Designers use physical prototypes to test a product’s scale, aesthetics, and function through direct observation and user interaction. Which aspects can be tested depends on the prototype’s purpose, materials, level of detail, and fidelity.
How Physical Prototypes Are Used
A physical prototype converts a design concept into a tangible, three-dimensional form. Under A2.2 Prototyping techniques, it allows designers to collect evidence, identify weaknesses, and modify the design through iterative development.
| Aspect tested | What designers evaluate | Example |
|---|---|---|
| Scale | Dimensions, proportions, spatial relationships, reach, clearance, and suitability for the intended user | A full-size chair prototype can test whether its seat height and width accommodate the target users’ anthropometric data. |
| Aesthetics | Form, colour, texture, surface finish, visual balance, and the product’s sensory or emotional appeal | A casing model can reveal whether curved surfaces and material finishes communicate the intended style. |
| Function | Operation, mechanisms, strength, stability, ergonomics, usability, and performance against the design specifications | A working hinge prototype can test movement, durability, user effort, and possible points of failure. |
The prototype does not always need to reproduce the final product completely. A low-fidelity model made from card or foam may test scale and form effectively, while a high-fidelity prototype using realistic materials and mechanisms can produce more valid evidence about function and user experience.
A common misconception is that a scale model can fully test scale-related usability. A reduced model can show proportions and spatial organization, but tests involving ergonomics, reach, or human interaction normally require a full-size prototype or accurately reproduced interface components.
Exam Technique
In an IB response, do not merely state that prototypes “test the design.” Identify the specific characteristic being tested, explain how the prototype provides measurable or observable evidence, and show how the result supports iteration. For example: “A full-size prototype tests ergonomic scale by allowing target users to assess reach and comfort, enabling dimensions to be refined against the design specification.”