Alphabet of
Lines
ALPHABET OF LINES
 Lines
are the critical component of
sketching
 Lines have different types,
thickness and shape has its own
meaning
 Alphabet of Lines are also known as
“Line symbols”
OBJECT OR VISIBLE LINE
 Thick,
dark line used to show the
outline of the object. Define
features you can see in a particular
view
CONSTRUCTION LINE
 Lines
that are very light and very
thin use to construct layout work
DIMENSION LINE
 Thin
and dark lines use to show the
size (span) of an object with a
numeric value. Usually terminates
with arrowheads or tick markings.
HIDDEN LINE

Short dash lines use to show non visible
surfaces that are not visible in
orthographic view. Usually shows as
medium thickness.
CENTRE LINE
 Long
and shot dash lines. Usually
indicates centre of holes, circles
and arcs. Line is thin and dark.
EXTENSION LINE

A light line that extends from the edge
or end of a main object line on a
drawing, used in conjunction with
dimension lines to help determine
the dimension of a particular feature.
CUTTING PLANE LINE
 Extra
thick line use to show
cutaway views or plane of
projection where a section view is
taken. Arrow indicates direction of
view.
LEADER LINE
A
thin line used to connect a
dimension line with a particular
area or point on the drawing. It is
also use to show notes or labels.
PHANTOM LINE
 Long
line followed by two short
dashes use to show alternate
position of a moving part.
SHORT-BREAK LINE
 Thick
wavy line that is used to
break the edge of a surface of a
part for clarity on a hidden surface
LONG-BREAK LINE
 Long,
thin lines that is used to show
that the middle section of an object
has been removed so it can be
drawn on a smaller piece of paper