Orthographic Projection

12 Key excerpts on "Orthographic Projection"

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  Engineering Graphics & Technology NQF2 SB

  TVET FIRST

  • Sparrow Consulting(Author)
  • 2013(Publication Date)
  • Macmillan

    (Publisher)

  132 Module 8: Draw and interpret Orthographic Projections Module 8 Draw and interpret Orthographic Projections Overview At the end of this module, you should be able to: • Unit 8.1: Interpret the principles of visualisation in first and third-angle Orthographic Projection. • Unit 8.2: Explain the principles of first and third-angle Orthographic Projection. • Unit 8.3: Draw to scale 1:1; 1:2; 1:5; 1:10; 2:1 primary views of single engineering components in first and third-angle Orthographic Projection. Unit 8.1: Draw to scale primary views of prisms and pyramids in first and third-angle Orthographic Projection Introduction A technical drawing is a form of graphic communication, used to transform an idea into a physical form. In other words, an engineer makes use of technical drawings to instruct a manufacturer on how to form or fabricate objects, such as machine parts, cast iron forms and so on. Have you ever heard the phrase “a picture tells a thousand words”? Orthographic drawings are used to help visualise complicated or unique designs without misunderstandings or misconceptions and without using hundreds of words. Engineering drawings convey important information such as: • Physical appearance: What the object should look like • Size: The dimensions of the object and its various parts • Assembly: How the different parts of an object fit together Two-dimensional views of an object are done by Orthographic Projections . An Orthographic Projection is a graphic representation of a three-dimensional object in two dimensions . They are drawings of the views of each side (top, front, left and right sides) of an object. Visualise: Form a mental picture of something that is invisible or abstract, i.e. to “see” something that is not visible. Orthographic Projection: A graphic representation of a three-dimensional object in two dimensions. Words & Terms Three-dimensional (3D) object: An object that has length, width and height.

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  Engineering Drawing for Manufacture

  • Brian Griffiths(Author)
  • 2002(Publication Date)
  • Butterworth-Heinemann

    (Publisher)

  The word ortho means correct and the word graphic means drawing. Thus, orthographic means a correct drawing which prevents confusion and therefore can be a true specification which, because Orthographic Projections are clearly defined by ISO stan- dards, are legal specifications. Orthographic Projections can be sub- divided into first and third angle projections. The two projection 24 Engineering drawing for manufacture IPROJECTIONSI I I I Pictoral ! I Perspective I ~xonometr'i~ iVisualization I I I Orth~ hic I ,,I , I Oblique I I FirstAngle 'll Third Angle I /Specification I Figure 2.1 The different types of engineering drawing projections methods only differ in the manner in which the views are presented. The third angle projection method is preferred. Whichever projection method is used, the representation is achieved by projectors which are effectively rays of light whose sources are on one side of an artefact passing over the artefact and projecting its image onto a 2D drawing sheet. This is similar to the image or shadow an artefact would produce when a single light source projects the shadow of an artefact onto, say, a wall. In this case, the wall is the picture plane. The various types of pictorial and Orthographic Projections are explained in the following sections. 2.1 Perspective projection Perspective projection is as shown in Figure 2.2. Perspective projection is reality in that everything we see in the world is in perspective such that the objects always have vanishing points. Perspective projection is thus the true view of any object. Hence, we use expressions like 'putting something in perspective'! Projectors radiate from a station point (i.e. the eye) past the object and onto the 2D picture plane. The station point is the viewing point. Although there is only one station point, there are three vanishing points. A good example of a vanishing point is railway lines that appear to meet in the distance.

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  Autodesk Inventor 2022 and Engineering Graphics

  An Integrated Approach

  • Randy H. Shih(Author)
  • 2021(Publication Date)
  • SDC Publications

    (Publisher)

