Computer-Aided Drawing (CAD)Computer-Aided Drawing (CAD)

Graphic CommunicationGraphic Communication

Knowledge & InterpretationKnowledge & Interpretation

CAD Drawing ClassificationsCAD Drawing Classifications

The following terms describe the The following terms describe the common types of computer-aided common types of computer-aided drawings:drawings:

2-D2-D - orthographic projection in which each - orthographic projection in which each view shows only two dimensionview shows only two dimension

2 1/2-D2 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 drawingpictorial drawing

3-D3-D - a 3-D computer model is a ‘virtual - a 3-D computer model is a ‘virtual object’ which can be rotated on screen to be object’ which can be rotated on screen to be viewed from any angle.viewed from any angle.

General Features of 2-D CAD package (e.g. General Features of 2-D CAD package (e.g. AutoCAD)AutoCAD)

Uses xy co-ordination systemUses xy co-ordination system can create 2-D orthographic can create 2-D orthographic

projections and 2 1/2-D projections and 2 1/2-D (isometric, planometric, oblique (isometric, planometric, oblique and perspective) drawingsand perspective) drawings

incorporates layer system of incorporates layer system of

constructing drawingsconstructing 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 engineers, who previously produced drawings on paper, could produce the same types of drawing on computers.same types of drawing on computers.

There are enormous benefits in using a CAD system instead of a drawing There are enormous benefits in using a CAD system instead of a drawing system.system.

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 systemUses xyz co-ordinate system automatically generates orthographic views from 3-D modelautomatically generates orthographic views from 3-D model rendering features can create tonal effects and surface texturesrendering 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.

3-D CAD Modelling3-D CAD Modelling The development of 3-D modelling software enables architects The development of 3-D modelling software enables architects

and designers to create 3-D models of their designs. Previously, and designers to create 3-D models of their designs. Previously, 3-D models had to be ‘built’ from materials such as card, clay and 3-D models had to be ‘built’ from materials such as card, clay and polystyrene blocks.polystyrene blocks.

Advantages of 3-D computer modelling over Advantages of 3-D computer modelling over traditional ‘built’ models:traditional ‘built’ models:

can be produced much more quicklycan be produced much more quickly can be modified very quicklycan be modified very quickly enable the designer to try colours and surface texturesenable the designer to try colours and surface textures can be used to test structural designs before they are built, can be used to test structural designs before they are built,

e.g. bridges and buildingse.g. bridges and buildings can be realistically renderedcan be realistically rendered take up less storage space than ‘built’ modelstake 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.

3-D Modelling3-D ModellingThere are three types of 3-D models:There are three types of 3-D models:

wireframe modelwireframe model - is built up - is built up using a series of connected lines. using a series of connected lines. This image can be simplified by This image can be simplified by removing lines that are hidden.removing 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 Colours, shading and textures can be added to produce realistic-be added to produce realistic-looking images.looking images.

solid modelsolid model - is built up using - is built up using simple geometric forms such as simple geometric forms such as cones, cylinders, prisms and cones, cylinders, prisms and cuboids. These can be added or cuboids. These can be added or subtracted to produce complex 3-subtracted to produce complex 3-D models D models

CAG – Animation & SimulationCAG – Animation & Simulation

Knowledge & InterpretationKnowledge & Interpretation

Graphic CommunicationGraphic Communication

Animation & SimulationAnimation & Simulation

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

Computer AnimationComputer 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 graphics by hand. Each one progressed the one progressed the movement a little bit movement a little bit further. It was a very slow further. It was a very slow and labour intensive and labour intensive process. process.

Modern animation software Modern animation software creates on-screen creates on-screen movement by moving movement by moving graphic images along graphic images along plotted paths. It is quick, plotted paths. It is quick, smooth and realistic. smooth and realistic.

Computer AnimationComputer 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.

Computer SimulationComputer 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 predicting outcomes are the areas in which the areas in which simulation is most useful.simulation is most useful.

Computer SimulationComputer Simulation

3-D simulators are commonly used 3-D simulators are commonly used to train pilots or drivers how to to train pilots or drivers how to cope in dangerous situations such cope in dangerous situations such as landing an aeroplane or driving as landing an aeroplane or driving a tank in battle. The user can a tank in battle. The user can ‘Interact’ with the simulation and ‘Interact’ with the simulation and control his/her vehicle with a control his/her vehicle with a joystick.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 prototype of e.g. testing the stability of ships or the strength of stability of ships or the strength of a bridge.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.

Computer SimulationComputer Simulation

In medicine, surgeons In medicine, surgeons often make use of often make use of simulated operations to simulated operations to predict the difficulties predict the difficulties of a medical procedure of a medical procedure before the patient is before the patient is put at risk.put 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.