Low-fidelity prototypes are quick, inexpensive, simplified representations used mainly to explore and communicate early ideas. High-fidelity prototypes closely represent the intended product's appearance, dimensions, interaction, or function and are used for more realistic testing later in development.
In A2.2 Prototyping techniques, fidelity describes how closely a prototype represents the proposed final design. Fidelity is not determined only by appearance: a prototype may accurately reproduce ergonomic dimensions while using substitute materials and simplified mechanisms.
| Factor | Low-fidelity prototyping | High-fidelity prototyping |
|---|---|---|
| Main purpose | Explore, communicate, and compare initial concepts | Test, validate, and refine a developed design |
| Detail | Simplified form, features, or interaction | Realistic form, dimensions, interface, or function |
| Typical resources | Paper, card, foam, basic modelling materials, or simple digital wireframes | Accurate CAD models, functional components, realistic materials, or advanced digital simulations |
| Time and cost | Usually fast and inexpensive | Usually slower and more expensive |
| Suitable testing | Layout, overall form, scale, concept selection, and early user feedback | Ergonomics, usability, performance, assembly, appearance, and detailed user feedback |
| Main limitation | Results may not predict realistic performance | Greater investment makes major changes more costly |
For example, a designer developing a handheld controller might first make several card models to compare button layouts. After selecting a concept, the designer could produce a dimensionally accurate, 3D-printed prototype with working buttons to test grip, reach, interaction, and user comfort.
The prototyping process is often iterative: test results generate feedback, which informs modifications and further prototypes. Designers should therefore choose an appropriate level of fidelity for the specific design question rather than automatically pursuing maximum realism.
A common misconception is that a high-fidelity prototype is the final product. It is still a testing and development artefact and may not use final manufacturing processes or production materials.
Exam technique: If asked to distinguish the two, identify differences in detail, purpose, cost, development stage, and testing capability. For an explain question, link each prototype's fidelity to the type and reliability of feedback it can generate.