Multi-View Drawing Review Sacramento City College EDT 300/ENGR 306 EDT 300 / ENGR 306 - Chapter 5 1
Objectives Identify and select the various views of an object. Determine the number of views needed to describe fully the shape and size of an object. Define the term orthographic projection Describe the difference between first and third-angle projection. 2 EDT 300 / ENGR 306 - Chapter 5
Objectives Visualize the glass box concept and apply it to the process of selecting and locating views on a drawing. 3 EDT 300 / ENGR 306 - Chapter 5
Objectives Develop a multi-view drawing, following a prescribed step-by-step process, from the initial idea to a finished drawing. 4 EDT 300 / ENGR 306 - Chapter 5
Vocabulary First angle projection Front View Horizontal Plane Implementation Multi-view Drawing Negative Cylinder Normal Views Orthographic Projection Pictorial Drawing 5 EDT 300 / ENGR 306 - Chapter 5 Profile plane Quadrant Right-side View Solid Model Spherical Third-angle Projection Top View Vertical Plane Visualization
Communication People communicate by verbal and written language and graphic (pictorial) means. Technical drawings are a graphical means to communicate. When accurate visual understanding is necessary, technical drawing is the most exact method that can be used. 6 EDT 300 / ENGR 306 - Chapter 5
Visualization and Implementation Technical drawing involves: Visualization The ability to see clearly in the mind s eye what a machine, device or object looks like. Implementation The process of drawing the object that has been visualized. 7 EDT 300 / ENGR 306 - Chapter 5
Visualization and Implementation A technical drawing, properly made, gives a clearer, more accurate description of an object than a photograph or written explanation. 8 EDT 300 / ENGR 306 - Chapter 5
Visualization and Implementation Technical drawings made according to standard rules result in views that give an exact visual description of an object. The multi-view drawing is the major type of drawing used in the industry. 9 EDT 300 / ENGR 306 - Chapter 5
Multi-View Drawing A photograph can show three views Front. Top. Right Side. Nearly all objects have six sides, not three. 10 EDT 300 / ENGR 306 - Chapter 5
Multi-View Drawing 11 EDT 300 / ENGR 306 - Chapter 5
Multi-View Drawing If an object could be shown in a single photograph, it would also include A left-side view. A rear view. A bottom view. 12 EDT 300 / ENGR 306 - Chapter 5
Pictorial Drawing An object cannot be photographed if it has not been built (!) This limits the usefulness of photographs to show what an object looks like (!) 13 EDT 300 / ENGR 306 - Chapter 5
Pictorial Drawing A pictorial drawing Is a drawing. Shows an object as it would appear in a photograph. Shows the way an object looks, in general. It does not show, the exact forms and relationships of the parts that make up the object. 14 EDT 300 / ENGR 306 - Chapter 5
Pictorial Drawing A pictorial drawing Shows the object as it appears, not as it really is. Holes in the base appear as ellipses, not as true circles. 15 EDT 300 / ENGR 306 - Chapter 5
Pictorial Drawing Photograph Pictorial Drawing 16 EDT 300 / ENGR 306 - Chapter 5
Multi-View Drawing The goal, is to represent an object on a sheet of paper in a way that described its exact shape and proportions. To do this: Draw views of the object as it is seen from different positions. 17 EDT 300 / ENGR 306 - Chapter 5
Multi-View Drawing These views are then arranged in a standard order. Anyone familiar with drafting practices can understand them immediately. 18 EDT 300 / ENGR 306 - Chapter 5
Multi-View Drawing To describe accurately the shape of each view imagine a position Directly in front of the object. Directly above the object. On the right side of the object. 19 EDT 300 / ENGR 306 - Chapter 5
Multi-View Drawing The front, top and right side views are the ones most often used to describe an object in technical drawing. They are called the Normal views. 20 EDT 300 / ENGR 306 - Chapter 5
The Relationship of Views Views must be placed in proper relationship to each other. The Top View is directly above the Front View The Right-side View is directly to the right of the Front View. 21 EDT 300 / ENGR 306 - Chapter 5
The Relationship of Views When the views are placed in proper relationship to one another, the result is a multi-view drawing. Multi-view drawing is the exact representation of an object on one plane. 22 EDT 300 / ENGR 306 - Chapter 5
