DRAFTING
THE UNIVERSAL
LANGUAGE
SKETCHING
Rough Sketches are the most common recording method. The term
“rough” describes the state of the design ideas. It suggests that the
designs are incomplete and unrefined.
Refined Sketches are refined design ideas. They may not look anything
like the original rough sketches.
Detailed Sketches communicate size, in addition to the shape and
proportion communicated in the first two drawings. It also communicates
the information needed to build a model of the product or structure.
Developing Pictorial Sketches
Different techniques are used to show the artifact as the human eye would see
it. Therefore, a single view is used to show how the front, sides, and top would
appear.
Isometric Sketches
Oblique Sketches
Perspective Sketches
OBLIQUE SKETCHES
The easiest pictorial sketches to produce.
Show the front view as if you were looking straight at it.
Sides extend back from the front view.
Sides shown with parallel lines that are generally drawn at 45 degrees
to the front view.
Cavalier oblique drawings cause the sides and top to look deeper than
they are.
Cabinet oblique drawings shorten the lines that project back from the front to
one-half their original length.
ISOMETRIC SKETCHES
Isometric means equal measure.
Angles formed by the
lines at the upper right
corner are equal to 120
degrees.
Object is shown as if
viewed from one corner.
PERSPECTIVE SKETCHES
Show how the
human eye and
camera would
see it.
Most realistic, yet, most
difficult of the three
sketches.
Realism is
obtained by
having parallel
lines meet at a
distance vantage
point.
TYPES OF PERSPECTIVE
VIEWS
Three major types: one-point, two-point, and three-point.
One-point perspective shows an object as if you were directly in front of it.
Two-point perspective shows how an object would appear if you stood at
one corner.
Three-point perspective shows how the eye sees the length, width and height
of an object.
Detail Drawings
Most are prepared using the multi-view method.
This method places one or more views of the object in one drawing.
Generally, a top, right side, and end view are shown.
Multi-view drawings use orthographic projection to project information at the
right angles to new views.
Front view is drawn in the lower left quadrant of the paper.
Projection lines are extended to the top and right of a front view to form the
top and side views.
DRAWING LINES
Different lines are used to show the outlines and major details on an object.
Object lines are the darkest lines which show the outlines and major details.
Hidden lines are dotted lines used to show outlines which are not visible in a certain
view.
Center lines locate holes in a part. These lines pass through the center of the hole.
Extension lines, used in dimensioning, indicate the points from which the measurements
are taken.
Between the extension lines are the dimension lines. These have arrows pointing to the
extension lines that indicate the range of the dimension.
GLOSSARY
Rough sketches- incomplete and unrefined design ideas.
Refined sketches- refined design sketches.
Detailed Sketches- communicate size, in addition to the shape and proportion
communicated in the first two drawings.
Oblique sketches- Shows the front view as if you were looking straight at it, and the
sides extend back from the front. Parallel lines drawn to 45 degrees to the front view.
Isometric sketches- shows object as if viewed from one corner. Angle measures in
upper right corner are equal to 120 degrees.
Perspective sketches- realistic sketches that have parallel lines that meet at a distance
vantage point.
GLOSSARY
One-point perspective- shows an object as if you were directly in front of it.
Two-point perspective- shows how an object would appear if you stood at one corner.
Three-point perspective- shows how the eye sees the length, width and height of an
object.
Multi-view method- a method that places one or more views of the object in one
drawing.
Orthographic projection- top and side views are projected up to the right of the front
view.
Object lines- are the darkest lines which show the outlines and major details.
GLOSSARY
Hidden lines- dotted lines used to show outlines which are not visible in a certain
view.
Center lines- lines that locate holes in a part and pass through the center of the hole.
Extension lines- lines used in dimensioning, indicate the points from which the
measurements are taken.
Dimension lines- lines that have arrows pointing to the extension lines that indicate
the range of the dimension.