  Now, if the projection lines are parallel to each other and the image plane is also perpendicular (normal) to the projection lines, the result is what is known as an Orthographic Projection. When the projection lines are parallel to each other, an accurate outline of the visible face of the object is obtained. The term orthographic is derived from the word orthos meaning perpendicular or 90º. Orthographic Projection and Multiview Constructions 7-5 In Engineering Graphics, the projection of one face of an object usually will not provide an overall description of the object; other planes of projection must be used. To create the necessary 2D views, the point of sight is changed to project different views of the same object; hence, each view is from a different point of sight. If the point of sight is moved to the front of the object, this will result in the front view of the object. And then move the point of sight to the top of the object and looking down at the top, and then move to the right side of the object, as the case may be. Each additional view requires a new point of sight. Multiview Orthographic Projection In creating multiview Orthographic Projection, different systems of projection can be used to create the necessary views to fully describe the 3D object. In the figure below, two perpendicular planes are established to form the image planes for a multiview Orthographic Projection. The angles formed between the horizontal and the vertical planes are called the first, second, third and fourth angles, as indicated in the figure. For engineering drawings, both first angle projection and third angle projection are commonly used. Six Principal Views (Each with its point of sight) 7-6 Autodesk Inventor and Engineering Graphics First-Angle Projection First-angle Orthographic Projection is commonly used in countries that use the metric (International System of Units: SI) system as the primary units of measurement.

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  Introductory Engineering Graphics

  • Edward E. Osakue(Author)
  • 2018(Publication Date)
  • Momentum Press

    (Publisher)

  CHAPTER 2 STANDARD ORTHOGRAPHIC DRAWING VIEWS

  2.1 INTRODUCTION

  Orthographic views are 2D images of a 3D object obtained by viewing it from different orthogonal directions. Six principal views are possible and are named top, bottom, front, rear, left, and right views. However, three of the six views are regarded as standard views. The U.S. standard views are the top, front, and right views and are based on third angle Orthographic Projection. The European standard views are the front, top, and left views and are based on first angle Orthographic Projection. 2D orthographic views can be generated directly from solid models, which is much faster than constructing the views. Multiview drawings consist of two or more views with appropriate annotations arranged in some preferred pattern. They include standard orthographic views, auxiliary views, and section views. Auxiliary and section views are used to supplement standard views in order to clarify views, improve visualization of designs, and facilitate dimensioning of drawings. Detail component drawings are most often 2D engineering drawings of parts with necessary information for construction, manufacturing, or inspection. 2D assembly drawings are extensively used in the building of equipment and structures. Multiview drawing guidelines are prescribed by ANSI/ ASME Y14.3M in the U.S standards.

  2.2 PROJECTION TYPES

  Projection is the graphic technique of connecting points on a 3D object by straight lines (linear projection) to points on an image planes so as to create its image(s). Natural objects are in 3D solid form bounded by vertices, edges, and faces. Vertices are points on objects, edges are lines on objects, and faces are flat and curved surfaces on objects. These and other geometric entities that make the solid are called features. As points are the most basic graphic features, images of objects may be created from points on it. In a projection, points on a 3D object are used to create its image(s) on a projection or picture or image plane. The image plane is an imaginary transparent flat surface that coincides with the drawing surface, which may be a paper or computer screen. A projection relates an observer and an object to an image plane through the lines of sight or projection. In an Orthographic Projection, the views of the object are obtained by viewing it from different orthogonal directions. This technique allows a 3D object to be accurately represented on a 2D plane with multiple views. There are two types of projections: parallel and perspective projections. Figure 2.1

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  SOLIDWORKS 2021 and Engineering Graphics

  An Integrated Approach

  • Randy H. Shih(Author)
  • 2021(Publication Date)
  • SDC Publications

    (Publisher)

  Imagine yourself standing in front of a glass window, IMAGE PLANE, looking outward—the image of a house at a distance is sketched onto the glass which is a 2D view of a 3D house. Orthographic Projection The lines connecting from the Point of Sight to the 3D object are called the Projection Lines or Lines of Sight. Note that in the above figure, the projection lines are connected at the point of sight, and the projected 2D image is smaller than the actual size of the 3D object. Now, if the projection lines are parallel to each other and the image plane is also perpendicular (normal) to the projection lines, the result is what is known as an Orthographic Projection. When the projection lines are parallel to each other, an accurate outline of the visible face of the object is obtained. The term orthographic is derived from the word orthos meaning perpendicular or 90º. Orthographic Projections and Multiview Constructions 7-5 In Engineering Graphics, the projection of one face of an object usually will not provide an overall description of the object; other planes of projection must be used. To create the necessary 2D views, the point of sight is changed to project different views of the same object; hence, each view is from a different point of sight. If the point of sight is moved to the front of the object, this will result in the front view of the object. And then move the point of sight to the top of the object and looking down at the top, and then move to the right side of the object, as the case may be. Each additional view requires a new point of sight. Multiview Orthographic Projection In creating multiview Orthographic Projection, different systems of projection can be used to create the necessary views to fully describe the 3D object. In the figure below, two perpendicular planes are established to form the image planes for a multiview Orthographic Projection.

