Class 12 presentation


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Class 12 presentation

  1. 1. 2D ESSENTIALSInstructor: Laura Gerold, PECatalog #10614113Class # 22784, 24113, 24136, & 24138Class Start: January 18, 2012Class End: May 16, 2012
  2. 2. Reminders• Final Project is due on May 9th.• Final Exam is May 16th.
  3. 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. 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. 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. 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. 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. 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?
  10. 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. 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. 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. 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
  15. 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: 040_41.htm
  16. 16. UNDERSTANDING AUXILIARY VIEWSAuxiliary views are useful for both design and documentation. Manyobjects are shaped so that their principal faces are not parallel to thestandard 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. 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 perpendicularto the frontal plane of projection andhinged to it. It is angled to the horizontal (top)and profile (side) viewing planes.
  18. 18. Classification of Views• Auxiliary Views are classified depending on which principal dimension is shown in the projection
  19. 19. Depth Auxiliary ViewsAll these views show the object’s depth and therefore are all depthauxiliary views.
  20. 20. Height Auxiliary ViewsThe front view and all these auxiliary views show the height of the object.Therefore, all these auxiliary views are height auxiliary views.
  21. 21. Width Auxiliary ViewsThe front view and all these auxiliary views are width auxiliaryviews.
  22. 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. 23. Primary Auxiliary ViewsA primary auxiliary view is projected onto a plane that is perpendicular to oneof the principal planes of projection and is inclined to the other two.
  24. 24. Successive Auxiliary ViewsFrom a primary auxiliary view , a secondary auxiliary view can be drawn, thenfrom it a third auxiliary view, and so on. Successive Auxiliary Views
  25. 25. Secondary Auxiliary ViewsA secondary auxiliary view is projected from a primary auxiliary viewonto a plane that is inclined to all three principal projection planes. Second Auxiliary View, showing the True Size of the Top Oblique Surface
  26. 26. Pop Quiz – Primary or Secondary? Source:
  27. 27. Pop Quiz – Primary or Secondary?Primary Source:
  28. 28. Pop Quiz – Primary or Secondary? Source:
  29. 29. Pop Quiz – Primary or Secondary?Secondary Source:
  30. 30. Pop Quiz – Primary or Secondary? Source:
  31. 31. Pop Quiz – Primary or Secondary?Secondary Source:
  32. 32. Pop Quiz – Primary or Secondary? Source:
  33. 33. Pop Quiz – Primary or Secondary?Primary Source:
  34. 34. Pop Quiz – Primary or Secondary?Source:
  35. 35. Pop Quiz – Primary or Secondary?PrimarySource:
  36. 36. Reference PlanesInstead of using one of the planes ofprojection, you can use a reference plane If you are using 2D CAD, youparallel to the plane of projection that can draw half of the view and then mirror the object.touches or cuts through the object.
  37. 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. 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. 39. USING GRID PAPER TO SKETCH AUXILIARY VIEWSYou can use grid paperto help sketch auxiliaryviews by orientingthe lines of the gridpaper underneath yourvellum or othersemitransparentdrawing sheet so thatthe grid is parallel tothe inclined edge in thedrawing…
  40. 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. 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. 42. CIRCLES AND ELLIPSES IN AUXILIARY VIEWSCircular shapes appear elliptical when viewed at an angle other than 90° (straighton to the circular shape). This is frequently the case when constructing auxiliaryviews.
  43. 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 linesfor visualization practice, especially if the auxiliaryview of the entire object is shown. Later, when you arefamiliar with drawing auxiliary views, omit hiddenlines when they do not add needed information to thedrawing.
  44. 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. 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. 46. Auxiliary Views on Youtube•
  47. 47. REVERSE CONSTRUCTIONTo complete the regular views, it is oftennecessary to first construct an auxiliaryview where critical dimensions will beshown true size.
  48. 48. PARTIAL AUXILIARY VIEWSUsing an auxiliary view often makes it possible to omit one or more regularviews, but auxiliary drawings are time consuming to create and may even beconfusing because of the clutter of lines. Partial views are often sufficient andeasier to read.
  49. 49. AUXILIARY SECTIONSAn 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. 50. VIEWING-PLANE LINES AND ARROWSWhen the drawing sheet is too crowded to show the auxiliary view indirection projection you can use a viewing-plane line or a viewingdirection arrow to indicate the direction of sight for the auxiliary view.
  51. 51. What’s Next?• Finish Chapter 8 Auxiliary Views• Chapter 10 - Dimensioning
  52. 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. 53. HomeworkRead Chapter 10Chapter 8 Review Questions: 1, 3, 4Chapter 8 Exercises: 8.5 [Draw necessary views andauxiliary view (s) ]