Textbook of Engineering Drawing, Second Edition

5.6 Textbook of Enginnering Drawing------------------

BIS Specification (SP46 : 2003)

BIS has recommended the use of First angle projection in line with the specifications of ISO
adapted by all countries in the world.

VIEWING

,st ANGLE

b

t

VIEWING

<¢::J

e

(a) (b)

Fig. 5.6 Principles of orthographic projection.

Designation and Relative Position of Views

An object in space may be imagined as surrounded by six mutually perpendicular planes. So, it is
possible to obtain six different views by viewing the object along the six directions, normal to the six
planes. Fig.5.6 shows an object with the six possible directions to obtain the six different views
which are designated as follows.

1. View in the direction a = front view


2. View in the direction b = top view


3. View in the direction c = left side view

4. View in the direction d = right side view

5. View in the direction e = bottom view

6. View in the direction f= rear view

The relative position of the views in First angle projection are shown in Fig.5.7.

Note: A study of the Figure 5.7 reveals that in both the methods of projection, the views are

identical in shape and size but their location with respect to the front view only is different.

5.5 Projecton of Points

A solid consists of a' number .... " planes, a plane consists of a number of lines and a line in turn

consists of number of points:-'From this, it is obvious that a solid may be generated by a pl~