- Assembly
- A mid-level node type containing parts that work together as a unit.
- Behavior
- How a node operates over time, typically modeled as a state machine.
- Budget
- An allocated limit for a rollup property (mass, power, cost).
- Causality Lens
- Visualization showing technology dependencies as Harney’s Pyramid.
- ChangeSet
- A batch of proposed model operations that can be reviewed and accepted or rejected.
- Completeness Lens
- Analysis view showing gaps in the model.
- Constraint
- A requirement type that limits solution space.
- Decomposition
- Breaking a node into smaller child nodes to add detail.
- Dendritic Lens
- Visualization showing the decision tree including pruned alternatives.
- Derives
- A trace link where a child requirement is allocated from a parent.
- External
- A node type representing systems outside your design authority.
- Guard
- A condition on a state transition that must be true for it to fire.
- Hierarchy
- The tree structure of nodes from system to parts.
- Interface
- A connection between two nodes defining what flows between them.
- Lens
- A view mode showing the model from a specific analytical perspective.
- Mainstay
- In the Narrative lens, the critical path through the system.
- Node
- The fundamental building block of a model.
- Part
- A leaf-level node representing an individual component.
- Property
- A key-value pair representing an engineering parameter.
- Pruned
- A design alternative that was considered and rejected.
- Requirement
- A statement of what a node must do or how well it must perform.
- Rollup
- Automatic aggregation of child property values to compute parent values.
- Signal
- A single flow within an interface — data, power, material, or thermal.
- State
- A mode a node can be in, as part of a state machine.
- State Machine
- A behavior model defining states, transitions, triggers, guards, and actions.
- Subsystem
- A major functional group within a system.
- System
- The top-level node representing the product being designed.
- Systemigram
- A visual narrative diagram showing how system elements connect functionally.
- Trace Link
- A relationship connecting model elements (satisfies, verifies, derives, etc.).
- Transition
- A connection between two states triggered by an event.
- TRL
- Technology Readiness Level. NASA’s 1-9 maturity scale.
- Trigger
- An event that causes a state transition to fire.
- Verification
- Confirmation that a requirement is satisfied via test, analysis, demo, or inspection.