Domain relationship directionality

Purpose

This page provides guidance on relationship directionality between domains in the Orthogramic Metamodel. It helps ensure consistency in how relationships are modelled, interpreted, and visualised across business architecture artefacts.

Directional modelling

In Orthogramic, relationships between domains are directional. One domain acts as the initiator (source), and the other as the receiver (target). This direction reflects intent, influence, responsibility, or dependency.

Correct directionality helps:

• Clarify business meaning

• Improve reasoning and alignment checking

• Avoid circular or misleading models

Active and passive domains

Some domains typically initiate relationships ("active"), while others are more often the target ("passive"). This distinction supports modelling discipline.

Active domains:

• Strategy

• Capability

• Value Stream

• Initiative

• Policy

• Stakeholder

Passive domains:

• Information

• Performance

• Product

• Service

Passive domains do not initiate relationships. For example, you should model:

• Capability → Information : uses

• Initiative → Performance : contributes to

...not the reverse.

Examples of valid directionality

Inter-unit relationships

While this page focuses on cross-domain relationships, directionality also applies to inter-unit domain relationships. However, in those cases, the emphasis is on organisational dependencies, so passive domains (e.g. Service) may appear as sources to reflect ownership or provision across units.

Usage in diagrams and APIs

In visual diagrams and API data:

• Always model relationships from initiator → target

• Avoid reversing direction for stylistic or layout reasons

• Use consistent verb types to preserve meaning

Related guidance

• Cross Domain Relationships

• Inter-unit domain relationship