This document contains information about the course 20ME272 Computer Aided Engineering Graphics taught at Sri Ramakrishna Engineering College. It includes the course objectives, list of experiments, and information about various drafting and dimensioning techniques. It also provides details about different drawing tools, standards, and concepts such as projection of points and lines. The document uses diagrams and images to explain key drafting concepts and principles in engineering graphics.

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20ME272
COMPUTER AIDED ENGINEERING GRAPHICS
Semester - II
B.Tech. Information Technology
Academic Year : 2020-21
REGULATIONS 2020
Sri Ramakrishna Engineering College
Vattamalaipalayam, Coimbatore – 22
Department of Mechanical Engineering

2. 20ME272
COMPUTER AIDED ENGINEERING GRAPHICS
2
P.Saravanakumar
Assistant Professor(OG)
Department of Mechanical Engineering
Sri Ramakrishna Engineering College
Coimbatore-641022

3. 3
20ME272 COMPUTER AIDED
ENGINEERING GRAPHICS
On successful completion of the course, the student will be able to
Course Objectives
CO1
Create geometric models using the basic commands and features
of the drafting software.
CO2
Construct simple geometric entities and their projections as per
the BIS conventions.
CO3
Convert the pictorial projections of geometric entities into
orthographic projections.
CO4 Draw the isometric view of simple geometric models.
CO5 Manipulate the geometric entities created using drafting software

4. SYLLABUS
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5. LIST OF EXPERIMENTS
1. Creation of drawing sheet layouts and title block.
2. Model simple two-dimensional graphical entities
using absolute and relative co-ordinate methods.
3. Projection of points.
4. Projection of straight lines.
5. Projection of simple solids.
6. Construction of orthographic views of simple
solids.
7. Modeling of isometric view of simple solids.
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6. Effectiveness of Graphics Language
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7. Effectiveness of Graphics Language
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8. Effectiveness of Graphics Language
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9. Effectiveness of Graphics Language
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10. Freehand drawing
• The lines are sketched without using
instruments other than pencils and erasers.
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11. Freehand drawing
• The lines are sketched without using
instruments other than pencils and erasers.
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12. Drawing by use of Instruments
• Instruments are used to draw straight lines,
circles, and curves concisely and accurately.
Thus, the drawings are usually made to scale.
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13. Drawing by use of Instruments
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14. Drawing by use of Computer
The drawing are usually made by commercial
software as AutoCAD, Solid works etc.
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15. Drawing by use of Computer
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16. Engineering Drawing
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17. Elements of Engineering Drawing
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18. Basic Knowledge for Drafting
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19. DEFINITION
Standards are set of rules that govern how
Technical drawings are represented.
Drawing standards are used so that
drawings convey the same meaning to everyone
who reads them.
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20. Standard Code
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21. Drawing Sheet
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22. Drawing Scales
Definition:
Scale is define as ratio of linear dimensions of an
element of an object represented in the original
drawing to the linear dimension of the same element of
the object by itself
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23. Basic Line Types
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24. Meaning of Lines
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25. 1/3/2023 25

26. DRAWING INSTRUMENTS USED IN
ENGINEERING GRAPHICS
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27. DRAWING INSTRUMENTS
1.Drawing Board
2.Drawing Sheets
3.Standard Set-scales
4.Mini-Drafter
5.Instrument Box
6.Set-Squares (45,30 & 60 deg)
7.Protractor-cum-Procircle
8.Drawing Pencils (HB,H and 2H )
9.Sharpener and Emery Paper
10.Adhesive Tape (Cello-Tape )/ Clips
11.Pencil Eraser
12.French Curves
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28. DRAWING BOARD
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29. DRAWING BOARD TYPES
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30. DRAWING SHEETS
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31. Drawing sheet sizes
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32. DRAFTER
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33. DRAFTER
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34. Drawing Instruments
Typical Drawing Equipment
Objectives in
Drawing
1. Accuracy
2. Speed
3. Legibility
4. Neatness
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35. Drawing Instrument
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36. Compasses
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37. Compasses
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38. Compasses
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39. DRAWING INSTRUMENTS
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40. PENCILS
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41. Drawing Pencils
Wooden pencils – are graded and designated by numbers and letters
Mechanical clutch pencils – Not allowed
• 7B, 6B, 5B, 4B, 3B, 2B, B - in decreasing order of softness and blackness
• HB to F – Medium grade
• H, 2H, 3H, 4H, 5H, 6H, 7H, 8H, 9H – increasing order of
hardness.
Drawings are done using 2H pencils and finished with H
and HB pencils – to be practiced in this course.
41

