1. TEST 2 REVIEW: Communication Technology Test Thursday and Friday
Draft orthographic projections from a given parallel projection drawing.
Draw an isometric drawing from given orthographic projections.
Friday
Multiple choice
Calculators not allowed on either portion. No extra time to complete test will be available.

2. The large orange # refers to the test review sheet
IOT POLY ENGINEERING
2-1
When answering this type of question…
SOURCE of communication to
DESTINATION of communication
The large orange # refers to the test review sheet
Alarm Clock
Telephone 1
Thermostat
T.V. Remote

3. Communication Technology
IOT POLY ENGINEERING
2-1
Communication Technology
Inform Persuade Entertain Control Manage Educate
INPUTS
PROCESSES
OUTPUTS
GOALS
FEEDBACK
Control
SOURCE
TECHNOLOGY
DESTINATION
Input
Process
Output
Transmitted Communication
Encoder Transmitter Receiver Decoder Storage Retrieval
Received Communication 2

4. Telephone Communication
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2-1
Telephone Communication
One of the simplest devices in your house
What part of this technology system is an example of Human to Machine communication?
Processes
Input
Output
Encoder
You speak into the microphone
Friend hears voice
Transmitter
Receiver
Decoder
Storage
Retrieval 4
Answering Machine – friend isn’t home, and this machine stores your communication
Wires – the electrical energy travels from your phone, via exchanges, to your friend’s
Play Button – friend gets home, presses play, hears your recorded voice
Receiver – friend’s earpiece speaker converts the electrical energy back to sound
Microphone – converts sound energy of voice into electrical energy (encodes)

5. Communication Technology
IOT POLY ENGINEERING
2-4
Communication Technology
Television (1925)
Greek: tele – far, Latin: visio – seeing
4 main parts (cathode ray tube)
Electron gun fires 3 beams
Steering coils move electron beam across screen
Phosphorus screen has over 200,000 pixels
Glass tube holds it all together
Signals are broadcasted like radio signals
Telecommunications 4

6. Last Night’s Homework - REVIEW
IOT POLY ENGINEERING
2-2
Last Night’s Homework - REVIEW
Radio:
Goal: Inform Persuade Entertain Control Manage Educate
Source: Sounds and Information
Encoder: Devices that convert sound and info into a modulated sine wave (rapidly changing electric current in a wire)
Problem: 4
Sine wave contains no information.
We need to modulate (vary) it.

7. Last Night’s Homework - REVIEW
IOT POLY ENGINEERING
2-2
Last Night’s Homework - REVIEW
Radio:
Goal: Inform Persuade Entertain Control Manage Educate
Source: Sounds and Information
Encoder: Devices convert sound and info into modulated sine waves
Transmitter: Antennas radiate the radio waves into air (medium)
Receiver: Antennas capture the radio waves from air
Decoder: Devices convert radio waves back into sounds and data
[Storage: Recording devices store sounds and data for playback]
[Retrieval: Stored data can be accessed and played] 4
Destination: Consumers’ ears and eyes

8. IOT POLY ENGINEERING
2-2
September 30, 2008
Match the statements with the correct term below:
A device that changes a message into a form that can be transmitted
A device that sends a signal (i.e., encoded message)
A device that acquires a signal (i.e., encoded message)
A device that changes a coded message into an understandable form 4
Decoder
Receiver 3
Data 5 1 2
Encoder
Transmitter

9. Communication Technology
IOT POLY ENGINEERING
2-2
Communication Technology
Match the statements with the correct term below:
Unorganized facts
Organized data
Information applied to a task
The sending and receiving of information
Communication 4 1
Information 2
Data 5
Knowledge 3
Storage

10. Last Night’s Homework - REVIEW
IOT POLY ENGINEERING
2-2
Last Night’s Homework - REVIEW
Radio:
Encoder: Devices that convert sound and information into a modulated sine wave
Pulse Modulation: turn the voltage (sine wave) on/off (Morse Code) PM
Amplitude Modulation: vary the amplitude (peak-to-peak) voltage AM
Frequency Modulation: vary the frequency (speed) 6 FM

