**A UML-offshoot used for Systems Engineering** SysML is a offshoot of [[UML]] 2.0 that aims to achieve Model-Based Systems Engineering ([[MBSE]] ). It supports specification analysis, design, verification and validation of a broad range of systems including hardware, software, information, processes, personnel, and facilities. SysML is codified into **ISO/IEC 19514:2017** - "Information Technology - Object Management group systems modeling language" by the Object Management Group and [[ISO]]. ### Quirks of SysML SysML model organization is up to the modeler, which frankly sucks. Folders are called *packages*. [[Package Diagrams]] are there to explain your organizational scheme, which means it's not self explanatory. To make matters more confusing, there's a difference *containment* and *ownership*. It's possible for packages to *contain* elements that are *owned* by other elements. ### V2 SysML 2.0 is coming out SOON™️ and will represent a serious, massive improvement over the current standard (my opinion). It will include a further break from UML, but in doing so a more consistent and refined language. And, most importantly, a *textual* language and standard API to go along with the Graphical language. Although, unlike [[OPM]] that textual language does not read like regular english. ### UAF [[UAF]] is a superset of SysML used for representing enterprise architectures. # Four Pillars of Systems & SysML ## Structure SysML uses [[SysML Blocks]]. Is a strengthened "Class" from UML. See also [[SysML Block Property Types]] and[[Standard SysML Block Extensions]] ### [[Block Definition Diagram ]] BDD - How parts are related to one another ### [[Internal Block Diagram]] IBD - how parts within a single Block are connected. ## Behavior SysML has many ways to illustrate behavior. ### [[Sequence Diagrams]] SD - shows how messages are passed in order between participants. ### [[State Diagrams]] SD - also from UML. Describes states blocks can have, and how they transition between them. ### [[Activity Diagrams]] AD - for unconstrained behavior, use cases, and functional requirements. ## Requirements ### [[Requirements Diagram]] REQ - What the requirements are, how they are related, what parts of the system they relate to, and how they are verified. ## Parametrics ### [[Parametric Diagram]] PAR - Shows how blocks and properties are related to one another through the use of mathematical constants # Connecting the Pillars ![[D1D6FC32-278A-46F4-80B3-014A00FC462E.jpeg.jpeg]] There is also the concept of "allocation" between the parts of diagrams. Parts of the activity diagram can become associated with parts inside an internal block diagram. Requirements can be related ("satisfied") by parts in ibd or act diagrams. Values between parametrics and other parts of the models can be bound.  Source: [Skygazer Consulting YouTube](https://youtu.be/998UznK9ogY) ## Highly Related Softwares SysML is not software-specific, but it's well-supported by multiple software packages. - Cameo/MagicDraw - "The Cadillac of SysML Tools" - Visual Paradigm - available for free - [[Mermaid JS]] & [[PlantUML]] - neither are truly SysML, but capable of drawing many graphs from SysML **** ### Source - [[SysML Distilled]] - [[MIT 16 842 Fundamentals of Systems Engineering MIT Course]] - [[YouTube]] - [The Four Pillars of SysML (in 30 minutes)](https://youtu.be/998UznK9ogY) - [SysML Open Source Project - What is SysML? Who created it?](https://sysml.org/) ### Related - [[UML]] - [[UAF]]