National 4/5
Graphic
Communication
Advantages of CAD
3D Modelling
Computer Knowledge
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You will need to know about how computers
are used with Graphic Communication and
how this impacts upon the design and
manufacture of products.
You will learn about advantages of using
CAD (Computer Aided Drawing).
You will need to know how to use some
commands and techniques used in 3D CAD
packages.
Advantages of CAD
Reduced storage space required.
 Previously, paper drawings would
have required whole rooms to store
the drawings for a building.
 Now this information can be stored on
a single disk.
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Advantages of CAD
Corrections can be made easily.
 Before, whole drawings may have had
to be reproduced on paper if a
mistake has been made.
 Now a single line is deleted and
redrawn in the correct place.
 It takes less time to produce drawings
using CAD systems than traditional
manual drawing methods.
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Advantages of CAD – CAD library
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Repetitive parts of the drawing can be
saved and imported as part of a CAD
library.
A CAD library stores frequently used
symbols.
Paper drawings require objects to be
redrawn each time manually which is time
consuming.
Being able to call the parts in from a library
saves the user time.
Advantages of CAD
Drawings offices often produce their
drawings using a standard layout so
that people can immediately identify
the drawings as belonging to that
particular company.
 Templates can be set up on a
computer to make this easier.
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Advantages of CAD
CAD systems can be linked with CAM
machines to produce objects straight
from the drawings.
 This is referred to as CAD/CAM
 CAM stands for Computer Aided
Manufacture.
 This is a cheaper and quicker method
of producing the final product.
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Advantages of CAD
No matter what size of drawing is
being produced CAD systems can be
used to produce them accurately.
 Grid Snap, Zoom and Attach
commands are 3 examples of
methods of producing accurate
drawings easily.
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Advantages of CAD – virtual reality
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Designers can use powerful CAD computer packages to
make virtual reality simulations of the layout of their
buildings.
This means that the client can have a “look around” the
building as a virtual tour before it is built and changes
can be made at this early stage.
This results in a faster design of the building and a
higher quality end product.
It is also cheaper to make any changes at this stage
rather than while the building is being constructed.
Advantages of CAD – the Internet
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On an ever greater scale, the Internet can
be used to share plans and designs with
anyone in the world that also has an
Internet connection.
This means that specialised work can take
place between different countries quickly
and cheaply.
Another benefit is that multi national
companies can have 24 hour designing
happening in offices across the world.
3D Modelling
3D Modelling is widely used by most
design companies to create their
products.
 There are many advantages of using
3D Modelling over old fashioned 2D
CAD packages.
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3D Modelling - Advantages
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The main difference between 2D and 3D
packages is that the actual model of an object
is made 3D rather than 2D views of it.
Orthographic and pictorial views can be
produced from the 3D model.
3D models can be animated to show
movement.
Simulations can be run from 3D models.
3D printing means that products can be
manufactured directly from the 3D model of an
object.
Animation
Computer animation shows how an
object moves.
 It is a set, predefined sequence that
can only be watched, its outcome
cannot be changed.
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Animation - advantages
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Some advantages of using simulation
are:
to describe how an object can be
assembled
 to use as a set of instructions for
people to follow.
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Simulation
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Computer simulation is when the user can
interact with an object to effect the outcome.
When using computers to design things, we
can use computer simulation to test
components.
This could be a wide range of factors.
It can range from testing brake systems, the
aerodynamic performance or cars or flight
simulators.
Simulation - advantages
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Some advantages of using computer
simulation are:
It is a safer way of training people.
 It is cheaper to test designs without
destroying manufactured components.
 Changes can be made to designs
then tested immediately.
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3D Modelling – rendering
3D models can be rendered to make
them look very realistic.
 Materials can be applied to any part of
a 3D model.
 Lights can be shone onto the model to
create tone, shadows and reflections.
 To further enhance the look of an
object you can create suitable
environments to place them in.
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3D Modelling – rendering
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Here a pen was produced using 3D modelling software.
The room, table and paper was then produced to help
enhance the look of it.
3D Modelling - commands
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There are a large number of commands
available to a user of 3D modelling
software.
The most common commands you will use
at N4 & N5 are:
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Extrude
Revolve
Round
Chamfer
3D Modelling - extrude
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Extruding a sketch is like
stretching it in a straight line
to create a solid object.
The sketch of the circle
(shown below) has been
extruded into a cylinder.
3D Modelling - revolve
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When you want to extend or extrude an object around a
radius then you would use the revolve command.
Here the sketch (shown below left) has been revolved to
make a bowl.
3D Modelling - round
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Rounds can be added to corners of shapes.
Here the corners of the support plate have
been rounded.
3D Modelling - chamfer
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Chamfers are 45° edges that are added to
corners to remove the sharp corners from an
object.
3D Modelling – planning
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When creating a 3D model of an object it is
a good idea to plan the sketches and the
different types of commands you will use.
This will allow you to keep a track of all the
dimensions you use throughout your model.
NOTE: you should keep your planning
notes you use when producing a 3D model
as they will be used when assessing your
N4 or N5 coursework.
3D Modelling – planning your model
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The next few slides
will explain how
you can plan how
to create the hinge
pin shown on the
right.
3D Modelling – planning your model
To make a plan of how you will create
your 3D model you need to manually
sketch the shape you need to extrude
or revolve to make the 3D object.
 It is important that you add the main
dimensions to this sketch.
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3D Modelling – planning your model
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Once you have manually sketched the
shape you need, you need to say what
command you will use to make it 3D.
As described earlier, some of the most
commonly used commands are:
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Extrude
Revolve
Round
chamfer
Any other suitable command could be used.
3D Modelling – the plan