A particular use case is a transactional scenario between an external actor and the system of interest. In this context the external actor may be a natural person, an organization or an entity outside of the system of interest's boundary.

The use case model does not define scenarios but is a view of an instance of the system.

The use case model also gives context to system requirements.

Use case modeling allows including other secondary use cases but use cases should not be used to decompose system behavior.

The rationale of using use case modeling, rather then directly modeling system behaviors, is to analyze the scenarios that the system of interest will undergo and how, under these scenarios, the external actors and the system of interest expect to interact.

1. Identify stakeholders who will interact with the system
   1. Consider stakeholders who positively / negatively interact
2. Define the system of interest as an abstract block
3. …

• Context of use:
• Scope:
• Level: {User Goal}
• Primary Actor:
• Stakeholders & Interests:
• Preconditions: Conditions that need to be true for the use case to start.
• Success End Condition:
• Failed End Condition:
• Trigger: Logistical need to move payloads within facility.
• Main Success Scenario:
• 1.
• 2.
• …
• n.
• Extensions:
• *a.
• 1a.
• 1b.
• Frequency of Occurrence:
• Open Issues: