“What exactly do you mean by prototype?”
I have heard this question countless times in product development. Whether it’s a mockup, a quick model, a sketch, a CAD design, or a near-production sample: strictly speaking, all of these are prototypes. Yet, we often talk far too imprecisely about “the prototype,” as if there were only one option. In reality, the opposite is true: there is a wide variety of very different ways to realize a prototype – and each serves a different purpose.
Four Dimensions of Prototypes
To bring clarity, I like to classify prototypes along four dimensions:
1. Form – How is the prototype created?
The spectrum ranges from quick 2D sketches and hand scribbles, to digital 3D models (like CAD or simulations), all the way to physical prototypes – such as paper models, 3D prints, or even near-production versions. Each step makes the idea more tangible, but also more complex and resource-intensive.
2. Purpose – What do I want to find out or demonstrate?
Prototypes are tools for learning: they help gather customer feedback, literally grasp the problem, or test manufacturing processes. They are used to explore different options, optimize functional principles, or simply to communicate with the team, stakeholders, and investors. The objective determines how much effort is truly necessary.
3. Scope – How much of the product does the prototype represent?
Sometimes you need the whole picture, sometimes it’s enough to isolate and examine a single module or function. Testing under laboratory conditions also differs fundamentally from trials under real-world conditions.
4. Level of Detail – How close is the prototype to reality?
People often talk about high or low fidelity. I find that too vague. Instead, I prefer to explicitly refer to mockups, concept prototypes, functional prototypes, and near-production prototypes.
Terms for Different Levels of Prototyping Detail
Mockups are the simplest and often most underestimated members of the prototype family. Their focus is not on function, but entirely on the external appearance, form, and feel of a product. Mockups are used to make the design, proportions, and “look & feel” of an idea tangible – long before technical details or functionality are considered. They are often made from inexpensive materials such as foam, cardboard, wood, or plastic, or created digitally, and can be produced quickly and cost-effectively. Especially in the early development phases, mockups help to “grasp” the product in the truest sense: How does it feel in the hand? How does it look in the room? Are ergonomics and aesthetics right? Mockups are also unbeatable for communication within the team or with customers, as they make abstract concepts tangible and prevent misunderstandings. They are the ideal tool for testing design ideas and obtaining early feedback – all without the effort of integrating working technology.
Concept prototypes are the first bold steps from theory into practice. Their main purpose is “proof of concept” – demonstrating that a fundamental idea or functional principle is even plausible. Here, improvisation is not only allowed but encouraged: concept prototypes are often greatly simplified, abstract, or “hacked together” with minimal effort. The perfect appearance or proximity to series production doesn’t matter here; what counts is quickly testing a central assumption. This could be a mechanism held together with tape, an Arduino-driven FDM monster, or a digital prototype that simulates a function. What’s important is that mistakes are allowed and even desired at this stage – discovering them now is inexpensive and provides valuable insights for the next steps.
Functional prototypes take things a step further and approach real-world conditions. They show how the product – or at least its central functions – actually works in practice. Simplifications are still often made: development boards replace custom electronics, components are made using professional 3D printing instead of injection molding, and not all requirements for durability, cost, or manufacturing are met. Nevertheless, functional prototypes are designed to answer key technical questions and demonstrate the interaction of the most important components under realistic conditions. They are the bridge between pure ideas and industrial implementation.
Near-production prototypes are the final link to market readiness. They are manufactured using the same production processes and technologies that will be used in the final series. Typical examples include pilot series, validation prototypes, or samples for end-user testing. Here, all requirements must be met – from dimensional accuracy and function to safety aspects and planned production costs. Near-production prototypes are used to validate the product under real conditions, identify final sources of error, and secure the production processes before taking the big step into mass production.
Each of these prototype types has its rightful place in the development process – and those who use them purposefully not only save time and money but also increase the chances of success for the final product.
The Art of Choosing the Right Prototype
The real challenge – and the true art – lies in choosing the right prototype for the right goal. All too often, early, simple prototypes are skipped, and the first functional prototype is suddenly expected to do everything: design, function, user feedback, manufacturing. This is expensive, risky, and rarely effective.
It is much more sensible to plan for several prototypes from the outset and to define for each hypothesis or requirement which prototype will be used to validate it. This allows effort and costs to be managed in a targeted way – very much in the spirit of the Minimum Viable Product (MVP).
A Call to Practice
My advice from many years of experience: Plan your prototypes strategically – with minimal effort but maximum learning. And above all: Talk very specifically with your team about what kind of prototype you mean. Because even engineers often talk about completely different things when they say “prototype.”
When was the last time you deliberately built a simple, quick prototype to test a central assumption – instead of trying to solve everything at once?
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