You want High Performance! Absolutely. And Cheap! Of course. Only the best Quality! We agree. Now let me show you this awesome new material we call Unobtainium. It delivers exceptional performance, costs very little, with flawless quality! 😉
Unobtainium is my favorite material . . . but of course, it is only a dream. In the real world, engineering decisions must live within unavoidable constraints. The goal is not to ignore the limits, but to work thoughtfully within them, because every decision affects another. Yes, trade-offs are the language of great engineering.
To help guide the process, we use a simple visual tool to align engineering decisions with high-level product goals. We call it The Triangle of Achievable Engineering. This tool helps frame the engineering trade-offs – not as settling for less, but as informed choices leading to the best available balance within the limits.
What Is This Triangle?
The triangle has three sides, each representing a fundamental engineering goal. All three exist in every project, and none is inherently more important than the others – until we define priorities.
In this triangle there are three equal sides, each facing, but not opposing, the other two. The relationship is intentional, because in practice every project can prioritize only two.
So, Pick 2.
The third does not disappear, but in a practical sense it becomes constrained by the other choices. We will look at some examples below.
To interpret the triangle and the examples correctly, it is important to see the three terms as context-sensitive. When developing a massive custom machine, Low Cost is very different than it is for a small plastic widget. The same is true for Quality and Performance. The definitions depend on the product, the application, and the expectations.
Examples To Illustrate The Triangle
Here are some simple examples of how the triangle, and the concept of Pick 2, play out.
- Performance and Quality
If we focus on high performance and quality, cost becomes a result of those priorities. A Mercedes S-Class Coupe fits fits this category well: excellent performance and quality, but cheap? Not so much. - Performance and Cost
How about High Performance and Low Cost? That means we take Quality out of the focus. Cheap children's toys are a familiar example. They are inexpensive and often work surprisingly well - until they break. As an engineer for such toys, shifting focus toward durability and quality inevitably increases cost. (Toy markets are actually a good place to see how relationships in the Triangle of Achievable Engineering play out.) - Cost and Quality
Bolts provide a simple illustration of this pairing. A high-quality Grade 2 bolt can be inexpensive, but it will not perform like a Grade 8 bolt under load. Shifting from Grade 2 to Grade 8 brings performance into focus, though at higher cost, or by accepting a compromise in quality.
I use the example of bolts because I have heard it said, "There is no such thing as a quality Grade 2 bolt."
For a bolt, quality can mean smooth threads, consistent dimensions, surface finish, or coatings. While quality is often confused with performance, within its intended use, a Grade 2 bolt can be high quality. Likewise, a Grade 5 or Grade 8 bolt can be poor quality having rough threads or flaking finish. Remember, the legs of the triangle depend on the product, the application, and the expectations – they are context-sensitive.
With these relationships in mind, we can now look more closely at each side of the triangle, and why we 'pick sides' in engineering.
Exploring the Triangle of Achievable Engineering
Engineering For Performance
We will start with performance, because as an engineer, this one is my favorite. Faster, Lighter, Stronger, and More Efficient! Or another defining attribute.
Performance can mean many things, depending on the product and the goals. Once defined, the engineering decisions naturally follow. Performance cannot be optimized in isolation; it always shapes, and is shaped by, the rest of the triangle as it balances with cost and quality.
One of my favorite paradigms for performance comes from automotive engines. If you want super performance, then pick a top fuel dragster motor. Though it is really expensive, it offers super high output. The goal of a top fuel motor is just a few seconds of maximum performance without blowing apart.
If we change the paradigm to "let's go camping", a few seconds of maximum performance will not get us far. I love the illustration because the definition of performance is truly in context of the goal.
Performance can also be an attribute of art, or other subtle characteristic. These are not often thought of as "performance" traits, but they reflect Science, Function & Style where performance is subjective. As with the bolt example, the achievable engineering line can blur between performance and quality.
Certainly, performance is the broadest and perhaps most exciting side of the triangle. When performance is one of the two priorities, be precise about what performance means for the situation.
Engineering For Cost
In engineering product development, cost appears in three ways: engineering and development cost, production setup cost, and production unit cost. Each is influenced by design decisions, and each plays a role in how cost balances within the triangle.
Engineering & Development Cost
Engineering and development cost includes all of the effort required to define, design, refine, and prove a product before it goes to production. This includes engineering time, development work, prototypes, testing, and the iterations required to make the design work as intended.
These costs are influenced by project scope, and also by choices made within the Triangle of Achievable Engineering. For example, if we want super high quality, it often requires more design time, deeper analysis, and additional rounds of prototyping.
On the other hand, we can drive cost down by reduced or relaxing optimization goals – like aggressive weight reduction – where diminishing returns quickly appear.
Engineering activities also have a strong influence on costs later in the development cycle. Choices made at this stage – like whether a part is die-cast, sheet metal, or forged – directly affect both production setup cost and unit cost.
