1. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 1 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Bruce Mayer, PE Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege.edu Engineering 22 Hand Drawing → Sketching

2. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 2 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Learning Goals  How to use sketching as an effective tool → In The Engineering Design Process For REAL TIME Graphical Communication –“Table/Desk” Discussions –“WhiteBoard” Presentations  Use Sketching to form a 3D visualization of objects Described by 2D MultiView Drawing (BluePrint Reading)

3. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 3 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Learning Goals cont.  List the “Tools of the Trade” Pencils, Paper, Erasers  Develop Mechanical Skills for Drawing Plan View; i.e., “Straight-On” Sketches Isometric Sketches Oblique Sketches

4. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 4 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Sketching  Definition A Rough Freehand Drawing Used To Document, Communicate, And Refine Concepts Developed Primarily In The Ideation Phase Of The Design Process  Follows Standard Tech Dwg Practices  A Developed Skill → Practice Required  Typically The First Step Of Any CAD or Mechanical Drawing

5. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 5 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Communication by Sketching  An Effective Means Of Communication During A Group Brainstorming Session Understand your audience Who is looking at the sketches? What details are they interested in? What type of sketch will they best understand?

6. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 6 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Leverage Drawing Standards  Follow Standard Technical Drawing Practices You May Not Always Accompany Your Sketches Others May Misinterpret Your Drawing  Provides a Log Of Ideas That Were Considered in Creative Meetings

7. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 7 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Recall Std Lines  Line Patterns Communicate What The Line Represents In The Drawing  Line Patterns Tell You Information Such As Whether The Line Is Hidden, Visible, Or A Centerline Visible line Hidden line Hatching Centerline Dimension Extension Leader Cutting Plane Viewing Plane Short break Long break Phantom Stitch Chain

8. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 8 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Creative Design by Sketching  Quickly Translate Thoughts To Paper Do NOT Use Mechanical Tools (Ruler, Compass, Etc.) –Requires Practice To Be Neat And Fast –Does Not Need To Be An Exact Representation –Objects May Be Simplified –Parts May Be Missing Avoid erasing –As New Ideas Are Developed Make New Sketches –Start With Light Lines And Then Darken With Softer Lead Or Heavier Strokes

9. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 9 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Creative Visualization  Sketching Stimulates Creativity And Helps Visualization Sketching Ideas That Are Partially Developed Often Aids The Design Process  Do Not Wait Until You Have A Clear Picture Before You Start Sketching  Allow Yourself The Freedom To Make Mistakes  Visualization Of The Entire Design Is Essential But Often IMPOSSIBLE Without the Aid Of Sketches

10. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 10 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Sketching Practices  To Create Good Quality Sketches, Use The Correct Grades Of Lead And Keep Your Pencil Sharpened.  Sketches Use Different Line Weights (Thicknesses) To Show The Relative Importance Of Different Lines.  The OBJECT You Are Drawing Should Be Thick And Black In The Sketch So That It Stands Out From The Dimensions, Notes, And Other Lines.  The OBJECT Is The Subject Of Your Drawing And Should Be Communicated Clearly.

11. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 11 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Sketching Mechanics  Pencils Use a mechanical pencil (0.5/0.7 mm lead) Practice Using Different Pressure To Produce Desired Linetypes; e.g. Construction Lines  Paper Square Grid Paper Is Often The Most Useful Unlined paper is useful for “Blank Sheet” Thinking

12. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 12 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Pencils and Lead  Two Pencils Should be available 0.5 mm Lead-Width for Fine-Line Work 0.7 mm Lead-Width for Visible-Lines, Lettering, and Sketching  “HB” Lead is sufficient for all around use Drawings can be enhanced thru the use of 4H-6H Lead for Guide/Construction Lines

13. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 13 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Engr Comp Pad  A valuable Sketch Aid Tremendous Help with “Blocking In” Sketch Objects Sketch on this side!

14. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 14 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Sketching Mechanics cont  Eraser A Good Eraser Is Worth The Investment Do Not Overuse Your Eraser (Save Some Mistakes)  Good Sketching Techniques

15. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 15 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Sketching Straight Lines  Mark starting and ending point  Start With A Light Pass If Necessary And Then Darken  Draw Long Lines With Short Light Segments Before Making A Continuous Dark Pass  Use a Loose, Comfortable Grip  Re-orient The Paper To Your Convenience  Test Your Skill With Different Orientations An Awkward Orientation May Occasionally Produce Positive Results

16. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 16 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Straight Lines  Straight Lines are the FOUNDATION of FreeHand Sketching Used to “Block-In” All Other Shapes DON’T USE A STRAIGHT EDGE!

17. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 17 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Sketching Curved Lines  Break large arcs/circles into small segments Make at least 3 guide marks for each segment  Circles Sketch a Light Square And Diagonals Mark 2/3 Distance Along Diagonals Connect Intersections

18. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 18 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Circle Sketching  2/3 Method Diameter 2/3 of center distance PLUS SIGN MARKS CENTER SKETCH SQUARESKETCH AND MARK DIAGONALS SKETCH ARCS FOR CIRCLE DARKEN CIRCLE

19. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 19 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Curved Lines cont.  Ellipses Are DIFFICULT Use Block-In Method as With Circles –Start With Rectangle Start With Light Lines –Darken When Proportions Are Pleasing

20. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 20 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Scale & Proportion  Sketches Are NOT Usually Made To A Particular Scale.  It is Important To Keep The Sketch In PROPORTION  Use Engr Comp Pad Paper Or Estimate Proportions By Comparison

21. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 21 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Blocking-In is Critical  Sketch the Main Enclosing Rectangle Construction Lines 1. 2. 3. 4.  Block-In Significant Feature Locations  “Fair” in Curved-Feature Construction Lines  Dim/Lighten Construction Lines w/ Soft Eraser, then Darken Visible Lines

22. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 22 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Sketches for Patent Doc.

23. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 23 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics USA Patent App. 20030113451

24. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 24 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Pictorials  Goal How to represent a 3-D object effectively on a 2-D drawing surface  Definition: A Sketch Developed For Ease Of Visualization That Shows An Object’s Height, Width, And Depth In A Single View

25. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 25 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Pictorial Utility  A Powerful Communication Tool Particularly Useful for Non-technical Audiences –NonEngineers Often Have Difficulty Visualizing True-Length-Projection Sketches/Dwgs Typical Uses –Assembly Drawings –Marketing & Product-Promotion Discussions

26. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 26 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Pictorial Utility  Helpful In The Ideation Phase Of The Design Process  How We Picture Objects In Our Mind  How We Visualize Spatial Relationships  A Nice Concept Sketch

27. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 27 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Pictorial Sketches - Types  Parallel Projection Parallel lines are ALWAYS drawn Parallel Easy to draw –But…Often appears distorted Two Common Types –Oblique Pictorials  Easiest to Draw; But Most Distorted in Depth –Isometric Pictorials  More “Realistic” Impression

28. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 28 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Pictorial Types cont.  Perspective Projection – Special Case Conveys Information About Distance And Size Most “Realistic” and Artistic of the Pictorial Representations Most Difficult to Draw –Not as Common As Parallel Projection

29. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 29 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Oblique Sketching  Best When Most of Information is on the “Front” of The Part The Forward Facing View is a True-Length Projection-Type Image → Curves in this View “Depth” Lines –Can be Projected Backward at ANY Angle  Perfect for Engr-Comp-Pad as Sketch Medium –Can Appear Badly Distorted  Full-Length Depth Images Are called “Cavalier” (without regard) Oblique  ½ or ¾ Depth Scale Usually Yields a More Natural Image  Called a “Cabinet” Oblique Drawing

30. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 30 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Oblique Sketching 1.Start with Engineering Comp-Pad 2.Block-in Main Features Using 45° Depth Lines  Locate Block Faces at Proper Depth 3.Suggest Using Cabinet Oblique at 1/  2 Scale  Depth Lines Recede at Rate of 1 Diagonal per 2 True-Length Units 4.Sketch all Arcs & Circles (Hopefully on Front-V) 5.Darken all Visible Lines

31. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 31 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Cabinet Oblique – 0.707 Scale  “Guide Block” Sketch  Quickly Drawn on Engineer Comp-Pad  Depth Scale is 70% Technically it’s One Depth Diagonal per Two True-Length Units: 5 Squares 2.5 Diagonals

32. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 32 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Isometric Pictorials  Most Common Surfaces On All Principle Planes Distorted –All Circles appear as ellipses –Perpendicular Lines Drawn at 60° or 120° angles Height Drawn Along Vertical Axis Width And Depth Drawn at 30° to Horizontal –Can Use Other Angles For Receding Lines to Achieve More Realistic Image  Typically About 20°

33. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 33 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Isometric Sketching  Begin Drawing By Blocking In Height, Width And Depth Of Entire Object  Continue to Block-In Smaller Features  Add Curved Surfaces Last Circles Appear As Ellipses Lines Tangent To Arcs Locate The Edge Of Curved Surfaces  Isometric Grid Paper Can Help Follow direction of axis and count intersections Use tracing paper or grid paper with light lines

34. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 34 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Receding Line Direction  The Receding Line Typically “recedes” UP and to the RIGHT But Any Direction of Recession is Acceptable –UP and to LEFT is also quite often used

35. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 35 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Sketch Mechanics Summary 1.Learn to Sketch Straight Lines Critical to Effective Sketch Communication 2.BLOCK-IN Feature Outlines using STRAIGHT Lines 3.Draw “Decent” Circles 4.Develop a Sense for Proper Proportions 5.Emphasize IMPORTANT Features With DARKER Lines

36. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 36 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics All Done for Today Try 0.7mm MechPencil w/ HB or B Lead

37. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 37 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Bruce Mayer, PE Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege.edu Engr/Math/Physics 25 Appendix 

38. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 38 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics

39. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 39 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics

40. BMayer@ChabotCollege.edu ENGR-22_Lec-07_Sketching.ppt 40 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Sketch City