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Multiview Drawing
OBJECTIVES
At the conclusion of this unit you should be able to accomplish the following
with a 70% accuracy
1. explain the importance of mulitview drawing as a communication tool far
designers
2. explain the concept of multiview drawing through the use of the transparent
box method
3. explain the concept of projection plans
4. use parallel projectors to develop mechanical drawings
5. use the three principle planes orthographic projection to develop
mechanical drawing
5.1 frontal
5.2 horizontal
5.3 profile
6. use the six different view of a multiview drawing to develop mechanical
drawing
Chapter 6
6.1
6.2
6.3
6.4
6.5
6.6
Multiview Drawing
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front
top
right side
left side
back
bottom
7. use three-view drawing to describe the physical shape of an abject
7.1 front
7.2 top
7.3 right wide
8. select the appropriate view(s) to describe the physical appearance of an
object with the last amount of hidden lines
8.1 number of views
8.2 selecting of front view
9. apply the concept of paint numbering to the development of mulitview
drawings
10. identify the type of plane and line in multiview drawings
11. apply the use of standard lines to multiview drawings
12. apply the rules of line conventions to multiview drawings
13. use standard techniques governing intersecting and overlapping lines in
multiview drawing
14. center a multi view drawing
15. develop a three view drawing (given an isometric of an object or idea) based
on line quality, correct scale, positioning, centering, and overall neatness of
the drawing
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Applied Geometry for Engineering Design
General Information
Many times pictorial drawings cannot give a full description of an object.
Important details on a back, side or bottom surface may be hidden. A product
cannot be manufactured without a completely detailed description of it. Because
pictorial drawings usually cannot completely describe objects, the multiview
drawing system is used to describe them. Multiview (mechanical drawing) is a
system of representing three dimensional objects through the arrangement of
separate two-dimensional views. These views are arranged in a standard
manner, and the system used to construct them is called orthographic
projection. If dimensions and specifications are noted on the multiview drawing,
it is referred to as a working or detail drawing.
The Transparent Box
One way to explain and remember orthographic projection is through the use of
a transparent box. The six sides of the transparent box are all two dimensional.
Each side will provide two dimensions (width, height, or depth) of the three
dimensional box. The front and back sides of the box provide the dimensions of
width and height. The two sides of the box provide the dimensions of height and
depth. And the top and bottom sides of the box provide the dimensions of width
and depth. Now rename the front and back, sides, and the top and bottom of the
box and call them projection planes. The front and back sides of the box will now
be called and located on what is called the frontal projection plane. The two
sides of the transparent box will now be renamed and located on what is called
the profile plane. The top and bottom sides of the transparent box will now be
called and located on what is called the horizontal plane. In each case the planes
will contain the same two dimensions as the sides of the box which they
replaced (see Figure 7.1).
Now imagine that an object is placed within the transparent box. As you look
into the box from the front you will see the front of the object through the side of
the transparent box. If you were to draw the outline of the object on the side of
the box it would be the same as projecting the outline of the object onto the
frontal plane. This would give you the width and height of the object on the two
dimensional frontal plane. This could be done to the back side of the box by
projecting it onto the frontal plane of the transparent box. Each side of the box
could be projected in a similar manner. The sides of the object would be traced
(or projected) onto the sides (profile projection plane) of the transparent box
Chapter 6
Multiview Drawing
Figure 7.1 The orthographic transparent box.
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Applied Geometry for Engineering Design
and they would give you the dimensions of height and depth of the object.
Finally, the top and bottom sides of the object could be traced (or projected)
onto the top and bottom sides (horizontal plane) of the box and they would give
you the dimensions of width and depth of the object (see Figure 7. 1).
Now if the box is torn open and each side (or projection plane) is positioned on a
flat surface, the different sides of the abject will describe all three dimensions of
the object through separate two dimensional views. This is the basic concept of
orthographic projection (sea Figure 7.1).
