Multi-View Drawing
Review
Sacramento City College
EDT 300/ ENGR 306
EDT 300 / ENGR 306 - Chapter 5
1
Objectives
Identify and select the various views of
an object.
Determine the number of views needed
to describe fully the shape and size of
an object.
Define the term orthographic projection
Describe the difference between first
and third-angle projection.
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EDT 300 / ENGR 306 - Chapter 5
Objectives
Visualize the glass box concept and
apply it to the process of selecting and
locating views on a drawing.
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EDT 300 / ENGR 306 - Chapter 5
Objectives
Develop a multi-view drawing, following
a prescribed step-by-step process, from
the initial idea to a finished drawing.
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EDT 300 / ENGR 306 - Chapter 5
Vocabulary
First angle
projection
Front View
Horizontal Plane
Implementation
Multi-view
Drawing
Negative Cylinder
Normal Views
Orthographic
Projection
Pictorial Drawing
5
Profile plane
Quadrant
Right-side View
Solid Model
Spherical
Third-angle
Projection
Top View
Vertical Plane
Visualization
EDT 300 / ENGR 306 - Chapter 5
Communication
People communicate by verbal and
written language and graphic (pictorial)
means.
Technical drawings are a graphical
means to communicate.
When accurate visual understanding is
necessary, technical drawing is the
most exact method that can be used.
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EDT 300 / ENGR 306 - Chapter 5
Visualization and Implementation
Technical drawing involves:
Visualization
The ability to see clearly in the mind s
eye what a machine, device or object
looks like.
Implementation
The process of drawing the object that
has been visualized.
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Visualization and Implementation
A technical drawing, properly made,
gives a clearer, more accurate
description of an object than a
photograph or written explanation.
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EDT 300 / ENGR 306 - Chapter 5
Visualization and Implementation
Technical drawings made according to
standard rules result in views that give
an exact visual description of an object.
The multi-view drawing is the major
type of drawing used in the industry.
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Multi-View Drawing
A photograph can show three views
Front.
Top.
Right Side.
Nearly all objects have six sides, not
three.
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Multi-View Drawing
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EDT 300 / ENGR 306 - Chapter 5
Multi-View Drawing
If an object could be shown in a single
photograph, it would also include
A left-side view.
A rear view.
A bottom view.
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Pictorial Drawing
An object cannot be photographed if it
has not been built (!)
This limits the usefulness of
photographs to show what an object
looks like (!)
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Pictorial Drawing
A pictorial drawing
Is a drawing.
Shows an object as it would appear in
a photograph.
Shows the way an object looks, in
general.
It does not show, the exact forms and
relationships of the parts that make
up the object.
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Pictorial Drawing
A pictorial drawing
Shows the object as it appears, not
as it really is.
Holes in the base appear as ellipses,
not as true circles.
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Pictorial Drawing
Photograph
Pictorial Drawing
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Multi-View Drawing
The goal, is to represent an object on a
sheet of paper in a way that described
its exact shape and proportions.
To do this: Draw views of the object as
it is seen from different positions.
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Multi-View Drawing
These views are then arranged in a
standard order.
Anyone familiar with drafting practices
can understand them immediately.
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Multi-View Drawing
To describe accurately the shape of
each view imagine a position
Directly in front of the object.
Directly above the object.
On the right side of the object.
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EDT 300 / ENGR 306 - Chapter 5
Multi-View Drawing
The front, top and right side views are
the ones most often used to describe
an object in technical drawing.
They are called the Normal views.
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The Relationship of Views
Views must be placed in proper
relationship to each other.
The Top View is directly above the
Front View
The Right-side View is directly to the
right of the Front View.
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EDT 300 / ENGR 306 - Chapter 5
The Relationship of Views
When the views are placed in proper
relationship to one another, the result is
a multi-view drawing.
Multi-view drawing is the exact
representation of an object on one
plane.
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EDT 300 / ENGR 306 - Chapter 5
The Relationship of Views
Other views may also be required.
The proper relationship of the six views
is shown below
Top View
Rear
View
Left-side
View
Front View Right-side
View
Bottom View
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Normal
views
EDT 300 / ENGR 306 - Chapter 5
V-Block
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EDT 300 / ENGR 306 - Chapter 5
Orthographic Projection
These views are developed through the
principles of orthographic projection
Ortho - straight or at right angles .
Graphic - written or drawn .
Projection - from two Latin words:
Pro, meaning forward
Jacere, meaning to throw
The literal meaning is thrown
forward, drawn at right angles .
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Orthographic Projection
Definition: Orthographic projection is:
the method of representing the exact
form of an object
in two or more views
on planes usually at right angles to
each other,
by lines drawn perpendicular from the
object to the planes.
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Orthographic Projection
An orthographic projection drawing is a
representation of the separate views of
an object on a two-dimensional surface.
It reveals the width, depth and height
of an object.
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Orthographic Projection
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Angles of Projection
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Angles of Projection
On a technical drawing, a plane is an
imaginary flat surface that has no
thickness.
Orthographic projection involves the
use of three planes.
Vertical plane.
Horizontal plane.
Profile plane.
A view of an object is projected and
drawn on each plane.
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Angles of Projection
The vertical and horizontal planes divide
space into four quadrants (quarters of a
circle).
In orthographic projection, quadrants
are usually called angles.
Thus we get the name, first-angle
projection and third angle projection
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Angles of Projection
First angle projection is used in
European countries.
Third angle projection is used in the US
and Canada.
Second and fourth angle projection is
not used.
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First Angle Projection
First angle projection
Front view = vertical plane.
Top view = horizontal plane.
Left side view = profile plane.
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First Angle Projection
In first angle projection, the Front View
is located above the Top View.
The Left-side View is to the right of the
Front View.
Refer to Figure 5-12.
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First Angle Projection
In first-angle projection, the projection
plane is on the far side of the object
from the viewer.
The view of the object are projected to
the rear and onto the projection plane
instead of being projected forward.
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Third Angle Projection
Third angle projection
Front view = vertical plane.
Top view = horizontal plane.
Right side view = profile plane.
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Third Angle Projection
In third angle projection, the Top View
is located above the Front View.
The Right-Side View is to the right of
the Front View.
Refer to Figure 5-14.
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Third Angle Projection
In third-angle projection, the projection
plane is considered to be between the
view and the object, and the views are
projected forward to that plane.
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Third Angle Projection
The views appear in their natural
positions when the views are revolved
into the same plane as the frontal plane
The top view appears above the front
view.
The right-side view is to the right of
the front view.
The left view to the left of the front
view.
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The Glass Box
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The Glass Box
In each case the three views have been
developed by using imaginary
transparent planes.
The views are projected onto these
planes.
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The Glass Box
Visualize a glass box around the object
Project the view of the object onto a
side of the box.
Unfold the box to one plane.
The views will be in their relative
positions.
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The Glass Box
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The Glass Box
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Projection of Lines
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Projection of Lines
There are four kinds of straight lines
found on objects in drawings
Horizontal.
Vertical.
Inclined.
Oblique.
Each line is projected by locating its
endpoint.
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Horizontal Lines
Horizontal lines
Are parallel to the horizontal plane of
projection.
Are parallel to one of the planes.
Are perpendicular to the third plane.
Appear as true length in two of the
planes.
Appear as a point in the third.
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EDT 300 / ENGR 306 - Chapter 5
Vertical Lines
Vertical Lines
Are parallel to the frontal plane.
Are parallel to the profile plane.
Are perpendicular to the horizontal
plane.
Appear true length in the frontal and
profile planes.
Appear as a point in the horizontal
plane.
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Inclined Lines
Inclined Lines
Are parallel to one plane of
projection.
Are inclined in the other two planes.
Appear true length in one of the
planes.
Appear shortened in the other two
planes.
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Oblique Lines
Oblique Lines
Are neither parallel nor perpendicular
to any of the planes or projections (!)
Appear shortened in all three planes
of projection.
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Curved Lines
Curved Lines may be
Circular.
Elliptical.
Parabolic.
Hyperbolic.
Some other geometric curve form.
They may also be irregular curves.
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Projection of Surfaces
Surfaces may be
Horizontal.
Vertical.
Inclined.
Oblique.
Curved.
They are drawn by locating the end
points of the lines that outline their
shape.
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Horizontal Surfaces
Horizontal surfaces
Are parallel to the horizontal
projection plane
Appear true size and shape in the
Top View.
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Vertical Surfaces
Vertical surfaces
Are parallel to one or the other of the
frontal or profile planes, and
Appear in their true size and shape in
the Front View or the Right-side View.
They are perpendicular to the other two
planes and appear as lines in these
planes
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Inclined Surfaces
Inclined surfaces
Are neither horizontal nor vertical
Are perpendicular to one of the
projection planes and appear as a
true length line in this view
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Oblique Surfaces
Oblique Surfaces
Are neither parallel nor perpendicular
to any of the planes of projection.
They appear as a surface in all views
but not in their true size and shape
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Curved Surfaces
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Curved Surfaces
May be
a single curved surface (cone or
cylinder)
a double curved surface (sphere,
spheroid or torus
a warped surface
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Curved Surfaces
Appear as circles in one view and as
rectangles in the other view
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Techniques for Special Lines and
Surfaces
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Techniques for Special Lines and Surfaces
To describe an object fully, show every
feature in every view, whether or not it
can ordinarily be seen
Also include other lines that are not part
of the object to clarify relationships and
positions in the drawing
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Techniques for Special Lines and Surfaces
Special line symbols are used to
differentiate between object lines and
lines that have other special meanings
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Hidden Lines
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Hidden Lines
Both interior and exterior features are
projected in the same way.
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Hidden Lines
Parts that cannot be seen in the views
are drawn with hidden lines.
Hidden lines are made up of short
dashes.
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Hidden Lines
The first line of a hidden line touches
the line where it starts.
Refer to Figure 5-18A.
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Hidden Lines
If a hidden line is a continuation of a
visible line, space is left between the
visible line and the first dash of the
hidden line.
Refer to Figure 5-18B.
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Hidden Lines
If the hidden lines show corners, the
dashes touch the corners.
Refer to Figure 5-18C.
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Hidden Lines
Dashes for hidden arcs start and end at
the tangent points.
Refer to Figure 5-19A.
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Hidden Lines
When a hidden arc is tangent to a
visible line, leave a space.
Refer to Figure 5-19B.
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Hidden Lines
When a hidden line and a visible line
project at the same place, show the
visible line.
Refer to Figure 5-19C.
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Hidden Lines
When a centerline and a hidden line
project at the same place, draw the
hidden line.
Refer to Figure 5-20A.
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Hidden Lines
When a hidden line crosses a visible
line, do not cross the visible line with a
dash.
Refer to Figure 5-20B.
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EDT 300 / ENGR 306 - Chapter 5
Hidden Lines
When hidden lines cross, the nearest
hidden line has the right of way
Draw the nearest hidden line through
a space in the farther hidden line.
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Centerlines
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Centerlines
Centerlines are special lines used to
locate views and dimensions.
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Centerlines
Primary centerlines
Locate the center on symmetrical
views in which one part is a mirror
image of another.
Are used as major locating lines to
help in making the views.
They are also used as base lines for
dimensioning.
Are drawn first.
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Centerlines
Secondary centerlines are used for
drawing details of a part
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Precedence of Lines
EDT 300 / ENGR 306 - Chapter 5
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Precedence of Lines
The following priority of lines exists:
1. Visible lines.
2. Invisible lines.
3. Cutting-plane lines.
4. Center lines.
5. Break lines.
6. Dimension and extension lines.
7. Section lines (crosshatching).
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Curved Surfaces
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Curved Surfaces
Some curved surfaces, such as cylinders
and cones do not show curved surfaces
in all views.
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Curved Surfaces
A cylinder with its axis perpendicular to
a plane will show as a circle on that
plane and as a rectangle on the other
two planes.
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Curved Surfaces
A cylinder with its axis perpendicular to
a plane will show as a circle on that
plane and as a rectangle on the other
two planes.
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Curved Surfaces
The holes may be thought of as
negative cylinders
In mathematics, negative means an
amount less than zero.
A hole is a nothing cylinder, but it
does have size.
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Cones
A cone appears as a circle in one view.
It appears as a triangle in the other
view.
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Cones
One view of a frustum of a cone
appears as two circles
In the top view, the conical surface is
represented by the space between
the two circles.
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Cones
Cylinders, cones and frustums of cones
have single curved surfaces.
The appear as circles in one view and
straight lines in another.
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Deciding Which Views To Draw
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Deciding Which View to Draw
Six views are not needed to describe
most objects.
Usually three views are sufficient.
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Deciding Which View to Draw
Most pieces can be recognized because
they have a characteristic view.
This is the first view to consider, and
usually is the first view to draw.
Next, consider the normal position of
the part when it is in use.
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Deciding Which View to Draw
Views with the fewest hidden lines are
easiest to read, and require less time to
draw.
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EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw
The main purpose of drawing views is
to describe the shape of the object.
It is a waste of time to make more
views than are necessary to describe
the object.
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Deciding Which View to Draw
Some parts can be described in only
one view.
Figure 5-23 A.
Sheet material: plywood
Parts of uniform thickness
The thickness can be given in a note.
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Deciding Which View to Draw
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Deciding Which View to Draw
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Deciding Which View to Draw
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Deciding Which View to Draw
Some parts can be described in only
one view.
Compare 5-24 C and D.
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EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw
Some parts can be described in two
views.
Figure 5-25 A, B, C, D, E.
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Deciding Which View to Draw
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Deciding Which View to Draw
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EDT 300 / ENGR 306 - Chapter 5
Deciding Which View to Draw
Examples of parts that can be drawn in
two views:
Figure 5-26 A - F.
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Deciding Which View To Draw
Long and narrow objects may suggest
top and front view.
Short and broad objects may suggest
top and right-side views.
Right side is preferred over left-side
when a choices is available.
Top view is preferred over bottom view
when a choice is available.
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Placing Views
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Placing Views
The size of the drawing sheet should
allow enough space for the number of
views needed to give a clear description
of the part.
The method for determining the
positions of the views is the same for
any space.
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Placing Views
The working space of a drawing is the
area inside the border.
Objects are never drawn directly
touching the border.
Objects are drawn so there is a space
between the object and the border line.
Refer to Figure 5-28.
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Placing Views
1. Measure the available drawing area using the scale
of the drawing.
2. Subtract out the space occupied by the object
Horizontal:
Vertical:
Front View
Right side View
3. Divide the remaining area by 4
Put one part each
On left of Front View
On right of Front View
On left of Right Side View
On right of Right Side View
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Front View
Top View
Placing Views
Converting decimals to fractions.
1. Use page 699 in text
Look up decimal
Look to left to find equivalent fraction
2. Convert fractions to 12ths of an inch
0.38 = 3/8
3/8 = x/12
8x = 36
x = 4.5 /12
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Figure 5-28
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Figure 5-29
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Placing Views
1. Add the width and the depth of the
object.
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Placing Views
1. Add the width and the depth of the
object.
For the Base, Fig 5-63, p152,
The width is: 7.50
The height is: 2.25 + 1.62
The depth is: 3.25
Width + depth = 7.50 + 3.25 = 10.75
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Placing Views
2. Subtract this total from the width of
the drawing space.
Refer to Figure 5-30.
A space of about 1 is commonly left
between the Side View and the Front
View.
Space may be larger or smaller,
depending upon the shapes of the
views.
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Figure 5-30
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Placing Views
2. Subtract this total from the width of
the drawing space.
For the Base, Fig 5-63, p152,
Drawing Space width =
11 - 0.25 - 0.25 = 10.5 max.
Width + depth = 7.50 + 3.25 = 10.75
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Placing Views
3. Add the height and the depth of the
object.
4. Subtract this total from the height of
the drawing space.
5. Divide the remaining space evenly.
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Figure 5-30
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Locating and Transferring
Measurements
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Locating Measurements
Measurements made on one view can
be transferred to another.
This process also insures accuracy.
Refer to Figure 5-33.
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Locating Measurements
1. Draw upward from the Front view to
locate width measurements in the Top
view
Draw downward from the top view to
locate width measurements on the
Front view.
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Locating Measurements
2. Draw a light line across to the Side
view from the Front view to locate
height measurements
Use a similar method to project height
measurements from the side view to
the front view
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Locating Measurements
Height of Front view - transfer to Rightside view.
Depth measurements show as vertical
distances in the Top view and as
horizontal distances in the the Rightside view.
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Locating Measurements
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Locating Measurements
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Locating Measurements
3. Depth measurements show as
Vertical distances - Top view
Horizontal distances - Right-side view
To transfer these measurements use
Arcs
45o triangle
Dividers
Scale
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Using Arcs to Transfer
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Using Scale to Transfer
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Using 45 Line to Transfer
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Summary of Steps
Follow a step-by-step method to insure
accuracy
Carry all views along together
Do not attempt to finish one view
before starting the others
Use a hard lead pencil (4H or 6H) and
light, thin lines for preliminary (layout)
lines
Use F, HB or H for final lines
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Summary of Steps
1.
2.
3.
4.
Consider the Characteristic View first.
Determine the number of views.
Locate the views.
Block in the views with light, thin
layout lines.
5. Lay off the principal measurements.
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Summary of Steps
6. Draw the principal lines.
7. Lay off the measurements for details
such as centers for arcs, circles and
ribs.
8. Draw the circles and arcs.
9. Draw any additional lines needed to
complete views.
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Summary of Steps
10. Darken the lines where necessary to
make them sharp and black and of
proper thickness
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