The Relationship of Views Other views may also be required. The proper relationship of the six views is shown below Top View Normal views Rear View Left-side View Front View Right-side View Bottom View 23 EDT 300 / ENGR 306 - Chapter 5
V-Block 24 EDT 300 / ENGR 306 - Chapter 5
Orthographic Projection These views are developed through the principles of orthographic projection Ortho - straight or at right angles. Graphic - written or drawn. Projection - from two Latin words: Pro, meaning forward Jacere, meaning to throw The literal meaning is thrown forward, drawn at right angles. 25 EDT 300 / ENGR 306 - Chapter 5
Orthographic Projection Definition: Orthographic projection is: the method of representing the exact form of an object in two or more views on planes usually at right angles to each other, by lines drawn perpendicular from the object to the planes. 26 EDT 300 / ENGR 306 - Chapter 5
Orthographic Projection An orthographic projection drawing is a representation of the separate views of an object on a two-dimensional surface. It reveals the width, depth and height of an object. 27 EDT 300 / ENGR 306 - Chapter 5
Orthographic Projection 28 EDT 300 / ENGR 306 - Chapter 5
Angles of Projection EDT 300 / ENGR 306 - Chapter 5 29
Angles of Projection On a technical drawing, a plane is an imaginary flat surface that has no thickness. Orthographic projection involves the use of three planes. Vertical plane. Horizontal plane. Profile plane. A view of an object is projected and drawn on each plane. 30 EDT 300 / ENGR 306 - Chapter 5
Angles of Projection The vertical and horizontal planes divide space into four quadrants (quarters of a circle). In orthographic projection, quadrants are usually called angles. Thus we get the name, first-angle projection and third angle projection 31 EDT 300 / ENGR 306 - Chapter 5
Angles of Projection First angle projection is used in European countries. Third angle projection is used in the US and Canada. Second and fourth angle projection is not used. 32 EDT 300 / ENGR 306 - Chapter 5
First Angle Projection First angle projection Front view = vertical plane. Top view = horizontal plane. Left side view = profile plane. 33 EDT 300 / ENGR 306 - Chapter 5
First Angle Projection In first angle projection, the Front View is located above the Top View. The Left-side View is to the right of the Front View. Refer to Figure 5-12. 34 EDT 300 / ENGR 306 - Chapter 5
First Angle Projection In first-angle projection, the projection plane is on the far side of the object from the viewer. The view of the object are projected to the rear and onto the projection plane instead of being projected forward. 35 EDT 300 / ENGR 306 - Chapter 5
Third Angle Projection Third angle projection Front view = vertical plane. Top view = horizontal plane. Right side view = profile plane. 36 EDT 300 / ENGR 306 - Chapter 5
Third Angle Projection In third angle projection, the Top View is located above the Front View. The Right-Side View is to the right of the Front View. Refer to Figure 5-14. 37 EDT 300 / ENGR 306 - Chapter 5
Third Angle Projection In third-angle projection, the projection plane is considered to be between the view and the object, and the views are projected forward to that plane. 38 EDT 300 / ENGR 306 - Chapter 5
Third Angle Projection The views appear in their natural positions when the views are revolved into the same plane as the frontal plane The top view appears above the front view. The right-side view is to the right of the front view. The left view to the left of the front view. 39 EDT 300 / ENGR 306 - Chapter 5
The Glass Box EDT 300 / ENGR 306 - Chapter 5 40
The Glass Box In each case the three views have been developed by using imaginary transparent planes. The views are projected onto these planes. 41 EDT 300 / ENGR 306 - Chapter 5
The Glass Box Visualize a glass box around the object Project the view of the object onto a side of the box. Unfold the box to one plane. The views will be in their relative positions. 42 EDT 300 / ENGR 306 - Chapter 5
The Glass Box 43 EDT 300 / ENGR 306 - Chapter 5
The Glass Box 44 EDT 300 / ENGR 306 - Chapter 5
Projection of Lines EDT 300 / ENGR 306 - Chapter 5 45
Projection of Lines There are four kinds of straight lines found on objects in drawings Horizontal. Vertical. Inclined. Oblique. Each line is projected by locating its endpoint. 46 EDT 300 / ENGR 306 - Chapter 5
Horizontal Lines Horizontal lines Are parallel to the horizontal plane of projection. Are parallel to one of the planes. Are perpendicular to the third plane. Appear as true length in two of the planes. Appear as a point in the third. 47 EDT 300 / ENGR 306 - Chapter 5
