IDEF3
A process-description methodology with support for temporal sequence and logical relations, complementing the functional IDEF0.
Purpose
IDEF3 was developed as an extension of the IDEF family, complementing IDEF0 with a description of the temporal sequence of a process. If IDEF0 answers “what is done?”, IDEF3 answers “in what order?”.
Two kinds of diagrams
IDEF3 includes two diagram types:
Process Flow Description (PFD)
Describes the temporal sequence of actions — close to classic flowcharts, but with stricter link semantics.
Object State Transition Network (OSTN)
Describes changes in the state of objects over time — close to UML state diagrams.
PFD elements
- Unit of Behavior (UOB) — a unit of behavior, an action
- Links — relations between UOBs of different kinds: precedence, object flow, relational
- Junctions — synchronization nodes with different semantics: AND, OR, XOR, synchronous and asynchronous
Where it is used
IDEF3 is rarely used on its own. It is usually applied together with IDEF0 for projects that need both functional decomposition and a description of temporal order — most often in the military and aerospace industries, which use the whole IDEF stack.
Limitations
- Low popularity in modern BPM practice
- Weak tooling support
- BPMN covers everything IDEF3 does, and more