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S5 Orthographic Projections

Study Guide

Directions:

1) Download this document (it will go to your download folder) Use the File Icon (Windows Explorer) to navigate to your download folder. Cut or copy and paste the file to your S5 theory folder on the your hard Drive.

2) Use Ms Word on your hard drive to edit your copy of the document.

3) Click on the Hidden Header at the top of the document and type Your Name Hour & Team Number. (if this step does not work ask Mrs. Kitchen for help before continuing.

4) Complete whatever you can today. The last 10 minutes of class print this document and turn it in to Mrs. Kitchen Today (done or Not)

PART 1 - Find the link that looks like this near the top of the Anchor Bay CAD Segment 5 webpage 5. ADDA COMPETENCY 5 - ORTHOGRAPHIC PROJECTION open the document and use it to answer the following questions. (If you cannot figure out the answer to any of part 1 you may find the answers in part 2 so skip the ones you do not know and come back to them later)

1) List the rule for selecting the number of required views.

Draw only the number of views required to completely describe the object so that it may be manufactured with repeatability.

2) Complete the following sentences for the three precedence of lines used in drafting rules.

a) Visible line has precedence over hidden____ and __center____ lines. b) Hidden line has precedence over ____centerline____ lines.

3) List the three most common views displayed in 3rd Angle projection.

Top, Front, and Side

4) Insert the image for 3rd angle projection symbolto the right

5) List the 3 points listed in the text about 1st

1. First angle projection is used outside the United States and most Canadian Drawings.

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angle projection. 2. Views are projected on planes behind the part.3. First angle projections are usually drawn in metric.

6) Insert the image for 1st angle projection symbolto the right 7)When line CD is projected to the given plane, it will appear to be:

UNDERLINE & BOLD YOUR ANSWER A) Point B) ForeshortenedC) Truncated D) Oblique

8) Straight lines that do not meet or intersect and are an equal distance apart at all points are known as perpendicular lines.

UNDERLINE & BOLD YOUR ANSWER True False

9) In orthographic projection, the projection lines are?

UNDERLINE & BOLD YOUR ANSWER a. At a 45° angle to the surface projected. b. Parallel to the surface projected.c. Perpendicular to the surface projected.d. Adjacent to the projection plane.

10) Outside the United States and Canada the rest of the industrial world uses which type of orthographic projection?

First angle projection

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11) Pick the missing view indicated by the question mark.

ANSWER: A12) Pick the correct view as indicated by the arrow and question mark.

ANSWER: D 13) Pick the correct view as indicated by the arrow and question mark.

ANSWER: B14) The United States uses 1st angle projection for orthographic views.

UNDERLINE & BOLD YOUR ANSWER:True False

PART 2 Use the 1st Reading Link under MULTI-VIEW CONCEPTS & THEORIES TO ANSWER THE FOLLOWING QUESTIONS & Define the terms.

15) How do engineers determine which type of sketch is appropriate for the design problem in question?

Communicating their ideas through some form of a drawing or sketch

Define the following terms (get these from the reading)

16) projection theory

Comprises the principles used to graphically represent 3D objects and structures on 2D media such as a paper and the computer screen.

17) lines of sight LOS

Imaginary rays of light between an observer’s eye and an object

18) parallel projection

Requires that the object be positioned at infinity and viewed from multiple points on an imaginary line parallel to the object

19) plane of projection

an imaginary flat plane upon which the image created by the LOS is projected.

20) multiview orthographic projection

An object behind the plane of projection is oriented in such a way that only two of its dimensions are shown

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21) frontal plane projection

Is the plane onto which the view selected as the front of an object is projected

22) horizontal plane projection

A plane suspened above and parallel to the top of the object

23) profile plane of projection

A plane that is parallel to the right side of the object

24) principle view The six mutually perpendicular views that are produced by six mutually perpendicular planes of projection

25) fold lines The imaginary hinged edges of the glass box26) adjacent views Two views separated by 90 degrees of viewing rotation27) related views Two views that are adjacent to the same view28) alphabet of lines

A set of standard linetypes established by the American Society of Mechanical Engineers (ASME) for technical drawing

29) edge line The intersection of two planes and is represented as a line on multimew drawings

30) normal line An edge line that is parallel to a plane of projection and thus perpendicular to the lines of sight

31) inclined line Parallel to a plane of projection but inclined to the adjacent planes, and it appears foreshortened in the adjacent planes

32) oblique line Not parallel to any principal plane of projection33) principal plane Parallel to one of the principal planes of projection and is therefore

perpendicular to the lines of sight34) inclined plane Perpendicular to one plane of projection and inclined to adjacent planes35) oblique plane Not parallel to any of the principal planes of projectoin

You Can Google the definitions to the following : 36) adjacent Lying near37) symbol Something used for or regarded as representing something else38) indicate To be a sign of39) transfer To convey or remove from one place, person, etc. to another 40) Explain conventional view placement and alternative view arrangement

Conventional view placement – the three-view multiview drawing is the standard used in engineering and technology, because many times the other three principal views are mirror images and do not add to the knowledge about the object.Alternative view arrangement – two orthohgraphic views are placed next to each other in such a way that the dimension they share in common is aligned, using parallel projectors.

