This document provides information about engineering drawings, including: 1) It discusses orthographic projections, which use multiple views (top, front, side) to represent a 3D object in 2D. 2) It describes different types of lines used in engineering drawings to represent features like centers, edges, breaks. 3) It introduces pictorial drawings like isometric, oblique, and perspective projections which show a 3D object in a single view.

1. ‫بلقيهجفريﮐجروترأنﻣﮐتب‬
MAKTAB KEJURUTERAAN JEFRI BOLKIAH
KUALA BELAIT
NEGARA BRUNEI DARUSSALAM
ASSIGNMENT 1
SESSION 2012/2014

Please Tick (  ) First Attempt: Re-Do:
TITLE: ENGINEERING DRAWING FUNDAMENTAL,GEOMETRICAL
CONSTRUCTION, ORTHOGRAPHIC & PICTORIAL PROJECTIONS AND
PATERN DEELOPMENT
UNIT TITLE: ENGINEERING DRAWING
NAME/ID CARD NUMBER: Abd Ammar Ar-rasyid bin Razali(01-061196)
GROUP/LEVEL: Diploma Year 1 Marine Engineering (A)
DATE GIVEN: 6TH/ FEB/ 2013 DATE SUBMITTED:
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2. TABLES OF CONTENT
 INTRODUCTION PG.3
 ENGINNEERING DRAWING PG.4
 ORTHOGRAPHIC PROJECTION PG.5
 TYPES OF LINES USED IN ENGINEERING DRAWING PG.6
 PICTORIAL DRAWING PG.7
 ISOMETRIC PROJECTION PG.8
 OBLIQUE PROJECTION PG.9
 PERSPECTIVE PROJECTION PG.11
 CONCLUSION PG.12
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3. Introduction
Engineering drawing is not only the province of the draftsperson. It is the
language of the engineer. It is their means of developing and recording their
ideas, and conveying them to others. Every engineer will be using and referring to
some form of drawings almost daily. They will often be producing or directing the
preparation of drawings. Usually, they make the preliminary sketches and design
drawings in accordance with principles of engineering drawing. Because this is the
most unambiguous way of to convey and record information. It is also likely that
every engineer at sometime will be checking the work of designer drafters and
approving drawings before they are sent to manufacturing. When engineers sign
off the final approval of a drawing, they take responsibility for it.
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4. Engineering Drawing
All forms of engineering and technical work require that a two dimensional surface
(paper) be used to communicate ideas and the physical description of a variety of shapes.
Here projections have been divided in to two basic categories; pictorial and multi view.
This simple division separates single view projections (oblique, perspective and isometric)
from multi view projections (orthographic). Theoretically, projections can be classified as
convergent and parallel, or divided in to three systems of projection: perspective,
oblique, and orthographic. Division of types based on whether the drawing is a one view or
multi view projection sufficiently separate projection types in to those used for
engineering working drawings (orthographic) and those used for display (architectural
rendering, technical illustrations etc.)
In short, one of the best ways to communicate one's ideas is through some form of
picture or drawing. This is especially true for the engineer. The purpose of this chapter is
to give you the basics of engineering sketching and drawing. We will treat "sketching" and
"drawing" as one. "Sketching" generally, means freehand drawing. "Drawing" usually, means
using drawing instruments, from compasses to computers to bring precision to the
drawings.
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5. Orthographic Projection
Orthographic projections are a way of describing what an object looks like from several
different views. Orthographics are also called engineering drawings or plan views. Using a
set of orthographics an Illustrator can easily draw the three-dimensional object from any
angle and in perspective, isometric or any number of other drawing systems. 3D modelers
often use orthographics to accurately create an object in a 3D application.
An orthographic is one way to describe a three dimensional object in two-dimensional
space. Typically an orthographic will have the top, side and front views of an object
drawn together with some kind of scale
However, three views are shown in order to clarify internal and external detail.
The views are known as:
 FRONT VIEW
 TOP VIEW
 SIDE VIEW (left and/or right hand view)
 (And at times) BASE/SECTIONAL VIEWS
A comparisons of first angle projection and third angle projection
First angle Third angle
 The plan is BELOW the front view.  The plan view is ABOVE the front view.
 The right-hand side view is on the left-  The right-hand side view is on the right-
hand side of the front view. hand side of the front view.
 The left-hand side view is on the right-  The left-hand side view is on the left-hand
hand side of the front view. side of the front view.
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6. Type of Lines used in Engineering Drawing
A variety of line styles graphically represent physical objects. Types of lines include the
following:
 Object or visible lines are used to represent the outline or contour of the
object being drawn.
 Center lines are used to represent the center of round or cylindrical features,
or the symmetry of a feature
 Center marks are used to represent the center points of a radius (arc) or
circle.
 Hidden lines represents edges and outlines that are visible features of an
object in a particular view.
