The document provides information about a 2D essentials class being taught from January to May 2012, including reminders about assignments due like the final project and exam, as well as covering topics to be discussed in class like auxiliary views, dimensioning, and group projects to practice techniques.

1. 2D ESSENTIALS
Instructor: Laura Gerold, PE
Catalog #10614113
Class # 22784, 24113, 24136, & 24138
Class Start: January 18, 2012
Class End: May 16, 2012

2. Reminders
• Extra Credit (Write Exam Question) Due Next Week (May
2nd)
• Final Project is due in two weeks on May 9th.
• Final Exam is in three weeks on May 16th.

3. Group Project – Parallel Lines
• In your groups, discuss and practice the methods that can
be used to draw parallel lines on an object.
• Present your methods
• Group with the most methods receives an award . . .

4. CHAPTER 8 –
AUXILIARY VIEWS

5. Why Do We Need Auxiliary Views?
• Inclined Planes and Oblique lines do not appear true size
or true length in any orthographic views
• In order to show better detail on the inclined and oblique
planes, auxiliary views are used
• Auxiliary views are taken from an angle that is not one of
the primary standard orthographic views
Source:
http://draftingmanuals.tpub.com/14040/css/14
040_41.htm

6. What are the differences between
primary, secondary, and successive views?
• Primary auxiliary views are projected from one of the
principal planes (front, top, side).
Source: http://www.pleasantville.k12.ia.us/staff/fvanderpool/pages/draftingsg.html

7. What are the differences between primary,
secondary, and successive views?
• Secondary auxiliary are projected from the primary
auxiliary plane
Source: http://joekintercadportfolio.weebly.com/segment-8-supplemental-views.html

8. What are the differences between
primary, secondary, and successive views?
• A third auxiliary view can be obtained from a projection of
the secondary auxiliary view and so on . . . .

9. What are the differences between
primary, secondary, and successive views?
• Group Project
• Use a simple object with an inclined surface
• Draw the necessary views
• Draw a Primary Auxiliary View
• Draw a Secondary Auxiliary View
• Draw another “Successive View”
• Present results

10. HIDDEN LINES IN AUXILIARY VIEWS
• Hidden Lines can
clutter an auxiliary
drawing and are not
shown unless
essential to
understanding the
object.
• As a beginning
technical drawer, you
may want to show all
hidden lines for
visualization practice

11. CIRCLES AND ELLIPSES
IN AUXILIARY VIEWS
Circular shapes appear elliptical when viewed at an angle other than 90° (straight
on to the circular shape). This is frequently the case when constructing auxiliary
views.

12. Show an Inclined Elliptical Surface True
Size
• Let’s practice drawing an inclined elliptical surface to true
size in an auxiliary view.
• Practice with the Example on page 288 of the text book

13. Group Project – Elliptical Surfaces
• Use an object in the room, an object you brought, an
object you find outside the room, an object in the book, or
make up the necessary views of an elliptical surface.
• Draw an elliptical surface auxiliary view

14. Plotting Curves in an Auxiliary View
• Let’s practice plotting curves to draw in an auxiliary view.
• Practice with the Example on page 290 of the text book

15. Group Project – Plotting Curves
• Use an object in the room or make up the necessary
views of a curved object.
• Draw a curved auxiliary view

16. VIEWING-PLANE LINES
AND ARROWS
When the drawing sheet is too crowded to show the auxiliary view in
direction projection you can use a viewing-plane line or a viewing
direction arrow to indicate the direction of sight for the auxiliary view.

17. Uses of Auxiliary Views
• Auxiliary Views are often used to show the following:
• True length of a line
• Point view of a line
• Edge view of a plane
• True size of a plane

18. TRUE LENGTH OF A LINE
To show a line true length, make the fold line parallel to the line you want to show
true length in the auxiliary view. Whenever a line is parallel to the fold line between
two views, it will be true length in the adjacent view.

19. TRUE LENGTH OF A LINE – EXAMPLE
• Work through the true length of a hip rafter example on
page 295

20. TRUE LENGTH OF A LINE – GROUP
PROJECT
• Use an inclined surface that you brought with you, that I
have, or that you see around the room.
• Practice drawing the necessary views and an auxiliary
view with the true length of one of the inclined lines.

21. POINT VIEW OF A LINE
To show the point view of a line, choose the direction of sight parallel to the
line where it is true length. 1. Choose the direction of sight to be parallel to
line 1–2.
2. Draw folding line H/F between the top and
front views, as shown.
3. Draw folding line F/1 perpendicular to line 1–2
where it is true length, and any convenient
distance from line 1–2 (front view).
4. Draw projection lines from points 1 and 2 to
begin creating the auxiliary view.
5. Transfer points 1 and 2 to the auxiliary view at
the same distance from the folding line as they
are in the top view and along their respective
projection lines. They will line up exactly with
each other to form a point view of the line.

