Architecting and designing > IDEF > IDEF3 > Modeling processes with IDEF3 > Creating IDEF3 decomposition diagrams
  
Creating IDEF3 decomposition diagrams
When performing process modeling in IDEF3, you decompose Units of Behavior (UOBs) on an IDEF3 process flow diagram by creating a child IDEF3 Process Flow diagram for the UOB. On this child diagram you can model process flow details of the UOB.
1 Select a UOB symbol on an IDEF3 diagram; then right-click the symbol and select Child Create.
2 Type a name for the new IDEF3 diagram.
3 Ensure that Scenario Diagram is cleared.
4 Click OK; then, to save changes to the previous diagram, click Yes.
Shadow on UOB denotes decomposition
When you create a child diagram for a UOB, System Architect puts a shadow underneath the UOB.
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Automatic numbering of UOBs on child IDEF3 diagrams
When you create a child IDEF3 Process Flow diagram for a UOB, IDEF3 autonumbering standards are applied, as long as you have enabled autonumbering (Tools, Preferences, Number). Separated by periods, the numbers on a UOB represent, respectively, the parent UOB, the number of the child decomposition diagram, and the UOB itself.
System Architect automatically numbers the child IDEF3 process flow diagram with the number of the parent UOB plus the number of the child diagram (for example, if the parent UOB is numbered 5, then the child IDEF3 diagram will get a number of 5.1; if you create a second child IDEF3 diagram, it will be numbered 5.2, and so on.)
UOBs created on the child IDEF3 diagram will also be automatically numbered – they will be given the number of the parent diagram plus a number of their own added after a decimal point (for example, for a child IDEF3 diagram numbered 5.1, the first UOB added will be numbered 5.1.1).
The number assigned to the UOB can be manually added by opening up the definition of the UOB, turning to its Symbol tab, and editing the Number property.
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See also
Modeling processes with IDEF3