Chapter-1

Introduction

Engineering Graphics is the field of graphical problem solving and includes two areas of specialization: working drawings and descriptive geometry. Other areas that can be used for a wide variety of applications are nomography, graphical mathematics, empirical equations, technical illustration, vector analysis, data analysis, and computer graphics. Graphics is one of the designers primary methods of thinking, solving problems, and communicating ideas.INTRODUCTION

Father of Descriptive GeometryGaspard Monge (1746-1818)

Engineering drawing is a graphic language, a universal language, a language of use and ever-increasing value. Like every other systematized language it has its rules of grammar. To express ourselves in a literate fashion, then, we must master, as it were, laws of syntax and of concord. With a very little application we shall master the rules of the universal graphic language, and so be able to not only to express ourselves in it on drawing paper, but also to understand the expression of it by another. In a word, we set out to learn to draw so that our ideas may readily be interpreted by others; and to read drawings so as to gather a clear mental picture of what another wishes to convey to us.Graphic language

Almost everything around us has been created by, or is influenced by, engineers:Buildings, vehicles, roads, railways, food growing and processing, books, medical care, recreation, etc.All of these have either been conceived and created from scratch or have evolved from existing ideas. Either way, an engineering design process will have been followed, in one form or another.

Without a good knowledge of engineering graphics, engineers and scientists are no where. An engineer or a scientist needs skill in three areas: first, he must be able to imagine secondly, he must be able to draw clearly and rapidly, thirdly, he must be able to read the drawings drawn by others. By studying engineering graphics, student becomes aware of how industry communicates technical information. Engineering graphics teaches the principles of accuracy and clarity in presenting the information necessary to produce products. Finally it develops the imagination skill that is essential to the creation of successful design. Need of Engineering Graphics

COMPUTER-AIDED DRAFTING (CAD) and COMPUTER-AIDED DESIGN AND DRAFTING (CADD):

Using computer techniques with the aid of graphic data processing systems to graphically express or solve technical equations is called CAD or CADD.

ENGINEERING DRAWINGS and ENGINEERING DRAFTING:

Drawings used in technical work or industrial production are referred to as engineering drawings. The terms working drawings and machine drawings are also used in reference to engineering drawings.

ENGINEERING GRAPHICS or ENGINEERING DESIGN GRAPHICS:

Engineering graphics or engineering design graphics refers to the design and specifications for physical objects and data relationships as in engineering and science..

*AU 2005How Would You Describe This?In teams of two, describe using only wordsHow effective is this approach?

AU 2005

*AU 2005Freehand sketchesInstrument drawingsComputer drawings and modelsThree Basic Types of Technical Drawings

AU 2005

*AU 2005Introduction to Projections Present 3-D objects with 2-D mediaTwo Basic Categories

Orthographic Pictorial

AU 2005

3.To learn the descriptive geometry To learn the AutoCAD tool2.To learn the theory of projections 4.To learn a 3-D imaginational skillCourse Objectives

Course Coverage

Course ConductEngineering Graphics

Online Teaching through AutoCAD4 Lectures per Week

Tutorial Class Conduct on Grid Sheet1 Tutorial Hour per Week

Online Assignment4 Practicals, each of 2 hours (8 Hours per Week)

Online Examination & Evaluation

Evaluation Components & EvaluationAssignments120 Marks

2)Mid-Test 60 Marks

3)Compre. Exam. 120 Marks

Total 300 Marks

Assignments EvaluationTotal 25 AssignmentsFirst 5 Assignments on AutoCAD Commands Total 20 Assignments on course20 Assignments X 20 Marks Each = 400 Marks400 Marks X 0.3 = 120 Marks

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Instructor:

This is an in-class interactive exercise(active learning). Allow students about 5 minutes to discuss with partner and then ask random students to put in words their description. Then ask the class the question shown on the slide.

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In this class we will focus primarily on Freehand Sketching and Computer Based drawing

CAD programs have replaced much of Instrument drawing process.

Technical sketches are how engineers think and communicate with each other. All the way from napkin session at lunch to formal computer based solid models and flow charts.

*Definitions:

Projection: the process or technique of reproducing a spatial (3-D) object upon a plane or curved (2-D) surface

Orthographic sketches present the object in a series of projections, each one showing only two of the objects three dimensions.

Pictorial sketches present the object in a single view with all three dimensions represented

Discuss the trade-offs in using any type of projection; some are more realistic, some are easier to draw, and some are easier to interpret by non-technical people