11. Classes of Communication Technology
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2-4
Classes of Communication Technology
Print Graphic Communication
Visual, lingual messages that include printed media
Photographic Communication
Using photographs, slides, or motion pictures to communicate a message
Telecommunications
Communicating over a distance
Technical Graphic Communication
Specific information about a product or its parts
Size and shape, how to install, adjust, operate, maintain, or assemble a device 7

12. Matching Classes 2-4 7 Print Graphic Communication
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2-4
Matching Classes
Print Graphic Communication
Photographic Communication
Telecommunications
Technical Graphic Communication 3 1
2,3 2
Telephone Headphones
Book Computer
Videotape Remote Control
DVD Painting
Magazine Camera
Photograph Comic Strip
Newspaper Billboard 3 2
1,2 7

13. Communication Technology
IOT POLY ENGINEERING
2-4
Communication Technology
Major Processes:
Relief
A modeled work that is raised (or lowered) from a flat background.
Cuneiform by the Sumerians ~6000 years ago.
Wood block printing ~200 C.E.
Movable type printing ~1040 C.E. (Gutenberg ~1450)
Intaglio (in-tal-yo) ~1430
Rotary printing press ~1843
Lithography (offset printing) ~1796
The source and destination are not on raised surfaces
Grease and water do not readily mix
A chemical process
Most modern books and newspapers
Intaglio
(in-tal-yo)
2. The plate is covered in ink
By 593 A.D., the first printing press was invented in China, and the first printed newspaper was available in Beijing in 700 A.D. It was a woodblock printing. And the Diamond Sutra, the earliest known complete woodblock printed book with illustrations was printed in China in 868 A.D. And Chinese printer Bi Sheng invented movable type in 1041 A.D. in China.
3. Excess ink is removed from surface
1. Depressions cut into printing plate
Print Graphic Communication
4. Paper placed on plate and compressed
5. Paper is removed and ink has been transferred
Low Relief
Cuneiform 8
High Relief

14. Communication Technology
IOT POLY ENGINEERING
2-4
Communication Technology
Screen Printing (~1000 C.E., China; 1907 England)
Mainly billboards, package labels, fabric designs
Uses a woven mesh (a screen) to support an ink blocking stencil.
The stencil forms open areas of mesh that transfer ink as a sharp-edged image onto a substrate.
A roller or squeegee is moved across the screen stencil forcing or pumping ink past the threads of the woven mesh in the open areas.
Electrostatic (1938 / 1960s)
Photocopier, Laser Printer
Opposite charges attract
Ink Jet (1980s)
Use a series of nozzles to spray ink directly on paper
Print Graphic Communication 8

15. Communication Technology
IOT POLY ENGINEERING
2-4
Communication Technology
Photographic Communication
The process of using photographs to communicate a message
Photography – capturing light on a light-sensitive material such as film or electronic sensor
As a usable process, 1820s
Includes photographs, slides, and motion pictures
Photographic Communication 9

16. Communication Technology
IOT POLY ENGINEERING
2-4
Communication Technology
Telecommunication
Communicating over a distance
Tele – Greek, “far off” Communicare – Latin, “to share”
Rely on the principles of electricity and magnetism
2 types:
Hardwired systems (telephone, cable, fiber-optic)
Broadcast systems (radio and t.v., mobile phones)
Point-to-point:
One transmitter and one receiver
Broadcast:
One powerful transmitter to numerous receivers
Telecommunications 10

17. Communication Technology
IOT POLY ENGINEERING
2-4
Communication Technology
Smoke signals and drums
Chains of beacons (Middle Ages)
Navigation signals
Enemy troops approaching
Homing pigeons
Carrier pigeons used as early as 1150 in Baghdad
Olympic victors, Greece; Stock options, Europe
Optical telegraph (semaphore, 1792, France)
Towers with pivoting shutters
Information encoded by the position of the mechanical elements
Telecommunications 10

18. Communication Technology
IOT POLY ENGINEERING
2-4
Communication Technology
Telegraph (mid 1830s)
First instrument used to send messages by means of wires and electric current
A device interrupts the flow of a current through a wire
Uses shorter and longer bursts of current to represent letters
Device at receiving end converted electrical signal into clicks
Operator/mechanical printer converted clicks into words
Telegram – wires over land
Cable – wires under water
Telephone (1876 – Bell and Gray)
Greek: tele – far, phone – sound
Telecommunications 10

