TA 101: Technical Arts 2015-16 II Dr. Prishati Raychowdhury Department of Civil Engineering IIT Kanpur Office: FB 336; Phone: 6692 E-mail: prishati@iitk.ac.in

Engineering Drawing Basics Lecture 2 Engineering Drawing Basics

Section-wise Lab Schedule Day Sections Monday B4, B5, B6 Tuesday B1, B2, B3 Wednesday B7, B8, B9 Thursday B10, B11, B12

Section-wise Tutor Details SL. No. Section Day Tutor Dept Email Tel. Office Location 1 B1 Tue Ms. Nidhi Sharma AE snidhi@iitk.ac.in 2 B2 Dr. Ashish Dutta ME adutta@iitk.ac.in 7562 FB 338 3 B3 Dr. Ishan Sharma ishans@iitk.ac.in 6152 NL 102 4 B4 Mon Mr. Yasar Arafath yasaru@iitk.ac.in 5 B5 Mr. Rahul Oarath rahulo@iitk.ac.in 6 B6 Dr. Amritanshu Sriwastava CE amritan@iitk.ac.in 7 B7 Wed Dr. Tarun Gupta tarun@iitk.ac.in 7128 FB 310 8 B8 Dr. Ashu Jain ashujain@iitk.ac.in 7411 FB 315 9 B9 Dr. B L Sharma bls@iitk.ac.in 6173 FB 356 10 B10 Thu Mr. Subhabrata Koley skoley@iitk.ac.in 11 B11 Mr. Sarthak Sambit Singh sarthak@iitk.ac.in 12 B12 Dr. Mukesh Sharma mukesh@iitk.ac.in 7759 WLE 302

Reminder: Things to do before your first lab Purchase the “Instruction Manual” from Copy Point Purchase all the instruments Prepare the free-hand solutions for Laboratory Assignment 1 and bring it to the lab Bring A3 sheet to do lab#1 on it to the drawing hall. You are NOT required to submit the Home Assignment 1 next week Home Assignment 1 is due in the week of Jan 11th to 15th Lectures are available in http://home.iitk.ac.in/~prishati/TA101.htm

How to setup a drafter Tape the black back sheet to the board

Set up the drafter

Move the sheet around such that the drafter is able to reach the entire area

Identify the final position and tape the sheet securely

Drawing Basics

Scale How would you draw a 20 m high building on your drawing sheet? Or a 100 m long bridge?

Scale 1:2, 1:5, 1:10 etc Note: Actual dimension are always written on drawings Note: A drawing should always mention the SCALE

Some basic geometric shapes

Some basic geometric shapes Pyramids Cylinders & Cones

Basic conic surfaces Parabola Circle Ellipse Hyperbola http://2012books.lardbucket.org/books/advanced-algebra/s11-conic-sections.html

Importance of drawing an ellipse A circle looks as an ellipse when viewed at an angle Sharp edges are connected by arcs

Ellipse: Basics Ellipse is a curve generated by a point moving such that the sum of its distance from the focuses (focii) is equal to the major diameter AB : Major diameter DE : Minor diameter F1, F2 : Focii

Ellipse: Basics P Q N M A C D B • Any line through the center of an ellipse may serve as one of a pair of conjugate diameters. • Two diameters are said to be conjugate when each diameter is parallel to the tangents at the ends of the other diameter. • AB and CD are a pair of conjugate diameters: AB // MN, PQ and CD //MP, NQ. • A given ellipse may have an unlimited number of pairs of conjugate diameters.

Conjugate Diameter Method • From S, P, etc. draw lines parallel to QD and from S', P', etc. draw lines parallel to ER. Q S • Conjugate diameters AB and DE given. P • Draw a circle with AB as diameter. O • Draw OQ perpendicular to AB. • Intersection of lines through P & P', S & S', etc. give points on the ellipse. • From a number of points on either side of Q, such as P and S, draw perpendiculars PP', SS', etc. to AB. P’ S’ R An approx method

Concentric Circle Method P θ 2b 2a An exact method

Parallelogram Method D G 3 • Can be used either with the major and minor diameters or with any pair of conjugate diameters. 2 • Through these points draw lines from D and E as shown. 1 O A 1 2 3 B E • On the given diameters construct a parallelogram. • Their intersections will be points on the ellipse. D G 3 2 • Divide AO into any number of equal parts and AG into the same number of equal parts, numbering points from A. 1 Conjugate diameters O A B 1 2 3 E An exact method

4-Centered Method A’ P D F A B O Q S E R An approx method

Constructional geometry Draw a rhombus and inscribe an ellipse inside it (APPROXIMATE): 2 • Mark mid points of all sides as A,B,C,& D. • Taking 1 as center and 1-A radius draw an arc AB. • Join these points to the ends of smaller diagonals. 3 4 • Take 2 as center draw an arc CD and so on. • Mark points 1,2,3,4 as four centers. 1

Construction of A Parabola 7 6 5 4 3 2 1 6 7 5 4 3 2 1

Polygons: Hexagon Circumscribing circle Inscribing circle d d 60 Vertex-to-vertex distance Distance between flats

Polygons: Octagon

Polygons: Septagon or any regular polygon Given a side 3 4 2 5 6 7 B A

Thank you..