1. Lecture 1 Sunday, 09 September 2012 1
ENGINEERING GRAPHICS
1E9
Lecture 1: Introduction
Lecturer: Dr. Bidisha Ghosh (bghosh@tcd.ie)
2. Course Structure
Graphics
• Hand Drawing (part 1) -Dr. B. Ghosh
• Hand Drawing (part 2) -Dr. G. O’Donnell
CAE
• AutoCAD-Dr. S. Pavia
3. Assessment
• Examination: 75% of the overall mark
– 3 sections (A, B and C)
– 2 questions per section
– 3 questions to be answered, one from each
section
• Dr B. Ghosh : Sections A and B
• Dr G. O’Donnell : Section C
• Labs 25% - assessed by coursework
– 10 % AutoCAD
– 10% D.O. Tutorials Dr B. Gosh
– 5 % D.O. Assignment Dr G. O’Donnell
4. Time Table
Lecture Drawing Office practicals
(AutoCAD laboratories for wks 11-12)
Mon
10-11 a.m. Mon 2-5 p.m. (group C)
Tues 2-5 p.m. (group D)
Wedn 2-5 p.m.( group A)
Fri 9 a.m.-12 noon (group B)
Semester 1
Wk 1
Mon 28th Sept BG -
Wk 2 BG BG
Wk 3 BG BG
Wk 4 BG BG
Wk 5 Holiday -
Wk 6 GO’D GO’D
Wk 7 Reading wk Reading wk
Wk 8 GO’D GO’D
Wk 9 BG BG
Wk 10 SP -
Wk 11 SP SP
Wk 12 SP SP
BG - Hand drawing I- Dr Bidisha Gosh
GO’D - Hand drawing II- Dr Garret O’Donnell
SP - Autocad – Dr Sara Pavía
See JF timetable for venues
5. Lecture 1 Sunday, 09 September 2012 5
Syllabus – Hand Drawing 1
• Basic Construction
• Orthographic Projections
• Isometric Projections
• Auxiliary Views
• Perspective
6. Lecture 1 Sunday, 09 September 2012 6
Evaluation
• Examination (Sections A & B)
(2/3 of the total examination marks)
• Continuous Assessment
(10% of the total course marks)
– four drawing office tutorials
7. Lecture 1 Sunday, 09 September 2012 7
Aim of the Course
• Knowledge of engineering drawing
instruments
• Understanding and interpretation of
technical drawings
• Ability to develop projections of a 3D
object
8. Lecture 1 Sunday, 09 September 2012 8
Reference Books
• Technical Draughtsmanship
By Eanna O’Broin
• Engineering Drawing with Worked
Examples
By M.A. Parker & F. Pickup
• Technical Drawing
By F. E. Giesecke, A. Mitchell,
H. C. Spencer, I. L. Hill, J. T. Dygdon,
J. E. Novak
9. Lecture 1 Sunday, 09 September 2012 9
Technical
drawing is the
language of
engineers and
designers
Waterfall
M. C. Escher
10. Lecture 1 Sunday, 09 September 2012 10
Topics of Interest
• Drawing Instruments
• Lines
• Dimensioning
• Basic construction
26. Lecture 1 Sunday, 09 September 2012 26
DRAWING LINES
Bisection of A Line A B
1. Place your compass point on A and stretch the compass
MORE THAN half way to point B.
2. With this length, swing a large arc that will go BOTH
above and below segment AB.
3. Without changing the span on the compass, place the
compass point on B and swing the arc again. The new arc
should intersect the previous one above and below the
segment AB.
4. With your scale/ruler, connect the two points of
intersection with a straight line.
5. This new straight line bisects segment AB. Label the point
where the new line and AB cross as C.
6. Segment AB has now been bisected and AC = CB.
27. Lecture 1 Sunday, 09 September 2012 27
DRAWING LINES
Divide A Line into Multiple Sections
1. From one end of the given line AB (say, A) draw a line AC at
a convenient angle
2. Using a scale/ruler divide the BC into the required number of
parts making them of any suitable length.
3. Join the last point on line AC (say, C) to B
4. Draw construction lines through the other points on the line
AB which are parallel to CB
28. Lecture 1 Sunday, 09 September 2012 28
DRAWING LINES
Bisection of An Angle
1. Place the point of the compass on the vertex of angle BAC
(point A).
2. Stretch the compass to any length so long as it stays ON
the angle.
3. Swing an arc with the pencil that crosses both sides of
angle ABC. This will create two intersection points (E and
F) with the sides of the angle.
4. Place the compass point on E, stretch your compass to a
sufficient length and draw another arc inside the angle -
you do not need to cross the sides of the angle.
5. Without changing the width of the compass, place the
point of the compass on F and make a similar arc. These
two small arcs in the interior of the angle should be
crossing each other.
6. Connect the point of intersection of the two small arcs to
the vertex A of the angle with a straight line.
29. Lecture 1 Sunday, 09 September 2012 29
DRAWING LINES
Find the Centre of an Arc
1. Select three points A, B and C on the arc and join AB and BC
2. Bisect AB and BC.
3. Fine the intersection point of the bisecting lines/bisectors.
That is the centre of the arc.
30. Lecture 1 Sunday, 09 September 2012 30
DRAWING LINES
Inscribe a Circle in a Triangle
1. Bisect angle ABC and angle BAC.
2. Fine the intersection point of the bisecting lines/bisectors.
That is the centre of the circle.
3. The radius of the circle is the length of a perpendicular line
on any of the sides of the triangle drawn from the centre of
the circle.
31. Lecture 1 Sunday, 09 September 2012 31
DRAWING LINES
Circumscribe a Circle on a Triangle
1. Bisect sides AC and BC.
2. Fine the intersection point
of the bisecting
lines/bisectors. That is the
centre of the circle.
3. The radius of the circle is
the length of a line joining
any one of the vertices of
the triangle to the centre
of the circle.
32. Lecture 1 Sunday, 09 September 2012 32
Notes for Tutorials
• The tutorials start next Monday in drawing office in
museum building
• Each tutorial is worth 2.5%
• Bring your own drawing instruments
• Drawing sheets will be provided
Students will not be allowed in the tutorial without
instruments
