ISOMETRIC DRAWING

An Isometric Drawing is a three dimensional drawing with width, height and depth measurement

Front view Side view

Top view

height

depthwidth

Isometric projection is a pictorial method of drawing.

The receding lines are drawn at 30º and the others

are vertical.

All lines are drawn their true length.

As with all drawings, it is better to complete the

drawing in construction lines first, check that

everything is correct and then line in the outlines.

Normal isometric axes

Reversed isometric axes

Horizontal isometric axes

ISOMETRIC LINE

NON ISOMETRIC LINE

OBLIQUE SURFACE

Viewing direction A

A

Viewing direction B

B

Viewing direction C

C

C

Viewing direction D

D

D

Box Method

The Methods of Constructing a Isometric Drawing on normal axis

Three views of an object are shown. Draw in full size an isometric view of the object. The grid size is 10 mm x 10 mm.

EXAMPLE HOW TO CONSTRUCT A ISOMETRIC DRAWING ON NORMAL AXIS

back

Box method

Frame Method

FRAME METHODFRAME METHOD

Constructing of isometric drawing using frame method

STEP 1

Draw the quadrilateral ABCD from the top view

BA

D C

26

53

53

37

20

30

STEP 2

Draw the base of the pyramid on the isometric quadrilateral ABCD

C

D

A

B

STEP 3

Draw the height of the pyramid through the point M using the Height h

C

A

D B

h

M

STEP 4

Draw and darken the pyramid’s sides

frame method

Four Centre Method for constructing a isometric circle

Draw an isometric circle given diameter D

D

CONSTRUCTION OF ISOMETRIC CIRCLE USING FOUR-CENTRE METHOD

CONSTRUCTION OF ISOMETRIC CIRCLE USING FOUR-CENTRE METHOD

Step 1

Draw an isometric quadrilateral ABCD using side D.

D

D

B

C

A

Step 2

Draw the perpendicular lines on the bisector lines of isometric quadrilateral ABCD.

D

B

C

A

Step 3

Centred at A and C, construct an arc with radius R

D

B

C

A

R

R

Step 4

Centre at the intersection of the perpendicular lines, construct an arc with radius k

D

B

C

A k

k

EXERCISE 1 – Draw a Side View as per blue circle.

EXERCISE 2 – Draw a Top View as per red circle.

d

a

b

c

e

R

Draw an isometric curve with radius R based the given viewing direction.

CONSTRUCTING CURVES IN ISOMETRIC PLANE USING CORDINATE METHOD

CONSTRUCTING CURVES IN ISOMETRIC PLANE USING CORDINATE METHOD

CONSTRUCTING CURVES IN ISOMETRIC PLANE USING COORDINATE METHOD

d

a

b

c

e

R

STEP 1

Mark the coordinate points on the curve with respect to the vertical and horizontal planes.

w

x

y

z

d

a

b

c

e

R

e c

d

STEP 2

Draw an isometric box based on the given size. Mark e, c and d.

w

xy

z

d

a

b

c

e

R

Move the coordinates on the isometric plane. Plot the points on the curve using a flexible curve.

STEP 3

w

x

y

z w

xy

z

d

a

b

c

e

R

STEP 4

Darken the object lines.

w

xy

z

Exercise

Constructs an isometric drawing. Grid size is 10 mm x 10 mm.

Answer