A prototype is an original type, form, or instance of something serving as a typical example, basis, or standard for other things of the same category. The word derives from the Greek πρωτότυπον (prototypon), "archetype, original", neutral of πρωτότυπος (prototypos), "original, primitive", from πρώτος (protos), "first" + τύπος (typos), "impression".

Semantics

In semantics, prototypes or proto instances combine the most representative attributes of a category. Prototypes are typical instances of a category that serve as benchmarks against which the surrounding, less representative instances are categorized (see Prototype Theory).

Design and modeling

In many fields, there is great uncertainty as to whether a new design will actually do what is desired. New designs often have unexpected problems. A prototype is often used as part of the product design process to allow engineers and designers the ability to explore design alternatives, test theories and confirm performance prior to starting production of a new product. Engineers use their experience to tailor the prototype according to the specific unknowns still present in the intended design. For example, some prototypes are used to confirm and verify consumer interest in a proposed design where as other prototypes will attempt to verify the performance or suitability of a specific design approach.

In general, an iterative series or prototypes will be designed, constructed and tested as the final design emerges and is prepared for production. With rare exceptions, multiple iterations of prototypes are used to progressively refine the design. A common strategy is to design, test, evaluate and then modify the design based on analysis of the prototype.

In many products it is common to assign the prototype iterations greek letters. For example, an first iteration prototype may be called an "Alpha" prototype. Often this iteration is not expected to perform as intended and some amount of failures or issues are anticipated. Subsequent prototyping iterations (Beta, Gamma, etc.) will be expected to resolve issues and perform closer to the final production intent.

In many product development organizations, prototyping specialists are employed - individuals with specialized skills and training in general fabrication techniques that can help bridge between theoretical designs and the fabrication of prototypes.

Basic Prototype Categories

There is no general agreement on what constitutes a "prototype" and the word is often used interchangeably with the word "model" which can cause confusion. In general, “prototypes” fall into four basic categories:

Proof-of-Principle Prototype (Model) (also called a breadboard). This type of prototype is used to test some aspect of the intended design without attempting to exactly simulate the visual appearance, choice of materials or intended manufacturing process. Such prototypes can be used to “prove” out a potential design approach such as range of motion, mechanics, sensors, architecture, etc. These types of models are often used to identify which design options will not work, or where further development and testing is necessary.