 Phantom lines represent the outline of an adjacent part, show alternate
positions of a moving part, or replace repetitive details such as gear teeth and
threads.
 Break lines represents an area of an object that has been removed for clarity
or convenience.
 Cutting-plane lines represent an imaginary cut through a part to show a cross-
section.
 Viewing-plane lines represents the direction of sight used to view particular
feature.
 Section lines are used to show where material has been cut away in a section
view. A cutting-plane or break lines may used to expose the material.
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7. Lines can also be classified by a letter classification in which each line is given a
letter.
 Type A lines show the outline of the feature of an object. They are the
thickest lines on a drawing and done with a pencil softer than HB.
 Type B lines are dimension lines and are used for dimensioning, projecting,
extending, or leaders. A harder pencil should be used, such as a 2H.
 Type C lines are used for breaks when the whole object is not shown. They are
freehand drawn and only for short breaks. 2H pencil
 Type D lines are similar to Type C, except they are zigzagged and only for
longer breaks. 2H pencil
 Type E lines indicate hidden outlines of internal features of an object. They
are dotted lines. 2H pencil
 Type F lines are Type F[typo] lines, except they are used for drawings in
electro technology. 2H pencil
 Type G lines are used for Centre lines. They are dotted lines, but a long line of
10–20 mm, then a gap, then a small line of 2 mm. 2H pencil
 Type H lines are the same as Type G, except that every second long line is
thicker. They indicate the cutting plane of an object. 2H pencil
 Type K lines indicate the alternate positions of an object and the line taken by
that object. They are drawn with a long line of 10–20 mm, then a small gap,
then a small line of 2 mm, then a gap, then another small line. 2H pencil.
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8. Pictorial Drawing
Every person cannot understand the orthographic projection. Its execution requires a
thorough understanding of the principles of projection and its reading requires a good
practice of constructive imagination. Pictorial drawing is the drawing of a picture in
graphic language of engineers, to represent a real thing by means of picture views. It
shows the appearance of the object by one view only. Following three methods of pictorial
projections are commonly used in engineering drawing:
(a) Isometric projection
(b) Oblique projection
(c) Perspective projection
Isometric, Oblique and Perspective Drawing
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9. ISOMETRIC PROJECTION
Isometric projection is a method for visually representing three-dimensional objects in
two dimensions in technical and engineering drawings. An isometric view of an object can
be obtained by choosing the viewing direction in a way that the angles between the
projection of the x, y, and z axes are all the same, or 120°.
Isometric Projection
Isometric projection is a type of pictorial projection. Isometric means equal measure. In
this isometric projection, all the plane surfaces and the edges formed of these plane
surfaces should be equally inclined to the metric plane. Metric plane is the same
horizontal plane which is used in orthographic projection.
To represent the three dimensions (length, breadth and height) of the object,
there are three axes known as ISOMETRIC AXES. To start an isometric drawing, a reference
line (horizontal line) and the three axes (X, Y Z) are drawn by taking an angle of 30° from
the reference horizontal line as drawn in Fig 7.2. Z axis is a vertical line to the horizontal
line drawn from intersection point of X and Y axes.
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10. OBLIQUE PROJECTION
Oblique projection is a simple type of technical drawing of graphical projection used for
producing pictorial, two-dimensional images of three-dimensional objects. In an oblique
pictorial drawing, the angles displayed among the axes, as well as the foreshortening
factors (scale) are arbitrary. More precisely, any given set of three coplanar segments
originating from the same point may be construed as forming some oblique perspective of
three sides of a cube.
Oblique Projection
O O
Third Axis of the Oblique Projection may be Inclined at 30 or 45
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11. Inclination of Inclined Axis Oblique projection of a cube
Perspective Projection
Perspective projection or perspective drawing is the representation of an object on
a plane surface, called the picture plane, as it would appear to the eye, when viewed
from a fixed position. It may also be defined as the figure formed on the picture plane
when visual rays from the eye to the object cut the picture plane. Perspective is mainly
used in architecture. By means of perspective, the architecture is able to show how an
object would appear when constructed.
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12. Conclusion
With my skills and what I have studied about engineering so far, I have finished all the
drawings given neat and clean. I also did research on the internet to look for more
information about engineering drawing. I used all my engineering materials such as
pencils, tee-rule, Set Square, compass, drawing board and etc. It is a good engineering
practice to review what we have studied before, there were so many difficulties, but in
the end I encountered the problems through more research since we were given lots of
time.
Reference
http://www.csee.umbc.edu/~rheingan/435/pages/res/view/view2-4.gif
http://draftingmanuals.tpub.com/14276/img/14276_304_1.jpg
http://en.wikipedia.org/wiki/Oblique_projection
http://draftingmanuals.tpub.com/14040/img/14040_38_3.jpg
http://engineerharry.files.wordpress.com/2012/05/lines.png
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