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  Principles and Practice An Integrated Approach to Engineering Graphics and AutoCAD 2022

  • Randy H. Shih(Author)
  • 2021(Publication Date)
  • SDC Publications

    (Publisher)

  Orthographic Projection and Multiview Constructions 4-3 Introduction Most drawings produced and used in industry are multiview drawings. Multiview drawings are used to provide accurate three-dimensional object information on two- dimensional media, a means of communicating all of the information necessary to transform an idea or concept into reality. The standards and conventions of multiview drawings have been developed over many years, which equip us with a universally understood method of communication. Multiview drawings usually require several Orthographic Projections to define the shape of a three-dimensional object. Each orthographic view is a two-dimensional drawing showing only two of the three dimensions of the three-dimensional object. Consequently, no individual view contains sufficient information to completely define the shape of the three-dimensional object. All orthographic views must be looked at together to comprehend the shape of the three-dimensional object. The arrangement and relationship between the views are therefore very important in multiview drawings. Before taking a more in-depth look into the multiview drawings, we will first look at the concepts and principles of projections. 3D Object Multiview drawing (2D Views) 4-4 Principles and Practice Basic Principles of Projection To better understand the theory of projection, one must become familiar with the elements that are common to the principles of projection. First of all, the POINT OF SIGHT (a.k.a. STATION POINT) is the position of the observer in relation to the object and the plane of projection. It is from this point that the view of the object is taken. Secondly, the observer views the features of the object through an imaginary PLANE OF PROJECTION (or IMAGE PLANE). Imagine yourself standing in front of a glass window, IMAGE PLANE, looking outward; the image of a house at a distance is sketched onto the glass which is a 2D view of a 3D house.

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  SOLIDWORKS 2024 and Engineering Graphics

  An Integrated Approach

  • Randy H. Shih(Author)
  • 2024(Publication Date)
  • SDC Publications

    (Publisher)

  Imagine yourself standing in front of a glass window, IMAGE PLANE, looking outward—the image of a house at a distance is sketched onto the glass which is a 2D view of a 3D house. Orthographic Projection The lines connecting from the Point of Sight to the 3D object are called the Projection Lines or Lines of Sight. Note that in the above figure, the projection lines are connected at the point of sight, and the projected 2D image is smaller than the actual size of the 3D object. Now, if the projection lines are parallel to each other and the image plane is also perpendicular (normal) to the projection lines, the result is what is known as an Orthographic Projection. When the projection lines are parallel to each other, an accurate outline of the visible face of the object is obtained. The term orthographic is derived from the word orthos meaning perpendicular or 90º. Orthographic Projections and Multiview Constructions 7-5 In Engineering Graphics, the projection of one face of an object usually will not provide an overall description of the object; other planes of projection must be used. To create the necessary 2D views, the point of sight is changed to project different views of the same object; hence, each view is from a different point of sight. If the point of sight is moved to the front of the object, this will result in the front view of the object. And then move the point of sight to the top of the object and look down at the top, and then move to the right side of the object, as the case may be. Each additional view requires a new point of sight. Multiview Orthographic Projection In creating multiview Orthographic Projection, different systems of projection can be used to create the necessary views to fully describe the 3D object. In the figure below, two perpendicular planes are established to form the image planes for a multiview Orthographic Projection.

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  Representational Techniques for Architecture

  • Lorraine Farrelly, Nicola Crowson(Authors)
  • 2015(Publication Date)
  • Bloomsbury Publishing

    (Publisher)

  3 Orthographic Projection

  Displaying a proposed piece of architecture as a series of drawings presents an interesting challenge. The information in the drawings needs to be both accurate and interconnected to tell the story of the building and communicate the proposed scheme clearly using a system that is universally recognized and understood. These drawings are 2D images that need to be read and interpreted as a 3D building or space.

