Engineering Graphics Essentials with AutoCAD 2016 Instruction Text and Video Instruction ® By Kirstie Plantenberg

Engineering Graphics Essentials with AutoCAD 2016 Instruction Text and Video Instruction ® By Kirstie Plantenberg

CHAPTER SU

In Chapter 2 you will learn the importance of engineering graphics and how to create an orthographic projection. An orthographic projection describes the shape of an object. It is a two dimensional representation of a three dimensional object. Different line types are used to indicate visible, hidden and symmetry lines. By the end of this chapter, you will be able to create a technically correct orthographic projection using proper projection techniques.

2.1) INTRODUCTION TO ENGINEERING GRAPHICS

Engineering graphics is a set of rules and guidelines that help you create an engineering drawing. An engineering drawing is a drawing or a set of drawings that communicates an idea, design, schematic, or model. Engineering drawings come in many forms. Each engineering field has its own type of engineering drawings. For example, electrical engineers draw circuit schematics and circuit board layouts. Civil engineers draw plans for bridges and road layouts. Mechanical engineers draw parts and assemblies that need to be manufactured. This book focuses on the latter. This is not to say that only students in a mechanical engineering curriculum will benefit from learning engineering graphics. It benefits everyone from the weekend carpenter who wants to draw plans for his/her new bookshelf to the electrical engineer who wants to analyze electrical component cooling using a CAE program. Engineering graphics teaches you how to visualize and see all sides of an object in your mind. Being able to visualize in your mind will help you in several aspects of critical thinking.

2.2) ORTHOGRAPHIC PROJECTION INTRODUCTION

An orthographic projection enables us to represent a 3-D object in 2-D (see Figure 2.2-1). An orthographic projection is a system of drawings that represent different sides of an object. These drawings are formed by projecting the edges of the object perpendicular to the desired planes of projection. Orthographic projections allow us to represent the shape of an object using 2 or more views. These views together with dimensions and notes are sufficient to manufacture the part.