19. Communication Technology
IOT POLY ENGINEERING
2-4
Communication Technology
Engineering Drawing / Technical Illustration
Communicates specific information
Size and shape
How parts are assembled
How to install, operate, adjust, maintain a device
Hand methods
Sketching
Drafting
Computer methods
CAD (AutoCAD, Sketchup, Inventor, ProEngineer, etc.)
Technical Graphic Communication

21. Objectives 2-9 The remainder of Unit 2:
IOT POLY ENGINEERING
2-9
The remainder of Unit 2:
Technical Graphic Communication
Objectives
Cover the 3 main technical drawing types and their ~12 variations
Establish class standards for technical drawing
Further develop and apply skills in drafting
Develop and apply skills in AutoCAD and Sketchup
Technical Graphic Communication

22. SKETCHES 2-9 1 One of many drafting techniques
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2-9
SKETCHES 1
One of many drafting techniques
Quick way to show an idea that would be difficult to describe with words alone
Used mainly in Engineering Design Process Step 2: Brainstorm, Research, and Generate Ideas
NO DRAWING TOOLS (not even a straightedge)
Rules of drawing STILL APPLY
Pull, don’t push
LIGHT construction lines
Use appropriate line weight and type
TYPE 1: SKETCHES 14

23. MULTI-VIEW 2-9 2 Orthographic Projections:
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2-9
MULTI-VIEW 2
Orthographic Projections:
Ortho: straight or at right angles
Graphic: written down
Pro: forward
Jacere: to throw
“To throw straight forward and write down”
The method of representing the exact form of an object in 2 or more views on planes (usually at right angles to each other)
TYPE 2: MULTI-VIEW 14

24. MULTI-VIEW 2-9 2 There are 6 standard views: Which views to use?
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2-9
MULTI-VIEW 2
There are 6 standard views:
Which views to use?
The different features of an object will suggest which views to draw.
Standard is:
TYPE 2: MULTI-VIEW 14

25. How are orthographic projections drawn?
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2-9
MULTI-VIEW 2
TYPE 2: MULTI-VIEW 14
How are orthographic projections drawn?

26. MULTI-VIEW 2-9 2 TYPE 2: MULTI-VIEW Reference Planes:
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2-9
MULTI-VIEW 2
Reference Planes:
Frontal Reference Plane
Front View
Horizontal Reference Plane
Top View
Profile Reference Plane
Side View
TYPE 2: MULTI-VIEW 13

27. IOT POLY ENGINEERING
2-9
MULTI-VIEW 2
Frontal Reference Plane
Front View
Horizontal Reference Plane
Top View
Profile Reference Plane
Side View
Now, sketch the Horizontal Reference Plane and label the view and other planes.
Which Reference Plane?
HRP
TYPE 2: MULTI-VIEW
Which Reference Plane?
HRP
Which View?
FRONT
Which Reference Plane?
Which View?
PRP
RIGHT 13
Which Reference Plane?
FRP

28. MULTI-VIEW 2-9 2 TYPE 2: MULTI-VIEW 13 Reference Planes:
IOT POLY ENGINEERING
2-9
MULTI-VIEW 2
Reference Planes:
Frontal Reference Plane
Front View
Horizontal Reference Plane
Top View
Profile Reference Plane
Side View
TYPE 2: MULTI-VIEW
Which View?
Which Reference Plane?
TOP
PRP 13
Which Reference Plane?
FRP

29. MULTI-VIEW 2-9 2 13 Reference Planes:
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2-9
MULTI-VIEW 2
Reference Planes:
You can also have multiple positions of the same reference planes 13

30. SECTIONAL VIEWS 2-9 2 Sectional Views TYPE 2: MULTI-VIEW 13
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2-9
SECTIONAL VIEWS 2
Sectional Views
How an object looks if a cut were made through it perpendicular to the direction of sight.
For example, if we cut the shape below at PRP 2 and drew the shape (including its “insides”) we would have a sectional view:
TYPE 2: MULTI-VIEW 13

