Product and Object Design: Form, Function, Ergonomics, and Sustainability
This domain tests the relationship between form and function, ergonomics and anthropometrics, materials and production processes, sustainability, and user-centred design. You should be able to analyse an object, propose improvements, and justify them with functional and manufacturing evidence.
Form and function
Form should support use, assembly, maintenance, and meaning. A product can be functionally correct but ergonomically poor, or visually attractive but impossible to mould. Consider the user's sequence of actions, the forces involved, and the context of use. User-centred design involves observation, interviews, personas, task analysis, and testing rather than assuming the designer's own preferences.
Ergonomics and anthropometrics
Use percentile data, usually the 5th to 95th percentile, rather than an "average" person. Typical references: seat height 42-45 cm; worktop 90 cm; handrail 90-100 cm; door clear width 80-90 cm; comfortable reach and grip diameters. Provide adjustability where one size cannot fit all. Consider left- and right-handed use, loads, repetition, and accessibility.
Materials and processes
- Injection moulding: thermoplastic parts, wall thickness about 2-3 mm, draft angles of 1-2 degrees, radii instead of sharp corners.
- Extrusion: constant cross-section profiles such as tubes and frames.
- Die-cutting and folding: card packaging from a net.
- Joinery: screws, snap fits, welding, adhesives; design for disassembly where repair matters.
Sustainability
Move beyond material labels: consider lifetime, repairability, recyclability, energy in use, and end-of-life. A durable repairable product often beats a recyclable disposable one. Avoid greenwashing claims that cannot be verified.
Worked example
Redesign a public bench for a coastal promenade. Brief: withstand salt, accommodate elderly users, resist graffiti, and allow repair. Set seat height at 45 cm, depth 45 cm, back angle about 105 degrees, and add armrests to help standing. Choose powder-coated aluminium frame and removable timber slats; use stainless fixings. Slats can be replaced individually, and the frame can be recoated. Reasoning: the dimensions support comfort and accessibility; material choice addresses corrosion; modular slats extend life and reduce waste. A single moulded plastic shell would be cheaper initially but harder to repair and less suitable in hot sun.
Traps
Do not sacrifice function for styling without stating the trade-off. Do not ignore draft angles, wall thickness, or assembly. Do not call a product sustainable merely because it uses recycled material. Do not design for an imaginary average user.