41) Insert and example of the each image discussed in the question above.

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Conventional

Alternative

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42) INSERT an example of the alphabet of lines image with a legend (description of each line and its thickness) to the right you may expand as needed.

43) Explain when you need two use only 1 view

One view drawings are used in electrical, civil, and construction engineering

44) Explain what Cylindrical, conical, and pyramidal shapes are examples of such objects

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type of objects should only use 2 views45) List and explain the 4 steps for selecting views that are listed on page 282 of the text.

1. Determine the best position of the object. The object must be positioned with the imaginary glass box in such a way that the surfaces of major features are either perpendicular or parallel to the glass planes.2. Define the front view. The front view should show the object in its natural or assembled state and be the most descriptive. For example, the front view of an automobile would show the automobile in its natural position, on its wheels3. Determine the minimum number of views needed to completely describe the object so it can be produced.4. After the front view is selected, determine which other views will have the fewest number of hidden lines.

46) List and explain the rules for orthographic projection (hint: you may have to scroll around the text to find all of these)

Projection theory explains the ruels and comprises the principles used to graphically represent 3D objects and structures on 2D media such as paper and the computer screen. All projection theory is based on two variables: line of sight and plane of projection.Line of sight (rule) are imaginary rays of light between an eye and an object. These are also called projectors. When an object in your line of sight

47) List the names of the six Principle Views used in orthographic Projection.

Front, top, right side, left side, bottom, rear

48) Describe the major differences between parallel projection and perspective projection.

Parallel projection requires that the object be positioned at infinity and viewed from multiple points on an imaginary line parallel to the object, while perspective projection requires that the object be positioned at a finite distance and viewed from a single point, the station point.

Use the MULTIVIEW REPRESENTATIONS Reading to complete the following section (Define the following terms from the reading)

49) point Represents a specific position in space and has no width, height, or depth

50) edge view Line when it is parallel to the lines of sight in the current view51) foreshortened plane

Neither parallel nor perpendicular to the lines of sight

52) through hole Hole that goes all the way through an object, is represented in one view as two parallel hidden lines for the limiting elements, and the hole is shown as a circle in the adjacent view

53) blind hole One that is not drilled all the way through the material54) counter bored holes

Used to allow the heads of bolts to be flush with or below the surface of the part

55) fillet Rounded interior corner, normally found on cast, forged, or plastic parts

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56) round Rounded exterior corner, normally found on cast, forged, or plastic parts57) chamfer Beveled corner used on the openings of holes and the ends of

cylindrical parts to eliminate sharp corners 58) runout A special method of representing filleted surfaces that are tangent to

cylinders59) adjacent areas Similar to adjacent views, are surfaces that reside next to each other60) partial view Shows only what is necessary to completely describe an object61) revolution convention

You must visualize the object as if the ribs are revolved into alignment with the vertical center line in the front view

62) bolt circles Revolution conventions also can be used on parts that have bolt circles, which represent the positioning of bolts

63) removed view Complete or partial orthographic view that shows details more clearlyYou Can Google the definitions to the following :

64) eliminate To remove or get rid of, especially as being in some way undesirable65) ambiguity Doubtfulness or uncertainty of meaning or intention66) distorted Not truly or completely representing the facts or reality67) draft angle An angle incorporated into a wall of a mold so that the opening of the

cavity is wider than its base

68) Insert and image example in the column to the right of the following FilletRound Chamfer.

Fillets and

Rounds Chamfer69) List the 4 things 1. surfaces at different levels.

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adjacent areas represent.

2. inclined or oblique surfaces.3. cylindrical surfaces.4. a combination of the above.

70) Explain the use of surface labeling

When multiview drawings are created from a given pictorial view, surfaces are labeled to check the accuracy of the solution.

71) Describe the method used for locating missing lines in an incomplete multiview drawing.

Study each view and add any missing lines to the incomplete views. Lines may be missing in one or more other lines.

72) Explain vertex labeling.

During vertex labeling: vertices, including hidden ones are labeled with numbers

73) Identify the three things a point can represent.

The end view of a line. The intersection of two lines. A specific position in space.

74) Explain the basic techniques for creating a physical model.

The two basic techniques for creating these models are cutting the 3D form out of a rectangular shape and using analysis of solids.

Use the NORMAL VIEWS Reading to complete the following section

75) List the 3 "normal Views"

Top, Front, Right Side

Explain the following terms. & Insert and image of each 76) Normal surfaces

Normal surfaces are either horizontal or vertical in space. (Parallel to or perpendicular to the Solid Edge reference planes).

77) Inclined surfaces

Inclined surfaces have a single slant in space. These surfaces are very common in construction (roofs) and on machine parts.

78) Oblique surfaces

Oblique surfaces have a double slant in space They are referred to as compound-angle surfaces.

79) Oblique Views Oblique Views -neither perpendicular nor parallel to a given line or surface;slanting; sloping.

80) Explain the Glass Box method of getting views of an object. (You may need to watch the video's on the site to understand)

Most objects have six sides therefore six views may result we explain the theory of projecting all six views by imagining a galss box can help you understand how you can move it around to see all sides.

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