The document discusses computer-aided drawing (CAD), detailing its classifications including 2D, 2.5D, and 3D models, which allow architects and engineers to create designs digitally. It highlights the advantages of CAD over traditional methods, such as speed, flexibility, and space efficiency, emphasizing the role of 3D modeling in design and simulation. Additionally, it covers computer animation and simulation, explaining how advanced graphics enable quick and realistic representations for training, testing, and predicting real-life scenarios.

1. Computer-Aided Drawing (CAD)
Computer-Aided Drawing (CAD)
Graphic Communication
Graphic Communication
Knowledge & Interpretation
Knowledge & Interpretation

2. CAD Drawing Classifications
CAD Drawing Classifications
The following terms describe the common
The following terms describe the common
types of computer-aided drawings:
types of computer-aided drawings:
 2-D
2-D - orthographic projection in which each view
- orthographic projection in which each view
shows only two dimension
shows only two dimension
 2 1/2-D
2 1/2-D - isometric, planometric, oblique and
- isometric, planometric, oblique and
perspective views which show all three
perspective views which show all three
dimensions (length, breadth and height) on a
dimensions (length, breadth and height) on a
pictorial drawing
pictorial drawing
 3-D
3-D - a 3-D computer model is a ‘virtual object’
- a 3-D computer model is a ‘virtual object’
which can be rotated on screen to be viewed from
which can be rotated on screen to be viewed from
any angle.
any angle.

3. General Features of 2-D CAD package (e.g. AutoCAD)
General Features of 2-D CAD package (e.g. AutoCAD)
 Uses xy co-ordination system
Uses xy co-ordination system
 can create 2-D orthographic
can create 2-D orthographic
projections and 2 1/2-D (isometric,
projections and 2 1/2-D (isometric,
planometric, oblique and
planometric, oblique and
perspective) drawings
perspective) drawings
 incorporates layer system of
incorporates layer system of
constructing drawings
constructing drawings
Computer-aided drawing (CAD) was developed so that architects and design
Computer-aided drawing (CAD) was developed so that architects and design
engineers, who previously produced drawings on paper, could produce the same
engineers, who previously produced drawings on paper, could produce the same
types of drawing on computers.
types of drawing on computers.
There are enormous benefits in using a CAD system instead of a drawing system.
There are enormous benefits in using a CAD system instead of a drawing system.

4. General Features of 3-D CAD/Modelling Package
General Features of 3-D CAD/Modelling Package
(e.g. AutoCAD Inventor)
(e.g. AutoCAD Inventor)
 Uses xyz co-ordinate system
Uses xyz co-ordinate system
 automatically generates orthographic views from 3-D model
automatically generates orthographic views from 3-D model
 rendering features can create tonal effects and surface textures
rendering features can create tonal effects and surface textures

models can be rotated and viewed from any angle.
models can be rotated and viewed from any angle.

5. 3-D CAD Modelling
3-D CAD Modelling
The development of 3-D modelling software enables architects and
The development of 3-D modelling software enables architects and
designers to create 3-D models of their designs. Previously, 3-D
designers to create 3-D models of their designs. Previously, 3-D
models had to be ‘built’ from materials such as card, clay and
models had to be ‘built’ from materials such as card, clay and
polystyrene blocks.
polystyrene blocks.
Advantages of 3-D computer modelling over traditional
Advantages of 3-D computer modelling over traditional
‘built’ models:
‘built’ models:
 can be produced much more quickly
can be produced much more quickly
 can be modified very quickly
can be modified very quickly
 enable the designer to try colours and surface textures
enable the designer to try colours and surface textures
 can be used to test structural designs before they are built, e.g.
can be used to test structural designs before they are built, e.g.
bridges and buildings
bridges and buildings
 can be realistically rendered
can be realistically rendered
 take up less storage space than ‘built’ models
take up less storage space than ‘built’ models
 can be used to create realistic simulations and games.
can be used to create realistic simulations and games.