Projection Planes
There are three principle planes in orthographic projection: the frontal, profile
and horizontal. Each projection plane of an object contains two views of the
object. The frontal projection plane describes an object as it would appear if it
were viewed from the front or from the back. Thus if a view of an object is from
the front or back it is projected on the frontal plane. If a top or bottom view of an
object is given then these views are located on the horizontal planes. And if a
right or left side view of an object is given then these views are projected onto
the profile projection plane. Any view located on a principle plane is called a
principle view. Each principle view of an object will show two dimensions of the
object (see Figure 7.2).
Figure 7.2 The principle planes of orthographic projection.
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Multiview Drawing
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Parallel Projection
Each view of an object will be projected, with parallel projectors onto one of the
principle projection planes. Parallel projection is the term given to the
imaginary lines which are projected at ninety degrees from one side of an object
and locate points on the imaginary projection plane. These points locate the
outline of the object on the projection plane (see Figure 7.3).
Figure 7.3 Parallel projectors.
The Frontal Plane
The front and back views of an object are projected onto the frontal plane; they
are described by the dimensions of width and height (see figure 7.4).
Figure 7.4 The frontal plane.
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Applied Geometry for Engineering Design
The Horizontal Plane
The top and bottom views of an object are projected onto the horizontal plane.
They are perpendicular to the frontal plane and are described by the dimensions
of width and depth (see Figure 7 .5).
Figure 7.5 The horizontal plane.
The Profile Plane
The right and left-side views of an object are projected onto the profile plane.
They are perpendicular to both the frontal and horizontal planes, and are
described by the dimensions of height and depth (see Figure 7. 6).
Figure 7.6 The horizontal plane.
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Multiview Drawing
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The Six View Drawing
The maximum number of views which can be located on the principle planes of
an object is six. If you imagine an object located in the transparent box, there
will be two views on the frontal plane, two views on the horizontal plane, and
two views on the profile plane.
When the transparent box is unfolded the top view will appear over the front
view, the bottom view under the front view, the right-side view to the right of
the front view, the left-side view to the left of the front view, and the back view
to the left of the left-wide view. It is important that the views are located in this
manner and that the projections from all views align both vertically and
horizontally with the front view. This allows the dimensions of height, width,
and depth to be shown commonly among the views, thus eliminating the need to
repeat dimensions. This view arrangement is the standard arrangement used
throughout much of the western world (see Figure 7. 7).
This system of projection is ref erred to as 3rd angle projection. The system used
in many European countries is called 1st angle projection and the arrangement
of views may differ somewhat from the system presented here.
Figure 7.7 The view drawing.
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Applied Geometry for Engineering Design
The Three view Drawing
Although through the use of orthographic projection six views can be used to
describe an object, most objects are commonly described through the use of the
top, front, and right-side views. Many objects can be accurately described with
three views since additional views will usually only duplicate information
already supplied in one of the principle views ( see Figure 7. 8).
Figure 7.8 The three view drawing.
Many times an object can be described more accurately by using the front, top,
And left-side views. If a left-hand view will describe an object more clearly then
the left-side view should be used (see Figure 7.9).
Figure 7.9 Use of the left-side view.
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Multiview Drawing
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Some objects may require either more or fewer than three views to properly
describe them. If this is true than use the number of views needed to properly
describe the object.
One and Two View Drawing
Many objects can be described through the use of one or two view drawings. If
two views completely describe an object than only use two views to describe the
object. Cylindrical parts and parts with uniform thicknesses can be described by
one view. However, the one view drawing must contain a note which describes
the missing view or gives the thickness of the object (see Figure 7.10).
Figure 7.10 The one and two view drawings.
View Selection
The criteria for selection of views in multiview drawing is based on the view
which fully describes the object with the fewest number of hidden lines or
shows the outside contour of the object in the most descriptive manner. This
view will be used as the front view. All other views are than projected from the
front view. In Figure 7.11 "A" would be used as the front view because it
describes the outside contour of the object (see Figure 7.11).
