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Functional Modeling with PRIZ Innovation Platform

December 11, 2021

Functional modeling is probably the most powerful problem-solving tool available for us as engineers. The tool is applicable to both sudden, unpredictable deviations (AKA excursions) and for solving chronic problems.

The power of Functional Modeling

Functional modeling benefits us in a number of things. Here, however, we want to highlight just some of them.

  • Learn and understand how a system operates
  • Define and rank functionality of all system components
  • Define and rank the problematic level of the components  
  • Solve problems and improve the functionality of the system:
    • Enhance the functionality of the system by modifying the components having high functional rank
    • Eliminate components having low functional rank
    • Solve problems by modification or elimination of problematic components

How does System Functional Modeling work

There is astraightforward process and specific steps that we need to follow in order to build a functional model and achieve desired results:

  1. Collect relevant data about a system under investigation. Images, sketches, etc. – all of these are very useful to have infront of our eyes while building the model.
  2. Define the product of the system – what is the product that the systems is built for?
  3. Define and list the components of the system
  4. Define supersystem – components that do not belong to the system but impact its operation. Also, components that we can’t or don’t want to change.
  5. Define functions between all the components, including product and supersystem
  6. Map the functional model – all components and functions
  7. Rank the functions and components using the rules of functional modeling
  8. Think, create ideas and start enhancing the system



The “product” is what the engineering system was originally designed for or to produce. Most engineering systems have only one product.

The Main Function (Action) of the system can help us to define the Product:


A car is designed to move a person, which means that the main function of a car is to move. The product of a car is a person.

Define product

In this case, the product, PERSON, covers everything that might be a product in this system. But, in some cases, we can concentrate on some specific parts of the system depending on the goals of the investigation. For instance, if we want to improve the engine effectiveness and reduce pollution, we can take CO2 content as a product. If we need to reduce waring of tires, we can assign a rubber residue remaining on the road as a product.

Another example is a drill. One can say that the product of the drill is a hole. Generally, it is correct, but not very useful for problem solving and improvements. It would be much useful to assign sawdust as a product. This way, by analyzing sawdust, we can solve problems and innovate much more effectively.

But typically, the product is an object that the system was designed for.

It is important to mention that a product does not belong to the system.


The components are all physical components (parts) of the system. In the case of a car: wheels, body, engine, seats, etc.

System components


Components that contribute to the main function of a system but do not belong to the system are considered supersystem. Following our example: air, pollutions, rain, etc.

In some cases, components of the system can also be assigned as a supersystem if we are not willing to modify these components.



A function is an action between two parts of a system (any parts), between a subject and an object. A function exists if the subject changes a parameter of the object:



If I am dreaming about a glass of beer, this is not a function, because no parameter of the beer is changed.

I am drinking beer – the function exists because I (subject) change the parameter (volume) of beer (object). Also, beer has a function to me: in this case, the beer changes my parameter – it makes me happy.

Types of function

There are two contradicting types of functions: useful and harmful. A useful function can also be insufficient or excessive. The different types of functions are described below:

types of a function

Useful function – when the action leads to an expected change of parameter of an object

Insufficient function – is a useful function, but when the parameter change is below the expectation

Excessive functionis a useful function, but when the parameter change is above the expectation

Harmful function – when the action causes an unexpected (against expectations and potentially harmful) parameter change on an object

What does it mean to make a System Functional Model?

The main purpose of the functional modeling is to connect all the components including supersystem and product, with arrows (functions). Keep in mind that a function exists if a parameter of the object is changed.

A sample of a functional model is shown below:

functional model sample

Once the functional model is ready, both functional and problem rank are calculated for each component of the system. These ranks allow us:

  • To understand how the system is functioning
  • Create models of failuresMain Function (Action) of the systemPrevent possible excursions (deviations)
  • Generate solutions to existing problems
  • Propose innovative ideas
  • and so on

PRIZ Innovation Platform offers Functional Modeling as one of the creative thinking tools.

creative tools selectore

The process of a Functional Model is straightforward and easy to use. The calculation of the functional and problem ranks is completed automatically and appears in form of easy to read bar chart.

A sample from the platform is shown below.

functional modeling sample

More to read

Additional practical examples of Functional Modeling can be found in our previous articles:

About Cellphone Future with 9 Windows & Function Model

Innovate and solve problems to keep your business alive

Take a customer’s function away to satisfy the customer.

A problem solver is the main roadblock in problem solving processes

That is it. Try it yourself with PRIZ Platform. Contact us for any assistance.

Leave A Comment

  • David Harold Chester
    November 18, 2022

    My work in modelling our social system of macroeconomics has roughly followed the methods that you prescribe, but they were based on logic not somebody’s alternatrive ideas. I believe that we better need to understand how in general this logic is created and how it works, regardless of subsequently formulating a set of rules.

    What is interesting in my case is that our social system must be approached simultaneously from two different (actually opposing) perspectives in order to start the process of properly understanding its structure and operation. My working paper SSRN 2865571 “Einstein’s Criterion Applied to Macroeconomics Modelling” explains it in 7 pages and a diagram.

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