2. Section 2 Drafting Techniques and Skills
Chapter 8
Multiview Drawings
Section 2 Drafting Techniques and Skills

3. Objectives Explain the principles of orthographic projection.
Identify the number and types of views needed to make a multiview drawing.
Use orthographic projection to create multiview drawings.
Explain the differences between third-angle projection and first-angle projection.
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4. Multiview Drawing
Used to describe three-dimensional objects in two dimensions.
Normally includes three views.
Standard arrangement of views used.
Created with instruments in manual drafting.
Created with drawing commands in CAD.
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5. Standard Arrangement of Views
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6. Orthographic Projection
Synonymous with “multiview drawing.”
Views obtained by projecting lines of sight (or projectors) to projection plane.
Glass box helpful in visualizing views.
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7. Orthographic Projection (Cont.)
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8. Glass Box
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9. Projection Technique
Involves three principal planes (or coordinate planes) oriented at right angles.
Front view shown in frontal plane.
Top view shown on horizontal plane.
Side view shown on profile plane.
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10. Principal Planes of Projection
Front view also called front elevation.
Top view also called plan view.
Side view also called end view, side elevation, or end elevation.
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11. Object Views Six views possible for any given object.
Height shown in front, side, and rear views.
Width shown in top, front, bottom, and rear views.
Depth shown in top, side, and bottom views.
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12. Object Views (Cont.)
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13. Projecting Elements Between Views
Miter line drawn at 45° to project measurements.
Miter line meets projection planes at point between views.
Circles and arcs located initially in views where they appear naturally.
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14. Projecting Elements Between Views (Cont.)
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15. Projecting Points To locate point, measure from projection planes.
Measure in three directions (width, depth, and height).
Points for major features determine other point locations and layout of views.
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16. Drawing Layout
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17. Projecting Lines
Process used to represent intersections, edges, and surface limits.
Straight line connects two points.
Curved line used for arc and curve forms.
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18. Features Represented by Lines
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19. Types of Straight Lines
Horizontal lines
Vertical lines
Inclined lines
Oblique lines
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20. Horizontal Lines Parallel to horizontal plane and one other plane.
Perpendicular to third plane.
Shown true length in two planes.
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21. Vertical Lines Parallel to frontal and profile planes.
Perpendicular to horizontal plane.
Shown true length in frontal and profile planes.
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22. Inclined Lines Parallel to one projection plane.
Inclined and foreshortened in other two planes.
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23. Oblique Lines
Neither parallel nor perpendicular to any projection planes.
Foreshortened in all three planes.
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24. Projecting Surfaces
Plane surfaces and curved surfaces most typical for machine parts.
May be done by locating endpoints, plotting series of points, or creating special views.
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25. Types of Surfaces Horizontal surfaces Vertical surfaces
Inclined surfaces
Oblique surfaces
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26. Single-Curve and Double-Curve Surfaces
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27. Warped Surfaces
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28. Projecting Angles
True size projected when plane is parallel to a projection plane.
Foreshortening occurs when plane is inclined or oblique.
Right angles on inclined planes project true size on two planes.
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29. Projecting Angles (Cont.)
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30. Selecting Views Make front view most descriptive.
Identify most representative contour or shape.
Identify most natural or functioning position.
Arrange views to minimize hidden lines.
Consider space requirements.
Top and front view typical for long, narrow objects.
Front and side view typical for short, broad objects.
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31. Selecting Views (Cont.)
Choose between two equally important views unless space or other factors prohibit.
Choose right-side view over left-side view.
Choose top view over bottom view.
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32. Selecting Views (Cont.)
Use only sufficient number of views.
One view typically suitable for objects made from thin stock.
Two views normally used for cylindrical objects.
Three or more views may be required for more complex objects.
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33. Selecting Views (Cont.)
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34. Spacing Views on a Drawing
Calculate combined width of front and side views.
Add approximately 1 for spacing between views.
Divide amount of space remaining between ends of drawing area.
Determine vertical spacing in similar manner.
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35. Spacing Views on a Drawing (Cont.)
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36. Conventions for Hidden Lines
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37. Order of Visibility for Coinciding Lines
Visible lines
Hidden lines
Cutting-plane lines
Centerlines
Break lines
Dimension and extension lines
Section lines
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38. Removed Views Shown enlarged to clarify detail.
Placed at convenient location.
Identified in appropriate manner.
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39. Partial Views Typically used for symmetrical parts. Half views
Views with break lines
Partial side views
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40. Applications for Conventional Drafting Practices
Fillets and rounds
Runouts
Right-hand and left-hand parts
Cylinder intersections
Radial features
Alternate positions
Repeated details
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41. Fillet and Round Drawing Practices
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42. Runout Drawing Practices
Used for arms, spokes, and webs.
Arc should have same radius as fillet or round.
