This document discusses different types of projections used in engineering drawings. It describes parallel projections where lines never intersect and perspective projections where lines converge at a point. The main types of projections discussed are: - Orthographic projections where lines are perpendicular to the view plane. Multiview drawings use multiple orthographic projections. - Axonometric projections including isometric, dimetric, and trimetric which rotate the object along axes. - Oblique projections draw faces at arbitrary angles rather than 90 degrees. Specific types are cavalier and cabinet. - Perspective projections make distant objects look smaller to provide a realistic view, with one-point, two-point, and three-point varieties.

1. Muhammad Umair Akram 9/1/2015
MUHAMMAD UMAIR AKRAM 1
Types of Projections
Engineering Drawings
“It is actually the language of lines that is used to convey the concept of design of anything from
designer’s mind to the manufacturer or the reader”. Specifically the engineering drawing deals with the
line’s language that purely conveys all the technical concept and specifications that are needed to fulfill
the operations.
E.g. drawing of glass cup die with all required information. Such as material, pressure which it will bear,
and etc.
Projections
The easiest way to define the projections is
“It is the game of lines used in technical drawings on either three dimensional or on plane surface i.e.
2D page”.
3D projections although gives a clear view of the design object that how will it be after production but
in this projection it is quite difficult to convey all the details of object. Whereas the plane surface
views/projections are quite easy to describe all the necessary detail in epically the dimensions. 2D
projection of an object represents in more accurate manner. Actually we are here to discuss the possible
types of projections that can be used in Engineering Design. Following are the types to projections:
One Point
(one principal vanishing point)
Two Point
(Two principal vanishing point)
Three point
(Three principal Vanishing point)
Cavalier
Cabinet
Multi view Axonometric
Isometric
Dimetric
Trimetric
Projections
Parallel Projections Perspective Projections
Orthographic
(Projections perpendicular to view plane)
Oblique
(Projections not perpendicular to view plane)

2. Muhammad Umair Akram 9/1/2015
MUHAMMAD UMAIR AKRAM 2
Parallel Projection
“It is a type of projections in which the lines/rays of the 3D object do never intersect with each other
i.e. the rays always remains parallel to each other”. See figure 1.0
We can strongly say that for parallel projections distance from COP (center of projection) to PP
(Projection Plane) is infinite.
Orthographic:
“A way to project the object’s views on a 2D plane surface in which the
projection lines are perpendicular to the surface”.
These Projections are generally used for engineering drawings.
Multiview:
“When more than one projection planes are used the result is a Multiview projection”.
In other words Multiview drawing are those which based on the principles of orthographic projections. It
has the quality that these views are arranged in systematic manner so that reader can conceptualize it
easily. They also called 1st
angle projections or 3rd
angle projections. Figure 2.0 shows the Multiview
projections.
Axonometric:
“Axonometric means “to measure along axes”. It is a type of projection used to draw an object when
it is rotated along one or more of its axes relative to the plane of projection.” It has three types that
are isometric, Dimetric and trimetric.
Isometric:
The way to draw three
dimensional view of an object in
which the horizontal edges are
drawn on the 30° angle and
verticals are perpendicular from
horizontal base.
Dimetric:
A way to project the object such
that it two faces are equally
inclined then the third one.
Trimetric:
It is the one in which the angles
between the three projections
are unequal. Thus a separate
scale is need to draw trimetric
projections.
Figure 1: Parallel Projection lines
Figure 1.0: This shows about the parallel projection
lines that never intersect with each other.
Figure 2.0: Three basic projections planes
used to explain the Multiview drawings.

3. Muhammad Umair Akram 9/1/2015
MUHAMMAD UMAIR AKRAM 3
Oblique Projection
Method of drawing an object in a way that face parallel to the picture plane is represented in in
exact/accurate manner but the other faces are drawn on any convenient angle other than 90°. Figure
4.0 describes about the oblique projection.
Cavalier:
It is the one in which projection makes 45° with
view plane and projection lines perpendicular to
the view plane having the same length as the line.
Cabinet:
The one in which projection makes 63.4 degrees
angle with view plane and the projection lines
perpendicular to viewing surface are projected at
one half their actual length.
Perspective Projections
It is the way of projection in which the drawing is made on a plane in such a way that the near objects
looks larger than the far one. We can say that the perspective projection is the one in which rays other
object converges at one point. In this plane parallel lines remains parallel and this type of drawing looks
realistic. Figure 3.0 Shows how the lines intersect at a distance.
We can say that for Prespective projections the distance form COP (center of projection) to PP(Parallel
Plane) is finite. The types of perspective projections are discussed as under.
One-point:
A System of representing 3D
objects and space on a 2D
surface by means of intersecting
lines that are drawn vertically
and horizontally and that radiate
from one point on a horizon line.
Two-point:
A System of representing 3D
objects and space on a 2D
surface by means of intersecting
lines that are drawn vertically
and horizontally and that radiate
from two point on a horizon line.
Three-point:
A System of representing 3D
objects and space on a 2D
surface by means of intersecting
lines that are drawn vertically
and horizontally and that radiate
from three point on a horizon
line.
Figure 3.0: The two projection lines are going
to intersect at a point.
Figure 4.0: A basic sample for
oblique projection.