  Orthographic Projection refers to a system of interrelated 2D views of a building. This system includes the views from above or a horizontal cross-section of a building (the plan), the views from the side of a building (the elevation), and the views of vertical “cuts” or cross-sections of the building (the section). These drawings can be collectively referred to as a “full set” and will include all floor plans, the roof plan, all elevations, and a series of vertical “cuts” that explain the internal and external relationships of the building.

  The purpose of these drawings is to technically describe how to physically realize a conceptual idea. The plan, section, and elevation all relate to one another and depending on the conceptual idea of these drawings can be a starting point. Often, the plan is drawn first and section and elevations are then drawn alongside it. Using CAD software, the plans will be carefully drawn on different “layers” ensuring that the floor plan of the ground and subsequent floors align.

  Reading plan, section and elevation drawings correctly is a skill. This chapter describes how the convention of plan, section, and elevation are used to describe architectural ideas and design buildings and structures.

  3.1 Project: Thomas HouseLocation: Pencclawd, WalesArchitects: Hyde & Hyde

  This section drawing shows the relationship between the site and the proposed Thomas House. The drawing explains the key aspects of the project, a building elevated over an uneven terrain that has been utilized to provide a ramped driveway. The section is represented in black with photorealistic materials applied in elevation.

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  Engineering Design Graphics

  Sketching, Modeling, and Visualization

  • James M. Leake, Molly Hathaway Goldstein, Jacob L. Borgerson(Authors)
  • 2022(Publication Date)
  • Wiley

    (Publisher)

  CHAPTER 79 5 ❚ PLANAR PROJECTIONS Introduction Projection is the process of reproducing a spatial object on a plane, curved surface, or line by projecting its points. Common examples of projection include photography, where a 3D scene is projected onto a 2D medium, and map projection, where the earth is projected onto a cylinder, a cone, or a plane in order to create a map. Planar projection figures prominently in both engineering and computer graphics. For our purposes, a projection is a mapping of a three- dimensional (3D) space onto a two-dimensional subspace (i.e., a plane). The word projection also refers to the two-dimensional (2D) image result- ing from such a mapping. Every planar projection includes the follow- ing elements: • The 3D object (or scene) to be projected • Sight lines (called projectors) passing through each point on the object • A 2D projection plane 1 • The projected 2D image that is formed on the projection plane These elements are indicated in Figure 5-1. The projection is formed by plotting piercing points created by the intersection of the projec- tors with the projection plane. By mapping these points onto the projection plane, the 2D image is formed. In effect, three-dimensional information is collapsed onto a plane. The Albrecht Dürer drawing shown in Figure 5-2 further illustrates these projection ele- ments. The lute lying on the table is the object, the piece of string is a (movable) projector, and the frame through which the artist looks is the pro- jection plane. Two movable wires are mounted on the frame, allowing the artist to identify a single piercing point. A piece of paper hinged to the frame serves as the basis for the projected PLANAR PROJECTIONS AND PICTORIAL VIEWS 1 Although commonly represented as a bounded rectangle, the projection plane is infinite in extent. Object Projector Projected image Projection plane Figure 5-1 Elements of a planar projection CHAPTER 5 PLANAR PROJECTIONS AND PICTORIAL VIEWS 80 image.

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  Geometric and Engineering Drawing

  • Ken Morling, Stéphane Danjou(Authors)
  • 2022(Publication Date)
  • Routledge

    (Publisher)

  Figure 4.13 shows a small stepped pulley drawn twice in oblique projection. It is obvious that the drawing on the left is easier to draw than the one on the right.

  4.4 AXONOMETRIC PROJECTION (ISOMETRIC AND DIMETRIC)

  Another method of parallel projection is Orthographic Projection. In contrast to oblique projection where the projectors are at any angle other than 0° or 90°, in Orthographic Projection (ortho = right) all projectors are perpendicular to the plane of projection (Figure 4.14 ). There are two methods of Orthographic Projection. One is called multi-view projection and is used for engineering drawings. The other one, axonometric projection, is used to create pictorial drawings.