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43. Drawing Right-Hand and Left-Hand Parts
Conventional practice used when parts are not interchangeable.
View omitted to save time.
Note used to indicate information.
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44. Conventional Practices for Intersections
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45. Conventional Practices for Radial Features
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46. Drawing Parts in Alternate Positions
Conventional practice used to show limits and clearance.
Phantom lines show extents of movement.
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47. Drawing Repeated Details
Conventional practice used for common items.
Phantom lines indicate missing features.
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48. Orthographic Projection Methods
First-angle projection
Third-angle projection
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49. Third-Angle Projection
Frontal plane located between viewer and object.
Views projected forward to frontal plane from third quadrant.
Views appear in natural positions.
Used in United States and Canada.
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50. Third-Angle Projection (Cont.)
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51. First-Angle Projection
Frontal plane located on far side of object from viewer.
Views projected to rear from first quadrant.
View arrangement different from third-angle projection.
Used in European countries.
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52. First-Angle Projection (Cont.)
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53. Drawing Identification Symbols
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54. Visualizing a Three-Dimensional Object from a Multiview Drawing
Break views down mentally into geometric shapes.
Consider possibilities for each shape.
Identify hidden features and object centers.
Compare shapes and dimensions in different views.
Make freehand sketch.
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55. Visualizing a Three-Dimensional Object from a Multiview Drawing (Cont
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56. Laying Out a Drawing
Same principles apply whether drawing manually or using CAD.
Manual drawings must have good line quality and accuracy.
CAD drawings should be made accurately and efficiently.
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57. Lay Out a Multiview Drawing
Select appropriate sheet size and scale.
Draw light lines to “block in” views.
Locate arcs and circles before lines.
Omit hidden lines, centerlines, and dimension lines during layout.
Check for missing items.
Remove unnecessary construction lines.
Darken lines in appropriate order.
Letter notes and title block.
Check drawing for accuracy and appearance.
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58. Create a Multiview Drawing
Define drawing settings and layers or use template.
Use Xline command and other commands needed to “block in” views.
Draw object lines in each view using drawing commands.
Draw hidden lines and centerlines.
Draw filleted and chamfered features.
Use Text command to create text objects.
Freeze layers as needed.
Check drawing for accuracy and appearance.
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59. Review Questions
1. In orthographic projection, the projection on the profile plane is called the _____ view.
A. top
B. front
C. plan
D. side
D. side
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60. Review Questions
2. Which of the following is not a principal projection plane?
A. Frontal
B. Profile
C. Vertical
D. Horizontal
C. Vertical
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61. Review Questions
3. The _____ box is a helpful drafting aid used to develop skill in visualizing views.
glass
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62. Review Questions
4. In the standard arrangement of views, the top view appears above the _____ view.
front
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63. Review Questions
5. How many views are typically sufficient for a multiview drawing?
A. Three
B. Four
C. Five
D. Six
A. Three
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64. Review Questions
6. _____ lines are parallel to one plane of projection and inclined in the other two planes.
A. Oblique
B. Inclined
C. Horizontal
D. Vertical
B. Inclined
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65. Review Questions 7. _____ surfaces appear true size in the top view.
A. Oblique
B. Inclined
C. Horizontal
D. Vertical
C. Horizontal
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66. Review Questions
8. The _____ view should be the most representative of the shape of the object.
A. top
B. front
C. side
D. end
B. front
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67. Review Questions
9. Most drawings made in the United States use _____ projection.
A. first-angle
B. second-angle
C. third-angle
D. fourth-angle
C. third-angle
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68. Review Questions
In _____-angle projection, the frontal projection plane is on the far side of the object from the viewer.
first
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69. Glossary Fillet Foreshortened Frontal plane
A small, rounded, internal corner.
Foreshortened
Drawn shorter than true length.
Frontal plane
The principal projection plane projecting the front view in orthographic projection.
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70. Glossary Hidden lines Horizontal plane
Thin lines made up of short evenly spaced dashes, used to indicate edges, surfaces, and corners of an object that are concealed from the view of the observer.
Horizontal plane
The principal projection plane projecting the top view in orthographic projection.
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71. Glossary Multiview drawing Orthographic projection
A projection drawing that incorporates two or more views of a part or assembly on one drawing.
Orthographic projection
A system of drawing in which a projection of an object is formed on a picture plane by perpendicular projectors from the object to the picture plane.
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72. Glossary Plan view Point The top view of an object.
Something having position, but not extension. It has location in space, but no length, depth, or height.
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73. Glossary Principal planes Profile plane
The three primary planes (frontal, horizontal, and profile) used to project views in orthographic projection.
Profile plane
The principal projection plane projecting the side view (or “end” view) in orthographic projection.
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74. Glossary Round Runout A small, rounded, external corner.
The intersection of a fillet or round with another surface.
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