The initial node in the root window, named Rigi, represents the root level node in the layered, hierarchical graph stored in the rsf file.
At times there may be more than one node at the root level, each of which represents additional hierarchical structures.
To perform an overview of the subsystem hierarchy descending from the Rigi node:
Selected nodes are highlighted, that is, shown in a solid color.
A new Overview window appears, presenting the tree-like structure below the Rigi node. The Rigi node is at the top of the tree. An Overview window presents a vertical ``slice'' of the hierarchy. The arcs you see that span levels in the hierarchy are known as level arcs. For clarity, the arcs within a level and the node labels are filtered in an Overview window.
Tip: Resize this window and place it in a corner of the screen while you work.
To traverse down the hierarchy by opening nodes:
A new Children window appears, showing the children of Rigi in the hierarchy; the parent node, Rigi, is named in the window title. There is one node, named Base, in this particular example. For more complex software systems, there may be multiple at this level to, for example, represent several functional components.
A new Children window appears, showing the children of Base. Similarly, there is one node though there can be more. This node, named src, represents the directory which contains the source code of the list example. For a more complex system, there may be multiple directories containing its code.
A new Children window appears, becoming active and showing the children of src. This level is the lowest one in the current hierarchy; you will later identify subsystems at this level, collapse related nodes, and form an even deeper hierarchy.