AutoCAD 2D-1

Module Objectives

Upon the completion of this module the student will be

able to:

1. Explain the difference between Isometric and

oblique drawing.

2. Correctly produce an isometric drawing for cubes,

circles, and cylinders.

3. Draw isometric drawings for a combination of

cubes, circles, and cylinders.

Module Contents

Topic Page no.

1 Introduction page 3

2 Types of Pictorial drawing page 3

3 Isometric drawing page 4

4 Activities page 8

Introduction

The pictorial drawing is a three dimensional drawing

that shows an object’s three principal planes, much as

they would be captured by a camera.

2. Types of Pictorial drawing:

There are three types of pictorial drawings:

A. Isometric

B. Oblique, and

C. Perspective.

In this module only Isometric and Oblique will be dealt with.

2.1 Isometric.

Isometric drawing represents an object in three dimensions.

It helps to visualize the features of an object on at

least three sides.

The three axes forms an angle of 120 degrees between one another. See Fig.3.1.

2.2 Oblique.

Oblique projection is a method of drawing objects in 3

dimensions.

It is quite a simple technique compared to isometric drawing.

In the Oblique drawing instead of the two 30 degrees guide lines, there are one horizontal line and one 45 degree guidelines.

There are two types of oblique drawing as

shown in Fig.3.2. (a) Cavalier. (b) Cabinet.

Fig.3.1: Isometric

drawing in full scale

Fig.3.2:Types of

Oblique drawing

3. Isometric drawing

3.1 Isometric drawing of a cube

1. Draw two basic 30 degree (to the horizontal line)

guidelines, one to the left and one to the right, plus a

vertical guideline in the centre of the drawing as

shown in Fig.3.3. This will guide the isometric drawing of

the cube. The required tools are shown in Fig.3.3a.

2. Draw guidelines to help start constructing the left and

right sides of the cube. Remember to use a 30 degree

set square for the 'angled' lines. Fig.3.4.

(a)

(b)

Fig.3.3: Isometric

drawing

Fig.3.4: Isometric drawing

of a cube

3. The top of the cube can be drawn quite easily by using the set square

to draw one edge of the top and then ‘flipping’ it over to draw the

other. See Fig.3.5.

Fig.3.5: Drawing the top

of the cube

4. The Final isometric drawing of the cube is shown in Fig. 3.6.

Fig.3.6: Final Isometric drawing

of the cube

3.2 Isometric drawing of circles and cylinders

1. Construct an isometric square 60 mm by 60mm

mm using 30, and 60 degree set square as

shown in Fig.3.7. The isometric square will be

used to draw the isometric circle.

2. Construct a perpendicular bisector from each

side of the isometric square, then draw two

perpendicular bisectors (center lines) from each

midpoint as shown on the Fig.3.9.

Fig.3.7: Isometric

Square

Fig.3.8: Constructing

bisectors

3. Locate the two centers. By campus,

draw the two arcs as shown on the

Fig.3.9.

4. Draw the arcs with these centers and

tangent to isometric square. The final

front side isometric circle (ellipse) is shown

on the Fig.3.10.

Fig.3.9: Locating the

centers and drawing the

arcs.

Fig.3.10: Completing

the ellipse

5. The isometric circle (Ellipse) in Front, Right and Top views is

shown in Fig.3.11.

6. Drawing an isometric cylinder will be simply by drawing two

isometric circles opposite to each other and then connecting

them together. i.e.: top and bottom or front and back …etc.

Fig.3.11: Different views of an

Isometric circle.

4.Activities

4.1.Class Work

a) Draw an isometric view of the component shown below to the given

dimensions on the same A3 sheet. All dimensions are in mm.

b) Draw an isometric view of the component shown below to

the given dimensions on A3 sheet. All dimensions are in mm