Vertical Lines Vertical Lines Are parallel to the frontal plane. Are parallel to the profile plane. Are perpendicular to the horizontal plane. Appear true length in the frontal and profile planes. Appear as a point in the horizontal plane. 48 EDT 300 / ENGR 306 - Chapter 5
Inclined Lines Inclined Lines Are parallel to one plane of projection. Are inclined in the other two planes. Appear true length in one of the planes. Appear shortened in the other two planes. 49 EDT 300 / ENGR 306 - Chapter 5
Oblique Lines Oblique Lines Are neither parallel nor perpendicular to any of the planes or projections (!) Appear shortened in all three planes of projection. 50 EDT 300 / ENGR 306 - Chapter 5
Curved Lines Curved Lines may be Circular. Elliptical. Parabolic. Hyperbolic. Some other geometric curve form. They may also be irregular curves. 51 EDT 300 / ENGR 306 - Chapter 5
Projection of Surfaces Surfaces may be Horizontal. Vertical. Inclined. Oblique. Curved. They are drawn by locating the end points of the lines that outline their shape. 52 EDT 300 / ENGR 306 - Chapter 5
Horizontal Surfaces Horizontal surfaces Are parallel to the horizontal projection plane Appear true size and shape in the Top View. 53 EDT 300 / ENGR 306 - Chapter 5
Vertical Surfaces Vertical surfaces Are parallel to one or the other of the frontal or profile planes, and Appear in their true size and shape in the Front View or the Right-side View. They are perpendicular to the other two planes and appear as lines in these planes 54 EDT 300 / ENGR 306 - Chapter 5
Inclined Surfaces Inclined surfaces Are neither horizontal nor vertical Are perpendicular to one of the projection planes and appear as a true length line in this view 55 EDT 300 / ENGR 306 - Chapter 5
Oblique Surfaces Oblique Surfaces Are neither parallel nor perpendicular to any of the planes of projection. They appear as a surface in all views but not in their true size and shape 56 EDT 300 / ENGR 306 - Chapter 5
Curved Surfaces EDT 300 / ENGR 306 - Chapter 5 57
Curved Surfaces May be a single curved surface (cone or cylinder) a double curved surface (sphere, spheroid or torus a warped surface 58 EDT 300 / ENGR 306 - Chapter 5
Curved Surfaces Appear as circles in one view and as rectangles in the other view 59 EDT 300 / ENGR 306 - Chapter 5
Techniques for Special Lines and Surfaces EDT 300 / ENGR 306 - Chapter 5 60
Techniques for Special Lines and Surfaces To describe an object fully, show every feature in every view, whether or not it can ordinarily be seen Also include other lines that are not part of the object to clarify relationships and positions in the drawing 61 EDT 300 / ENGR 306 - Chapter 5
Techniques for Special Lines and Surfaces Special line symbols are used to differentiate between object lines and lines that have other special meanings 62 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines EDT 300 / ENGR 306 - Chapter 5 63
Hidden Lines Both interior and exterior features are projected in the same way. 64 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines Parts that cannot be seen in the views are drawn with hidden lines. Hidden lines are made up of short dashes. 65 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines The first line of a hidden line touches the line where it starts. Refer to Figure 5-18A. 66 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines If a hidden line is a continuation of a visible line, space is left between the visible line and the first dash of the hidden line. Refer to Figure 5-18B. 67 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines If the hidden lines show corners, the dashes touch the corners. Refer to Figure 5-18C. 68 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines Dashes for hidden arcs start and end at the tangent points. Refer to Figure 5-19A. 69 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines When a hidden arc is tangent to a visible line, leave a space. Refer to Figure 5-19B. 70 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines When a hidden line and a visible line project at the same place, show the visible line. Refer to Figure 5-19C. 71 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines When a centerline and a hidden line project at the same place, draw the hidden line. Refer to Figure 5-20A. 72 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines When a hidden line crosses a visible line, do not cross the visible line with a dash. Refer to Figure 5-20B. 73 EDT 300 / ENGR 306 - Chapter 5
