Engineering 22
OrthroGraphic
View Dwgs-1
Bruce Mayer, PE
Licensed Electrical & Mechanical Engineer
BMayer@ChabotCollege.edu
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Learning Goals
 How to Unfold the “Glass” Box to draw
Perpendicular Projection (OrthoGraphic)
Views
 Determine the Minimum No. of Views
Needed to Fully Describe an Object
 Properly Place Views Relative to Each
Other
 Which Views show Which Combination
of the Object’s H, W, & D
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Learning Goals cont
 Understand the Criteria for Selecting the
CENTRAL View
 Apply the Guidelines for the Proper Use
of Hidden Lines
 Determine When Lines/Shapes are in
TRUE Length/Shape as opposed to
FOREshortened
 Construct MultiView Orthographic
Projection Drawings
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
OrthoGraphic View Drawing
 All Objects Are Three Dimensional (3-D)
• Height, Width, and Depth
 Drawings are done on a 2-D surface
 Multiview Sketching (Orthographic
Projection) Represents A 3-D Object With
A Series Of 2-D Views
• Best Understood By Technical People
• In Contrast To “Pictorials” Which Show Three
Dimensions In A Single View
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Projection Planes Versus Views
 Projection planes:
• Objects are Formed From Parallel “Sight
Lines” Projected Perpendicularly Onto A
Projection Plane
• Horizontal, Frontal, Profile
• Each Projection Plane
Is Perpendicular To the
Adjacent Projection Planes
• Lines/Features Parallel to
Proj Plane are TRUE Length/Size
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Principle Views
 The Object Is Rotated 90° About The
Horizontal Or Vertical Axis To Yield the
Six Principle Views
• Top, Bottom, Front, Rear, Left & Right Side
 Common views:
• Top
• Front
• Right Side
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
View Selection
 Only Use The Views That Are Needed
To Represent The Object
• One view drawings
– Stamped part: Specify
uniform thickness with a note
• Two view drawings
 A Cylindrical Part
• Three view drawings
– Usually Sufficient For
All Other Objects
– Top, Front, And Right-Side Views
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
General Guidelines
 The Most DESCRIPTIVE View Should Be
The FRONT, or CENTRAL, View
 Views MUST Be ALIGNED
• Top View ABOVE Front View
• Right-Side View To The RIGHT Of Front View
 Hidden lines
• Represented With Dashed Lines
• Precedence of lines (Visible, Hidden, Center)
• Views Should Be Selected To MINIMIZE
The Use Of HIDDEN LINES
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Parallel Projection
 Preserves true relationship between
features
• Parallel lines are drawn parallel
• The geometry is generally not distorted
 Parallel projectors
• Light from a point-source at an -distance
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
The Glass Box
 Projection Planes
Placed Parallel
to the Principle
Faces of an
Object Form a
Glass Box
• What An Observer
Would See From
the OUTSIDE
Looking IN
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Unfolding The Glass Box
 Hinge the Four Intersections on The
Frontal Plane And “Flatten Out” the Box
• Maintains the
TRUE-Length
Of Lines Parallel
to the Viewing
Planes
• The 5 Hinge Lines
are Known as
FOLDING Lines
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
The Unfolded Glass Box
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Common Dimensions


Every 3-D Object Can Be Described
By its Height, Width, and Depth
The Views from the Glass Box Share
These Dimensions in This Form
Views that Share
H only W only D only H&W H&D W&D
F
F
LS
F
LS
T
LS
T
RS
R
RS
B
RS
B
T
R
B
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Central View = Front View
 Criteria for Selecting Central View
• Front View Shows The Shape Of The
Object MOST Clearly
• Chose Front View So That It Has A Large
Number Of Normal () Surfaces
• Minimize Hidden Lines
• Show The Object In A
Usual Or Operating Position
– i.e., Do NOT show the
Object “UpSide Down”
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
The Primary Views
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Producing a Multiview Drawing
 Select Front View As Before
 Align View Bounding Boxes
• i.e., Block-In Views
• Approx. Center on Drawing Border
 Draw Features Using Instruments/CAD
• True Shapes Remain
• Project Between Views
• Use 45° “Mitre” Lines to Xfer Depth Dims
• Label Vertices if Needed
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Align Bounding Boxes
DEPTH
WIDTH
TOP
DEPTH
WIDTH
HEIGHT
HEIGHT
Miter line at 45°
FRONT
Engineering 22 – Engineering Design Graphics
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RIGHT
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Construction Lines to Xfer Dims
TOP
Use 45° Miter
Line to Transfer
Dims Between
Top & Side View
FRONT
Engineering 22 – Engineering Design Graphics
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RIGHT
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Label Vertices
C
 An Intermediate
Step to Aid
Construction
 Only If needed
A
to Clarify
Positions For
the Designer
C
A
B
Engineering 22 – Engineering Design Graphics
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B
C
A
B
B ,A
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
C
Views FULLY
Aligned
Very FEW
Hidden Lines
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
True Length Vs. Foreshortened
 Only Lines/Planes that Are PARALLEL
to the Projection Plane are (LoS 
Plane) show in TRUE LENGTH/SHAPE
• Others are ForeShortened in the View
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Hidden Line Usage
 Hidden Lines can Greatly-CLARIFY or
Greatly-CONFUSE a Drawing View
• Visible Lines are Usually Easy
– Exceptions = Fillets & Rounded Edges
• Creating Useful Hidden Lines Requires
– Judgment
– Adherence to
Convention
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Draw Hidden Lines
 Dashes are 2X to 3X Longer Than Spaces
• .e.g.; Dashes 1/8” (3mm) Long, Spaces 1/16”
(1.5mm) Long.
 Should Intersect Neatly Except Where A
Line Of A Different Linetype Would Appear
To Be Extended
 “Jump” Visible Lines That They Cross
 Closely Spaced Parallel Hidden Lines Are
Drawn With The Dashes STAGGERED if
Possible
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Conventions for Hidden Lines

Hidden lines should
join neatly with visible
lines except when it
causes a visible line
to be extended.
When two different
lines join to form a
single line, leave a
gap on the less
important line.

