Prototyping. An overused buzzword? A misunderstood concept? A noun, a verb, and an adjective? Prototyping is a philosophy. Actually, prototyping is the philosophy when it comes to making top notch designs in today’s hyper competitive market.

When most people think of a prototype, they are thinking of a comprehensive physical prototype (also called a pre-production, alpha, or beta prototype). Essentially a version that looks and functions like the final product. A completed design, less some bells and whistles and manufacturing issues, which need to be resolved to bring it to production. They are thinking of one very specific kind of prototype on one end of the prototyping spectrum. They imagine the concept car at the auto show, with a model making elaborate arm gestures towards it. We need to break away from this notion, and do a paradigm shift, so when people think of a prototype, they think messy not sexy, and grimey not shiny.

This topic has been written about extensively. In fact, it has been hammered more over the course of its lifetime than an ingot of brass alloy into a cymbal. But I am going to pull from some of my favorite writings on the topic, and try to put my own spin on it, because I am a renegade designer and that’s what I do.

Defining Prototyping

If someone asked you “What is a prototype?” Would you be able to answer? What would your answer be? When I thought about it myself, I found it surprisingly difficult to define. Sort of like defining what is “love”. So let’s talk about love and prototyping.


Before we define a prototype, it is helpful to understand the purpose of a prototype. Prototypes are used for four basic purposes; learning, communication, integration, and milestones.

Textbook Definition One:
“The use of simplified and incomplete models of a design to explore ideas, elaborate requirements, refine specifications, and test functionality.”Universal Principles of Design

Textbook Definition Two:
“An approximation of the product along one or more dimensions of interest.”Product Design and Development

There are many more dry and technically correct definitions of a prototype. But we can’t talk about prototyping without talking about risk. Specifically, prototypes are all about mitigating risk. In the book, Great by Choice, they use the analogy of “First bullets, then cannonballs”. Using this analogy, they define a bullet (prototype) as “a low-cost, low-risk, and low-distraction test or experiment.” Conversely, a cannonball is an idea that an organization puts a large amount of organizational resources and energy into. The purpose of bullets is to refine aim, and calibrate a trajectory before firing a cannonball. Because cannonballs sink ships, not bullets.

Let’s apply this concept to the example of an injection molded enclosure for a medium sized electronics device. The first step be might be to fire aesthetics “bullets” like researching enclosures for similar or competing products, hiring an industrial designer to create some concept models, and requesting color and texture samples from vendors. Then you might fire some function “bullets” like running mold flow analysis, stress analysis on snap fits, and then ordering an outsourced stereolithography model. This is all in preparation for the “cannonball”, of costly, time consuming, and permanent mold tooling.

Analytical vs. Physical Prototyping

Virtual prototyping is when the designer takes the white board drawing from the meeting and starts modeling it in 3D CAD with dimensions, quickly realizing it is totally not to scale, and completely infeasible. This hopefully takes only a few hours, and in the grand scheme of the overall project, the time and cost is negligible. Remember this, paper money and boyfriends/girlfriends need to be real, prototypes do not. At least not to start. Virtual prototyping is generally the first tool in the modern designer’s shed. The benefits of virtual prototyping are huge, in that cost (risk) is low, it is easy to make changes, and it is a powerful communication tool. Parameters can be easily changed with a few clicks of a button. The color of the exterior can be changed, or initial conditions of a finite elements analysis changed almost effortlessly, as opposed to the real world of painting or designing and building test fixtures. Analytical prototyping allows for testing fit and assembly, manufacturability, form and style, kinematics, finite elements, crash testing, and many other that can all be simulated with modern software packages.

All projects have limited resources, and it takes resources (risk) like time, money, and energy to turn those screen pixels into real life atoms. It would, therefore, seem that by waiting as long as possible to make something real would be mitigating risk. This is a logical fallacy based on one key concept, which is that virtual prototyping is always only an approximation of reality. All designers have had the experience of modeling a conceptually flawed design, which through inexperience, sheer desire, or perhaps delusion, they convince themselves and others will work. Names for this phenomena include “Artificial reality problem”, “tunnel vision” or “CAD Eye”. I am always paranoid until, in reality, I see the physical incarnation function as designed. It is often difficult to predict and model all physics at play in a design, as well things like human interactions or features, and stresses that may be byproducts of manufacturing processes.

The right time to bring a concept out of the virtual world into the real world is a judgement call, based on the difficult to quantify factors of risk and confidence. The right time to transition is usually earlier than one might think, or, in other words, if you suspect it might be time to transition to a physical prototype, then the answer is probably yes. When things become real, something is always learned, and not in ways that are expected. Virtual prototyping is like online dating. Online dating can save a huge amount of time and energy, compared to going out to bars. It provides a comfortable setting to practice your conversational skills, and see what personal style works the best. That’s all fine and good, but if you want success, ultimately you have to meet people IRL.

Focused vs. Comprehensive Prototypes

Focused prototypes implement one or a few aspects of the final design. These can be “looks-like” or “works-like” models, and can be powerful tools for learning and communication. Focused prototyping should start early in the design process, and evolve in complexity as information is learned. Many focused prototypes can be made in parallel and in conjunction with virtual prototypes. Focused prototyping is like dating. You may, for example, start with a coffee date, if things go well, you move on to a movie date, and then up to dinner at a restaurant with an actual table cloth. A focused prototype doesn’t need to be built with longevity, real world conditions, or many other constraints that are put on the final product. COTS components can be used instead of custom, material and processes can be ignored, and general approximations can be used. Consequently, focused prototypes can be much less expensive, and have much quicker cycle times (and provide a lot of instant gratification), compared to a comprehensive prototype. Because you are only looking for an analog yes or no answer to a question, in order to move on to the next step or a second date.

Comprehensive prototyping is required for integration and milestones. Comprehensive prototyping is going on a long trip with that special someone. This is when the little quirks you thought were so cute can morph into a level of aggravation as bad as sitting in traffic by a paper plant, with a screaming baby . You have taken someone out of a perfect situation, where they are well rested, and on their best behavior, and put them in a stressful and unfamiliar situation. And in these situations, for better or worse, people’s true character will come out.

Prototyping is an invaluable tool, because it helps the individual designer, and the team at large. Prototyping gives the designer concrete certainty that things will work and direction on a path forward. It allows for providing some order to the extremely chaotic process of research and development. It makes designers team players, and shows off their talent, so they can be recognized as the rock stars they are. Prototyping promotes efficiency and communication. It helps the organization by ideally getting the best possible product to market with the least amount of resources. I love prototyping.


Dan Slaski is the Lead Renegade for Renegade Prototyping and your new secret weapon/best friend for design domination. A Virginia Tech Mechanical Engineer with a long list of credentials to accompany his years of industry experience in fields including the medical, robotics, and military sectors. He has designed assemblies with hundreds of unique parts and moving components that have gone high into the earth's atmosphere, deep below the oceans and everything in between. All of this has contributed to his vast portfolio of knowledge dealing with difficult engineering problems, and a wide repertoire of skills in prototyping, manufacturing, and sourcing. Yet he still finds a way to remain humble. If you have a project that demands success you need to get on his client list ASAP.