**IDEF Process Description Capture.** IDEF3 is a method for capturing and documenting processes. Like the other IDEF methods, it’s primarily graphical in nature - but also specifies a textual representation. IDEF3 diagrams come in three varieties: **Process Schematics** are akin to [[SysML]] [[Activity Diagrams]]. **Object Schematics** are akin to SysML [[Block Definition Diagram ]]. **Transition Schematics** are akin to SysML [[State Diagrams]], or [[OPM]] diagrams. IDEF3 also specifies an **Elaboration Language**, which is a formal means of describing models using textual representation. There’s zero reason to ever learn it, and its syntax looks unapproachable to a layperson. Like most modeling techniques, IDEF3 supports [[Decomposition Understanding]]. You can “zoom in” to greater levels of fidelity, or “zoom out” to greater levels of scope.  # Process Schematics  Process Schematics describe processes. Above is an example of a process schematic. The fundamental unit of a Process Schematic is a ‘**unit of behavior**’ (UOB), which is a self-contained real-world process, individually labeled and indexed. The UOBs are connected via links, which may flow through aggregation points (AND, OR, XOR). They are indexed with a unique key, which can be used to positively identify any given UOB for unambiguous reference elsewhere (typically for elaboration).  # Object Schematics  Object Schematics describe objects. They are composed of each other, linked together via transition links or labeled relationship links, and may be stateful. IDEF defines first-order relations as relations between objects themselves, and 2nd order relations as relations between the _types_ of objects.  # Transition Schematic  The real power of IDEF3 is when Process and Object Schematics collide. A Transition Schematic describes how Processes and Objects inter-relate. They can _also_ contain sections that are process-specific and sections that are object-specific. ## Elaboration Language It’s there, so I’m including it. Don’t worry about it, though. I cannot imagine it’s in use in any real way today. Also it looks like this: ``` (forall (?coe : (activation-of ?coe PQD)) (forall (?sit : (and (occurs-in ?sit ?coe) (occurrence-of ?sit Paint-part))) (not (exists-5 ?x (and (instance-of ?x Part) (supports ?sit (in-queue ?x Q (start-of ?sit) +)))))) ``` **** ## Source [IDEF3 - Process Description Capture Method - IDEF](https://www.idef.com/idef3-process-description-capture-method/) ## Related - [[IDEF]] - [[IDEF5]] - [[Activity Diagrams]] - [[State Diagrams]] - [[Block Definition Diagram ]] - [[Diagram Types (index)]]