Not all systems solve the same problem. Classification is based on structure, not appearance.
Once simulation is defined and measured, it can be classified. Classification determines whether a system supports valid training or introduces deviation.
Simulation is not neutral. Systems that appear similar can produce fundamentally different outcomes. Classification separates systems that preserve correct timing and motion from those that do not.
Structure determines outcome.
Motion is driven directly by vehicle physics at the center of mass with independent degrees of freedom.
Motion is applied after the physics layer and is not directly driven by vehicle state at the center of mass.
Systems with minimal or no motion fidelity, relying primarily on visuals and controls.
| System Type | Architecture | Classification | Training Validity |
|---|---|---|---|
| True CoM Independent DOF System | Physics-driven, CoM aligned, independent axes | In-the-Loop | Valid |
| Stewart Platform / Hexapod | Mechanically coupled, inverse kinematics, platform-based | Out-of-the-Loop | Limited |
| Seat Mover | Localized motion, no CoM alignment | Out-of-the-Loop | Limited |
| Four-Post / D-BOX Type | Vertical displacement, no rotational fidelity | Out-of-the-Loop | Limited |
| Static Simulator | No motion system | Surface-Level | Invalid |
| Criterion | In-the-Loop | Surface-Level / Out-of-the-Loop |
|---|---|---|
| Motion Origin | Driven directly by vehicle physics state | Applied as effect; not derived from state |
| Center-of-Mass Alignment | Motion resolved at the vehicle's true center of mass | Rotation occurs at incorrect point; not CoM-referenced |
| Degrees of Freedom | Independent axes; each resolves separately and correctly | Coupled or blended; axes cannot be independently isolated |
| Yaw Fidelity | Present, continuous, and correctly timed | Absent, delayed, or approximated |
| Vestibular Validity | Physical cues match vehicle event timing | Cues absent, approximated, or delayed |
| Training Outcome | Correct timing and response patterns trained | Delayed, visual-dependent, or incorrect patterns trained |
Classification is based on structural criteria, not marketing claims.
If these conditions are not met, the system cannot be considered in-the-loop.
Many systems appear realistic due to large visuals, physical movement, or force feedback. These features can mask structural limitations.
Creates perceived realism without structural validity.
Creates perceived intensity without correctness.
Creates perceived effort without verified fidelity.
Perception is not proof of correctness.
SFR provides the measurement framework. Classification applies that framework to category definitions and system types. The scoring logic, measurement layers, and formula are owned by the SFR metrics page.
A system's SFR profile determines which structural category it occupies. Classification does not produce scores. It interprets them.
Once a system is classified, its impact on training, performance, and neurological response becomes predictable.
Incorrect classification leads to incorrect expectations.
See Consequences of Incorrect SimulationA simulation system must be classified by its structure, not by its appearance or marketing.
If the structure is wrong, the outcome is wrong.
View structured interpretations of common system types and architectural categories.
Apply the framework to a real system, environment, or use case through a structured review pathway.
For teams, facilities, researchers, and organizations seeking structured classification or review.