This document discusses orthographic projection, which is a method of representing three-dimensional objects in two dimensions using multiple views. It notes that at least two views are needed to describe even simple objects, and three views are generally used arranged in a specific format. The document also discusses different conventions for arranging the views between countries and defines first and third angle projections. It provides guidance on indicating hidden lines, using sectional views, and maintaining neat drawings with proper proportions.

1. Name : Vaghani Milan
: Shubham Patel
En.No :140420129027
:140420129026
Branch:textiles technology

2.  Orthographic Projection is a method of
representing a three dimensional object on paper
using several two dimensional views.
 It is the international language of Engineers and
Designers

3.  We look directly at the different faces of the object
(90˚ to the face) and draw the lines that we see.

4.  One view is never enough to describe an object.
 We need at least two views to accurately describe
even the most simple of objects.
 Generally we se three views and arrange them as
shown in the movie
 You can use as many views as the object
requires.

6.  Yes. However America and Australia arrange the
views differently.
 This arrangement of views is called third angle
projection.

8.  Each method has its own symbol and they are as
follows
 First angle projection
 Third angle projection

9.  The recommended proportions for the symbol are
as follows

10.  The name first angle is derived from the objects
position in the first quadrant of the planes of
reference.
 The name third angle is derived from the objects
position in the third quadrant of the planes of
reference.

12.  Sometimes features of an object are hidden (for
example they are at the back of the object)
 To show these features we add dashed lines in
their place.
 If a dashed line meets a thick line leave a gap as
shown.

14.  If there is too much hidden detail and the drawing
becomes confusing use a sectional view.
 Draw the Hatching lines at 45˚ as shown
 Always place the section line (the dashed line that
ends in arrows) exactly were you are cutting the
object.

16.  Make sure you keep your drawing neat.
 Recommended proportions are shown below.
 Keep construction lines light and finished lines
heavy