  Engineering drawings are usually drawn in multi-view projection, whose principles are explained in the subsequent section. For the presentation of detailed drawings, this system has been found to be far superior to all others. The system has, however, the disadvantage of being very difficult to understand by people not trained in its usage. It is always essential that an engineer be able to communicate his or her ideas to anybody, particularly people who are not engineers, and it is therefore an advantage to be able to draw using a system of projection that is more easily understood such as an axonometric projection.

  Figure 4.13

  A drawing of a stepped pulley.

  An axonometric projection is a projection method where a pictorial view is created by rotating the object on one of its axes, relative to the projection plane. In this way all three dimensions can be shown. However, not all of them are shown in true size (Figure 4.15 ).

  Axonometric projections can be further classified by the angles between the axonometric axes. When all angles are equal, the projection is classified as isometric projection. When two of the three angles are equal, the projection is referred to as dimetric. When none of the three angles differ in size, the projection is called trimetric

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  Digital Sketching

  Computer-Aided Conceptual Design

  • John Bacus(Author)
  • 2020(Publication Date)
  • Wiley

    (Publisher)

  Cutting planes work from an abstract notion that the world is made of some material that can be cut through cleanly to expose its internal properties. Some materials are rendered transparently, like air or glass. Others are rendered with opacity, like structural materials of wood, steel, or concrete. Some sectional views consider only a difference between solid and void, filling the inside of cut solids with a single fill color. When greater detail about constructability matters, sectional views may show solid material types with representational hatch patterns.

  Cutting planes are a powerful design tool, valuable from your earliest sketch to most precise construction details. They give you a supernatural power to understand both the interior and exterior of your design at the same time. Penetrations from inside to outside, as, for example, doors or windows, give your building's users a glimpse at this special point of view, but without the privileged oversight that you have with a full sectional view.

  Orthographic Projection

  Orthographic Projections of space are idealized abstractions that preserve true dimensions, in scale, while minimizing perspectival distortion. This is accomplished by passing a cutting plane through the space of the project parallel to and projecting plane, projecting project details beyond the cut directly onto the picture plane. In an Orthographic Projection, all dimensions parallel to the cutting plane are drawn at true scale (Figure 3.13 ).

  Encompassing plan, section, and elevation views, Orthographic Projections are a natural abstraction of space that predates the invention of perspective by thousands of years. Orthographic Projections can be found in drawings throughout ancient Egypt.4 Possibly the earliest identifiable architectural drawings, carved in clay tablets in ancient Mesopotamia, are orthographic in nature (Figure 3.14 ).

  If you are sketching by hand today, you are likely sketching orthographically. With a roll of trace and an architect's scale by your side, sketches of plans and elevations are among the fastest ways to churn through the essential spatial components of any architectural project. In plan, a single fat line drawn with a black marker can quickly progress a simple network diagram to a representation of a credible structure with walls and floors. Sketching in Orthographic Projection is easy, fast, and natural.

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  Visualization, Modeling, and Graphics for Engineering Design

  • Dennis Lieu, Sheryl Sorby(Authors)
  • 2016(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  six standard views (or six principal views): The drawing presentation of an object using the views produced by the glass box (i.e., the top, front, bottom, rear, left-side, and right-side views). third-angle projection: The process of creating a view of an object by imprinting its image, using orthogonal projection, on a translucent surface in front of that object. viewing plane: A hypothetical plane between an object and its viewer onto which the image of the object, as seen by the viewer, is imprinted. 8 . 1 0 G L O S S A R Y O F K E Y T E R M S 1. What is orthogonal projection? 2. What are the advantages and disadvantages of using pictorial images, such as isometric images, for the graphical representation of an object? 3. What is a multiview presentation? 4. What are the advantages and disadvantages of using a multiview presentation for the graphical representation of an object? 5. How are different views located with respect to each other on the same drawing? 6. Why should features be aligned between views in a multiview presentation? 7. Why is it important that different views have the same scale? 8. What are the advantages of having features of an object aligned between views? 8 . 1 1 Q U E S T I O N S F O R R E V I E W Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 8-32 section three Setting Up an Engineering Drawing 9. What are the standard (or principal) views? 10. What is the preferred configuration? 11. When should extra orthogonal views be used? 12. When should hidden lines be used? 13.

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