42. Grades and designation
of wooden pencils
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43. Line types
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44. Line types….CONTD
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45. DRAWING TOOLS
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46. DRAWING TOOLS
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47. DRAWING TOOLS
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48. DRAWING TOOLS
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49. DRAWING TOOLS
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50. DRAWING TOOLS
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51. French curve
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52. BIS conventions and specifications
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53. Experiment :01
Creation of drawing sheet layouts
and
title block
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54. Layout of A2 size Drawing Sheet
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55. Title Block
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56. Lettering Technique
Lettering Techniques
Most engineering lettering is single-stroke
Gothic font. Lettering is drawn freehand and
are drawn within light horizontal guidelines.
Typically lettering is 1/8” high.
All lettering uses upper case letters. Lower
case letters are rarely used in technical
drawings.
There are three aspects of good lettering:
proportions and forms of the letters,
composition and spacing, and practice.
There are six fundamental drawing strokes and
their directions in basic lettering. Horizontal
strokes are drawn from left to right, vertical
strokes are drawn from top to bottom, and
curved strokes are drawn downward.
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57. Lettering Technique
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58. Lettering
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59. Lettering
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61. Dimensioning
Elements of Dimensioning
1. Dimension line: Thin continuous line used to indicate the measurement.
2. Extension line: Thin continuous line extending beyond the outline of the
object.
3. Arrow-head: Used to terminate the dimension line. Length : width ratio is
3:1. Space filled up.
4. Note: Gives information regarding specific operation relating to a feature.
5. Leader: Thin continuous line connecting a note or a dimension figure with
the feature to which it is applied. Terminated by arrow-head or dot.
6. Symbol: The representation of any object by some mark on the drawing. It
saves time and labour.
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62. Dimensioning
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63. Methods of Dimensioning
Aligned Method
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64. Methods of Dimensioning
Aligned Method-Angular dimensions
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65. Arrangement of Dimensions
Chain Dimensioning:
Dimensions are arranged in a straight line.
Parallel Dimensioning:
All the dimensions are shown from a common base
line. The smaller dimension is placed nearer the
view.
Combined Dimensioning:
Chain and parallel dimensioning used simultaneously
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66. Arrangement of Dimensions
Chain Dimensioning
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67. Arrangement of Dimensions
• Parallel Dimensioning
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68. Arrangement of Dimensions
• Combined Dimensioning
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69. Symbols for Shape Indication
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70. Symbols for Shape Indication
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71. Rules for Dimensioning
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72. Rules for Dimensioning
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73. Rules for Dimensioning
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74. Rules for Dimensioning
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75. Rules for Dimensioning
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76. AUTOCAD
Example for computer aided drawing is
AutoCAD
• 2D and 3D computer aided drafting software
application
• Used for making blueprint
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77. AutoCAD Drawing
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78. AutoCAD Drawing
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In free hand or hand – held drawing error may
occured
• Dimensions are not in accurate points
• In computer aided drafting (AutoCAD) there
wont be any mistakes
• Time taken is less

79. APPLICATIONS
Civil Engineering
• For construction of bridges, buildings and for
making maps
Mechanical Engineering
• For designing machines, bike parts, car parts,
etc,...
Electronics and Communication Engineering
• For understanding circuit connections and
component diagrams
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80. Drawing sheet sizes
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81. Layout of A2 size Drawing Sheet
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82. Title Block
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83. Experiment:02
Model simple two-dimensional
graphical entities using
absolute co-ordinate methods
and
relative co-ordinate methods.
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84. Example
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85. Absolute Coordinate System
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86. Relative Coordinate System
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87. Exercise
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Draw following figures using line commands

88. Exercise
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89. Coordinate System
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Absolute Coordinate System Relative Coordinate System

90. Experiment:03
Projection of points
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91. Projection of Point
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92. Projection of Point in
different quadrants
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93. 1/3/2023 93

