About balancing OV-5 context or constraint diagrams
IDEF0 as a method requires lines to be balanced between parent activities and child diagrams. For example, if an input is added to a parent activity then it is required to be added to the child diagram of the activity, or if an output is added from a child activity it is required to be added to the parent symbol.
Automatically balancing parent or child diagrams
When you add, delete, tunnel, or disconnect ICOM arrows on OV-5 diagrams, System Architect will auto-balance the parent and child OV-5 diagrams. You are presented with a dialog of choices on how to balance the diagrams.
Note The parent and child diagram must both be open for auto-balancing to take place.
When you make a selection, the process is automatic and transparent to you; you do not have to refresh the child diagram to see it. The following sections provide detail on this behavior.
Full Grand Parent/Child: By toggling on Full Grand Parent/Child, automatic balancing works not only for the immediate parent or child diagram, but all grand parents or grand children to that diagram, as long as they are open.
Don't Ask Me This Question Again: Select this to perform automatic balancing without the IDEF0 Balancing dialog box appearing.
Parent-to-child balancing
When you add an ICOM Arrow to a Operational Activity symbol on a parent OV-5 diagram, System Architect adds a similar ICOM arrow of the same name to the diagram workspace on child OV-5 diagram. The arrow is added to the appropriate side of the diagram (input arrows on the left, controls on the top pointing down, mechanisms on the bottom pointing up, outputs on the right pointing right), but not attached to any child Operational Activity. This holds true for Input, Control, Output, or Mechanism (ICOM) arrows, but not for Call arrows.
Example
In the example below, adding an input ICOM arrow, named Input 1, to a Operational Activity symbol, named Parent Activity, on a parent OV-5 diagram automatically adds it to the diagram workspace of the child OV-5 diagram, on the left side of the workspace.
Adding Tunneled Arrows — Balancing from Parent to Child Diagrams:
In System Architect you can specify that an ICOM arrow be tunneled: select Tunneled (Parenthesis) in the arrow’s associative dialog (right-click the arrow, and then click Associative).
When adding a new ICOM arrow to a parent diagram, System Architect's auto-balancing functionality takes into account tunneled arrows. If you add an ICOM arrow to the parent diagram that has the same name as a tunneled ICOM arrow already existing on the child diagram, then System Architect will untunnel the ICOM arrow on the child to make the lines consistent (clear Tunneled (Parenthesis) in the line’s Associative dialog).
Deleting ICOM arrows
When deleting an ICOM arrow from a parent Operational Activity, you are presented with a set of choices on what action to take on the children.
In the dialog box above, for example, you can select:
Child: Deletes the corresponding ICOM arrow on the child OV-5 diagram.
Tunnel Only: As the arrow is removed from the parent, System Architect tunnels the arrow on the child diagram.
No Balance: Leaves the arrow on the child untouched.
Cancel: Leaves the arrow on the child untouched.
Non-Deletion of Local Arrows on Child Diagrams
If a line is deleted from the parent diagram, and the name of that line also appears as a local arrow on a child diagram, or a grandchild diagram, the local arrow is not removed. Only the arrows and arrow segments immediately attributable to the deleted line are deleted.
So for example if an ICOM arrow named Input 1 is deleted from the parent diagram, in the child diagram the line Input 1 that goes into Operational Activities 2 and 3 is deleted; the local arrow from Operational Activity 1 to 2 is not deleted.
Tunneling Existing ICOM arrows
You can make an existing ICOM arrow tunneled (by accessing the associative properties of the line and toggling on the Tunneled (Parenthesis) property). This has the same effect as deleting it from the child diagram. System Architect presents you with the same choices as if you were deleting the ICOM arrow from the parent. Selecting Cancel actually undoes the tunnel (clears the Tunneled (Parenthesis) property in the arrow’s associative dialog).
Disconnecting an ICOM arrow on the Parent Operational Activity Symbol (rather than deleting)
You cannot disconnect a line from the parent diagram; if you do so, this message appears:
The methodology does not allow the drawing of a line of type ICOM Arrow between those locations
Child-to-parent balancing
When you add an ICOM Arrow to Operational Activity symbol on a child OV-5 diagram, System Architect automatically adds a similar ICOM arrow of the same name to the appropriate side of the parent Operational Activity symbol on the parent OV-5 diagram. This holds true for Input, Control, Output, or Mechanism (ICOM) arrows. It does not hold true for Call arrows.
Tunneled arrows: Balancing from child to parent diagram
To specify that an ICOM arrow be tunneled, select Tunneled (Parenthesis) property in the arrow's associative dialog (right-click the arrow, and then click Associative).
If you select a tunneled ICOM arrow on a child diagram, and untunnel it, then the line will appear on the parent diagram.
Deleting ICOM arrows
When deleting an ICOM arrow from a child diagram, you are presented with a set of choices on what action to take on the parent. You can delete it, or tunnel it.
Disconnecting an ICOM arrow on the child diagram (rather than deleting)
If you disconnect an ICOM arrow on the child diagram, it has the same effect as deleting the symbol: System Architect provides you with the same set of choices for how to balance the parent diagram. Selecting Cancel actually undoes the symbol move that caused the disconnect (it reconnects the line symbol).