6. 3-D Modelling
3-D Modelling
There are three types of 3-D models:
There are three types of 3-D models:
 wireframe model
wireframe model - is built up using
- is built up using
a series of connected lines. This
a series of connected lines. This
image can be simplified by removing
image can be simplified by removing
lines that are hidden.
lines that are hidden.
 surface model -
surface model - is built up by
is built up by
drawing the surfaces of an object.
drawing the surfaces of an object.
Colours, shading and textures can be
Colours, shading and textures can be
added to produce realistic-looking
added to produce realistic-looking
images.
images.
 solid model
solid model - is built up using simple
- is built up using simple
geometric forms such as cones,
geometric forms such as cones,
cylinders, prisms and cuboids. These
cylinders, prisms and cuboids. These
can be added or subtracted to
can be added or subtracted to
produce complex 3-D models
produce complex 3-D models

7. CAG – Animation & Simulation
CAG – Animation & Simulation
Knowledge & Interpretation
Knowledge & Interpretation
Graphic Communication
Graphic Communication

8. Animation & Simulation
Animation & Simulation
The development of computers has significantly
The development of computers has significantly
changed the ways in which graphics are
changed the ways in which graphics are
produced. Recent advances in computer
produced. Recent advances in computer
technology enable designers to create complex
technology enable designers to create complex
and realistic graphic images quickly and easily.
and realistic graphic images quickly and easily.
Two examples of advanced computer graphics
Two examples of advanced computer graphics
are animation and simulation.
are animation and simulation.

9. Computer Animation
Computer Animation
 Animation (moving images)
Animation (moving images)
was traditionally created by
was traditionally created by
drawing thousands of ‘still’
drawing thousands of ‘still’
graphics by hand. Each one
graphics by hand. Each one
progressed the movement a
progressed the movement a
little bit further. It was a very
little bit further. It was a very
slow and labour intensive
slow and labour intensive
process.
process.
 Modern animation software
Modern animation software
creates on-screen movement
creates on-screen movement
by moving graphic images
by moving graphic images
along plotted paths. It is
along plotted paths. It is
quick, smooth and realistic.
quick, smooth and realistic.

10. Computer Animation
Computer Animation
•Computer animation is used to
increase the visual impact of
graphics on the viewer.
• A product with moving parts can
be animated to demonstrate how
it works, e.g. an elevator in a
design for a new office building.
• Animation can also assist in
education and training, e.g. to
show how blood flows around the
body.

11. Computer Simulation
Computer Simulation
 Computer simulation uses
Computer simulation uses
computer models to imitate
computer models to imitate
or predict behaviour in real
or predict behaviour in real
life situations.
life situations.
 A realistic experience is
A realistic experience is
provided within a simulated
provided within a simulated
environment.
environment.
 Training, testing and
Training, testing and
predicting outcomes are the
predicting outcomes are the
areas in which simulation is
areas in which simulation is
most useful.
most useful.

12. Computer Simulation
Computer Simulation
 3-D simulators are commonly used
3-D simulators are commonly used
to train pilots or drivers how to cope
to train pilots or drivers how to cope
in dangerous situations such as
in dangerous situations such as
landing an aeroplane or driving a
landing an aeroplane or driving a
tank in battle. The user can ‘Interact’
tank in battle. The user can ‘Interact’
with the simulation and control
with the simulation and control
his/her vehicle with a joystick.
his/her vehicle with a joystick.
 In civil engineering, simulation can
In civil engineering, simulation can
test the design of a structure that
test the design of a structure that
would be too big to make a
would be too big to make a
prototype of e.g. testing the stability
prototype of e.g. testing the stability
of ships or the strength of a bridge.
of ships or the strength of a bridge.
 In car design, the body shape is
In car design, the body shape is
tested for wind resistance even
tested for wind resistance even
before a prototype is built.
before a prototype is built.

13. Computer Simulation
Computer Simulation
 In medicine, surgeons
In medicine, surgeons
often make use of
often make use of
simulated operations to
simulated operations to
predict the difficulties of
predict the difficulties of
a medical procedure
a medical procedure
before the patient is put
before the patient is put
at risk.
at risk.
 In weather forecasting,
In weather forecasting,
simulations of weather
simulations of weather
systems are used to
systems are used to
predict the weather.
predict the weather.
 Computer models can
Computer models can
be modified in ‘real
be modified in ‘real
time’ to improve
time’ to improve
performance.
performance.