94. First angle vs Third angle
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95. ORTHOGRAPHIC PROJECTIONS OF
POINTS
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96. NOTATIONS
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98. 1/3/2023 98

99. PROJECTIONS OF A POINT
IN FIRST QUADRANT.
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104. Practice
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105. solution
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106. Experiment:04
Projection of straight lines
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107. Projection of straight lines
Straight Lines
A straight line is the shortest distance
between two given points.
Thus, the two ends of a straight line are
points.
Projection of a Straight line can therefore
be drawn by joining the respective projection of
its end points.
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108. Positions of a line
with Respect to HP and VP
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109. 1.Parallel to Both the Planes
HP and VP
A line CD 30 mm long is parallel to both the planes. The line is 40
mm above HP and 25 mm in front of VP. Draw its projections.
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110. Parallel to Both HP and VP
A line CD 30 mm long is parallel to both the planes. The line is 40
mm above HP and 25 mm in front of VP. Draw its projections.
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111. Line contained in one plane and
Parallel to the other
A line RS 60 mm long lies in HP and 45 mm in
front of VP. Draw its projections.
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112. Line contained in one plane and
Parallel to the other
A line RS 60 mm long lies in HP and 45 mm in
front of VP. Draw its projections.
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113. Line contained in one plane and
Parallel to the other
A line PQ 55 mm long is lying in VP and 45 mm
above HP. Draw its projections.
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114. Line contained in one plane and
Parallel to the other
A line PQ 55 mm long is lying in VP and 45 mm
above HP. Draw its projections.
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115. Line contained in Both HP and VP
A line AB 55 mm long is lying on both HP and VP.
Draw its projections.
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116. Line Perpendicular to one plane and
Parallel to the other
Line perpendicular to HP & parallel to VP
A line AB 25 mm long is parallel to VP and perpendicular to HP.
Point A is 35 mm above HP and 20 mm in front of VP. Point B is
10 mm above HP. Draw the projections of the line AB.
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117. Line Perpendicular to one plane and
Parallel to the other
Line perpendicular to HP & parallel to VP
A line AB 25 mm long is parallel to VP and perpendicular to HP.
Point A is 35 mm above HP and 20 mm in front of VP. Point B is
10 mm above HP. Draw the projections of the line AB.
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118. Line perpendicular to VP and
Parallel to HP
A line AB 25 mm long is perpendicular to VP and
parallel to HP. Its end A is 10 mm in front of VP and the
line is 20 mm above HP. Draw the projections of the
line.
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119. Line perpendicular to VP and
Parallel to HP
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120. Line Parallel to one plane &
Inclined to other
Line Parallel to VP & Inclined to HP
A line PQ 40 mm long is parallel to VP and inclined at an angle of
30 to HP. The lower end P is 15 mm above HP and 20 mm in
front of VP. Draw the projections of the line.
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121. Line Parallel to one plane &
Inclined to other
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122. Line Parallel to HP &
Inclined to VP
Draw the projections of a line EF 40 mm long parallel to
HP and inclined at 35 to VP. E is 20 mm above HP and
15 mm in front of VP.
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123. Line Parallel to HP &
Inclined to VP
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124. Line contained by one plane and
inclined to the other
Line contained in VP & Inclined to HP
A line AB 50 mm long is in VP and inclined at 35*
to HP. End A is 10 mm above HP. Draw the
projections.
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125. Line contained by one plane and
inclined to the other
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126. Line contained by one plane and
inclined to the other
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Line contained in HP & Inclined to VP
A line RS measuring 52 mm is in HP and inclined at an
angle of 45* to VP. The end R is 10 mm in front of VP.
Draw the projections.

