CAD (Computer Aided Design)

Question 1

What does CAD stand for?

Answer 1

Computer Aided Design—using software to create, modify and communicate designs.

Question 2

Two main categories of CAD for school projects.

Answer 2

2D drafting (e.g., profiles for laser cutting) and 3D modelling (parts/assemblies/drawings).

Question 3

What is an assembly in CAD?

Answer 3

A set of parts positioned together with joints/mates to show fit and motion.

Question 4

What is a technical drawing used for?

Answer 4

To communicate dimensions, tolerances and notes so parts can be made and inspected.

Question 5

Name three standard drawing views.

Answer 5

Orthographic (front/top/right), isometric, and section view.

Question 6

Orthographic projection—simple definition.

Answer 6

2D views of a 3D object taken from 90° directions to show true sizes.

Question 7

What does scale 1:2 on a drawing mean?

Answer 7

The view is half the real size (1 unit on paper = 2 units on the part).

Question 8

What is a section view for?

Answer 8

To show internal features by cutting through the part with a cutting plane.

Question 9

Dimensioning rule for clarity (simple).

Answer 9

Place each dimension once, on the most obvious view, and avoid crossing dimension lines.

Question 10

What is a tolerance?

Answer 10

The permissible variation in a dimension (e.g., 10.00 ±0.10 mm).

Question 11

Allowance vs tolerance—difference (simple).

Answer 11

Allowance is intentional fit difference between parts; tolerance is acceptable size variation for each part.

Question 12

What does ‘fit’ describe?

Answer 12

How tight/loose mating parts are (clearance, transition, interference).

Question 13

Which file format is best for 3D printing?

Answer 13

STL (triangulated surface mesh) or 3MF; ensure units and export quality are correct.

Question 14

Which format is typical for laser cutting from CAD?

Answer 14

DXF (2D curves) exported at the correct scale and units; use hairline/continuous lines for cuts.

Question 15

Name two common native CAD file types.

Answer 15

Part files (e.g., .sldprt/.ipt/.f3d) and assembly files (.sldasm/.iam/.asmb).

Question 16

Define coordinate system/origin in CAD.

Answer 16

Reference axes (X,Y,Z) and zero point used to position sketches, features and parts.

Question 17

Why use construction geometry in sketches?

Answer 17

To control shape with reference lines/circles without creating solid edges.

Question 18

Two tips for fully constrained sketches.

Answer 18

Add necessary dimensions and apply constraints until geometry turns ‘fully defined’ (often black).

Question 19

Name two CAD mass properties you can read.

Answer 19

Volume and mass (also centre of gravity and moments of inertia if material is set).

Question 20

Bill of materials (BOM)—what is it?

Answer 20

A list of all parts in an assembly with quantities and item numbers for drawings/purchasing.

Question 21

Interference check—purpose.

Answer 21

To detect overlapping solids in an assembly (parts occupying the same space).

Question 22

Exploded view—why useful?

Answer 22

Shows assembly order and part relationships for instructions or drawings.

Question 23

Rendering vs technical drawing—difference.

Answer 23

Rendering creates realistic images for presentation; drawings specify how to manufacture/inspect.

Question 24

CAM—how is it linked to CAD?

Answer 24

CAM uses CAD geometry to create toolpaths for CNC machines (milling, turning, laser, plasma).

Question 25

Post‑processor—what does it do?

Answer 25

Converts generic toolpaths into machine‑specific code (e.g., G‑code for a particular controller).

Question 26

Nesting—what is it?

Answer 26

Arranging 2D parts on sheet to minimise waste and cutting time (laser/waterjet/plasma).

Question 27

Why set correct units before exporting?

Answer 27

To avoid scaling errors (e.g., inch/mm mix‑ups) when sending files to machines or suppliers.

Question 28

Two common CAD mistakes to avoid.

Answer 28

Over‑defining sketches (conflicting constraints) and modelling without design intent (hard to edit).

Question 29

Design intent—what does it mean?

Answer 29

Building the model so expected changes are easy (use symmetry, patterns, parameters, and references).

Question 30

Best‑practice file naming for students.

Answer 30

Include project, part name, version/date (e.g., PhoneStand_Base_v3_2026‑02‑07).

Question 31

Revision vs version—simple difference.

Answer 31

Revision is a released drawing change noted in a table; version is a working save of the CAD file.

Question 32

What is a title block?

Answer 32

Drawing area with part name, scale, units, material, tolerances, drafter, date, and revision.

Question 33

What does a centreline show?

Answer 33

The axis/symmetry of circles/holes and cylindrical features on drawings.

Question 34

Hidden detail—how is it shown on drawings?

Answer 34

With dashed (hidden) lines unless a section view is used to reveal the interior.

Question 35

Geometric tolerancing (simple).

Answer 35

Controls shape and position (e.g., flatness, perpendicularity) so parts assemble reliably; often beyond L1 basics.

Question 36

Two checks before exporting DXF for laser cutting.

Answer 36

Delete duplicate/overlapping lines and ensure all paths are closed at the correct layer/colour.

Question 37

Two checks before exporting STL for 3D print.

Answer 37

Correct units and watertight (manifold) solids with suitable mesh resolution.

Question 38

How can CAD reduce TIMWOOD wastes?

Answer 38

Parametric edits cut Overprocessing; nesting reduces Transport/Inventory; accurate drawings reduce Defects.

Question 39

Assembly drawing essentials (two items).

Answer 39

Exploded view with item balloons and a BOM table with quantities.

Question 40

What is a datum in CAD/drawings?

Answer 40

A reference feature (plane, edge, point) from which dimensions or tolerances are measured.

Question 41

Why use patterns (linear/circular) in CAD?

Answer 41

To repeat features parametrically (e.g., bolt circles) and keep models easy to update.

Question 42

When would you use a loft instead of a sweep?

Answer 42

When transitioning between different shapes across multiple profiles (loft) rather than along one path (sweep).

Question 43

Shell feature—what does it do?

Answer 43

Hollows a solid to a set wall thickness—useful for lightweight prints or moulded parts.

Question 44

Mirror feature—why useful?

Answer 44

Creates symmetric geometry across a plane, reducing modelling time and ensuring symmetry.