In practice, time for engineering to understand and optimize production cost is usually time well spent.
Production Setup Cost
Of course, interaction with production starts long before the design is complete, yet it is useful to discuss production costs as distinct categories.
Many production setup costs are considered NRE – Non-Recurring Expense. In this context, we use NRE to describe the tooling and facilities investments required to enable production. For example, if a product will be made using injection molding, molds must be designed and built before the first part is produced. Molds are expensive, but once they exist, the cost of each molded part can be very low.
This introduces an important shift in the Triangle of Achievable Engineering: Quantity. High NRE is justified when production volume is large enough to amortize upfront costs across many units. In that case, higher setup cost will enable lower per-unit cost, changing how cost, performance, and quality balance for the project. We will visit these triangle shifts more later.
We describe the cost, quantity, and NRE relationship as The Manufacturing Cost Continuum, which we explore in Product Development Notes On Manufacturing.
NRE can be intentionally high to achieve a low unit cost, if per-unit cost is the priority, and expected production quantity justifies it. These priorities then drive manufacturing process selection and engineering effort to meet the goal. A big-picture focus in the triangle helps achieve a proper balance in context of each project.
Production Unit Cost
The cost to make, assemble, and package each individual product is the Production Unit Cost. While achieving a low unit cost is almost always a design objective, it must be framed by the two chosen choices in the triangle.
It is easy to get wrapped up in reducing production costs, and sometimes that can derail the goals we set in looking at the big picture. Just as the triangle is helpful looking at the whole project, it can also help us focus and optimize production cost.
Depending on the priority of cost in our triangle, additional engineering effort to optimize at the design level can reduce production cost.
Two, largely independent factors dominate unit production cost. First, Quantity is King. Producing more of almost anything reduces the unit cost. Second, the manufacturing method plays a major role. Selecting a process such as injection molding establishes a cost structure. Looking at these together, along with the product goals, helps make good engineering decisions for manufacturing cost.
From a planning standpoint, both production setup cost and unit production cost are difficult to estimate until engineering is well underway. When numbers are needed earlier, experience can provide reasonable directional guidance, but not commitments.
As we discuss Cost within the Triangle of Achievable Engineering, we are considering all three components together: engineering and development cost, production setup cost, and production unit cost. For simplicity, we refer to these collectively as Cost, even though that single word contains many engineering trade-offs.
Engineering For Quality
In engineering, quality is discussed broadly, but it has a very specific meaning when applied to individual products. At its core, quality is defined by the customer.
We have already spoken a lot about quality - both in this article and others. From quality in software, to giving quality in customer service.
At Synthesis, we work from a simple principle: Quality is what the customer says it is. That perspective brings the discussion back to the end user and designing the product - completing the achievable engineering - to meet their needs.
While the word Quality can feel vague, but customers recognize it immediately. If quality is a priority for your customer, then choices within the Triangle of Achievable Engineering must reflect it. Then, the product design must include the things your customer believes are quality.
A simple example comes from the license plate frame industry where many customers say weight is an indicator of quality. From an engineering standpoint extra weight is not needed, and it makes the part cost more. However, if the customer believes it shows quality, then that is what we give.
Interestingly, Cost and Quality are traded more often than Performance and Quality. That is certainly something interesting to think about when balancing the triangle for your new product.
How Do We Use The Triangle?
The triangle is a good conversation piece, though it is abstract without context. The value comes in the specifics of a new product or project. Context gives it meaning.
At Synthesis, we use the triangle in discussions about new projects. We like to create a product specification, and within that, capture the two chosen triangle attributes. This also serves as a guide when we Quote an Engineer Project.
As an eye-opening exercise, the triangle serves to give insight. With customers, we often contemplate how the project will turn out if we choose different pairs of the triangle sides. Comparing these thoughts with other products on the market often brings insight into potential market acceptance of the new idea.
We frequently say "Good Planning is the Start of a Successful Project". Using this triangle to align ideas to goals to reality is an excellent part of planning. It helps avoid the Unobtainium moments and prevents value misalignment before time and money are spent.
Shifts In The Triangle Of Achievable Engineering
In the discussion of production cost above, we say Quantity will shift the Triangle of Achievable Engineering. What do we mean by 'Shift'?
The triangle itself does not change, it is our perspective that shifts. The triangle helps us focus, and it grounds our high-level goals in reality. So, as project realities change, the way we balance cost, performance, and quality must also change.
Let's use Quantity for example. If the expected manufacturing quantity is 500 units, then our perspective on cost and quality must reflect processes suited for low volume. In other words, a focus on unit cost for 500 cannot be the same for a quantity of 1,000,000. Manufacturing processes like injection molding or progressive dies are not practical for 500 units.
On the other hand, if our priority is only on performance and quality, then cost may skyrocket, by choice, to achieve a goal. Supercars are an example. They are produced in small quantities, at a very high cost, to meet specific goals.
