1. Multiview Sketching & Projection Chapter 5 Print handouts
8/11/03
Chapter 5
Multiview
Sketching
&
Projection
Print handouts
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Ortho-1

2. Orthographic Projection
A system of drawing views of an object using perpendicular projectors from the object to a plane of projection (I.e. paper)

3. Six Standard Views Top, front, right side, left side, back and bottom
Usually shows most detail
If applicable – should show object in operating condition (I.e. car)

4. View Placement (3rd angle projection)
Front view usually shows the most detail
Projection Lines
Why must views be arranged so that they align?
To make it possible for someone to interpret the drawing.

5. Revolving an Object to Produce the Six Basic Views

6. 8/11/03
The Glass Box Metaphor
Imagine that the object you are going to draw is positioned inside a glass box, so that the large flat surfaces of the object are parallel to the walls of the box.
2 horizontal planes
2 frontal planes
2 profile planes
From each point on the object, imagine a ray, or projector perpendicular to the wall of the box forming the view of the object on that wall or projection plane.
2 horizontal planes (top and bottom views)
2 frontal planes (front and back views)
2 profile planes (right and left side views)
Ortho-1

7. Projection of an Object

8. Projection of an Object

9. Unfolding the Glass box
8/11/03
Unfolding the Glass box
For Third Angle Projection (the method in the U.S.)
Imagine that the walls of the box are hinged and unfold the views outward around the front view.
This will give you the standard arrangement of views for 3rd Angle Projection which is used in the US, Canada, and some other countries.
Ortho-1

10. Third Angle Projection:
8/11/03
Third Angle Projection:
Symbol for third angle projection shown on dwg
Third angle projection
Standard for USA,
Canada and our class!
First Angle Projection:
First angle projection
Primarily used in
Europe and Asia!
Symbol for first angle projection
Ortho-1

11. 8/11/03
Glass Box Method
Ortho-1

12. DEMO
If a point, line or plane is in one view, it must be in all the views.

13. Hidden Lines

14. Precedence of Lines
When visible lines, hidden lines and center lines coincide remember:
Visible lines take precedence over hidden lines
Hidden lines take precedence over center lines, For example:
Figure 5.32

15. Example Do Hands-On 3 together Label Need Follow instructions
HB pencil
Engineering Calculation Paper
Model
Instructions (Sept. Schedule of Assignments in Angel)
Follow instructions
Remember specs for the border & title block are included in the Penn State Erie Graphics Standards and in Handouts folder in Angel
Label
Views – TOP, FRONT, etc.

16. Hands-On 4
Instructions on the web

17. 8/11/03
Chapter 5
Multiview
Sketching
&
Projection
Part 2
Ortho-1

18. Necessary Views
A sketch or drawing should only contain the views needed to clearly and completely describe the object. Choose the views that show the shape most clearly, have the fewest hidden lines, and show the object in a usual, stable, or operating position.
One view drawing
of a shim
One view drawing
of a connecting rod

19. 3 Views - Most Common Three views necessary?
8/11/03
3 Views - Most Common
Three views necessary?
Which view could be eliminated?
Top
45°
Views?
Depth
Planes?
Dimensions? H F
Reference Line or Fold Line
Width
Depth
Projection Lines
Height
F P
Front
Right Side
Ortho-1

20. Transferring Dimensions
Mitered System
Dividers or Scale

21. Mitered System
Determine spacing necessary between the front and right side views.
For example, when dimensioning, more space is needed between the views.
This will be the left edge of the right side view
clear space

22. Mitered System
Extend a projection line from the bottom edge of the top view and one from the left side of the right side view until they intersect.
Bottom edge of the top view
Intersection
Left edge of the right side view
clear space

23. Mitered System
Extend a 45° angled line from the point of intersection.
45º
From point of intersection

24. Mitered System cont’d. Project additional points, surface by surface.2 4 3 1 1 1 3

25. Mitered System cont’d. Project additional points, surface by surface.2 4 3 1 8 7 6 5

26. Mitered System cont’d.
Draw the view locating each vertex of the surface on the projection and miter line. 2 4 3 1 8 7 6 5

27. Dividers or Scale
With folding lines
Without folding lines

28. Hidden Lines

29. Also Review
PENN STATE ERIE DRAFTING STANDARDS

30. 8/11/03
Chapter 5
Multiview
Sketching
&
Projection
Part 3
Ortho-1

31. Review Hidden Lines

32. Surface Identification

33. View Identification

34. Configuration Rule NORMAL SURFACE
Plane is shown true shape and size. In other words, parallel to one of the principal planes.
EDGE
EDGE TS
SURFACE B

35. Configuration Rule INCLINDED SURFACE
EDGE
INCLINDED SURFACE
Surface is perpendicular to one plane and will show as an edge on that plane.
And the surface is tipped, or inclined, to adjacent planes. The surfaces in these views are foreshortened.

36. Configuration Rule OBLIQUE PLANE
Surface is not parallel or perpendicular to any principal plane.
NORMAL PLANE
EDGE TS
? PLANE
EDGE

37. Configuration Rule
? PLANE
Is this one correct?

38. Points, Lines & Planes If all else fails,
Break the object down to simpler shapes
Locate the height, width and depth of each point.

39. Exercise

40. 8/11/03
Chapter 5
Multiview
Sketching
&
Projection
Part 4
Ortho-1

41. Center Lines ¾” – 1-1/2” LONG Thin dark line Purpose of a center line?
1/8” DASH
1/16” GAP
¾” – 1-1/2” LONG
Thin dark line
Purpose of a center line?
To show location of a hole, arc, cylinder, etc.

42. Center Lines Extend center line ¼” past the hole Extend center line
HOW MANY CENTER LINES MISTAKES?
Extend center line
¼” past the hole

43. Center Lines ¼” past the end of the hole and/or cylinder
End of cylinder
End of hole
End of hole

44. Precedence of Lines HIDDEN LINES TAKE PRECEDENCE OVER CENTER LINES
¼” FROM END OF HOLE
1/16” GAP
HIDDEN LINES TAKE PRECEDENCE OVER CENTER LINES
OBJECT LINES TAKE PRECEDENCE OVER HIDDEN LINES

45. Center Lines 1/16” gap If longer than 1-1/2” add a dash in the middle
INCORRECT

46. Projection of an Object
Fillets and Rounds: Self locating, so do NOT add center lines, but do draw where sharp corner would be.

47. Projection of an Object
Why?
POOR PRACTICE
PREFFERED
Adds clarity

48. Projection of an Object
POOR PRACTICE
PREFFERED PRACTICE

49. Projection of an Object
Runout
POOR PRACTICE
PREFFERED PRACTICE

50. 8/11/03
Chapter 5
Multiview
Sketching
&
Projection
Part 5
Ortho-1

51. Find Location & Size of a Thru Hole
Locate center
Measure the Depth
Parallel to isometric grid line
Tangent to ellipse
Enough information to determine diameter and location of hole on front surface

52. Find Location and Size
What is the diameter and length of the cylinder?
Ø1.5 X 3.75
1 Grid = .25

53. Find Location and Size
Size of hole?
Ø1.0 X 1.75

54. Find Location and Size
Size of Hole? Ø

55. Cylinders, Holes & Arcs
Diameter?
Ø2.0
Ø1.5
Ø2.0
Ø2.0
R.5