127. Line contained by one plane and
inclined to the other
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128. Projections of Solids
• Any machine part or element or component is
formed of a single solid or combination of solids
of different shapes, known as Prisms, cylinders,
Pyramids, Cones and Spheres.
• Solid: A Solid is defined as an object having three
dimensions, viz., length, breadth and height or
thickness, measured along the three mutually
perpendicular axes.
• It is bounded by plane faces or curved surfaces or
combination of both.
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129. Projections of Solids
Classification of Solids:
1.Polyhedra
1.1 Regular Polyhedra
i.Cube
ii.Tetrahedron
iii.Octahedron
iv.Dodecahedron
v.Icosahedron
1.2.Prisms
1.3.Pyramids
2.Solids of Revolution
2.1.Right Circular cylinder
2.2. Right Circular Cone
2.3.Sphere
3. Frustums & Truncated Solids
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130. Projections of Solids
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131. Projections of Solids
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132. Projections of Solids
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133. Projections of Solids
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134. Projections of Solids
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135. Projections of Solids
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136. Projections of Solids.
Projections of Solids.
Prism, Pyramid, Cylinder & Cone
Perpendicular to HP
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137. Projections of
Prism, Pyramid,Cylinder & Cone
Axis Perpendicular to HP
Problem:01
Draw the top and front views of a cube of 40 mm side resting
with one of its square faces on HP such that one of its vertical
faces is parallel to and 20 mm in front of VP.
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140. Problem:02
Draw the projection of a square prism of side of
base 30 mm and height 50 mm resting with its
base on HP such that one of its rectangular faces
is perpendicular to VP. The nearest edge parallel
to VP is 5 mm in front of it.
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143. Problem:03
A triangular prism side of base 35 mm and
height 50 mm rests with its base on HP such that
one of its rectangular faces is perpendicular to
VP. Draw its projections. The nearest edge
parallel to VP is 10 mm in front of it.
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146. Problem:04
A triangular prism side of base 35 mm and axis
50 mm long rests with its base on HP such that
one of its rectangular faces nearer to VP is
parallel to and 8mm in front of it. Draw its
projections.
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147. 1/3/2023 147

148. Problem:05
Draw the projections of a regular pentagonal
prism side of base 30 mm and axis 55 mm
resting with its base on HP such that one of its
rectangular faces is perpendicular to VP
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150. Problem:06
Draw the projections of a hexagonal prism of
side of base 25 mm and height 50 mm resting
with its base on HP such that one of its
rectangular faces is perpendicular to VP
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152. Problem:07
A triangular prism of side of base 30 mm and
height 45 mm rests with its base on HP such that
one of its rectangular faces is parallel to and 40
mm farther away from VP. Draw its projections.
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154. Problem:08
Draw the projections of a pentagonal prism side
of base 30 mm and axis 60 mm long resting with
its base on HP such that one of its rectangular
faces is parallel to and 10 mm in front of VP
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156. Axis Perpendicular to VP
A hexagonal prism, side of base 25 mm and axis
60 mm long, lies with one of its rectangular
faces on the HP such that the axis is
perpendicular to the VP. Draw its projections.
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158. Axis Perpendicular to VP
A hexagonal pyramid of base side 25 mm and
height 65 mm is kept such that the base is
parallel to and 15 mm in front of VP with the
edge perpendicular to HP. Draw the projections.
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160. Inclined to HP and Parallel to VP
• A pentagonal prism side of base 25 mm and
axis 50 mm long rests with one of its edges on
HP such that the base containing that edge
makes on angle 30* to HP and its axis is
parallel to VP. Draw its Projections.
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162. Sample Diagram
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163. Practice
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165. Practice
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167. Practice
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169. Practice
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170. 1/3/2023 170

171. Isometric Projection
• Isometric projection is a method for visually
representing three-dimensional objects in two
dimensions in technical and engineering
drawings. It is an axonometric projection in
which the three coordinate axes appear
equally foreshortened and the angles
between any two of them are 120 degrees.
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172. Isometric Terminology
• The three coordinate axes are called isometric
axes
• Any line parallel to isometric axes is called
isometric line
• A non-isometric line is a line not
parallel to any one of the three isometric axis
• In isometric projection of cube, the faces of the
cube and any plane parallel to them is called
isometric planes
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173. Isometric Scale
• True lengths of the edges of the object are equally
foreshortened
• Correct isometric projection can be drawn using an
isometric scale (always smaller than ordinary scale)
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174. Isometric Drawing
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175. Steps for construction of Isometric
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176. Steps for construction of Isometric
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177. Steps for construction of Isometric
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178. Steps for construction of Isometric
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179. Steps for construction of Isometric
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180. Objects with Circular Geometry
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182. Cylinder
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196. Thank you
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