22. POINT VIEW OF A LINE
GROUP PROJECT
• Use Picture from Previous Slide (Figure 8.26 on page 296
of your text book)
• After locating the points, how would you draw the rest of
the auxiliary view? Would you use a breakline? Or would
you ever just want to show the points?
• When do you think this would be useful when creating a
set of drawings?

23. EDGE VIEW OF A PLANE
To show the edge view of a plane, choose the direction of sight parallel to a
true-length line lying in the plane.
1. Choose the direction of sight to be parallel to line 1–2 in
the front view where it is already shown true length.
2. Draw folding line H/F between the top and front views, as
shown.
3. Draw folding line F/1 perpendicular to true-length line 1–2
and any convenient distance.
4. Draw projection lines from points 1, 2, 3, and 4 to begin
creating the auxiliary view.
5. Transfer points 1, 2, 3, and 4 to the auxiliary view at the
same distance from the folding line as they are in the top view
and along their respective projection lines. Plane 1–2–3–4
will appear on edge in the finished drawing.

24. EDGE VIEW OF A PLANE
GROUP PROJECT
• Use Picture from Previous Slide (Figure 8.28 on page 297
of your text book)
• After locating the edge view of the plane, how would you
draw the rest of the auxiliary view? Would you use a
breakline?
• When do you think this would be useful when creating a
set of drawings?

25. TRUE SIZE OF AN OBLIQUE
SURFACE
Showing the true size of a surface continues from the method presented for showing
inclined surfaces true size, where the edge view is already given. But to show an oblique
surface true size, you need first to show the oblique surface on edge and then construct a
second auxiliary view to show it true size.

26. TRUE SIZE OF AN OBLIQUE
SURFACE
• Let’s practice drawing the true size of an oblique surface
in an auxiliary view.
• Practice with the Example on page 298 of the text book

27. TRUE SIZE OF AN OBLIQUE
SURFACE GROUP PROJECT
• Use an object in the room, an object you brought, an
object you find outside the room, or Figures 8.32 or 8.33
in the book
• Draw the true size of an oblique surface in an auxiliary
view

28. Steps for drawing Auxiliary Views
1. Determine the direction of viewing.
2. Number the vertices on the inclined plane if needed.
3. Draw projectors along the direction of sight. The projectors will be
perpendicular to the inclined edge.
4. Pick an appropriate folding line or reference plane.
5. Transfer measurements from the adjacent view onto the projectors.
6. Join the projected points to get true shape of inclined plane.
7. Transfer rest of the object onto the Auxiliary view if required to do so,
else close by drawing a break line. Omit hidden lines in Auxiliary views.

29. Auxiliary Views Group Real-World Project
• My husband gave a set of plans to a builder for a unique
roof, but did not give an auxiliary view
• The builder called him to ask how exactly to build it
• Should he have used an auxiliary view?
• If so, what views would you have shown? Do a quick
sketch.
• Picture of Finished Building

30. Auxiliary Views Worksheet
• As a group, work on the Auxiliary Views Worksheet

31. Auxiliary Views Worksheet Answers
1. secondary
2. at right angles or parallel to the projection lines
3. the principal dimension not shown in the view being
projected from
4. dihedral angle
5. to show true size and true shape
6. creating the auxiliary view before creating the basic views.
7. A. True length of line
b. point view of line
c. Edge view of a plan
d. True size of a plane
8. Hidden lines are usually omitted in Auxiliary, unless required
for clarification. Beginning draftspersons usually add hidden
lines.

32. Auxiliary Views on Youtube
• http://www.youtube.com/watch?v=gzq48vBbODg

33. CHAPTER 10 –
DIMENSIONING

34. Why Do We Dimension Drawings?
• Dimensions describe the size, shape, and material of
objects
• Give detail on how to build an object from the designer to
the manufacturer
Source:
http://www.design-
technology.info/IndPro
d/page11.htm

35. UNDERSTANDING DIMENSIONING
The increasing need for precision manufacturing and interchangeability
has shifted responsibility for size control to the design engineer or detail drafter.
Practices for dimensioning architectural
and structural drawings are similar
in many ways to those for dimensioning
manufactured parts, but some practices
differ.
Refer to the following standards:
• ANSI/ASME Y14.5-2009 Dimensioning and Tolerancing
• ASME Y14.41-2003 Digital Product definition Data Practices Automatically Generated Dimensions.
• ASME B4.2-1978 (R1999) Preferred Metric Limits and Fits Views and dimensions can be generated
automatically from a solid model.
(Courtesy of Robert Kincaid.)

36. Three Aspects of Good Dimensioning
Technique of dimensioning
Placement of dimensions
Choice of dimensions

37. Three Aspects of Good Dimensioning
• Technique of dimensioning
• Standard appearance of lines
• Spacing of Dimensions
• Size of Arrowheads
• Etc.

