OOF™ Origin Open Foundation™

Independent Methodological Authority

Architecture Ecosystem: Structured Reality Standards™
Architecture Family: SIMULOS® — Simulation Governance Architecture
Parent Standard: Simulation Model & Environment Standard (SMES)
Operational Layer: Simulation Model & Environment Governance Layer
Category: Governance & Enforcement
Subcategory: Simulation Governance
Type: Parent Standard Module
Governed Space: Simulation Boundary Interaction
Version: 1.0
Status: Canonical · Open Module
Effective Date: 17 August 2026
Compatibility: OOF® Methodology OS™ · GOA™ · ORA™ · VALIDOS® · INTEGROS® · ADIT® · AGA™ ·
AIG® · CLIA® · MGIA™ · ASGA™ · RIS™
AI-Readable: Yes
Authority: OOF®
Protection: MIP® — Methodological Intellectual Property
Canonical Language: English (UCL™)

Governed Space

Simulation Boundary Interaction

Canonical Definition

Simulation Boundary Interaction Module (SBIM) defines the governance framework
for identifying, defining, controlling, documenting, and reconstructing the
interaction boundaries through which a governed Simulation Model exchanges
information, state, signals, actions, resources, events, or influence with the
Simulation Environment, external systems, human participants, physical
components, other models, or other simulation-relevant entities.

SBIM establishes the governed interaction layer between what belongs inside
the Simulation Model, what belongs outside the Simulation Model, and what may
legitimately cross the boundary between them.

Operational Role

SBIM is the third internal governance space of the Simulation Model &
Environment Standard (SMES).

The preceding modules establish:

SMMM — What is the Simulation Model structurally composed of?

SECM — Within what configured Simulation Environment does that model operate?

SBIM asks:

Where do the model and its surrounding environment meet, what may cross that
boundary, in which direction, under what interaction conditions, and how can
those interactions be reconstructed?

The governed progression is:

Governed Model Structure → Governed Environment Configuration → Boundary
Identification → Interaction Point Definition → Exchange Classification →
Direction & Control Definition → Boundary Condition Establishment →
Interaction Traceability → Governed Simulation Boundary Interaction

Module Operational Space

SBIM governs: Simulation Boundary identification, Model–Environment
boundaries, model-to-model boundaries, simulation-to-external-system
boundaries, virtual-to-physical boundaries, human-to-simulation boundaries,
simulation-to-human boundaries, boundary interaction points, boundary
interfaces, boundary channels, inbound interactions, outbound interactions,
bidirectional interactions, exchanged information, exchanged state, exchanged
signals, exchanged events, exchanged actions, exchanged resources, interaction
direction, interaction timing, interaction sequencing, interaction frequency,
interaction conditions, interaction permissions, interaction constraints,
interaction transformations, interaction mediation, boundary synchronization,
boundary failures, boundary interruption, boundary substitution, boundary
change, boundary traceability, and boundary interaction reconstruction.

Module Operational Scope

SBIM applies where Simulation Model behavior depends upon interaction across
an identifiable simulation boundary.

This may include: fully virtual simulations, digital twins,
software-in-the-loop simulations, hardware-in-the-loop simulations,
human-in-the-loop simulations, autonomous-system simulations, robotics
simulations, multi-agent simulations, distributed simulations, federated
simulations, cyber-physical simulations, industrial simulations,
infrastructure simulations, scientific simulations, financial simulations,
transportation simulations, aerospace simulations, defense simulations,
training environments, live-system-connected simulations, and future hybrid
simulation environments.

Governance depth should remain proportional to the material influence of
boundary interaction upon simulation behavior and intended simulation
reliance.

Module Function

A Simulation Model and Simulation Environment may both be correctly defined
while their interaction remains poorly governed.

A simulation can fail methodologically because: the wrong information enters
the model, outputs cross the wrong interface, timing differs from intended
conditions, a physical signal is transformed incorrectly, an external service
behaves differently, a human intervention is not visible, two models exchange
incompatible states, a boundary becomes unintentionally permeable, or an
assumed interaction never actually occurs.

SBIM exists to make these interactions explicit.

Its function is to determine:

where interaction occurs,

what crosses the boundary,

in which direction,

through which mechanism,

under which conditions,

and:

what happens when the interaction changes or fails.

Simulation Boundary

A Simulation Boundary is a governed separation between two simulation-relevant
domains whose interaction may materially affect simulation behavior.

Examples include:

Simulation Model ↔ Simulation Environment

Model A ↔ Model B

Simulation ↔ External Data Source

Simulation ↔ Physical Hardware

Simulation ↔ Human Operator

Simulation ↔ Live Operational System

A boundary is not merely a technical interface.

