MBSE STYLE GUIDE
Authoring Standards for the MPE MBSE Model
Conventions every modeler MUST follow before submitting a SPER. Enforced by automated lints in CI and reviewed at every SCCB. Aligns to INCOSE SE Handbook v5 and NDIA MBSE WG guidance.
◤ 01
Naming conventions
| ELEMENT | PATTERN | EXAMPLE |
|---|---|---|
| Requirement | MPE-L{level}-{NNN} | MPE-L2-014 |
| Use Case | UC-{DOMAIN}-{NN} | UC-EW-07 |
| Block (BDD) | PascalCase noun | MissionDataLoader |
| Activity | verbPhrase() | buildEZ() |
| Interface Block | I{Domain}{Purpose} | IMadlTimeSlot |
| Port | lowerCamel noun | threatFeed |
| Signal | PascalCase + Signal | EmitterDetectedSignal |
| State | PascalCase adjective | EmconAlpha |
| SysML Package | SYSML-PKG-{DOMAIN} | SYSML-PKG-EW |
| CI | CI-{HW|SW|FW|DOC}-{NNN} | CI-SW-022 |
◤ 02
Stereotypes
«hwci»
Hardware configuration item (Block)
«csci»
Software configuration item (Block)
«external»
Off-platform actor or system
«derived»
Requirement derived from a parent — must trace up
«allocate»
Requirement → Block / Activity → Block allocation
«verify»
Requirement ↔ Test Case relationship
«refine»
Use case → Activity refinement
◤ 03
Diagram rules
- ▸BDDs: max 9 blocks per diagram. Group by domain package. Composition diamonds at the parent end only.
- ▸IBDs: show only parts and connectors relevant to the message. Hide unused ports. Annotate every connector with the item-flow it carries.
- ▸Sequence diagrams: include EXACTLY one lifeline per CI. Time flows top-down. No more than 15 messages per diagram — split into sub-sequences.
- ▸State machines: explicit entry/exit actions. Guards in [brackets]. Never leave a composite state without a defined initial sub-state.
- ▸Activity diagrams: swimlanes per actor/CI. Decision diamonds always have an [else] branch. Object flows typed to a Block.
- ▸All diagrams must carry a frame header with: diagram kind, package path, owner, and revision.
◤ 04
RTM level schema
L0Mission / capability need (JCIDS)
L1System requirement (SRD)
L2Sub-system / segment (SSS)
L3CI requirement (SRS / IRS)
L4Software unit / detailed design
L5Verification procedure
L6Verification result / evidence
◤ 05
Pre-SCCB review checklist
- Every requirement has a parent (except L0) AND at least one «verify» link to a test case.
- Every Block on a BDD appears in at least one IBD or sequence diagram.
- Every Activity is allocated to a Block via «allocate».
- No orphan SysML elements (zero incoming AND zero outgoing relationships).
- Every interface flow is typed to a Signal or Block — no untyped item flows.
- Every state machine reaches a final state from every reachable state (no dead ends).
- Diagram count budget per package: ≤ 1 BDD overview + N IBDs + N sequence/state diagrams.
- Naming conforms to this style guide — automated check passes before SCCB submission.