Introduction to Basic I-TRIZ
 I-TRIZ Foundations
 Levels of Invention
 Inventive Problem
   Psychological Inertia
   Contradictions
 Patterns of Invention
   Analogical Thinking
   Directions
 Patterns of Evolution
 Ideality
   Ideal System
   Ideal Vision
   Functional Modeling
   Local Ideality
 Resources
   Derived Resources
   Insufficient Resources
 Problem Solving
 Brainstorming
 Ideation Process

Build a Functional Model and Formulate Tasks

According to the formula below, there are at least two approaches to increasing system ideality: (1) increase the number or magnitude of the useful functions; and (2) reduce the cost, number, or magnitude of the harmful functions.

To look for ways to increase a system's ideality it is necessary to create a functional model - a cause-effect diagram that describes the system's functions and the relationships between them. Functional modeling is also a powerful method for "untangling" a complicated situation. The basic elements of a functional model are functions and links. A link defines the relationship between functions.

 

To build a functional model:

1. Identify the useful and harmful functions related to the problem. A function is an activity, action, process, operation or condition. Functions are either Useful (green box) or Harmful (red box).

2. For each function you define, ask yourself the control questions below. Based on your answers to these questions, continue creating the functions that contribute to the problem situation.

  • Does this function produce another function?
  • Does this function counteract another function?
  • Is this function produced by another function?
  • Is this function counteracted by another function?

3. Identify the relationships between the functions by connecting the boxes with arrows. We will use two types of links: produce (an arrow) and counteract (a crossed arrow). Reveal the Contradiction by looking for functions that have both a useful and harmful outcome.

4. Formulate the following Tasks:

  • Modify a Useful Function - Determine how the system can be changed to improve its characteristics, functionality, etc.
  • Resolve a Contradiction: A Useful Function should exist in order to fulfill a Useful Purpose and should not exist in order to avoid a Harmful Function. - Change the system so that the desired results are achieved while the associated undesired results disappear or diminish.
  • Eliminate a Harmful Function - Change the system so that an undesired factor is eliminated or reduced.

5. You are ready now to Generate Ideas using Directions and Operators.