Sketching
Chapter 2
Sacramento City College
EDT 300/ENGR 306
EDT 300/ENGR 306
1
Objectives
‹ Describe
the importance of freehand
sketching for communicating technical
ideas.
‹ Letter
clear, neat, freehand notes and
directions on a technical drawing or
sketch.
‹ Communicate
technical ideas through
freehand sketching.
2
Objectives
‹ Develop
design ideas through multiview or pictorial sketches.
3
Sketching and Lettering
‹ Vocabulary
4
‹ oblique
‹ arcs
‹ overlay
‹ axis
‹ plane
(axes)
‹ composition
‹ concentric circles
‹ ellipses
‹ Gothic lettering
‹ guidelines
‹ isometric lines
‹ isometric sketch
‹ lettering
‹ line
‹ nonisometric lines
sketch
‹ point
‹ proportion
‹ radius
(radii)
‹ tangent arcs
‹ texture
Sketching
‹ Sketches
•
•
•
•
•
5
Sketches bring ideas to life.
Sketches communicate thoughts which
cannot be said.
Freehand sketching is the simplest form of
drawing.
Sketching is a quick way to express ideas,
A sketch can greatly simplify a technical
discussion.
Sketching
•
Professionals who use sketching
•
•
•
•
•
•
6
Designers
Drafters
Technicians
Engineers, and
Architects
Sketching is used to explain
complicated ideas or unclear thoughts.
The Language of Sketching
‹ Four
Basic Visual Symbols Which Can
Be Seen.
7
•
A point – a symbol that describes a
location in space.
•
A line – A path between two points.
•
A plane – two non parallel lines define a
plane which is a flat surface.
•
A texture or surface quality.
The Language of Sketching
•
8
Any idea, no matter how simple or
complicated can be sketched using
these four visual symbols.
Reasons For Sketching
‹ We
draw sketches
‹ 1.
To persuade people who make
decisions about a project that an idea is
good.
‹ 2.
To develop a proposed solution to a
problem so that a client can respond to it.
9
Reasons For Sketching
‹ We
draw sketches
‹ 3.
To clarify a complicated detail of a
drawing that has more than one view by
enlarging it or by creating a simple pictorial
(picture-like) sketch.
‹ 4.
To give design ideas to drafters to that
they can do the detail drawings.
10
Reasons For Sketching
‹ We
draw sketches
‹ 5.
To develop a series of ideas for refining
a new product or machine part.
‹ 6.
To develop and analyze the best
methods and materials for making a
product.
11
Reasons For Sketching
‹ We
draw sketches
‹ 7.
To record permanently a design
improvement on a project that already
exists.
‹ The
change may result from a need to repair a
part that breaks over and over again.
12
Reasons For Sketching (cont’d)
‹ We
draw sketches
‹ 8.
To show that there are many ways to
look at or solve a problem.
‹ 9.
‹ It
To spend less time in drawing.
is much quicker to make a sketch,
which takes only a pencil and an sheet
of paper, than to create a mechanical
drawing.
13
Types of Sketches
EDT 300/ENGR 306
14
Types of Sketches
‹ Any
image drawn on paper freehand
may be called a sketch.
‹ Most
drafters use several types of
sketches.
‹
15
The type of sketch used depends upon
the purpose and the lifespan required
for the sketch.
Rough Sketches
‹ Rough
Sketches
‹ Quick
and dirty
‹ Are usually drawn quickly with jagged
lines.
‹ Primary
quickly
‹ Refer
16
purpose is to express thoughts
to Figure 2-21.
Rough Sketches
‹ Guidelines
‹ Instruments
or straightedges are not used
to prepare a rough sketch.
‹ Instruments
tend to restrict the creative
expressions developed with god pencil
techniques.
‹ Avoid
mechanical hard-line look.
‹ Concentrate
17
on using good proportions.
Refined Sketches
‹ Refined
Sketches
‹ Are
drawn more carefully than rough
sketches.
‹ Show
good proportion and excellent
balance.
18
Refined Sketches
‹ Refined
Sketches
‹ You
may use a straightedge to control long
lines on a refined sketch.
‹ However,
never allow the line to look
mechanically drawn.
‹ Sketched
character.
19
lines should have some irregular
Presentation Sketches
‹ Presentation
Sketches
‹ Presentation
sketches are pictorial
sketches that have been greatly refined.
‹ Are
used to convince a client or
management to accept and approve the
ideas presented.
20
Presentation Sketches
‹ Presentation
Sketches
‹ Pictorial
sketches have a threedimensional view that can be understood
easily by non-technical people.
