A graphical representation Ecolego of the interactions and relationships between the building blocks of a model.

Blocks are put on the diagonal of the matrix, and are connected by special types of connecting block which are put on the off-diagonal elements. For more information about the structure of an iteraction matrix, see the matrix window.

The advantage with an interaction matrix is that the interactions are well organised and never overlap (like in a box diagram.

An interaction matrix becomes impractical when there are many diagonal blocks as the area required to display the model increases exponentially with the number of diagonal elements. This situation can be remedied by grouping blocks into sub-systems.

Typically only the most important blocks are put on the matrix, such as compartments.

• Box diagram
• The Matrix window