Hidden Lines When hidden lines cross, the nearest hidden line has the right of way Draw the nearest hidden line through a space in the farther hidden line. 74 EDT 300 / ENGR 306 - Chapter 5
Centerlines EDT 300 / ENGR 306 - Chapter 5 75
Centerlines Centerlines are special lines used to locate views and dimensions. 76 EDT 300 / ENGR 306 - Chapter 5
Centerlines Primary centerlines Locate the center on symmetrical views in which one part is a mirror image of another. Are used as major locating lines to help in making the views. They are also used as base lines for dimensioning. Are drawn first. 77 EDT 300 / ENGR 306 - Chapter 5
Centerlines Secondary centerlines are used for drawing details of a part 78 EDT 300 / ENGR 306 - Chapter 5
Precedence of Lines EDT 300 / ENGR 306 - Chapter 5 79
Precedence of Lines The following priority of lines exists: 1. Visible lines. 2. Invisible lines. 3. Cutting-plane lines. 4. Center lines. 5. Break lines. 6. Dimension and extension lines. 7. Section lines (crosshatching). 80 EDT 300 / ENGR 306 - Chapter 5
Curved Surfaces EDT 300 / ENGR 306 - Chapter 5 81
Curved Surfaces Some curved surfaces, such as cylinders and cones do not show curved surfaces in all views. 82 EDT 300 / ENGR 306 - Chapter 5
Curved Surfaces A cylinder with its axis perpendicular to a plane will show as a circle on that plane and as a rectangle on the other two planes. 83 EDT 300 / ENGR 306 - Chapter 5
Curved Surfaces A cylinder with its axis perpendicular to a plane will show as a circle on that plane and as a rectangle on the other two planes. 84 EDT 300 / ENGR 306 - Chapter 5
Curved Surfaces The holes may be thought of as negative cylinders In mathematics, negative means an amount less than zero. A hole is a nothing cylinder, but it does have size. 85 EDT 300 / ENGR 306 - Chapter 5
Cones A cone appears as a circle in one view. It appears as a triangle in the other view. 86 EDT 300 / ENGR 306 - Chapter 5
Cones One view of a frustum of a cone appears as two circles In the top view, the conical surface is represented by the space between the two circles. 87 EDT 300 / ENGR 306 - Chapter 5
Cones Cylinders, cones and frustums of cones have single curved surfaces. The appear as circles in one view and straight lines in another. 88 EDT 300 / ENGR 306 - Chapter 5
Deciding Which Views To Draw EDT 300 / ENGR 306 - Chapter 5 89
Deciding Which View to Draw Six views are not needed to describe most objects. Usually three views are sufficient. 90 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw Most pieces can be recognized because they have a characteristic view. This is the first view to consider, and usually is the first view to draw. Next, consider the normal position of the part when it is in use. 91 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw Views with the fewest hidden lines are easiest to read, and require less time to draw. 92 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw The main purpose of drawing views is to describe the shape of the object. It is a waste of time to make more views than are necessary to describe the object. 93 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw Some parts can be described in only one view. Figure 5-23 A. Sheet material: plywood Parts of uniform thickness The thickness can be given in a note. 94 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw 95 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw 96 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw 97 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw Some parts can be described in only one view. Compare 5-24 C and D. 98 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw Some parts can be described in two views. Figure 5-25 A, B, C, D, E. 99 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw 100 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw 101 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw Examples of parts that can be drawn in two views: Figure 5-26 A - F. 102 EDT 300 / ENGR 306 - Chapter 5
Deciding Which View To Draw Long and narrow objects may suggest top and front view. Short and broad objects may suggest top and right-side views. Right side is preferred over left-side when a choices is available. Top view is preferred over bottom view when a choice is available. 103 EDT 300 / ENGR 306 - Chapter 5
Placing Views EDT 300 / ENGR 306 - Chapter 5 104
Placing Views The size of the drawing sheet should allow enough space for the number of views needed to give a clear description of the part. The method for determining the positions of the views is the same for any space. 105 EDT 300 / ENGR 306 - Chapter 5