It is the point at which one governed simulation domain may influence another.

Boundary Interaction

A Boundary Interaction occurs when information, state, signals, events,
actions, resources, control, or other material influence crosses a Simulation
Boundary.

Conceptually:

Domain A → Boundary → Domain B

or:

Domain A ↔ Boundary ↔ Domain B Boundary
Identification

Material Simulation Boundaries should be explicitly identifiable.

Where relevant, boundary identification should establish: boundary identity,
connected domains, boundary type, interaction purpose, direction, applicable
interface, exchanged object or signal, interaction conditions, and applicable
configuration.

Boundary Type

A Simulation Boundary may be classified according to the domains it separates.

Possible types include:

Model–Environment Boundary

Model–Model Boundary

Simulation–External System Boundary

Simulation–Physical System Boundary

Simulation–Human Boundary

Simulation–Operational Reality Boundary

Simulation–Data Source Boundary

Simulation–Service Boundary

or another domain-specific boundary.

Interaction Point

An Interaction Point is the identifiable location, mechanism, interface,
event, or condition through which a boundary exchange occurs.

Examples include: API endpoints, message queues, sensor interfaces, actuator
interfaces, network ports, shared state objects, data feeds, event buses,
human controls, hardware interfaces, model coupling interfaces, or physical
measurement channels.

Boundary Interface

A Boundary Interface should remain distinguishable from the boundary itself.

The boundary establishes separation.

The interface provides a mechanism through which governed interaction may
occur.

Therefore:

Boundary ≠ Interface

and:

Interface ≠ Permission for unrestricted interaction.

Inbound Interaction

An Inbound Interaction introduces information, state, events, signals,
resources, commands, or influence into the governed Simulation Model or
Simulation Environment.

Conceptually:

External Domain → Simulation Boundary → Governed Simulation Domain Outbound
Interaction

An Outbound Interaction transfers simulation-generated information, state,
events, signals, actions, or influence beyond the governed domain.

Conceptually:

Governed Simulation Domain → Simulation Boundary → External Domain
Bidirectional Interaction

Some boundaries permit continuous or event-driven exchange in both directions.

Conceptually:

Domain A ↔ Domain B

Bidirectionality should remain explicit because feedback can materially alter
simulation behavior.

Interaction Direction

Interaction direction should be defined where material.

Possible states include:

Inbound

Outbound

Bidirectional

Conditional

or:

Dynamic

where direction changes according to governed simulation conditions.

Interaction Object

An Interaction Object is whatever materially crosses the boundary.

It may include: data, state, command, event, signal, measurement, resource,
control instruction, model output, environmental response, human input, or
physical response.

Interaction Classification

Material interactions may be classified according to their role.

For example:

Informational

State-Changing

Control

Resource

Observational

Triggering

Feedback

Synchronization

or:

Safety-Critical

Classification should support the level of governance required by the
simulation inquiry.

Interaction Conditions

A boundary interaction may occur only under defined conditions.

These may include: model state, environment state, scenario state, timing
condition, event trigger, threshold, permission state, resource availability,
synchronization condition, or external-system availability.

Boundary Interaction Rule

A Boundary Interaction Rule establishes the conditions under which an
interaction may occur and the expected behavior of the interaction mechanism.

Conceptually:

Trigger + Boundary Condition + Interaction Object + Direction + Transformation
+ Destination Interaction Timing

Timing may materially affect simulation behavior.

SBIM therefore governs relevant properties such as: interaction time, delay,
latency, timeout, frequency, sequence, synchronization, asynchronous behavior,
buffering, and timing uncertainty.

Interaction Sequence

Some boundary interactions must occur in a defined sequence.

For example:

Request → Authorization → Exchange →
Response → State Update

Changing the sequence may materially alter simulation behavior even when the
same information is exchanged.

Interaction Frequency

Interaction frequency may be:

Continuous

Periodic

Event-Driven

On-Demand

Single-Occurrence

or:

Adaptive

where frequency changes according to simulation state.

Boundary Synchronization

Where multiple simulation domains operate under different clocks, execution
rates, or event systems, boundary synchronization should be governed.

This may include: time synchronization, state synchronization, event
synchronization, step synchronization, clock conversion, or synchronization
tolerance.

Synchronization Failure

A technically functioning interface may still produce invalid simulation
behavior if the participating domains are not sufficiently synchronized.

SBIM therefore treats synchronization as a boundary-governance question where
it materially affects interaction.

Interaction Transformation

Information crossing a boundary may be transformed.

