Multi-View Drawing Chapter 5
Engineering Design Technology Sacramento City College
Multi-View Drawing 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 Multi-View Drawing Objectives Visualize the “glass box” concept and apply it to the process of selecting and locating views on a drawing.
3 Multi-View Drawing Objectives
Develop a multi-view drawing, following a prescribed step-by-step process, from the initial idea to a finished drawing.
4 Multi-View Drawing Vocabulary
First angle Profile plane projection Quadrant Front View Right-side View Horizontal Plane Solid Model Implementation Spherical Multi-view Third-angle Drawing Projection Negative Cylinder Top View Normal Views Vertical Plane Orthographic Visualization Projection Pictorial Drawing 5 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Visualization and Implementation A technical drawing, properly made, gives a clearer, more accurate description of an object than a photograph or written explanation.
8 Multi-View Drawing 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 Multi-View Drawing Multi-View Drawing A photograph can show three views Front. Top. Right Side.
Nearly all objects have six sides, not three.
10 Multi-View Drawing Multi-View Drawing
11 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Pictorial Drawing
Photograph
Pictorial Drawing
16 Multi-View Drawing 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 Multi-View Drawing Multi-View Drawing These views are then arranged in a standard order.
Anyone familiar with drafting practices can understand them immediately.
18 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing The Relationship of Views Other views may also be required. The proper relationship of the six views is shown below “Normal Top View views”
Rear Left-side Front View Right-side View View View
Bottom View
23 Multi-View Drawing V-Block
24 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Orthographic Projection
28 Multi-View Drawing Angles of Projection
Multi-View Drawing 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 Multi-View Drawing 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 names, first-angle projection and third angle projection
31 Multi-View Drawing 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 in any country.
32 Multi-View Drawing First-Angle Projection First-angle projection Front view = vertical plane. Top view = horizontal plane. Left side view = profile plane.
33 Multi-View Drawing 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 Multi-View Drawing First-Angle Projection In first-angle projection, the projection plane is on the far side of the object from the viewer.
The views of the object are projected to the rear and onto the projection plane instead of being projected forward.
35 Multi-View Drawing First-Angle Projection First-angle projection Front view = projected to vertical plane. Top view = projected to horizontal plane. Left side view = projected to profile plane.
First angle Third angle
36 Multi-View Drawing Third-Angle Projection Third-angle projection Front view = projected to vertical plane. Top view = projected to horizontal plane. Right side view = projected to profile plane.
First angle Third angle
37 Multi-View Drawing 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.
38 Multi-View Drawing Third-Angle Projection The views appear in their natural positions. The Top View appears above the front view. The Right-Side View is to the right of the Front View. The Left-Side View is to the left of the front view.
39 Multi-View Drawing The Glass Box
Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing The Glass Box
43 Multi-View Drawing The Glass Box
44 Multi-View Drawing Projection of Lines
Multi-View Drawing 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 Multi-View Drawing Horizontal Lines Horizontal lines Are parallel to the frontal plane. Are parallel to the top plane. Are perpendicular to the profile plane. (right-side view) (Parallel to 2; perpendicular to 1)
Appear as true length in two Frontal and Top planes. Appear as a point in the third. Right-side plane
47 Multi-View Drawing Vertical Lines Vertical Lines Are parallel to the frontal plane. Are parallel to the profile plane. Are perpendicular to the horizontal plane. (Parallel to 2; perpendicular to 1)
Appear true length in two planes: Frontal and Profile planes. Appear as a point in the third: Horizontal plane.
48 Multi-View Drawing Inclined Lines Inclined Lines Are parallel to one plane of projection. Are inclined in the other two planes. (Parallel to only 1; shortened in 2)
Appear true length in one of the planes. Appear shortened in the other two planes.
49 Multi-View Drawing Oblique Lines Oblique Lines Are neither parallel nor perpendicular to any of the planes or projections (!)
Appear shortened in all three planes of projection.
Can only be drawn by locating and connecting line endpoints.
50 Multi-View Drawing Curved Lines Curved Lines may be Circular. Elliptical. Parabolic. Hyperbolic. Some other geometric curve form.
They may also be irregular curves.
51 Multi-View Drawing 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 Multi-View Drawing Horizontal Surfaces Horizontal surfaces Are parallel to the horizontal projection plane Appear true size and shape in the Top View.
53 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Curved Surfaces
Multi-View Drawing 57 Curved Surfaces May be a single curved surface (cone or cylinder) a double curved surface (sphere, spheroid or torus a warped surface
58 Multi-View Drawing Curved Surfaces Appear as circles in one view and as rectangles in the other view
59 Multi-View Drawing Techniques for Special Lines and Surfaces
Multi-View Drawing 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 Multi-View Drawing Techniques for Special Lines and Surfaces
Special line symbols are used to differentiate between object lines and lines that have other special meanings
62 Multi-View Drawing Hidden Lines
Multi-View Drawing 63 Hidden Lines Both interior and exterior features are projected in the same way.