31. SECTIONAL VIEWS 2-9 2 Sectional Views TYPE 2: MULTI-VIEW 14
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2-9
SECTIONAL VIEWS 2
Sectional Views
Different materials have different sectional views
TYPE 2: MULTI-VIEW 14

32. Communication Technology
IOT POLY ENGINEERING
2-10
October 10, 2008
DRILL
In the right view of the drawing below (PRP), point A is 2’-3” away from the frontal reference plane.
In the top view drawing, how far will point A be from the frontal reference plane?
In the front view drawing, how far will point A be from the frontal reference plane?
2’-3”
If point A is 2’-3” away from the FRP in the right view, point A will ALWAYS be 2’-3” away from the FRP. A
Communication Technology 13

33. SECTIONAL VIEWS 2-10 2 Examples TYPE 2: MULTI-VIEW 14
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2-10
SECTIONAL VIEWS 2
Examples
TYPE 2: MULTI-VIEW 14

34. IOT POLY ENGINEERING
2-10
AUXILIARY VIEWS 2
So far, our standard 6 views are all visible using the three regular planes of projection
Frontal Reference Plane
Horizontal Reference Plane
Profile Reference Plane
Those views are drawn TRUE SIZE
However, inclines (slants) are not shown as true size in standard views.
TYPE 2: MULTI-VIEW 13

35. IOT POLY ENGINEERING
2-10
AUXILIARY VIEWS 2
Inclines (slants) are not shown as true size in standard views.
Each square below represents 1”. What are the widths of the front view and right side views?
9” and 4”, respectively
TYPE 2: MULTI-VIEW
Neither the front, top, or side view shows the true size and shape of the object’s inclined surface.
FRP
HRP
PRP 13

36. AUXILIARY VIEWS Which Reference Plane? 2-10 HRP ARP PRP FRP 2
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2-10
AUXILIARY VIEWS 2
The ARP shows true form (shape and size) for inclines
Which Reference Plane?
HRP
Auxiliary Reference Plane
ARP
TYPE 2: MULTI-VIEW
PRP
FRP
13/17

37. IOT POLY ENGINEERING
2-10
SURFACE DEVELOPMENTS 2
TYPE 2: MULTI-VIEW 14

38. SURFACE DEVELOPMENTS 2-10 2 Stretchout Pattern Development
IOT POLY ENGINEERING
2-10
SURFACE DEVELOPMENTS 2
Stretchout Pattern Development
Used by many industries:
Pipes and ducts
Aircraft and automobile parts
Storage tanks
Cabinets
Boxes and cartons
Packages
Packaging is a very large industry that uses surface developments.
TYPE 2: MULTI-VIEW 14

39. IOT POLY ENGINEERING
2-10
WORKING DRAWINGS 2
Tells all that needs to be known for making a single part or a complete machine or structure
Precise size and shape
What materials are used
How finishing should be done (roughness/smoothness)
Degree of accuracy (% Error allowed)
TYPE 2: MULTI-VIEW 14

40. IOT POLY ENGINEERING
2-10
PICTORIAL DRAWINGS 3
Pictorial drawings show a likeness (shape) of an object as viewed by the eye.
TYPE 3: PICTORIAL 14

41. ISOMETRIC 2-10 3 TYPE 3: PICTORIAL 14 From Greek: Equal Measure
IOT POLY ENGINEERING
2-10
ISOMETRIC 3
From Greek: Equal Measure
Isos: Equal
Metron: Measure
The scale along each axis of the projection is the same
True form parallel lines are shown as parallel (note colors below)
All isometrics: simple construction
TYPE 3: PICTORIAL
Isometric Cube:
1) all lines equal length;
2) all faces equal area;
3) perimeter is a hexagon 14

42. PERSPECTIVE 2-10 3 TYPE 3: PICTORIAL 14
IOT POLY ENGINEERING
2-10
PERSPECTIVE 3
Latin: perspicere – to see through
An approximate representation of an image as it is perceived by the eye.
The most characteristic feature of perspectives is that objects are drawn:
Smaller as their distance from the observer increases
TYPE 3: PICTORIAL 14

