> ## Documentation Index
> Fetch the complete documentation index at: https://docs.dalus.io/llms.txt
> Use this file to discover all available pages before exploring further.

# SysML v1 ⇄ SysML v2 ⇄ Dalus Mapping

This guide maps concepts between SysML v1, SysML v2, and Dalus to help you transition your modeling knowledge.

## Structural Elements

| SysML v1                      | SysML v2                           | Dalus                             |
| ----------------------------- | ---------------------------------- | --------------------------------- |
| Block / Part Property         | Part Definition / Part             | **Part**                          |
| Value Property / Value Type   | Attribute Definition / Attribute   | **Variable**                      |
| Proxy Port / Full Port        | Port Definition / Port             | **Port**                          |
| Interface Block               | Interface Definition / Interface   | **Interface**                     |
| Connector / Association Block | Connection Definition / Connection | **Connection** (inside Interface) |

## Behavioral Elements

| SysML v1                   | SysML v2                   | Dalus          |
| -------------------------- | -------------------------- | -------------- |
| Action / Activity          | Action Definition / Action | **Action**     |
| State / State Machine      | State Definition / State   | **State**      |
| Transition                 | Transition Usage           | **Transition** |
| Control Flow / Object Flow | Succession                 | **Signal**     |

## Requirements

| SysML v1            | SysML v2                             | Dalus                           |
| ------------------- | ------------------------------------ | ------------------------------- |
| Requirement         | Requirement Definition / Requirement | **Requirement**                 |
| Constraint Property | Constraint Definition / Constraint   | **Constraint** (on Requirement) |
| Satisfy / Verify    | Satisfy / Verification               | Requirement assignment to Parts |

## Mission Planning

| SysML v1         | SysML v2                       | Dalus           |
| ---------------- | ------------------------------ | --------------- |
| Use Case         | Use Case Definition / Use Case | **Mission**     |
| Actor            | Actor Definition / Actor       | **Actor**       |
| Subject          | Subject                        | **Subject**     |
| Include / Extend | Include / Specialization       | **Interaction** |

## Diagram / View Equivalence

| SysML v1 Diagram               | Dalus View                         |
| ------------------------------ | ---------------------------------- |
| Block Definition Diagram (BDD) | Part View                          |
| Internal Block Diagram (IBD)   | Part View (nested into subsystems) |
| Activity Diagram               | Action View                        |
| State Machine Diagram          | State View                         |
| Use Case Diagram               | Mission Planning                   |
| Requirement Diagram            | Requirements Page                  |
| Parametric Diagram             | Action View (with Variables)       |

## Key Differences

### Simplified Metamodel

Dalus uses a streamlined set of elements compared to full SysML. Instead of separate definition and usage concepts, Dalus elements serve both purposes contextually.

### Variables Replace Value Types

Dalus **Variables** unify value properties, attributes, and flow properties. A Variable can be:

* An attribute on a Part
* An input/output on an Action
* A connection property on an Interface

### Interfaces Contain Connections

In Dalus, an **Interface** groups multiple **Connections** together. Each Connection specifies the type (Matter, Information, Energy, Binding), direction, and properties of a single flow.

### Integrated Requirements

Requirements in Dalus include **Constraints** that reference Variables directly. Verification status is computed automatically based on constraint evaluation—no separate verification relationships needed.

### ConOps First

Dalus encourages starting with **Mission Planning** (Missions, Actors, Subjects) before detailed architecture, aligning with SysML v2's emphasis on use case-driven design.