Quantity shifts our perspective on the "achievable" part of the triangle. Available budget does the same.
Another important shift comes with invention and new technology. For example, a new invention may give both lower cost and higher performance. It may also improve quality. This shifts our perspective on what we can achieve. At Synthesis, we actively look for these opportunities — and sometimes we find them.
Shifts in the paradigms of the triangle, especially for expanding what is achievable, are always an opportunity to seek.
Deeper Into Achievable Engineering
If you want to go deeper with this tool, place a dot within the triangle indicating how to balance the attributes of the three sides. The position of the dot represents focus. Moving it closer to one side emphasizes that attribute, while pulling attention away from the others. This helps make trade-offs visible instead of implicit.
Remember, all three attributes – performance, cost, and quality – are present for every product, just at different levels.
Some say, "Well that's easy, just put the dot in the middle." While it seems obvious, it also means nothing is important – everything is generic – the product should excel at nothing.
It is when we think about what is required for high Quality, that we understand the engineering trade-offs with Performance and Cost. We can say the same for Performance. Each move of the dot forces decisions about what matters most, and what can be sacrificed.
The Triangle of Achievable Engineering is a pointer for our thoughts. It is there to help us think about what is important, and why. So much of engineering is trade-offs, and this triangle is a good tool to help guide decisions.
A Triangle To Guide Engineering Decisions
This article has focused on balancing constraints using the Triangle of Achievable Engineering. The tool helps us look at Performance, Cost, and Quality as attributes in setting goals and guiding engineering trade-offs.
Engineering is rarely about finding the perfect answer. It is more about making good engineering decisions within constraints. Performance, Cost, and Quality are always present, always connected, and always in tension with every project. The Triangle of Achievable Engineering makes the relationships visible, enabling honest and deliberate discussion.
The triangle is not a formula or a scoring system. Rather, it is a guide for thinking. It helps to clarify priorities in planning. By making priorities explicit, engineering can streamline development. As a result, a good plan reduces surprises later – when changes are more expensive and options are fewer.
Going beyond the focus of this article, the triangle concept is not limited to achievable engineering. We use the same triangle principle in other focus areas like managing conflicting constraints. With engineering trade-offs, it comes up a lot.
Good luck with your projects and exploring the Triangle of Achievable Engineering. Until we discover a source of the mythical Unobtainium, we will treat compromise and balance as trusted tools.
Frequently Asked Questions
These are common decision-making questions related to managing engineering constraints, trade-offs, and feasibility.
1. How do engineers decide what matters most in a product design?
Understanding top-level product goals, constraints, and intended uses is the first step in making good engineering decisions. In practice, not every goal can be optimized, so decisions must be guided by priorities that deliver value for the product and its users.
Tools like the Triangle of Achievable Engineering help make priorities visible by framing performance, cost, and quality around the top-level goals. Once priorities are clear, engineering effort can focus on decisions that matter most, rather than fighting conflicting objectives.
2. What does the engineering triangle mean by "Achievable"?
In the engineering triangle, "Achievable" refers to what can realistically be delivered. The world is full of constraints like budget, schedule, manufacturing limits, and available technology. The triangle, and especially the "Pick 2" paradigm, helps bring focus to the most important priorities. When we know what is most important, it is much easier to focus on what is "Achievable" within the constraints.
3. Where does this triangle fit among other engineering tools?
The Triangle of Achievable Engineering fits alongside, often in advance of, other engineering tools for early, top-level alignment of goals. This simple graphic offers perspective, not finished work. While software tools are excellent for schedules, analysis, simulation, and optimization, they do not decide what should be optimized. The triangle operates upstream of those tools, helping define priorities that guide engineering trade-offs later in the detailed work.
4. Is the engineering triangle a rule or a guideline?
Think of the triangle as a guide for thinking, rather than a rule or a prescriptive guideline. The engineering triangle is not an equation, and it does not dictate answers or prescribe specific solutions. Instead, it offers a simple, structured way to think about competing priorities to make decisions about engineering trade-offs easier. The value is in guiding judgment, not replacing it.
5. What is NRE in manufacturing, and why does it matter?
In the context of production, NRE, or Non-Recurring Expense, refers to one-time costs for things like tooling, fixtures, molds, or specialized equipment needed to produce the product. NRE matters because it directly affects how cost trade-offs are evaluated in product development. Understanding NRE helps engineers and managers make decisions about manufacturing methods, quantity, and overall product feasibility.
6. Can this triangle help explain engineering decisions to management?
Yes. One of the strengths of the triangle is that it provides a simple, visual way to explain complex engineering trade-offs. By framing decisions in terms of performance, cost, and quality, engineers can clearly communicate the "why" of decisions and how those decisions align with project goals. The Triangle of Achievable Engineering is a great communication tool for those of both technical and non-technical backgrounds. See the examples earlier in the article describing value in the "Pick 2" paradigm.