computer aided design

Question 1

what could CAD modelling include

Answer 1

• creating and modifying designs in 3D
• Graphic/interior design
• Data processing
• Finite element analysis
• Simulations
• Creating and modifying designs

Question 2

what other type of modifications can take place

Answer 2

> design features - changing form of parts, adding features to an design, rearranging

> material modifications

> changing size of parts

> changing aesthetics through rendering different materials

Question 3

Graphic/interior design

Answer 3

• creating of logos
• Creation of murals/ artistic drawings
• Architectural design
• Design layout of fixtures/ furnishings within a given room/ space

Question 4

Data processing

Answer 4

• technical data/dimensions of a product usually shown in 2D (through DWG for fusion 360)
• Parametric modelling

Question 5

Finite element analysis

Answer 5

• the calculations and simulation of unknown factors in products using CAD systems. For example, simulating the stresses within a prosthetic limb

Question 6

Motion simulations

Answer 6

simulation parts of a design or mechanisms to move to check functionality or desired outcome

Question 7

Advantages of CAD modelling

Answer 7

• changes to ideas can be made quickly and easily without deleting ideas
• Easy to repeat features, create patterns, quick rendering of material/colour
• Ideas look more realistic
• Communicate with client, manufacture more easily electronically
• Avoid costly mistakes as CAD models can provide aesthetic overview, form and shape study, motion simulation, FEA analysis for studying loads
• High level of accuracy/fidelity in dimensioning and intricacy of features

Question 8

Disadvantages of CAD modelling

Answer 8

• software may be expensive
• There may be a steep learning curve
• Quick and fast conceptual sketches where dimensioning is not critical may take more time with CAD

Question 9

Surface vs solid modelling

Answer 9

• surface modelling: models the surface of the product without showing internal details
• Solid modelling: clear representation of the final products, all internal parts are included

Question 10

Bottom up vs top down modelling

Answer 10

top down:
> design originates as a whole concept, and gradually evolves into a whole product consisting of components and sub assemblies

> design of parts have to fit into overall product criteria and there maybe greater communication among designers of sub-components

bottom up
> focus is on individual part modelling, design criteria are more focused for the individual part

> criteria may not be shared between models

> after individual parts are designed, they are then assembled together to make the whole product

Question 11

Data modelling (including statistical modelling)

Answer 11

• it is modelling that determines the structure of data
• Can be diagram accompanied by data
• Can be statistical chart
• Can be a pure database model consisting of just numbers and categories/labels
• Database models can be flat file, relational or hierarchical

Question 12

Database model types

Answer 12

flat file, relational database, hierarchical database

Question 13

flat file

Answer 13

> single table of data

> no interrelationship between data sets

Question 14

relational database

Answer 14

> two or more tables of data that are linked

> it can pull data from different tables and reassembles it

Question 15

hierarchical database

Answer 15

a clear hierarchy exists between different sets of data, can be arranged in tree like structure

Question 16

Virtual prototyping

Answer 16

• software driven modelling process that stimulates products and environments by mimicking real world behaviours
• Widely used in developing and testing of products
• Designers and engineers can simulate visually and also mathematically the design, assembly, and in-service use of complex products in range of environments and scenarios
• Process is faster, cost is reduced, more environment friendly due to minimisation of materials, design process shortened

Nasa used virtual prototyping to stimulate assemble process of the stardust spacecraft

Question 17

Digital humans

Answer 17

• computer simulations of the biomechanics of the human body
• Help to predict how a human (real) will react in a variety of situations or environments (places or locations)
• Can be used to represent joint resistance, discomfort, reach envelops and visual field and study ergonomics
• Can be used in training and performance
• Can be used in e-commerce, for example to model clothing products

Question 18

DH - motion capture

Answer 18

• employed to assist with the understanding of human factors, physical limitations of users, product evaluation as well as training and performance
• Used to record, track and analyse movement
• Special markers applied to strategic points of a moving body to identify key pieces of geometry
• Resultant changes in position are recorded and digitised for playback and analysis
• Focus on movement not visual appearance of the human
• Can also be able to derive physiological indices such as heart rate, breathing rate

Question 19

Advantages of digital humans using motion capture in product design

Answer 19

• test and evaluate product based on ergonomic factors
• Takes into account range of sizes and shapers of users
• Consider user safety factors in a range of environments
• Review human factors in design before building prototypes
• Save time and expensive resources

Question 20

Haptic technology

Answer 20

• emerging technology that interfaces the user via sense of touch
• Generally mechanical actuators apply forces to the user which gives them feedback. Simplest example would be a phone vibration
• Allows user to become part of a computer simulation and to interact with it, enabling the designer to observe the user’s performance and to design a better outcome
• Can be used for training or simulation of scenarios which are remote or dangerous or touch virtual objects which could be delicate
• Commonly used in gaming like wifi where user feels a touch sensation when in the game

Question 21

Virtual reality and animation

Answer 21

• the ability to simulate a real situation on the screen and interact with it in a near natural way
• animations help engineers understand complex mechanisms and alter design and components as required to alter outcome
• Helps to advance real time training
• Reduce product development cycles
• Save resources by removing reliance on physical modelling