Examples include:

Unit Conversion

Coordinate Transformation

Protocol Conversion

Data Encoding

Signal Scaling

State Mapping

Aggregation

Filtering

Normalization

or:

Abstraction

Material transformations should remain identifiable.

Transformation Traceability

Where a transformation materially affects meaning or behavior, SBIM should
preserve:

Source Interaction Object → Transformation → Resulting Interaction Object No
Invisible Transformation Principle

A material transformation must not alter what crosses a Simulation Boundary
without remaining visible to simulation governance.

Interaction Mediation

Some interactions are mediated by another component.

Conceptually:

Model → Middleware → Environment

or:

Physical Sensor → Interface Adapter →
Simulation

The mediator should remain identifiable where its behavior may materially
affect the interaction.

External Service Interaction

A Simulation Model may rely upon external services.

Examples include: external APIs, mapping services, weather services, AI
models, databases, cloud services, communication services, or live operational
feeds.

SBIM governs the interaction boundary.

SECM governs the environmental dependency where the service forms part of the
Simulation Environment configuration.

Model-to-Model Interaction

Where multiple models interact, SBIM governs the exchange relationship between
them.

For example:

Vehicle Dynamics Model ↔ Control Model

or:

Economic Model ↔ Population Model

SMMM governs their structural composition.

SBIM governs what crosses the boundary separating them.

Federated Simulation Interaction

In distributed or federated simulations, independent simulation components may
operate under separate execution contexts.

SBIM should preserve sufficient governance over: participant identity,
interaction boundaries, exchanged state, timing, synchronization,
transformation, and interaction dependencies.

Human-to-Simulation Interaction

Human participants may materially influence simulation behavior through:
commands, decisions, manual overrides, classifications, scenario
interventions, control inputs, or observational feedback.

Such interaction should remain visible where material.

Simulation-to-Human Interaction

The simulation may also influence human behavior through: displays, alerts,
recommendations, control interfaces, training feedback, or decision-support
outputs.

SBIM governs the simulation interaction boundary, not the broader governance
of human cognition or decision accountability.

Hardware-in-the-Loop Boundary

Hardware-in-the-loop simulations create a boundary between:

Simulated Domain ↔ Physical Hardware

The boundary may involve: physical signals, sensor emulation, actuator
commands, timing, conversion, communication, and hardware response.

These interactions should remain sufficiently reconstructable to determine
what the simulation and physical component actually exchanged.

Software-in-the-Loop Boundary

Software-in-the-loop environments may connect:

Simulation Environment ↔ Operational
Software Component

The operational software may behave differently from a simplified simulated
component.

The boundary should therefore preserve the identity and configuration of the
interacting software where material.

Live-System Interaction

Some simulations interact with live operational systems.

SBIM requires clear separation between:

Simulated State

and:

Operational State

where the distinction matters.

Simulation-generated actions should not silently enter Operational Reality
merely because a technical connection exists.

Simulation-to-Reality Boundary

The boundary between simulation and actual Operational Reality is especially
significant.

SIMULOS® governs how the simulation interacts with that boundary.

ORA™ governs the actual Operational Reality beyond it.

Conceptually:

Simulation Domain → Governed Simulation
Boundary → Operational Reality

The architectures remain adjacent rather than duplicative.

Boundary Permission

Technical connectivity does not itself establish legitimate interaction.

Where relevant, the simulation should identify whether an interaction is:

Permitted

Conditionally Permitted

Restricted

Prohibited

or:

Undetermined

within the governed simulation configuration.

Boundary Constraint

A Boundary Constraint limits how interaction may occur.

Examples include: permitted data types, maximum signal range, frequency
limits, latency limits, directional restrictions, state restrictions, rate
limits, prohibited commands, or interaction-duration limits.

Boundary Condition

A Boundary Condition establishes the governed conditions under which the
behavior of the model at a simulation boundary is defined.

Boundary conditions may be: fixed, dynamic, stochastic, scenario-dependent,
state-dependent, time-dependent, or externally supplied.

Boundary Condition ≠ Simulation
Parameterization

SBIM governs the existence and interaction role of boundary conditions.

SPHM governs the broader controlled parameterization of the Simulation Model
and Environment.

This separation prevents duplication between the two modules.

Boundary Failure

A Boundary Failure occurs when an intended interaction cannot occur or occurs
outside its governed conditions.

Examples include: lost communication, malformed exchange, interface failure,
timing failure, synchronization failure, unavailable external service, missing
response, incorrect transformation, or prohibited interaction.

Boundary Failure Behavior

Where material, the simulation should define what happens when boundary
interaction fails.

