Lecture 1 Sunday, 09 September 2012 1 ENGINEERING GRAPHICS 1E9 Lecture 1: Introduction Lecturer: Dr. Bidisha Ghosh (email@example.com)
Course StructureGraphics• Hand Drawing (part 1) -Dr. B. Ghosh• Hand Drawing (part 2) -Dr. G. O’DonnellCAE• AutoCAD-Dr. S. Pavia
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
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 1Mon 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
Lecture 1 Sunday, 09 September 2012 5 Syllabus – Hand Drawing 1 • Basic Construction • Orthographic Projections • Isometric Projections • Auxiliary Views • Perspective
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
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
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
Lecture 1 Sunday, 09 September 2012 9 Technical drawing is the language of engineers and designers Waterfall M. C. Escher
Lecture 1 Sunday, 09 September 2012 10 Topics of Interest • Drawing Instruments • Lines • Dimensioning • Basic construction
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.
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
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.
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.
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.
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.
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