43. OBLIQUE 2-10 3 A way of showing depth, like isometric
IOT POLY ENGINEERING
2-10
OBLIQUE 3
A way of showing depth, like isometric
Part orthographic / part isometric:
One face is true form
Parallel lines behind; either:
Full scale
Half scale
Three-quarter scale
TYPE 3: PICTORIAL 14

44. IOT POLY ENGINEERING
2-10
EXPLODED ASSEMBLY 3
Take an object and separate into individual parts
Usually employed in instruction manuals
Typically drawn in parallel projection (notice there is no perspective in the examples below)
TYPE 3: PICTORIAL 14

45. CUT-AWAY PICTORIAL 2-10 3 Show the interior details of a product
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2-10
CUT-AWAY PICTORIAL 3
Show the interior details of a product
Often employed in instruction manuals
Assists in understanding operation of product
TYPE 3: PICTORIAL 14

46. Communication Technology
IOT POLY ENGINEERING
2-11
October 13, 2008
DRILL
Turn in your 3-view assignment (include NAME)
Match the type of Technical Graphics below with its type:
Isometric
Section
Standard View
Development
Perspective
Oblique
Cut-away Pictorial B C A E B C F G D A D E F
Communication Technology G 14

47. Technical Graphic Communication
IOT POLY ENGINEERING
2-11
TECHNICAL GRAPHICS
Which of the following images are parallel projections?
Technical Graphic Communication 14

48. Technical Graphic Communication
IOT POLY ENGINEERING
2-11
[REVIEW]
SKETCHES 1
No drawing tools
Technical Graphic Communication 14

49. Technical Graphic Communication
IOT POLY ENGINEERING
2-11
[REVIEW]
MULTI-VIEW DRAWINGS 2
Standard Views
Sectional Views
Auxiliary Views
Developments
Working Drawings
Technical Graphic Communication 14

50. [REVIEW] PICTORIAL DRAWINGS 2-11 3 Technical Graphic Communication 14
IOT POLY ENGINEERING
2-11
[REVIEW]
PICTORIAL DRAWINGS 3
Show a likeness of an object as viewed by the eye
Isometric
Perspective
Oblique
Exploded Assembly
Cutaway Pictorial
Technical Graphic Communication 14

51. Technical Graphic Communication
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2-11
CLASS STANDARDS
Line Weights
Line Types
Dimensioning
Scales
Technical Graphic Communication 15

52. Technical Graphic Communication
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2-11
LINE WEIGHTS
Four Weights in this class:
Light: not noticeable from 2’ (nearly invisible)
Medium: just noticeable from 2’
Heavy: obvious from 2’ (final weight for most objects)
Very Heavy: only used for borders
Technical Graphic Communication 15

53. CLASS STANDARDS LINE TYPES 2-11 Construction/Layout Lines Guidelines
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2-11
LINE TYPES
Construction/Layout Lines
LIGHT WEIGHT
ALL lines begin as these
DO NOT ERASE (unless there is a measuring error)
Guidelines
Used for LETTERING
CLASS STANDARDS 15

54. CLASS STANDARDS LINE TYPES 2-11 Object Lines: Hidden Lines: 15
IOT POLY ENGINEERING
2-11
LINE TYPES
Object Lines:
HEAVY WEIGHT
The final line type for most
objects
Hidden Lines:
Everything must be represented in each view, whether or not it can be seen
Interior and exterior features are projected from view to view in the same way
Parts not seen on the exterior of a view are drawn with hidden lines – short DASHES
CLASS STANDARDS 15

55. CLASS STANDARDS LINE TYPES 2-11 Centerlines: 15 MEDIUM WEIGHT
IOT POLY ENGINEERING
2-11
LINE TYPES
Centerlines:
MEDIUM WEIGHT
Centers of symmetrical objects, including circles
Used to locate views and dimensions
CLASS STANDARDS 15