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Applied Geometry for Engineering Design
Figure 7.11 Selection of the front view an object.
The front, top, and side views are considered the standard views of many
objects. A chair; for example, has a front, top, and side view which can be
recognized by everyone. Thus the views describing the chair should properly
correspond to the commonly recognized views of the chair (see Figure 7. 12).
Figure 7.12 View selection of a chair.
Point Numbering
If you are having trouble interpreting a multiview drawing of an object a method
of numbering points on the object may be helpful in the visualization of it. Figure
Chapter 6
Multiview Drawing
12
7.13 is an example of point numbering. Each point is labeled on the isometric
drawing. These points are then transferred to the multiview drawing.· The
points which are closest to you (5 & 6 on the front view of Figure 7. 13) will be
labeled on the outside of the multiview drawing. The paints which are farthest
away from you (7 & 8 on the front view of Figure 7. 13) will be labeled on the
inside of the multiview drawing (see Figure 7. 13).
Figure 7.13 Point Numbering.
Lines and Planes
In multiview drawing a line can appear as a point, true length, or foreshortened.
A plane can appear as an edge, true size, or foreshortened (see Figure 7.14).
Figure 7.14 Lines and planes in multiview drawing.
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Applied Geometry for Engineering Design
Standard Lines
As mentioned in chapter two, different types of lines with varying line weights
will represent various components of an object in multiview drawing.
Depending on the paper, different leads are used to produce standard lines.
Except for guidelines and construction lines which are drawn very light, all
other lines are drawn black. Standard lines are Distinguished by their varying
widths and configurations. Designers must know the difference between the
standard lines and how to apply them to multiview drawings (see Figure 7. 15)
Object Lines
Object lines are the most important lines on a multiview drawing. They
represent the actual outline of an object. Object lines like all other lines except
for construction lines and guidelines should be drawn to appear as black as ink.
Their width (.5mm) should be consistent throughout the drawing (see Figure
7.15).
Figure 7.15 Standard lines or the alphabet of lines.
Hidden Lines
Hidden lines as their name implies represent surfaces which cannot be seen in·a
view of an object but must be shown to represent the object completely. Hidden
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Multiview Drawing
14
lines are drawn as short black dashes (118", 3mm) with a small break (1/16",
2mm) lef t between the dashes. Like object lines their width is .5mm (see Figure
7.15).
Center lines
Center lines are used to locate the center paints for circles and to describe axes
of symmetry. They are drawn as alternate long ( 3/4", 19mm to 1 1/2", 38mm)
and short (1/8", 3mm) dashes. The space between the dashes should be 1/16"
(2mm). When the center paint of a circle is described by center lines the short
dashes are intersected. The line weight of center lines is 0.3mm (See Figure
7.15).
Although object, hidden, and center lines are the most commonly used type of
lines, you should be able to recognize and draw all the other standard lines.
These are drawn as they should appear on a drawing in Figure 7.15.
Line conventions
Line conventions are the rules which govern overlapping and intersecting lines
in multiview drawing. If two lines are located in the same position on a
multiview drawing, object lines will take precedence overall other lines. Hidden
lines will take precedence over all other lines, followed by center lines if the
lines in the same location (see Figure 7.16).
Figure 7.16 Line conventions in multiview drawing.
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Applied Geometry for Engineering Design
Intersecting lines
It is common for lines to overlap and intersect each other in multiview drawings.
When this occurs the overlapping and intersecting lines are drawn in a standard
manner which is understood by all designers (see figure 7.17).
Figure 7.17 Intersecting and overlapping lines techniques.
Centering a Multiview Drawing
There are many ways to center a multiview drawing. Depending on the number
of dimensions and notes needed to explain an object more space may be needed
between the views of the drawing. The method explained here will leave equal
distance between the front and side views horizontally and the front and top
views vertically in a multiview drawing.
To center the front and side views of a multiview drawing: 1) determine the
horizontal drawing space between the border lines, 2) add the width from the
Chapter 6
Multiview Drawing
16
front view to the depth of the side view, 3) subtract the combined distance of the
front and side views as determined in step two from the drawing area between
borders from step one, 4) divide t his number by three, 5) locate this distance in
from either t he left or right hand border line. Use the same procedure to locate
the bottom line of the front view or the top line of the top view. The intersection
of vertical and horizontal centering lines will be the beginning point of
construction for the multiview drawing (see Figure 7.18).
Figure 7.18 Centering a multiview drawing.
Summary
A thorough understanding of orthographic projection and how to apply
multiview drawing is essential to designers. Through the use of multiview
drawing almost any object idea can be presented. But without the knowledge of
how to properly use multiview drawings, the effectiveness of an idea or the
description of an object may not be complete or expressed properly.
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Applied Geometry for Engineering Design
Technical terns
1. Frontal plane - the projection plane onto which the front and back views of
an object are projected and describes the height and width of the object.
2. Horizontal plane - the projection plane onto which the top and bottom views
of an object are projected and describes the width and depth of the object.
3. Line conventions - rules which exist concerning overlapping and
intersecting lines in multiview drawing.
4. Multiview drawing - a system of representing three dimensional objects
through the arrangement of separate two dimensional views of the object.
5. Orthographic projection - the representation of an object with the use of
various two dimensional views which are projected onto a projection plane
with the use of parallel projectors.
6. Parallel projectors - imaginary lines which are drawn perpendicular to an
object and locate a view of the object onto a projection plane.
7. Perpendicular – a line or plane which is located 90 degrees to another line or
plane.
8. Profile plane - the projection plane onto which the right and left-side views
of an object are projected and describes the height and depth of the object.
9. Projection - the concept of projecting or drawing one surface of an object
onto a plane.
10. Projection plane - an imaginary plane or surface onto which a view of an
object is drawn.
11. Six view drawing - an orthographic projection of an object which describes
the object with the use of the front, top, right-side, left-side, back, and
bottom views.
12. Standard lines - lines which are universal to the field of mechanical drawing,
and represent various surfaces of objects.
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Multiview Drawing
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13. Three view drawing - an orthographic projection of an object which typically
describes the object with the use of a front, top, and side view.
14. Working drawing - a mechanical drawing which contains dimensions and
specification notes.
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Applied Geometry for Engineering Design
Assignment 5.1
DIRECTIONS: Place the letter from the surface of the object in the multiview
drawing onto the corresponding circle on the isometric drawing. The
assignment grade will be based upon the correct identification of the surfaces on
the isometric drawing (objectives 3, 4, 5, 6, a, 10, & 11).
DIRECTIONS: Place the letter from the surface of the object in the isometric
drawing onto the carrespand1ng circle on the multiview drawing. The
assignment grade will be based upon the correct identification of the surfaces on
multiview drawing (objectives 3, 4, 5, 6, 8, 10, & 11).
Chapter 6
Multiview Drawing
Assignment 5.2
DIRECTIONS: Sketch in the missing lines needed to complete the three-view
drawings. The assignment grate will be based upon correct completion of the
multiview drawings (objectives 6, B, 10, & 11).
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Applied Geometry for Engineering Design
Assignment 5.3
DIRECTIONS: Sketch the correct amount of views needed to completely describe
the given objects. The assignment grade will be based upon correct view
selection, proper projection techniques, use of standard lines, line conventions
and rules governing intersecting and overlapping lines (objectives 5, 6, 7, 9, 10,
11, 12, 13, & 14).
Chapter 6
Multiview Drawing
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Assignment 5.4
DIRECTIONS: Select a scale and draw the following three view drawings by
completing the missing view. The assignment grade will be based upon proper.
Multiview drawing techniques, line quality, centering and overall neatness
(objectives 6, 8, 10, 11, 12, 13, & 14).