Possible responses include:

Retry

Fallback

Hold State

Substitute Value

Terminate Interaction

Terminate Simulation

or another governed response.

Boundary Substitution

A failed or unavailable boundary interaction may be replaced by another
mechanism.

For example:

Live Weather Feed → Synthetic Weather
Generator

Such substitution may materially change the simulation context.

It should therefore remain visible.

Interaction Interruption

Temporary interruption should be distinguishable from permanent boundary
failure where the difference affects simulation behavior.

Boundary Change

A boundary may change through: interface replacement, interaction-object
change, protocol change, timing change, transformation change, permission
change, connected-domain change, synchronization change, or interaction-rule
change.

Material boundary changes should remain identifiable.

Boundary Drift

Boundary Drift occurs where actual interaction behavior progressively differs
from the governed boundary definition without an equivalent governed change.

Examples include: undocumented API changes, increasing latency, new message
fields, changed transformation logic, changed external service behavior,
altered synchronization, or unintended new interaction channels.

No Hidden Boundary Principle

A material interaction boundary must not remain outside simulation governance
merely because the exchange is technically automatic, externally managed,
embedded, inherited, or assumed to be stable.

No Hidden Interaction Principle

A material influence crossing a Simulation Boundary must not affect simulation
behavior without remaining identifiable as part of the governed interaction
structure.

No Boundary Bypass Principle

A governed Simulation Boundary must not be bypassed through an alternative
interaction path that escapes the controls, conditions, or traceability
established for that boundary.

No Simulation-Reality Leakage Principle

Simulation-generated state, commands, or actions must not silently become
operational actions merely because the simulation is technically connected to
a live environment.

Boundary Equivalence

Two boundary configurations should not be treated as equivalent merely because
they connect the same domains.

Material differences may include: protocol, latency, transformation,
direction, frequency, synchronization, permission, or failure behavior.

Boundary Interaction Completeness

Boundary Interaction Completeness asks:

Have all material interaction pathways capable of influencing the governed
simulation inquiry been identified?

A technically undocumented pathway may still be governance-relevant.

Boundary Interaction Consistency

Boundary Interaction Consistency asks whether the defined interactions remain
compatible with: Model Structure, Environment Configuration, Simulation
Purpose & Scope, Reality Representation, and Simulation Assumptions.

Boundary Interaction Coherence

An interaction may be technically valid while still being incoherent with the
simulation design.

For example, correct data delivered at the wrong simulation time may create
behavior inconsistent with the intended environment.

SBIM therefore distinguishes:

Technical Connectivity

from:

Governed Interaction Coherence.

Boundary Interaction Change Propagation

A material boundary change may propagate into later SIMULOS® governance
spaces.

Conceptually:

Boundary Change

↓

Parameter / Input Effect

↓

Scenario Effect

↓

Execution Effect

↓

Output Effect

↓

Reality-Correlation Effect

SBIM identifies and preserves the boundary change.

Affected downstream spaces govern their respective consequences.

Interaction Binding

Material boundary interactions should be bindable to the applicable:
Simulation Model version, Simulation Environment configuration, boundary
configuration, and simulation execution.

Conceptually:

Simulation Execution → Model Version + Environment Configuration + Boundary
Interaction Configuration Boundary Interaction Reconstruction

SBIM should enable reconstruction sufficient to answer:

Which boundaries existed?

Which domains did they connect?

What crossed each boundary?

In which direction?

Through which interface?

Under which conditions?

Which transformations occurred?

Which timing and synchronization rules applied?

Did any boundary fail, change, or become substituted?

Boundary Interaction Traceability

A complete traceability path may be represented as:

Simulation Model

↓

Simulation Environment

↓

Simulation Boundary

↓

Interaction Point

↓

Interaction Object

↓

Direction

↓

Transformation / Mediation

↓

Boundary Conditions

↓

Interaction Event

↓

Simulation Execution

Minimum Implementation Framework

1. Identify Material Simulation Boundaries

Determine where the Simulation Model interacts with the environment, other
models, humans, hardware, services, or external systems. 2. Define Boundary
Interaction Points

Identify the mechanisms through which material interaction occurs. 3. Classify
Boundary Exchanges

Determine what crosses each boundary and its simulation role. 4. Establish
Direction and Conditions

Define interaction direction, timing, triggers, constraints, and applicable
conditions. 5. Govern Transformation and Mediation

Preserve material transformations and intermediary mechanisms. 6. Establish
Synchronization

Define timing and state synchronization where interaction depends upon
coordinated execution. 7. Establish Boundary Failure Behavior

Determine how interruption, failure, substitution, and unavailable
interactions are handled. 8. Bind Boundaries to Model and Environment
Configuration

Ensure the interaction configuration corresponds to the governed model and
environment. 9. Control Material Boundary Change

Preserve changes capable of affecting simulation behavior. 10. Preserve
Interaction Reconstruction

Maintain sufficient traceability to reconstruct material boundary interactions
associated with simulation execution.

