In this chapter, we will take a look at how child diagrams are created and combined and how instantiating an element works.
A model can include multiple diagrams, which create hierarchy in the model. Each diagram can be viewed as a separate diagram, which is part of the parent diagram. Diagrams are created by using for example subprocesses. Creating a subprocess on a diagram creates a new child diagram under the current one. This subprocess can then be modeled in more detail in its own diagram.
Same element can be used or referenced in several places in the model. This is especially useful for subprocesses, which are similar in several processes. This is done by instantiating the element. Two or more subprocesses can also be combined into one single child diagram.