38. Three Aspects of Good Dimensioning
• Placement of dimensions
• Logical Placement to make dimensions:
• Legible
• Easy to Find
• Easy for the Reader to Interpret

39. Three Aspects of Good Dimensioning
• Choice of dimensions
• Show how the design is manufactured
• Dimension first for Function
• Add dimensions for ease of manufacturing

40. Tolerance
Tolerance is the total amount that the feature on the actual part is allowed
to vary from what is specified by the drawing or model dimension.
ALL TOLERANCES ±.02 INCH
E
UNLESS OTHERWISE NOTED.
X
A
M
P
L
E
S
A Title Block Specifying Tolerances. (Courtesy of Dynojet Research, Inc.)

41. Geometric Breakdown
Engineering structures are composed
largely of simple geometric shapes, such
as the
prism, cylinder, pyramid, cone, and
sphere. They may be exterior (positive)
or interior (negative) forms.

42. LINES USED IN DIMENSIONING
• Dimension Line
• A thin, dark, solid line terminated by an arrowhead, indicating
the direction and extent of a dimension
• Usually Perpendicular to extension lines
• The distance is indicated numerically at the midpoint of the
dimension line, either adjacent to the dimension line, or in a
gap provided for it.
• First Dimension Line should be at least 3/8” away from
object
• Subsequent lines can be ¼” apart and should be uniform

43. LINES USED IN DIMENSIONING
• Extension Line
• Thin, dark, solid line that extends from a point on a drawing to
which a dimension refers
• Typically Perpendicular to Dimension Lines
• A small gap (1/16”) should be left between the extension line
and the object
• Extension line should extend 1/8” beyond the outermost arrow
• An extension line does not have arrows

44. LINES USED IN DIMENSIONING
• Example Dimension and Extension Lines
Source:
http://www.theswg
eek.com/2008/05/
29/hide-show-
extension-and-
dimension-lines/

45. LINES USED IN DIMENSIONING
• Centerlines
• Thin dark line alternating long and short dashes
• Commonly used as extension lines in locating holes
and other symmetrical features
• When extended for dimensioning, cross over the
other lines of a drawing with no gaps
• End centerlines using a long dash

46. Guidelines for
USING DIMENSION
AND EXTENSION LINES
a. Shorter dimensions are nearest the object outline
b. Do not place shorter dimensions outside, which result in
crossing extension lines
c. Okay to cross extension lines, but they should not be
shortened
d. A dimension line should never coincide with or extend from any
line of a drawing

47. Guidelines for
USING DIMENSION
AND EXTENSION LINES
Dimensions should be lined up and grouped together
as much as possible.

48. Guidelines for
USING DIMENSION
AND EXTENSION LINES
a) Extension and Centerlines must cross visible lines of an object in
many cases.
b) When this occurs, do not leaves gaps

49. ARROWHEADS
• Arrowheads
• Should be uniform in size and style
throughout the drawing
• Length and width should have a ratio of
3:1
• Length of arrowhead should be about
1/8” long
• Should be filled in to look better
When you are drawing by hand and using
the arrowhead method in which both
strokes are directed toward the point, it is
easier to make the strokes toward yourself.

50. LEADERS
A leader is a thin, solid line directing attention to a note or dimension and
starting with an arrowhead or dot.
For the Best Appearance, Make Leaders
• near each other and parallel
• across as few lines as possible
Don’t Make Leaders
• parallel to nearby lines of the drawing
• through a corner of the view
• across each other
• longer than needed
• horizontal or vertical

51. Group Project
• Look at the drawings on page 401 & 402 of the text
• Identify the extension, dimension, center, and leader lines
• Note the style and location of the arrowheads

52. DRAWING SCALE AND DIMENSIONING
Drawing scale is noted in the title block. The drawing should not be scaled for
dimensions. (Courtesy of Dynojet Research, Inc.)
Many standard title blocks include a
note such as:
DO NOT SCALE DRAWING
FOR DIMENSIONS

53. DIRECTION OF DIMENSION
VALUES AND NOTES
All dimension values and notes are lettered horizontally to be read from the bottom of the
sheet, as oriented by the title block.

54. DIMENSION UNITS
A note stating ALL MEASUREMENTS IN MILLIMETERS or ALL MEASUREMENTS IN
INCHES UNLESS OTHERWISE NOTED is used in the title block to indicate the
measurement units…
(Courtesy of Dynojet Research, Inc.)

55. Project Time!
• Share your projects with your group.
• Discuss dimensioning your project.
• Make a list of dimensioning questions you have about
your project and turn it in for specific instruction next class

56. What’s Next?
• Finish Chapter 10 - Dimensioning

57. Questions?
• On one of your sketches, answer the following
two questions:
• What was the most useful thing that you
learned today?
• What do you still have questions about?

58. Homework
Chapter 8 Review Questions: 1,6
Chapter 8 Exercises: 8.28