Governance Outputs

SBIM may produce: Simulation Boundary Register, Simulation Boundary
Identifier, Boundary Type Record, Boundary Interaction Map, Interaction Point
Register, Boundary Interface Record, Interaction Object Record, Interaction
Classification Record, Interaction Direction Record, Interaction Condition
Record, Boundary Interaction Rule, Interaction Timing Record, Interaction
Sequence Record, Interaction Frequency Record, Boundary Synchronization
Record, Interaction Transformation Record, Transformation Traceability Record,
Interaction Mediation Record, External Service Interaction Record,
Model-to-Model Interaction Record, Human-Simulation Interaction Record,
Hardware-in-the-Loop Boundary Record, Software-in-the-Loop Boundary Record,
Live-System Interaction Record, Boundary Permission Record, Boundary
Constraint Record, Boundary Condition Record, Boundary Failure Record,
Boundary Substitution Record, Boundary Change Record, Boundary Drift Record,
Boundary Interaction Completeness Assessment, Boundary Interaction Consistency
Assessment, Boundary Interaction Coherence Assessment, Boundary Interaction
Configuration, Boundary Interaction Reconstruction Record, and Simulation
Boundary Interaction Traceability Map.

Use Case 1 — Autonomous Vehicle
Hardware-in-the-Loop Simulation

Scenario

An autonomous driving simulation connects a virtual road environment to a
physical vehicle controller.

The boundary carries:

Virtual Sensor Signals → Physical
Controller

and:

Controller Commands → Virtual Vehicle
Model Application

SBIM governs: signal direction, timing, conversion, synchronization, interface
conditions, and failure behavior.

A 100 ms additional interface delay cannot remain invisible if it materially
changes controller behavior. Result

The simulation execution can later demonstrate exactly how the virtual
environment and physical controller interacted. Use Case 2 — Multi-Model Space
Mission Simulation

Scenario

A mission simulation couples:

Orbital Model ↔ Guidance Model ↔ Communication Model ↔ Ground-System Model
Application

SBIM establishes the boundaries between the models and governs: exchanged
states, message direction, timing, synchronization, transformations, and
failure behavior.

Result

If the communication model becomes unavailable during a simulation run, the
resulting substitution or interruption remains visible rather than becoming an
unexplained change in mission behavior. Use Case 3 — Digital Twin Connected to
Operational Reality

Scenario

A digital twin receives live sensor data from an industrial facility and may
generate recommendations for operators. Application

SBIM separates:

Operational Sensor Data → Simulation

from:

Simulation Recommendation → Human Operator

and prevents the latter from being treated as direct operational control
unless such interaction is explicitly governed. Result

The simulation-to-reality boundary remains explicit, preserving the
distinction between simulated state, operational state, and any permitted
interaction between them.

Architectural Position

Simulation Boundary Interaction is the third internal governance space of the
Simulation Model & Environment Standard (SMES).

The complete SMES progression is:

Simulation Model Structure → Simulation Environment Configuration → Simulation
Boundary Interaction → Simulation Parameterization → Simulation Environment
Versioning

SBIM receives the governed model structure from SMMM and the governed
environment configuration from SECM.

It establishes the interaction layer required before the model and environment
can be parameterized as a controlled simulation configuration.

Within the broader SIMULOS® lifecycle:

Simulation Object → Simulation Purpose & Scope → Reality Representation →
Simulation Assumptions → Simulation Model & Environment → downstream
simulation governance

SBIM therefore governs the interfaces through which otherwise separately
governed simulation domains become behaviorally connected.

Foundational Principle

A simulation boundary is governable only when the material interactions
crossing it can be identified, bounded, controlled, and reconstructed.

Canonical Closing Statement

Simulation Boundary Interaction Module establishes the interaction-boundary
governance layer of the Simulation Model & Environment Standard by defining
how Simulation Models, Simulation Environments, external systems, physical
components, humans, services, and other models may exchange material
information, state, signals, events, actions, resources, and influence.
Through boundary identification, interaction classification, direction,
timing, synchronization, transformation, mediation, permission, constraints,
failure behavior, substitution, change control, execution binding, and
reconstruction, SBIM ensures that simulation behavior cannot be materially
shaped by invisible or uncontrolled exchanges across the boundaries separating
the governed components of the simulation.

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