QCAA Design cheat sheet

Design practice in industry is typically iterative, not linear: brief, research, ideation, prototyping, testing, and refinement often loop back to earlier stages.

A design brief states the problem, target user, constraints, and success criteria; it is not a solution and should not prescribe the final outcome.

Constraints fall into categories: functional, aesthetic, economic, legal, ethical, environmental, and time/resource limits; each constrains the solution space.

Intellectual property relevant to designers includes copyright (automatic on expression), registered designs (appearance), patents (function), and trademarks (brand identity).

Australian Design Rules and Standards (e.g., AS/NZS) set mandatory and voluntary benchmarks that manufactured products must meet for safety and performance.

Professional practice requires documented records: design files, revision control, and traceability of decisions, because liability and quality assurance depend on evidence.

Stakeholders in a project include the client, end user, manufacturer, regulator, and community; conflicting needs are resolved by explicit weighted criteria.

A design specification is a measurable statement of requirements derived from the brief; it converts qualitative goals into testable targets.

The design process is cyclic and convergent-divergent: alternate between generating options (divergent) and selecting/refining (convergent).

Problem framing precedes solution generation; a poorly framed problem produces technically sound but irrelevant solutions.

Common ideation techniques include brainstorming, SCAMPER, morphological analysis, and analogy; each widens the solution space before evaluation.

The double diamond model has four phases: Discover, Define, Develop, Deliver; the first diamond explores the problem, the second the solution.

Functional decomposition breaks a system into sub-functions; each sub-function can then be solved independently before recombination.

Design fixation is attachment to an early idea; it is countered by parallel prototyping, forced constraint changes, and external critique.

Iteration count and prototype fidelity are decisions: low-fidelity prototypes test concepts cheaply, high-fidelity prototypes test usability and manufacture.

A decision matrix scores options against weighted criteria; the weighting must be set before scoring to reduce bias.

Materials selection criteria include strength-to-weight ratio, durability, cost, workability, thermal/electrical properties, and end-of-life recyclability.

Mechanical advantage = output force / input force; for a lever, MA = effort arm length / load arm length.

Stress = force / cross-sectional area (σ = F/A); strain = change in length / original length; Young's modulus = stress / strain in the elastic region.

Ohm's law: V = IR; power P = VI = I²R; series resistances add, parallel resistances satisfy 1/R_total = Σ1/R_i.

In structures, triangulation provides rigidity; a truss resists shear by converting loads into tension and compression members.

Manufacturing scales differ: one-off (craft), batch, and mass/continuous production each change tooling cost, unit cost, and design freedom.

CAD/CAM workflow: parametric model → toolpath generation → machine control; tolerances must be specified because machines cannot hit exact nominal size.

Sustainable technology choices include design for disassembly, material substitution, energy efficiency, and closed-loop material recovery.

Orthographic projection shows a 3D object in multiple 2D views (front, top, side); first-angle and third-angle layouts place views differently and must not be mixed.

Isometric drawings show three axes at 120° with true lengths along axes; they communicate form but not true angles or foreshortened faces.

Scale drawings state a ratio (e.g., 1:10); dimensions in technical drawings are given in millimetres by convention unless stated otherwise.

Line conventions: continuous thick for visible edges, dashed for hidden edges, chain lines for centre lines, and thin lines for dimension and projection lines.

Section views reveal internal features by cutting the object; hatching indicates cut material and section lines show the cutting plane.

Perspective drawing uses a horizon line and vanishing points (one, two, or three) to represent depth as the eye perceives it.

A rendering communicates material, finish, and context; it must be consistent with the technical drawings it supports or it misleads the client.

Digital communication includes CAD models, exploded views, animations, and annotated prototypes; each is chosen for the audience's decision needs.

Life cycle assessment (LCA) stages: raw material extraction, manufacture, distribution, use, and end-of-life; impacts are compared per functional unit.

The triple bottom line evaluates designs against social, environmental, and economic outcomes; a solution failing any one dimension is not sustainable.

Cradle-to-cradle treats materials as nutrients in closed loops; cradle-to-grave treats product life as a linear throughput.

Inclusive and universal design targets usability across age, ability, and context; accessibility standards (e.g., WCAG for digital) set minimum thresholds.

Ethical design obligations include informed consent, privacy by design, data minimisation, honesty in claims, and avoidance of planned obsolescence.

Cultural appropriation occurs when a dominant group adopts elements of a marginalised culture without attribution or benefit; respectful design requires consultation.

Planned obsolescence (functional, aesthetic, or technological) shortens product life; it conflicts with circular-economy principles.

Energy and emissions can be estimated using an energy budget: power × time of use × usage frequency, converted with grid emissions factors.

Evaluation compares measured outcomes against the specification criteria; without measurable criteria, evaluation becomes opinion.

Formative evaluation occurs during development to guide changes; summative evaluation occurs at completion to judge fitness for purpose.

Usability testing metrics include task completion rate, time on task, error rate, and satisfaction (e.g., SUS score).

A prototype test must control variables and record method, sample, and conditions so results can be reproduced and trusted.

Reflection frameworks (e.g., What? So what? Now what?) move from describing an event to interpreting it and planning changed action.

Triangulation uses multiple evidence sources (user feedback, test data, expert review) to strengthen a judgement about a design.

Failure analysis (e.g., root cause, FMEA) treats faults as data: identify the cause, rate severity and likelihood, then redesign.

Evaluation reports state limitations and uncertainty; overclaiming from a small or biased sample undermines credibility.