Element - Name of Feature - Value of Feature (ENV) is just oneof numerous thinking models coming from OTSM-TRIZ. However, as it is used in the materials offered at this site, it is this model we chose to describe in detail. The descripton below is adapted from the materials of the TETRIS project.

The ENV model is a universal language for problem solving. It allows to produce descriptions that are easy to use in the process of solving a problem.

The ENV model comprises three parts:

• Element
• Name of feature
• Value of feature

Example:
Normally we use a simplified version of the ENV model (see Fig. 1 – Model 'Element – Feature'). For example, when describing an apple to someone who has never seen it before or clarifying the meaning of the word 'apple' to a foreigner, we say that it is a fruit; hard enough; it could be green, yellow or red; usually sweet enough but not too much; round or oval; it grows on trees, etc. As a rule, such a description is enough for most contexts. It is referred to as 'Element – Feature'.

Fig 1. Model «Element - Feature»

However, in order to overcome mental inertia and cope with problem situations efficiently, one is to use a more specific variant of this model, where features are split into Names and Values. The term «feature» denotes variables or parameters — in other words, everything that is used for the description of a specific element and can be represented in the form Name of feature and a set of the Values of feature.

Fig. 2. Feature is split into Name of feature and Values of feature.

Example:
The element «apple» can be represented through a set of parameters: type of plant, degree of hardness, colour, degree of sweetness, shape, etc.

Each of these parameters has a specific value. For example, parameter «type of plant» has a value fruit, parameter «degree of hardness» has a value «rather hard», parameter «colour» can have several values - «green», «yellow», «red», etc.

Fig 3. Main model: «Element — Name of feature — Value of feature» (ENV)

It should be noted that any parameter used for the description of a specific object could have different values when used for the description of other elements. For example, parameter «colour» had values «green», «yellow» and «red» when describing an apple but it can also have values «violet», «orange», «purple» when other elements are described.

The ENV model should be viewed as a tool for representation of the multidimensional space. This treatment of the model allows to increase the level of formalization when dealing with problem solving in various fields.