Cad Questions

Question 1

Describe two advantages of top down modelling

Answer 1

● It is an efficient way of modelling because it is more accurate when complex parts are involved in the modelling.
● It ensures parts fit together at the modelling stage without the need for constraints.
● It speeds up the process of CAD Modelling.
● When a size in a part is changed, the sizes in the components that share this sketch also change.

Question 2

Explain bottom up modelling

Answer 2

● Each part of a model is made individually and saved as an individual component.
● All components made using Bottom-Up Modelling require to be placed into an assembly.
● Constraints are required at the assembly stage for Bottom-Up Models.

Question 3

What are two advantages of top down modelling

Answer 3

● One part of the model helps to make the next part of the model by projecting either features or sketches.
● The Top-Down Modelling approach helps to ensure that all components fit together in the modelling stage.

Question 4

Name two disadvantages of bottom up modelling

Answer 4

● Geometry (including sketches and dimension) and features are not shared or transferred between parts.
● It takes more time to model and assemble component parts using Bottom-Up Modelling.
● When a size needs to be changed, the sizes in all the components using the sketch need to be changed individually.

Question 5

What is the modelling tree

Answer 5

The modelling tree shows the CAD Technician the process that has been followed to make their CAD Model.

Question 6

Name two advantages of the modelling tree

Answer 6

● The CAD Technician can edit sketches and features already made, meaning they do not have to remake the model if a mistake is made.
● It allows parts of the model to be suppressed to increate ease of editing.

Question 7

Explain why editing the modelling tree is an efficient way of changing the number of grips.

Answer 7

● Using the modelling tree to change the number of grips is efficient because it would be much quicker to edit the radial array command than spending time to redo the part form the start.

Question 8

What are cad libraries

Answer 8

CAD libraries are the backbone of 3D Modelling on companies. Most products are creates using ‘Standardised components’ that are saved into one large library. Any CAD Technician can access these to ensure consistency across all models produced by the company. It also speeds up production time as not all parts have to be made entirely from scratch.

Question 9

Name two advantages of cad libraries

Answer 9

● Reduces time to model each component.
● Reduces the chance of CAD Technicians making errors.
● Represents actual standard component parts.
● The same component parts would be used by all CAD Technicians in the company ● Library of components can be used by CAD users worldwide.

Question 10

What is an array

Answer 10

Array is the process of creating a pattern of 2D shapes or 3D Features.

Question 11

What is needed for a radial array

Answer 11

● Sketch of shape (with sizes)
● Axis of Resolution.
● Number of feature
● PCD (Circle the Radial Array follows)

Question 12

What is needed for a box array

Answer 12

● Sketch of shape (with sizes)
● Pitch (distance between shapes) ● Number of Rows.
● Number of Columns.

Question 13

What must be mentioned when answering an extrude question

Answer 13

PROFILE: This is the shape of the face (square, circle etc) including dimensions.
DIMENSION: How much should the shape be Extrude or Extrude Subtract.
MENTIONING THE COMMAND: Extrude or Extrude Subtract

Question 14

What must be mentioned when answering a revolve question

Answer 14

PROFILE: This is the shape of the face (square, circle etc) including dimensions.
AXIS OF REVOLUTION: The line the profile will rotate round the required degree
MENTIONING THE COMMAND: Revolve

Question 15

What must be mentioned when answering a loft question

Answer 15

PROFILES: One featuring a shape with vertices and one without vertices including dimensions.
WORKPLANES: Mention using two workplanes and the distance they are offset.
MENTIONING THE COMMAND: Loft

Question 16

What must be included in a sweep along a path question

Answer 16

PROFILE: This is the shape of the face (square, circle etc) including dimensions.
PATH: The line that the profile (shape needs to follow including dimensions.
MENTIONING THE COMMAND: Sweep Along a Path.

Question 17

What must be included when answering a helix question

Answer 17

PROFILE AND CENTRE LINE: A centre line with a radius to the centre of a circle showing the radius and the diameter of the circle.
PITCH: The distance between the rotations
REVOLUTIONS: How many rotations are included?
MENTIONING THE COMMAND: Helix

Question 18

What is a fillet

Answer 18

● Command used to add a curved edge to a feature.
● Select a size by adding a radius.
● Fillets can be applied to both sketches and solid features.

Question 19

What is a chamfer

Answer 19

● Command used to add an angled edge to a feature. ● Select a size by adding the depth of the chamfer. ● Chamfers can be applied to both sketches and features.

Question 20

Name 3 types of constrains

Answer 20

• MATE CONSTRAINT: This is when a CAD Technician makes a face of one part, touch the face of a different part.
• ALIGN CONSTRAINT: This is when a CAD Technician makes a face of one part, line up with the face of a different part.
• CENTRE AXIS CONSTRAINT: This is when a CAD Technician constrains parts using their centre lines.
• ORIENTATE: Use the orientate command to turn parts the required number of degrees once a constraint has been added.
• OFFSET: Use the offset command to move a component the required distance away from another once a constraint has been added.

Question 21

Describe, giving two reasons, the purpose of an exploded isometric view

Answer 21

Shows how the parts fit together
Shows how many parts there are
Allows someone to see how to assemble the object
Allows someone to see the order of the assembly

Question 22

Describe two advantages to the designer of using digital sketching instead of manual sketching

Answer 22

The sketches could include realistic material representations.
Further illustration techniques can be applied to enhance the initial sketch.
They can be built up in a series of layers to ease editing.
They are automatically stored electronically and do not require scanning to upload to the website.
Sketches can be exported into other packages.
A wider range of tools/brushes are available.
Easy to share with an example.
Library of resources can be utilised.

Question 23

Describe three benefits of using rendered 3D CAD illustrations to show design concepts to a client

Answer 23

Photo real image of how the product will look.
Realistic representation of materials.
Useful for users who cannot read or interpret 2D drawings.
Rendered CAD pictorials can be sent out to users via email.
Alternative versions showing different colours or finishes can be quickly and easily edited.
Light sources can be simulated.

Question 24

Describe, giving two reasons, the purpose of a sited environment.

Answer 24

A rendered scene that places an object in a physical setting/environment.
A rendered scene that places the object in a specific context and gives a greater sense of believability.
A rendered scene that uses the surrounding environment to show how products appears in light/sunny/dark conditions.
Gives sense of scale.

Question 25

Explain, giving two reasons, why a raster file format is used

Answer 25

High resolution images allow for photorealistic images to be saved as each pixel can be different colour allowing for subtle changes in colour.
Allows for rich and detailed images due to use of pixels over shapes.
Do not require specialist software to open so can be used almost anywhere and on any device.

Question 26

Explain giving two reasons, the benefits of using cloud computing

Answer 26

Cloud computing gives the ability to work remotely which allows ease of collaboration
Companies working on a project across different locations can give access to the same files which ensures they work from the most up to date versions.
Cloud computing allows employees to be more flexible in their work practices in terms of the ability to quickly and easily access data at any time.
Cloud computing systems are regularly updated making sure the latest versions of software is being used.
Cloud computing can allow access to more high spec. Servers which will allow for a higher quality output.

Question 27

Describe, giving two examples, the benefits of using 3D CAD models in manufacturing

Answer 27

3D models can be used to directly manufacture (CNC/CAM)
To enable dimensions to be extracted from the CAD model without production drawings
3D models can be used to show how complex items are assembled
3D models do not need a manufacturer to interpret complex production drawings
Production drawings can be created and fully dimensioned from the CAD model
Allows for a range of tests to be undertaken prior to manufacture