Diagram types

A model is viewed through diagrams, and different questions call for different diagram types. TraceUnified supports the SysML diagram set, so you can describe structure, behavior, and constraints — all against the same underlying model.

The core structural diagrams

Most architecture work centers on three structural views:

• Block Definition Diagram (BDD) — defines the building blocks of the system and how they relate: composition, generalization, and the parts a block is made of. The BDD answers “what are the things, and how are they organized?”
• Internal Block Diagram (IBD) — looks inside a block to show how its parts are connected through ports and connectors. Where the BDD defines the blocks, the IBD shows how they’re wired together to work.
• Parametric Diagram (PAR) — captures constraints and the values they bind, letting you express the engineering relationships and equations that govern the design. This is where performance, safety margins, and other analyses are modeled.

Behavioral and other views

Beyond structure, the model can be viewed behaviorally and organizationally:

• Activity Diagram — flows of actions and how work or data moves through the system
• Sequence Diagram — interactions between parts over time
• State Machine Diagram — the states a part can be in and the transitions between them
• Use Case Diagram — the system’s actors and what they need it to do
• Package Diagram — how the model itself is organized into packages

One model, many views

Whichever diagram you open, you’re working against the same model. An element defined on a BDD can appear on an IBD; a change in one view propagates everywhere it’s shown. You pick the diagram type that fits the question, and the model keeps everything consistent underneath.