I85PREP
⌘ K
OCSMP Model Builder Intermediate study materials
OCSMP Model Builder Intermediate study resources

OCSMP Model Builder Intermediate: Structure Modeling with the Full SysML Feature Set

OCSMP Model Builder Intermediate · Work through your exam, one topic at a time.

All guide sections

Structure Modeling with the Full SysML Feature Set

Structure modeling

The structure domain tests precise block definition and internal structure: properties, ports, connectors, item flows, and classifier relationships.

Core rules

  • A Block Definition Diagram (BDD) shows classifiers and their relationships: generalization, association, composition/aggregation, and dependencies. An Internal Block Diagram (IBD) shows the internal structure of one block: part properties, ports, connectors, and item flows.
  • Property kinds are distinct: a part is a composite property owned by the block; a reference is a shared property; a value property is typed by a value type; a port is a property typed by an interface block or block; a constraint property is typed by a constraint block.
  • Multiplicity belongs on the property, not on the connector. A part wheel: Wheel [4] means four owned wheels.
  • A proxy port is typed by an «interfaceBlock» and exposes only interface features; a full port is typed by a block and may have internal structure. Conjugate a port to invert flow direction.
  • Item flows on connectors must carry an item type compatible with the flow properties at both ends.
  • Value types carry units and dimensions; use them instead of primitives when units matter.

Worked example

Vehicle has engine: Engine [1] and wheel: Wheel [4]. Engine has proxy port shaftOut: ShaftPort, and Transmission has shaftIn: ShaftPort conjugated. On the Vehicle IBD, connect engine.shaftOut to transmission.shaftIn and add an item flow of type Torque. Reasoning: the parts are composite with explicit multiplicity; the ports are proxy ports typed by an interface block that declares the Torque flow property; conjugation makes the receiving port’s flow direction opposite to the sending port. The item flow type must match the flow property type, or the model is inconsistent.

Traps

Confusing part and reference properties; omitting multiplicity; using a block where a value type is required; putting ports on an IBD without typing them; connecting ports with incompatible item flows; drawing generalization as an association; forgetting that a full port can own structure while a proxy port cannot.