Requirements → Diagrams → Tests: Traceability in Draw Plus

The Problem with Disconnected Tools

In most engineering workflows, requirements live in a spreadsheet or wiki, diagrams are drawn in a separate tool, tests are tracked in yet another system, and project tasks float in a Kanban board. When a requirement changes, the team has to manually chase down every affected diagram, test case, and task — hoping they don't miss anything.

This “tool sprawl” problem is what Model-Based Systems Engineering (MBSE) tries to solve at the methodology level. But most MBSE tooling is enterprise-grade, expensive, and complex. Draw Plus takes the core traceability concept and makes it accessible in a single macOS workspace.

What Are Trace Links?

A trace link is a directed connection between two artifacts. In Draw Plus, any item can link to any other item across all four modules:

• Requirement → Diagram — “This requirement is visualized in this BPMN diagram.”
• Requirement → Test Case — “This requirement is verified by this test.”
• Requirement → Task — “This requirement is implemented in this sprint task.”
• Diagram → Test Case — “This diagram element is validated by this test scenario.”

These links are stored bidirectionally in the Core Data model, so navigating in either direction is instantaneous.

Impact Analysis in Practice

When you modify a requirement in Draw Plus, the trace link system instantly answers three questions:

1. Which diagrams are affected? — Every diagram element linked to this requirement is highlighted.
2. Which tests need updating? — Test cases linked to the changed requirement are flagged for review.
3. Which tasks are impacted? — Project tasks connected to the requirement show a “needs review” indicator.

This turns change management from a manual, error-prone process into an automatic, visual one.

Coverage Gaps

Trace links also reveal what's missing. Draw Plus can surface:

• Requirements with no linked test cases (untested requirements)
• Requirements with no linked diagram elements (undocumented behavior)
• Test cases not linked to any requirement (orphan tests)
• Tasks not linked to any requirement (untracked work)

This coverage view gives project leads a single dashboard to assess completeness, instead of cross-referencing multiple tools.

Technical Implementation

Trace links are modeled as a many-to-many relationship in Core Data, with a “TraceLink” entity that stores:

• Source artifact type and ID
• Target artifact type and ID
• Link type (derives, verifies, implements, visualizes)
• Creation timestamp and optional note

Because all four modules (requirements, diagrams, tests, tasks) share the same Core Data store, trace link queries are local fetches — no network calls, no API latency. Even projects with thousands of artifacts resolve impact analysis in milliseconds.

MBSE Roots

My background at IBM working on systems engineering tooling directly informed this design. Enterprise MBSE tools like IBM Engineering Requirements Management DOORS and Rhapsody use similar traceability concepts, but they require significant setup, training, and infrastructure. Draw Plus distills the core value — “show me what's affected when I change something” — into a lightweight, offline-capable macOS app that a single developer or small team can adopt immediately.

Explore Further