‹ Generally
drawn so that they look
glamorous, artistic or eye-appealing.
21
Temporary and Permanent Sketches
‹ Sketches
may be temporary or
permanent.
‹ Some
are done just to solve an
immediate problem.
‹ Others
22
are kept longer.
The Overlay
‹A
good way to refine a sketch is to use
overlay paper.
‹ Overlay
is a piece of translucent tracing
paper that is placed on top of a sketch
or drawing.
‹ Because
23
you can see through the
paper, you can quickly trace the best
parts of the sketch or drawing
underneath.
The Overlay
‹ Overlay
ways:
‹ 1.
is used in three important
Reshaping a design (Fig 2-22).
‹ 2.
Used to refine the drawing itself without
really changing its shape entirely.
‹ 3.
Can be used to add various options to a
basic drawing.
24
25
26
Views Needed For A Sketch
‹ There
are two types of drawings that
you can sketch easily:
‹ 1.
‹ 2.
Pictorial drawing.
Multi-view Projection or Orthographic
Projection.
27
Views Needed For A Sketch
‹ Pictorial
‹ The
drawing -
width, height, and depth of an object
are shown in one view.
28
29
Views Needed For A Sketch
‹ Multi-view
Projection
‹ An
Projection or Orthographic
object is usually shown in more than
one view.
‹ You do this by drawing sides of the object
and relating them to each other.
30
31
One-View Sketches
‹ If
an object can be described in two
dimensions, a one-view drawing is
generally sufficient.
‹ These
objects generally have a depth or
thickness that is uniform.
‹ The
drafter may just give the third
dimension as a numerical value, instead
of showing the third view.
32
33
34
Two-View Sketches
‹ Many
objects can be described in two
views.
‹ Select
the views carefully which
describe the object well.
35
36
37
38
Multi-View Sketches
‹A
pictorial drawing shows how the
object looks in three-dimensional form.
‹ However,
a pictorial drawing may not
show all the information desired.
‹ Some
of the lines and details may not
be visible.
39
Multi-view Sketches
40
The Glass Box
‹ Use
the "Glass box" to determine how
many views are required to describe an
object.
‹ By
"opening up" the glass box into one
plane, you can see how it would be
drawn on paper.
41
42
43
Materials For Sketching
‹ Sketching
has two major advantages
over formal drawings.
‹ Only
a few materials are required to create
a sketch.
‹ Pencil,
Paper
‹ You
can create a sketch anywhere. No
drafting table required.
‹ You
are ready to sketch with a pencil,
an eraser, and a pad of paper.
44
Paper
‹ Plain
‹ If
paper can be used for sketching.
you need to refine the sketch, use
tracing paper
45
Paper
‹ You
may also use graph paper to
control proportions while sketching.
‹ Alternative:
Place graph paper
underneath plain paper.
46
Paper
‹ Generally
8-1/2 by 11 is the best size
for making small sketches quickly.
47
Paper
‹ You
can hold the paper on stiff
cardboard, or a clipboard while working
on it.
‹ Place
graph paper under the tracing
paper to help guide line spacing.
48
Pencils and Erasers
‹ Most
drafters like to use soft lead
pencils (Grades F, H, or HB).
‹ Use
an eraser that is good for soft
leads,
‹ Plastic
49
eraser or kneaded-rubber eraser.
Pencils and Erasers
‹ Four
types of pencil points are used for
sketching:
‹ Sharp.
‹ Near-sharp.
‹ Near-dull.
‹ Dull.
50
Pencil Sharpness
51
Line Types Used
‹ Many
line types are used in sketching
‹ Visible.
‹ Hidden.
‹ Cutting
Plane.
‹ Center Line.
‹ Construction Line.
‹ Extension Line.
‹ Refer
52
to Figure 2-33.
53
Drawing Lines
‹ Lines
look”.
‹ The
drawn freehand have a “natural
slight changes in direction show
freedom of movement.
54
Drawing Lines
‹ To
draw an object line:
‹ Hold
the pencil far enough from the point
that you can move your fingers easily and
yet can put enough pressure on the point
to make dense, black lines when
necessary.
55
Drawing Lines
‹ To
draw a construction line.
‹ Use
very little pressure on the point.
‹ They
should be light enough that they need
not be erased.
56
Drawing Straight Lines
‹ Methods
‹ 1.
57
of Sketching Straight lines
Draw one continuous line.
Drawing Straight Lines
58
Drawing Straight Lines
‹ 2.
Draw short dashes where the line
should start and end.
‹ Then,
place the pencil point on the
starting dash.
‹ Keeping
your eye on the end dash,
draw toward it.
59
Drawing Straight Lines
60
Drawing Straight Lines
‹ 3.
Draw a series of strokes that touch
each other or are separated by very
small spaces.
61
Drawing Straight Lines
62
Drawing Straight Lines
‹ 4.
63
Draw a series of overlapping strokes.
Drawing Straight Lines
64
Drawing Straight Lines
‹ Practice
sketching straight lines before
you try to draw objects.
‹ Draw
‹ Draw
vertical lines from the top down.
horizontal lines from left to right if
you are right handed (opposite if you
are left handed).
65
Slanted Lines and Specific Angles
‹ Sketch
slanted, or inclined lines from
left to right.
‹ It
might be easiest to turn the paper
and draw an inclined line the same way
as a horizontal line.
66
Slanted Lines and Specific Angles
67
Slanted Lines and Specific Angles
‹ When
trying to sketch a specific angle,
first draw a vertical line and a horizontal
line to form a right angle.
‹ Divide
the right angle in half to form two 45
degree angles.
‹ Or divide in thirds to make 30 degree
angles.
68
Slanted Lines and Specific Angles
69
Drawing Circles
‹ Sketch
a circle
‹ 1.
Estimate the length of the radius and
mark it off.
‹ Use
the marks as guides, draw a square in
which you can sketch the circle.
70
Drawing Circles
71
Drawing Circles
‹ 2.
Draw very light centerlines and draw
bisecting lines through the center at
convenient angles.
‹ Estimate
the length of the radius and mark
off this distance on all the lines.
‹ The bottom of the curve is generally easier
to form, so draw it first.
‹ Then turn the paper so that the rest of the
circle is on the bottom.
‹ Finish drawing the circle.
72
Drawing Circles
73
Drawing Circles
74
Drawing Circles
75
Drawing Circles
76
Drawing Circles
77
Drawing Circles/Arcs
78
Drawing Circles
‹ 3.
Use your hand as a compass
‹ Use
your little finger as a pivot at the
center of the circle.
‹ Use your thumb and forefinger to hold the
pencil rigidly at the radius you want.
‹ Turn the paper carefully under your hand.
79
80
Drawing Circles
‹ 4.
Use two crossed pencils
‹ Hold
them rigidly with the two points as far
apart as the length of the desired radius.
‹ Put one pencil point at the center.
‹ Hold it there firmly and turn the paper,
drawing the circle with the other point.
81
82
Proportions
EDT 300/ENGR 306
83
Proportions for Sketching
‹ Sketches
‹ BUT,
are not made to scale.
a good sketch should always
maintain the correct proportion.
84
Estimating Proportions
‹ To
sketch well, you must learn to
eyeball (estimate by eye) an object's
proportions.
85
Estimating Proportions
‹ To
estimate an objects proportions:
‹ 1. Look at an objects largest overall
dimension, usually width, and estimate
the size
‹ 2.
Next determine the proportion of the
height to the width
86
Technique In Developing Proportions
‹ Through
practice you can train your eye
to work in two directions so that you
can both divide and extend lines
accurately.
‹ You
should learn how to divide a line in
half by estimating.
‹ You
can divide the halves to get
fourths.
87
Technique In Developing Proportions
‹ Using
a similar technique, you can
expand lines one at a time
‹ Start
by drawing a line of one unit, then
increase it by one equal unit so that it is
twice as long as the first.
‹ Practice techniques both horizontally and
vertically.
88
89
90
Making a Proportional Sketch
‹ Proportional
‹ 1.
91
Sketch Seven Step Process
Observe the object
Making a Proportional Sketch
‹ Proportional
‹ 2.
92
Sketch Seven Step Process
Select the views needed
Making a Proportional Sketch
‹ Proportional
‹ 3.
Sketch Seven Step Process
Estimate proportions carefully.
‹ Mark
off major distances for width, height
and depth in all three views.
93
Making a Proportional Sketch
‹ Proportional
‹ 4.
94
Sketch Seven Step Process
Block in the enclosing rectangles
Making a Proportional Sketch
‹ Proportional
‹ 5.
95
Sketch Seven Step Process
Locate the details in each of the views
Making a Proportional Sketch
‹ Proportional
‹ 6.
Sketch Seven Step Process
Finish the sketch by darkening the
object lines.
96
Making a Proportional Sketch
‹ Proportional
‹ 7.
97
Sketch Seven Step Process
Add dimensions and notes as needed.
98
99
100
101