56. CLASS STANDARDS LINE TYPES 2-11 Section Lines: 15 MEDIUM WEIGHT
IOT POLY ENGINEERING
2-11
LINE TYPES
Section Lines:
MEDIUM WEIGHT
Show materials in cross-section views
Different materials use different section lines
CLASS STANDARDS 15

57. CLASS STANDARDS LINE TYPES 2-11 Extension Lines: Dimension Lines: 15
IOT POLY ENGINEERING
2-11
LINE TYPES
Extension Lines:
MEDIUM WEIGHT
Extend from objects
Used for dimensioning
Dimension Lines:
Go between extension lines
CLASS STANDARDS 15

58. CLASS STANDARDS DIMENSIONING 2-11
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2-11
DIMENSIONING
2 things are needed to describe an object completely:
Shape
Size
Dimensioning: Size description
Units are required
Decimal or Fraction
Dimensions read from bottom or right side
Include:
Extension line: begin 1/16” away from object and extend 1/16” beyond Dimension Line
Dimension line: use arrowheads, guidelines, and LETTER
CLASS STANDARDS
PREFERRED

59. CLASS STANDARDS SCALES 2-11 Objects to be drawn may be small
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2-11
SCALES
Objects to be drawn may be small
Nanotechnology machine parts, for example
Objects to be drawn may be big
Buildings, bridges, airliners, oil rigs, trucks, cars
Full Scale drawings will not always fit on a sheet of paper
Scale down or scale up
½” = 1’-0” ¼” = 1’-0” ” = 14’-0”
Scale must be indicated in your title block
Architect’s Scale, Engineer’s Scale, Metric Scale make scaling drawings simpler.
CLASS STANDARDS 19

60. IOT POLY ENGINEERING
2-12
DRAFTING TOOLS 16

61. Technical Graphic Communication
IOT POLY ENGINEERING
2-17
QUIZ – Slide 1
Write the correct name for each drawing type next to the correct letter on your paper. A B C D
Technical Graphic Communication E F G 14

62. Technical Graphic Communication
IOT POLY ENGINEERING
2-17
QUIZ – Slide 2
Write the correct name for each reference plane next to the correct letter on your paper. Use ENTIRE name, not the acronym. B A
Technical Graphic Communication C 13 D

63. Technical Graphic Communication
IOT POLY ENGINEERING
2-17
QUIZ – Slide 3
Write the correct NAME and WEIGHT for each line type next to the correct letter on your paper: E A F D C
Technical Graphic Communication B
2.5” G 15

64. Technical Graphic Communication
QUIZ – Slide 4
Give an example of something a designer would scale up for drawing.
Give an example of something a designer would scale down for drawing.
If a point on an object is 14’-3” away from the frontal reference plane in the front view and 7’-6” away from the horizontal reference plane in the front view, how far away is the point from the frontal reference plane in the right side view?
To draw what type of drawing would designers use more than one position for any reference plane?
Technical Graphic Communication 19

65. HORIZONTAL STARTING POINT
1. Add width of front view to width of right view (depth).
4.5” + 2” = 6.5”
2. Add the space we will put between: 1.5”
6.5” + 1.5” = 8”
3. Subtract from the total width.
10” – 8” = 2”
4. Divide by 2. 16
Horizontal Starting Point = 1”

66. VERTICAL STARTING POINT
1. Add height of front view to height of top view (depth).
3” + 2” = 5”
2. Add the space we will put between: 1.5”
5” + 1.5” = 6.5”
3. Subtract from the total height.
7.25” – 6.5” = .75” = 3/4”
4. Divide by 2. 16
Vertical Starting Point = .375” = 3/8”

67. Horizontal Starting Point = 1”
Vertical Starting Point is 7/8” 16

68. review Thursday’s Test
You will be given the sheet below, including the border and title block.
Draw lettering guidelines 1/16”
Complete title block
Calculate starting point (vertical and horizontal) – NO CALCULATOR ALLOWED
IOT POLY ENGINEERING
review

69. Technical Graphic Communication
IOT POLY ENGINEERING
2-18
DRAWING ISOMETRICS
Isometrics are drawn with:
All object vertical lines are vertical
All object horizontal lines are drawn 30 degrees from the horizontal
All lines are drawn true size
Technical Graphic Communication 16

