54
PROJECTION SYSTEMS AND THEORETICAL
DRAWINGS
Theoretical drawing systems include
orthographic drawings, planometric drawings,
isometric or parallel drawing systems,
trimetric, and perspective.
These drawing systems are very useful
particularly for architects and designers. They
are usually used as presentation drawings for
clients. The orthographic or the planometric
system of drawing is probably the easiest to
understand as this is just a flat representation
of an object, usually from the front and is done
to a scale. See the example on page 55 of a pair
of scissors, and pliers. Sometimes in these
drawings, you will have tonal keys to give you
the idea of plane recession, and form. The
easiest way to go about producing one of these
drawings is to place an object like a pair of
scissors down on to a piece of paper and then
draw around them. What you will have
produced in this drawing is an outline of the
object and that is what an orthographic
projection is. To complete the drawing,
observe, and draw in the rest of the detail of
the object and then code it tonally or texturally
accordingly.
ORTHOGRAPHIC OR ELEVATION PLAN
Orthographic drawings represent the object
being drawn or designed as flat. They can
represent the design as linked individual
drawings from all sides. This is usually referred
to as plan, front and side elevations.
They can best be described as representing
a silhouette of an object on the picture plane
from one side or the other of the plan. They
Part One – THE PENCIL
A table, showing front, side and plan
elevations.The shape of an object from the front can be
understood by placing it in a box or
rectangle that relates to its proportions.show one face of the object and from that face
the other faces can be planned and plotted.
This is technically referred to as the first angle
projection. First introduced by a French
military engineer, Monge, at the beginning of
the 18th century, it was very quickly adopted.
Orthographic drawings represent the
object being drawn, or the face of, and from
that face the other faces can be planned and
plotted.Front elevationFrontPlanSide