Illustrative diagrams may use drawings, 3D modelling, symbols or graphical illustration techniques to communicate complex or essential attributes of a system (also see Illustrations). This type of diagram helps to clarify concepts, show relationships and processes, and synthesise key messages (see example below).

Illustrative diagrams are very useful in depicting aspects of a system by:

• labelling the components
• changing the scale of the components to make them easy to see
• showing where the components are located within the system
• showing how something works, moves or changes.

Source: Adapted from Department of Industry (2013). Your home: Australia’s guide to environmentally sustainable homes, 5th edn.

Figure 3  Turbulence extends upwards up to 2 times the height of an obstacle and 20 times downwind: turbine sweep area must be clear of turbulence