Preparing a Design Brief and Client Specifications

A design brief is the reference document for the entire design project. It contains: (1) Client/user description — who will use this and what do they currently do? (2) Problem statement — what specific problem needs solving? (3) Constraints — what limits apply (size, cost, material, time)? (4) Success criteria — how will we know the design succeeded? (5) Deliverables — what will be produced and when? A brief is approved BEFORE design work begins.

Success criteria must be testable — you must be able to measure whether the design passed or failed each criterion. Not testable: 'looks good,' 'is comfortable,' 'users like it.' Testable: 'holds 6 pens without tipping,' 'outer dimensions ≤80×80×120mm,' 'wall thickness ≥3mm,' 'user completes task in ≤5 seconds without instruction.' At Grade 6, every success criterion must have a pass/fail test defined alongside it.

Not all constraints are equal. MoSCoW prioritisation: Must — non-negotiable constraints (if violated, design fails). Should — important but can be compromised if necessary. Could — nice to have but not required. Won't — explicitly not included in this version. Example: Must: fits in a 200mm cube. Should: name embossed. Could: colour-matched to school colours. Won't: moving parts in V1.

In professional design, the client approves the brief before any design work begins. If the brief is wrong and work proceeds, all work must be redone. Brief approval confirms: the problem statement is correct, the constraints are accurate, the success criteria are agreed. At Grade 6, your teacher acts as the client — your brief must be approved (signed or initialled) before you begin CAD modeling.