70. Technical Graphic Communication
IOT POLY ENGINEERING
2-18
DRAWING ISOMETRICS
One of the most effective ways to sketch an object pictorially is to sketch it in isometric.
Start by sketching an enclosing box (absolute height, width, depth) – Construction Lines
Add in features
Darken all final lines
Technical Graphic Communication 16

71. ISOMETRICS from ORTHOGRAPHICS
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2-18
ISOMETRICS from ORTHOGRAPHICS
Let each grid space = ½”
Front view is typically drawn first
You must look at all views
Technical Graphic Communication 16

72. DRAFTING ISOMETRIC DRAWINGS
IOT POLY ENGINEERING
2-21
DRAFTING ISOMETRIC DRAWINGS
Describe an isometric view
Prepare drawing paper
Locate center of drawing space
Plot starting point of drawing
Complete isometric drawing
Technical Graphic Communication 16

73. DRAFTING ISOMETRIC DRAWINGS
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2-21
DRAFTING ISOMETRIC DRAWINGS
Describe an isometric view
Height
Width
Depth
(of the front view)
Technical Graphic Communication 16

74. DRAFTING ISOMETRIC DRAWINGS
Prepare drawing paper
Locate center of drawing space
Construction Lines
Technical Graphic Communication
45 degree triangle 16

75. DRAFTING ISOMETRIC DRAWINGS
Plot starting point of drawing
1) ½ W
2) ½ D
3) ½ H
Technical Graphic Communication
triangle 16
Starting Point

76. DRAFTING ISOMETRIC DRAWINGS
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2-21
DRAFTING ISOMETRIC DRAWINGS
Complete isometric drawing
Technical Graphic Communication 16
Starting Point

77. DRAFTING ISOMETRIC DRAWINGS
IOT POLY ENGINEERING
2-21
DRAFTING ISOMETRIC DRAWINGS
Technical Graphic Communication 16

78. review Thursday’s Test
You will be given the sheet below, including the border, title block, and isometric guidelines.
Draw lettering guidelines 1/16”
Complete title block
Calculate starting point
Draw “X” across drawing space
Pick the nearest intersection
Measure down to right ½ width
Measure down to left ½ depth
Measure straight down ½ height
Each grid space = ¼”
IOT POLY ENGINEERING
review

79. Introduction to AutoCAD
IOT POLY ENGINEERING
2-24
Introduction to AutoCAD
AutoCAD is a communication technology tool:
Creating neat, accurate drawings and designs.
There are numerous features – we will concentrate on the most important ones.
Technical Graphic Communication
One of the most important actions within the AutoCAD program is the drawing of straight lines.
Before we learn the LINE command, let’s take a look at how we normally draw lines by hand. 18

80. Absolute Coordinates 2-3
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2-3
Absolute Coordinates
Absolute coordinates are based on the origin (0,0), expressed as an ordered pair x,y. All other points are also expressed in the form x,y and the values of x and y are based on the distance from the origin.
If we desire to draw a line, we must give the location of both endpoints, expressed as an ordered pair x,y where the origin is used as a reference point. 18

81. Communication Technology Introduction to AutoCAD
IOT POLY ENGINEERING
2-24
Communication Technology Introduction to AutoCAD
Relative coordinates are not based on the origin (0,0). Instead, we use symbol followed by an ordered pair x,y. This means “starting where we are AT, go over (or back) x and up (or down) y.
If we desire to draw a line using relative coordinates, we must give the location of the first endpoint (usually using Absolute coordinates), followed for the second endpoint. 18

82. IOT POLY ENGINEERING
2-3
Polar Coordinates
Polar coordinates are used to draw lines at specific angles.
When using Polar coordinates, angles are measured according to the following tradition: 90 90
150 30
180
330 = -30
210 18
270
270 = -90

83. IOT POLY ENGINEERING
2-26
Polar Coordinates
Polar coordinates are used to draw lines at specific angles.
When using Polar coordinates, angles are measured according to the following tradition: 90
45 degrees
135 degrees
225 degrees = -135 degrees
180
315 degrees = -45 degrees
360 degrees = 0 degrees 18
270