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
• Final Project is due on May 9th.
• Final Exam is May 16th.

3. Extra Credit # 4
• For ten extra points, write a question for our upcoming
final exam (final exam is in one month on May 16th )
• Question can be in any of the following formats
• Question with a drawing/sketch for an answer
• Essay Question
• Fill in the blank question
• True/False
• Multiple Choice
• Question can cover any topics we have covered in class
since Exam 1 (Orthographic, Isometric, Section Views).
Also can include Auxiliary Views and Dimensioning.
• Please include your answer
• Question & Answer are due in two weeks on May 2nd for
extra ten points

4. Why Your Instructor Can’t Win . . .
• Thank-you to all who filled out the mid-term survey.
• Don’t like the instructor showing drawing examples that
are in the book
• Best / most helpful is the instructor explaining the
examples in the book

5. Example Competencies
• Identify full sections
• Identify half sections
• Identify the hatch pattern for cast iron
• Create full section sketches of simple objects
• Create half section sketches of simple objects

6. New Groups!!
• We are going to mix up the groups in class today.
• Make a new group of 2 to 3 people composed of one
person from each row.
• Make sure your new group is different than your new
group was last week.

7. Homework Problem 3.1 (i)
• Raise your hand if you completed homework problem 3.1
(i)
• If you didn’t complete this homework problem, partner up
with someone who did.
• Work out the problem together in a pair or group
• Turn in the problem if you didn’t turn it in before for credit.

8. Another Group Project – Isometric
Drawings with Angles
• In your group, do an isometric drawing of Exercise 5.2
• What method do you find useful for drawing an angle in
isometric?

9. LINGERING QUESTIONS
ABOUT CHAPTER 7 –
SECTION VIEWS

10. How common is it to see section views in
isometric drawings?
• Not too common, but they are shown at times to show
detail, especially in buildings.

11. How much artistic license can you take on
a technical drawing?
• Depends on the purpose
• Representative drawing . . . If you are just trying to create a quick
sketch to work out details with a colleague, everything doesn’t have
to be spot on.
• Otherwise a technical drawing should not be “too artistic” and
should be accurate (especially angles and dimensions) to ensure
that it will be built correctly.

12. Are there dimensioning restrictions on
aligned sections?
• Correct dimensions should be shown
• We’ll discuss this in more detail over the next two weeks
as we get into Chapter 10 (Dimensions)
Aligned Section

13. Intersections in Section Views
• In your groups, find objects around the room that show an
intersection
• Draw a section view
• Is the intersection small an unimportant, or is it large
enough to show as a true projection?
• See page 262 for examples

14. CHAPTER 8 –
AUXILIARY VIEWS

15. 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

16. UNDERSTANDING AUXILIARY VIEWS
Auxiliary views are useful for both design and documentation. Many
objects are shaped so that their principal faces are not parallel to the
standard planes of projection.
To show the true circular shapes, use a direction of sight perpendicular to the
plane of the curve, to produce an Auxiliary View.

17. The Auxiliary Plane
To show the inclined surface (P) true size, the
direction of sight must be perpendicular to the
inclined plane.
The auxiliary plane in this case is perpendicular
to the frontal plane of projection and
hinged to it. It is angled to the horizontal (top)
and profile (side) viewing planes.

18. Classification of Views
• Auxiliary Views are classified depending on which
principal dimension is shown in the projection

19. Depth Auxiliary Views
All these views show the object’s depth and therefore are all depth
auxiliary views.

20. Height Auxiliary Views
The front view and all these auxiliary views show the height of the object.
Therefore, all these auxiliary views are height auxiliary views.

21. Width Auxiliary Views
The front view and all these auxiliary views are width auxiliary
views.

22. Group Project – Classify Auxiliary Views
• Draw the necessary views of a simple object with an
inclined or an oblique surface
• Create a simple auxiliary view
• Classify your view as a depth, height, or width view
• Revolve your object and practice drawing the other two
types of auxiliary views

23. Primary Auxiliary Views
A primary auxiliary view is projected onto a plane that is perpendicular to one
of the principal planes of projection and is inclined to the other two.