Engineering 22 – Engineering Design Graphics
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Hidden lines should
join neatly to form “T”
or “L” shaped intersections.


Hidden lines should
jump visible lines that
they do not intersect.
It is permissible for a
hidden line to cross a
visible line.
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
More Hidden Line Conventions

Stagger the dashes
on closely spaced
parallel hidden lines.

Engineering 22 – Engineering Design Graphics
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Hidden line dashes
should intersect
neatly to from clear
corners, as in the
bottom of this drilled
hole.

Intersecting hidden
lines should form
neat corners, as in
this countersunk
hole.
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Curved Hidden Lines
 Curved hidden lines should
not extend a visible curve in
the same direction. Leave a
gap on the hidden line so
that you can easily see
where the visible line ends.
Engineering 22 – Engineering Design Graphics
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 Curved hidden lines dashes
should extend to the point of
tangency. Don’t end with a
gap at the point of tangency.
It makes it hard to see the
location.
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Hidden Lines

Hidden Lines Can be Made A number
of ways in AutoCAD
1. Draw Line in a LAYER with Hidden Form
2. Draw a SOLID Line, then CHANGE to a
Hidden LAYER (Described Last Lecture)
3. Draw a SOLID Line, then CHANGE to a
Hidden LINETYPE using PROPERTIES
ToolBar
4. Draw a SOLID Line, then CHANGE to a
Hidden LINETYPE using PROPERTIES
Side-Menu
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Chg Hidden-Line by ToolBar
 Want
1. Select Line to
Light-Up Handles
2. Click on “Layer
Control” Box to
PullDown
LineTypes Menu
Engineering 22 – Engineering Design Graphics
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3. Select HIDDEN
4. Deactivate Grips
by Hitting Esc
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Chg Hid-Ln by Properties Menu
 Want
•
Rt-Click Line or
Grips to Activate
the Context
PullDown Menu
– Select properties
1. Select Line to
Light-Up Handles
•
Double-Click an
END Grip
2. Activate the
Properties Side
Menus by one of
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Chg Hid-Ln by Properties Menu
3. On Properties Side
Menu Activate the
LineType PullDown
4. Select Hidden and
Deactivate Grip by
Hitting Esc

NOTE
•
Engineering 22 – Engineering Design Graphics
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The Prop-ToolBar
or Prop-Menu Can
also Change Line
Color, and
Thickness
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Visualization: Ortho → 3D
 For a Practicing Engineer with DetailDesign Assistance, READING
Projection Drawings Is as Important as
MAKING them
 The Practicing Engineer Must be Able to
Think in 3-D Using 2-D Projections
• i.e., To Visualize a 3-D Object Given Front,
Top and Side Views
• This is Inverse of Creating Views from
the 3-D Object
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Visualization Aids
1
S
1
S
3
3
 Using Labels on Multiview Drawings
• Label surfaces; e.g., S
• Label vertices; e.g., 1,3
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Visualization Continued
 Recognize Similar Shapes in Different
Views
• Equal number of sides
• Parallel edges
 Best Way to “Read” Engineering
Drawings is the “Writing” of Great
Numbers of them
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Eliminate Unnecessary Views
 Show Only The Views Needed Drawing To Fully
Define The Shape Of The Object
 Choose The Views Which Show The Shapes Of
The Features Most Clearly
 The Right Side View Is Preferred To The Left
Side View If They Show The Object Equally Well
 The Top View Is Preferred To The Bottom View If
They Show The Object Equally Well
 Showing Only The Necessary Views Saves Time,
Makes The Drawing Less Cluttered, And Makes It
Easier To Interpret
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
All Done for Today
Try 0.7mm
MechPencil
w/ HB or B
Lead
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Engr/Math/Physics 25
Appendix
f x   2 x  7 x 
9x  6
3
2
Bruce Mayer, PE
Licensed Electrical & Mechanical Engineer
BMayer@ChabotCollege.edu
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Visible line
Hidden line
Hatching
Centerline
Dimension
Extension
Leader
Cutting Plane
Viewing Plane
Short break
Long break
Phantom
Stitch
Chain
Engineering 22 – Engineering Design Graphics
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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
 Line Precedence:
• Visible → Hidden
→ Center
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
Hidden Line Example
2
6
 Block-In sizes
11
2
Ø2
3
3
4
4
• FView → 15W x 7H
• TView → 15W x 6D
• RView → 7H x 6D
3
3
4
8
11
Engineering 22 – Engineering Design Graphics
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3
1Hx2D Groove, Ctr’d
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt
OrthoGraphic View Sketching
1. Block-In Views Using Approximately
True-Length Dimensions

Engr-Comp-Pad Grid is Useful for Scaling
2. Block-In all Details Such as Corners,
Notches, Circles, etc.
3. Dim All Construction Lines with Eraser
4. Darken All Final Lines to Emphasize
Object in All Views
Engineering 22 – Engineering Design Graphics
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-22_Lec-08_Ortho_View-1.ppt