Placing Views The working space of a drawing is the area inside the border. Objects are never drawn directly touching the border. Objects are drawn so there is a space between the object and the border line. Refer to Figure 5-28. 106 EDT 300 / ENGR 306 - Chapter 5
Placing Views 1. Measure the available drawing area using the scale of the drawing. 2. Subtract out the space occupied by the object Horizontal: Vertical: Front View Right side View 3. Divide the remaining area by 4 Put one part each On left of Front View On right of Front View On left of Right Side View On right of Right Side View Front View Top View 107 EDT 300 / ENGR 306 - Chapter 5
Placing Views Converting decimals to fractions. 1. Use page 699 in text Look up decimal Look to left to find equivalent fraction 2. Convert fractions to 12ths of an inch 0.38 = 3/8 3/8 = x/12 8x = 36 x = 4.5 /12 108 EDT 300 / ENGR 306 - Chapter 5
Figure 5-285 109 EDT 300 / ENGR 306 - Chapter 5
Figure 5-295 110 EDT 300 / ENGR 306 - Chapter 5
Placing Views 1. Add the width and the depth of the object. 111 EDT 300 / ENGR 306 - Chapter 5
Placing Views 1. Add the width and the depth of the object. For the Base, Fig 5-63, p152, The width is: 7.50 The height is: 2.25 + 1.62 The depth is: 3.25 Width + depth = 7.50 + 3.25 = 10.75 112 EDT 300 / ENGR 306 - Chapter 5
Placing Views 2. Subtract this total from the width of the drawing space. Refer to Figure 5-30. A space of about 1 is commonly left between the Side View and the Front View. Space may be larger or smaller, depending upon the shapes of the views. 113 EDT 300 / ENGR 306 - Chapter 5
Figure 5-305 114 EDT 300 / ENGR 306 - Chapter 5
Placing Views 2. Subtract this total from the width of the drawing space. For the Base, Fig 5-63, p152, Drawing Space width = 11-0.25-0.25 = 10.5 max. Width + depth = 7.50 + 3.25 = 10.75 115 EDT 300 / ENGR 306 - Chapter 5
Placing Views 3. Add the height and the depth of the object. 4. Subtract this total from the height of the drawing space. 5. Divide the remaining space evenly. 116 EDT 300 / ENGR 306 - Chapter 5
Figure 5-305 117 EDT 300 / ENGR 306 - Chapter 5
Locating and Transferring Measurements EDT 300 / ENGR 306 - Chapter 5 118
Locating Measurements Measurements made on one view can be transferred to another. This process also insures accuracy. Refer to Figure 5-33. 119 EDT 300 / ENGR 306 - Chapter 5
Locating Measurements 1. Draw upward from the Front view to locate width measurements in the Top view Draw downward from the top view to locate width measurements on the Front view. 120 EDT 300 / ENGR 306 - Chapter 5
Locating Measurements 2. Draw a light line across to the Side view from the Front view to locate height measurements Use a similar method to project height measurements from the side view to the front view 121 EDT 300 / ENGR 306 - Chapter 5
Locating Measurements Height of Front view - transfer to Rightside view. Depth measurements show as vertical distances in the Top view and as horizontal distances in the the Rightside view. 122 EDT 300 / ENGR 306 - Chapter 5
Locating Measurements 123 EDT 300 / ENGR 306 - Chapter 5
Locating Measurements 124 EDT 300 / ENGR 306 - Chapter 5
Locating Measurements 3. Depth measurements show as Vertical distances - Top view Horizontal distances - Right-side view To transfer these measurements use Arcs 45 o triangle Dividers Scale 125 EDT 300 / ENGR 306 - Chapter 5
Using Arcs to Transfer 126 EDT 300 / ENGR 306 - Chapter 5
Using Scale to Transfer 127 EDT 300 / ENGR 306 - Chapter 5
Using 45 Line to Transfer 128 EDT 300 / ENGR 306 - Chapter 5
Summary of Steps Follow a step-by-step method to insure accuracy Carry all views along together Do not attempt to finish one view before starting the others Use a hard lead pencil (4H or 6H) and light, thin lines for preliminary (layout) lines Use F, HB or H for final lines 129 EDT 300 / ENGR 306 - Chapter 5
Summary of Steps 1. Consider the Characteristic View first. 2. Determine the number of views. 3. Locate the views. 4. Block in the views with light, thin layout lines. 5. Lay off the principal measurements. 130 EDT 300 / ENGR 306 - Chapter 5
Summary of Steps 6. Draw the principal lines. 7. Lay off the measurements for details such as centers for arcs, circles and ribs. 8. Draw the circles and arcs. 9. Draw any additional lines needed to complete views. 131 EDT 300 / ENGR 306 - Chapter 5
Summary of Steps 10. Darken the lines where necessary to make them sharp and black and of proper thickness 132 EDT 300 / ENGR 306 - Chapter 5