Package Diagrams – Detailed Notes

1. Introduction to Package Diagrams

Package Diagram: A UML/SysML diagram used to show the organization and structure of a system model by illustrating how model elements are grouped into packages.

Package diagrams focus on the containment structure of a model. They do not describe behavior or internal logic, but instead provide a high-level organizational view.

2. Purpose of Package Diagrams

3. Containment and Namespaces

Containment: An ownership relationship where one element owns other elements.
Namespace: A model element that defines a naming scope for elements it contains.

Packages are the primary namespaces in SysML models. Every element exists within exactly one containment path from the model root.

Containment Tree (Conceptual)

Model Behavior Structure Internal Behavior

4. Visual Representations of Containment

4.1 Nesting

Nesting visually places elements inside their owning package.

4.2 Crosshair Notation

Crosshair notation references ownership without nesting.

Subsystem Component

4.3 Qualified Names

VehicleModel::Powertrain::Engine

5. Types of Packages

5.1 Model

The model is the root package of the entire containment hierarchy and may be stereotyped with «model».

5.2 Model Library

A model library contains reusable definitions such as value types and signals. It is stereotyped with «modelLibrary».

5.3 Profiles

Profiles extend SysML/UML with domain-specific stereotypes and tagged values.

5.4 Views and Viewpoints

A view is a package that contains elements addressing specific stakeholder concerns and conforms to a viewpoint.

6. Relationships Between Packages

6.1 Dependency

A dependency indicates that one package (client) relies on another (supplier).

6.2 Package Import

Package import brings references of elements into another package without duplicating or allowing modification.

7. Package Diagrams in Cameo

  1. Right-click the containment tree
  2. Select Create Diagram → Package Diagram
  3. Choose a purpose (e.g., Model Organization)

8. Exam-Ready Notes (High-Yield)

9. Terminology Alignment (SysML / Course Language)

Instructor language tip: When asked “why” in exams or reviews, always answer in terms of stakeholders, reuse, traceability, and complexity management.