24. Successive Auxiliary Views
From a primary auxiliary view , a secondary auxiliary view can be drawn, then
from it a third auxiliary view, and so on.
Successive Auxiliary Views

25. Secondary Auxiliary Views
A secondary auxiliary view is projected from a primary auxiliary view
onto a plane that is inclined to all three principal projection planes.
Second Auxiliary View, showing
the True Size of the Top Oblique
Surface

26. Pop Quiz – Primary or Secondary?
Source: http://www.pleasantville.k12.ia.us/staff/fvanderpool/pages/draftingsg.html

27. Pop Quiz – Primary or Secondary?
Primary
Source: http://www.pleasantville.k12.ia.us/staff/fvanderpool/pages/draftingsg.html

28. Pop Quiz – Primary or Secondary?
Source: http://www.pleasantville.k12.ia.us/staff/fvanderpool/pages/draftingsg.html

29. Pop Quiz – Primary or Secondary?
Secondary
Source: http://www.pleasantville.k12.ia.us/staff/fvanderpool/pages/draftingsg.html

30. Pop Quiz – Primary or Secondary?
Source: http://joekintercadportfolio.weebly.com/segment-8-supplemental-views.html

31. Pop Quiz – Primary or Secondary?
Secondary
Source: http://joekintercadportfolio.weebly.com/segment-8-supplemental-views.html

32. Pop Quiz – Primary or Secondary?
Source: http://joekintercadportfolio.weebly.com/segment-8-supplemental-views.html

33. Pop Quiz – Primary or Secondary?
Primary
Source: http://joekintercadportfolio.weebly.com/segment-8-supplemental-views.html

34. Pop Quiz – Primary or Secondary?
Source: http://www.door-hardware-
genius.com/?p=216

35. Pop Quiz – Primary or Secondary?
Primary
Source: http://www.door-hardware-
genius.com/?p=216

36. Reference Planes
Instead of using one of the planes of
projection, you can use a reference plane If you are using 2D CAD, you
parallel to the plane of projection that can draw half of the view and
then mirror the object.
touches or cuts through the object.

37. What Methods do you use for Parallel
Lines?
• I use
• My beloved (but now broken) roller ruler
• Triangles
• Grid Paper (if possible)
• Best guess (and inaccurate) with ruler
What do you use?

38. Projecting an Auxiliary View
• Let’s practice using a reference plane to draw an auxiliary
view.
• Practice with the Example on page 286 of the text book

39. USING GRID PAPER TO SKETCH
AUXILIARY VIEWS
You can use grid paper
to help sketch auxiliary
views by orienting
the lines of the grid
paper underneath your
vellum or other
semitransparent
drawing sheet so that
the grid is parallel to
the inclined edge in the
drawing…

40. Group Project – Auxiliary View of an
Inclined Surface
• Use an inclined surface that you have brought to class,
one that you see around the classroom, or one that I have
to create a drawing with necessary views and an auxiliary
view using a reference plane or the grid paper method

41. Project Time!
• Share your projects with your group.
• Discuss whether an auxiliary view is necessary for your
project
• Rough sketch the auxiliary view

42. 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.

43. HIDDEN LINES
IN AUXILIARY VIEWS
Generally, hidden lines
should be omitted in
auxiliary views, unless they
are needed to clearly
communicate the drawing’s
intent.
Your instructor may ask you to show all hidden lines
for visualization practice, especially if the auxiliary
view of the entire object is shown. Later, when you are
familiar with drawing auxiliary views, omit hidden
lines when they do not add needed information to the
drawing.

44. 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

45. 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

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

47. REVERSE CONSTRUCTION
To complete the regular views, it is often
necessary to first construct an auxiliary
view where critical dimensions will be
shown true size.

48. PARTIAL AUXILIARY VIEWS
Using an auxiliary view often makes it possible to omit one or more regular
views, but auxiliary drawings are time consuming to create and may even be
confusing because of the clutter of lines. Partial views are often sufficient and
easier to read.

49. AUXILIARY SECTIONS
An auxiliary section is simply an auxiliary view in section.
Note the
cutting-plane line and the terminating arrows that indicate the direction
of sight for the auxiliary section. In an auxiliary section
drawing, the entire portion of the object behind the cutting plane
may be shown, or the cut surface alone may be shown.

50. 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.

51. What’s Next?
• Finish Chapter 8 Auxiliary Views
• Chapter 10 - Dimensioning

52. 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?

53. Homework
Read Chapter 10
Chapter 8 Review Questions: 1, 3, 4
Chapter 8 Exercises: 8.5 [Draw necessary views and
auxiliary view (s) ]