Box method.
CO-ORDINATE METHOD OR OFFSET METHOD
The isometric projections of pyramids and cones are
generally drawn by Co-ordinate or Offset method
EXAMPLES OF BOX
METHOD
E
D
C
A′
E′
D′
C′
B′
A
B
30o 30o
B
C
D
E
A
1.5"
ISOMETRIC VIEW OF A REGULAR PENTAGONAL PRISM (Resting on one of its faces on H.P)
2.5"
F′
A′
E′
D′
C′ B′
E F
D
C A
B 30o 30o
ISOMETRIC VIEW OF A REGULAR HEXAGONAL PRISM (Resting on one of its faces on V.P)
D
B
C
D E
A
1.0"
3"
EXAMPLES OF FOUR-CENTRE
METHOD
C
R D
S
P A
B
Q
O1
O2
30o 30o
ISOMETRIC VIEW OF A CYLINDER (Lying on H.P)
1"
C
R
D
S
P
A B
Q
30o 30o
ISOMETRIC VIEW OF A CYLINDER (Lying on V.P)
1"
O1 O2
EXAMPLES OF CO-ORDINATE
OR OFFSET METHOD
The isometric view of a hexagonal pyramid of side of base 30 mm and
height 75 mm, when it is resting on H.P such that an edge of the base is
parallel to V.P
A
B
Q
C
R D
E
F
S
P
O
O1
A
B
C
D
E
F
O
O1
30 mm
y
F C
S E D R
P A B Q
OO1
F AE BD C
O
75 mm
Draw the isometric projection of a cone of base 40 mm diameter and
height 58 mm when it rest with its base on H.P
O
A BD
C
x
x
40 mm OO1
O
A B
C D
Q
R
S
P
O1
O
O1
A B
C D
Q
R
S
P
58 mm
DRAW FRONT, LEFT, RIGHT
& TOP VIEW FROM A
ISOMETRIC VIEW
30o 30o
6"
10"
10"
6"
6"
1′ – 6"
Landing
3′
Riser
Tread
1′ – 6"
1
10"
10"
1′ – 6"
TOP VIEW
FRONT VIEW 10"
10"
1′ - 6"
LEFT VIEW
3 ′
6 "
6"
6"
3 ′
6 "
6"
6"
½"
½"
½"
3"
1¼"
2¾"
2¼"
2
TOP VIEW
½"
2½"
FRONT VIEW LEFT VIEW
3"
½" 1¼"
½"
2¾"
3
1"
3½"
5½"
2¾"
3 ¾"
FRONT VIEW
5½"
3½"
11/8"
2¾"
LEFT VIEW
15/8"
3¾"
TOP VIEW
½"
½"
½"
½"
2.5"
1"
1"
1"
½"
½"
½"
4
½" ½" 1"
1"
1"
1"
TOP VIEW
½"
½"
½"
½"
½"
1.5" ½" ½"
FRONT VIEW
½"
½" 1"
½"
LEFT VIEW
1" 1" 1"
½"
½" 1"
½"
1" 1" 1"
RIGHT VIEW
5 1"
1"
½"
½"
1"
1"
1"
FRONT VIEW
½"
½"
½"
½"
1" 1"
TOP VIEW
1"
1"
1" 1"
LEFT VIEW
½"
½"
½"
½"
1" 1"
RIGHT VIEW
½"
½"
½"
½"
1" 1"
1"
1"
1"
1"
½"
½"
½"
1"
1"
½"
½"
1"
6
1 1 1
½
½
½
FRONT VIEW
1 1
½
½
½
LEFT VIEW
½
½
½
1 1
RIGHT VIEW
1
1
1 1 1
TOP VIEW
1 -6
10 -0
3 -0
3 -0
15 -0 2 -6
4 -8
5 -0
5 -0
2 -6
12 -6
16 -8
14 -6
7 -0
7
7 -0
2 -0
1 -0
3 -6
3@6 =1 -6
1 -0 5 -0 5 -0 5 -0 1 -0 1 -1 1 -1
FRONT VIEW
1 -0 3@10 =2 -6 3 -0 4 -9 4 -9
4 -0
3 -0
4 -6
3 -0
3@6 =1 -6
LEFT VIEW
Draw isometric view from the given orthographic projections.
Draw isometric view from the given orthographic projections.
Draw isometric view from the given orthographic projections.
Thank You
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