64 Multi-View Drawing Hidden Lines Parts that cannot be seen in the views are drawn with hidden lines.
Hidden lines are made up of short dashes.
65 Multi-View Drawing Hidden Lines The first line of a hidden line touches the line where it starts. Refer to Figure 5-18A.
66 Multi-View Drawing 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 Multi-View Drawing Hidden Lines If the hidden lines show corners, the dashes touch the corners. Refer to Figure 5-18C.
68 Multi-View Drawing Hidden Lines Dashes for hidden arcs start and end at the tangent points. Refer to Figure 5-19A.
69 Multi-View Drawing Hidden Lines When a hidden arc is tangent to a visible line, leave a space. Refer to Figure 5-19B.
70 Multi-View Drawing 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 Multi-View Drawing Hidden Lines When a centerline and a hidden line project at the same place, draw the hidden line. Refer to Figure 5-20A.
72 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Centerlines
Multi-View Drawing 75 Centerlines Centerlines are special lines used to locate views and dimensions.
76 Multi-View Drawing 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 Multi-View Drawing Centerlines Secondary centerlines are used for drawing details of a part
78 Multi-View Drawing Precedence of Lines
Multi-View Drawing 79 Precedence of Lines The following priority of lines exists: 1. Visible lines. 2. Hidden lines. 3. Cutting-plane lines. 4. Center lines. 5. Break lines. 6. Dimension and extension lines. 7. Section lines (crosshatching).
80 Multi-View Drawing Curved Surfaces
Multi-View Drawing 81 Curved Surfaces Some curved surfaces, such as cylinders and cones do not show curved surfaces in all views.
82 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Cones A cone appears as a circle in one view. It appears as a triangle in the other view.
86 Multi-View Drawing 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 Multi-View Drawing Cones Cylinders, cones and frustums of cones have single curved surfaces. The appear as circles in one view and straight lines in another.
88 Multi-View Drawing Deciding Which Views To Draw
Multi-View Drawing 89 Deciding Which View to Draw Six views are not needed to describe most objects.
Usually three views are sufficient.
90 Multi-View Drawing 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 Multi-View Drawing Deciding Which View to Draw Views with the fewest hidden lines are easiest to read, and require less time to draw.
92 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Deciding Which View to Draw
95 Multi-View Drawing Deciding Which View to Draw
96 Multi-View Drawing Deciding Which View to Draw
97 Multi-View Drawing Deciding Which View to Draw Some parts can be described in only one view. Compare 5-24 C and D.
98 Multi-View Drawing Deciding Which View to Draw Some parts can be described in two views. Figure 5-25 A, B, C, D, E.
99 Multi-View Drawing Deciding Which View to Draw
100 Multi-View Drawing Deciding Which View to Draw
101 Multi-View Drawing Deciding Which View to Draw Examples of parts that can be drawn in two views: Figure 5-26 A - F.
102 Multi-View Drawing 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 Multi-View Drawing Placing Views
Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing 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 Front View Right side View Top 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
107 Multi-View Drawing 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 Multi-View Drawing Figure 5-28
109 Multi-View Drawing Figure 5-29
110 Multi-View Drawing Placing Views 1. Add the width and the depth of the object.
111 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Figure 5-30
114 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Figure 5-30
117 Multi-View Drawing Locating and Transferring Measurements
Multi-View Drawing 118 Locating Measurements Measurements made on one view can be transferred to another. This process also insures accuracy. Refer to Figure 5-33.
119 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Locating Measurements Height of Front view - transfer to Right-side view.
Depth measurements show as vertical distances in the Top view and as horizontal distances in the the Right-side view.
122 Multi-View Drawing Locating Measurements
123 Multi-View Drawing Locating Measurements
124 Multi-View Drawing Locating Measurements 3. Depth measurements show as Vertical distances - Top view Horizontal distances - Right-side view To transfer these measurements use Arcs 45o triangle Dividers Scale
125 Multi-View Drawing Using Arcs to Transfer
126 Multi-View Drawing Using Scale to Transfer
127 Multi-View Drawing Using 45 Line to Transfer
128 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing 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 Multi-View Drawing Summary of Steps 10. Darken the lines where necessary to make them sharp and black and of proper thickness
132 Multi-View Drawing 133 Multi-View Drawing 134 Multi-View Drawing 135 Multi-View Drawing 136 Multi-View Drawing 137 Multi-View Drawing