Vehicle interiors and instruments

Each vehicle owns its cabin in its main GLB. Windows, seats, panels, instruments and controls are model geometry, visible from outside and from the seated camera. Boarding moves the camera to the model's authored pilotEye or driverEye; it does not substitute a cockpit mesh. Authors can build a warbird, helicopter or airliner flight deck without changing the renderer.

Platform: simulation data to model geometry

The shared primitive is model signals, not a built-in cockpit. Add model.signals beside renderable on any entity: a vehicle, a machine with a pressure gauge, or a building with a lift. The normal client automatically reads the entity's components after snapshots/deltas and poses the named GLB nodes. No vehicle-specific renderer or per-frame browser script is required.

{
  "renderable": { "kind": "gltf", "ref": "my.airliner" },
  "model.signals": {
    "sources": {
      "engine2rpm": { "component": "avionics", "path": ["engines", 1, "rpm"] },
      "airspeed": { "component": "aircraftState", "path": ["airspeed"] }
    },
    "bindings": [
      { "node": "engine-two-pointer", "source": "engine2rpm", "property": "rotation", "axis": "z", "scale": 0.0015, "offset": -2.3 },
      { "node": "speed-tape", "source": "airspeed", "property": "position", "axis": "y", "scale": 0.001, "max": 0.4 }
    ]
  }
}

Sources use explicit path segments, not JavaScript expressions or dot-split strings. Reads stay on the same entity; numbers are passed through, booleans become 0/1, and missing/nonfinite values are ignored. Declare custom components such as avionics in the scene or type registry; deterministic entity scripts can publish calculated RPM, sensor values, or switch positions to them. Unit conversions and instrument calibration belong in the asset's bindings, or in a simulation script for nonlinear/computed readings. Render bindings never write back to physics.

Bindings receive the latest values even if the GLB finishes loading later. Replacing/removing bindings restores their authored transforms. Signal-driven models stay out of static mesh batching. Signals take precedence over animation clips on the channels they own; avoid assigning the same channel to multiple systems. Other clip channels keep animating normally.

Custom hosts can use createModelSignalVisual(model, spec) and readModelSignals(sources, readComponent) from @bendyline/molen-client. update(signals) accepts arbitrary named numeric telemetry, reset() restores the authored pose, and missingNodes diagnoses unresolved names. This is a transform-binding foundation for analog gauges, tapes, levers and moving parts; text readouts, emissive annunciators and render-to-texture avionics screens are not implemented.

Source ownership

Vehicle bundles contain models/source.glb, entity.types.json and scripts/interactions.ts. Aircraft also have models/interior.json (gauge positions, labels, sizes, panel, seats, switches and horizon placement) and models/interior.mjs (their local cockpit builder). models/generate.mjs includes that cockpit in the main GLB. Each aircraft can change its layout and builder independently. All of these files are inventoried by source.json.

The five road vehicles have editable GLB interiors. Their current basic dashboard/chassis geometry is merged into body, with a separate steering wheel. Edit these meshes in a DCC to add cabin detail. There is no universal dashboard fabricated by the runtime.

Aircraft generators accept --out /path/to/candidate.glb for reviewing changes without overwriting the master or baseline. Import an approved master with molen asset import, update the source manifest hash, and run the entity package's generate command for aggregate types.

Model-specific bindings

aircraft.spec.visual.interior and vehicle.visual.interior share this shape:

{
  "nodes": ["flight-deck"],
  "bindings": [
    {
      "node": "left-speed-pointer",
      "source": "airspeed",
      "property": "rotation",
      "axis": "z",
      "scale": 0.023,
      "offset": -2.3,
      "min": -2.3,
      "max": 2.3
    }
  ]
}

Bindings add clamp(signal * scale + offset, min, max) to a node's authored local transform. rotation uses radians; position uses meters (useful for tapes and levers). Limits are optional. Repeated updates do not accumulate movement. Missing/nonfinite signals leave channels unchanged. Duplicate names animate together, but GLTFLoader can suffix duplicate GLB names with _1; bind the loaded names explicitly. Two bindings cannot write the same node/property/axis. nodes identifies cabin geometry and never changes its visibility.

Aircraft signals are airspeed (m/s), altitude/altitudeAGL (m), verticalSpeed (m/s), heading/pitch/roll (radians), rpm/power (0–1), pitchInput/rollInput/yawInput (-1–1), and gear/flaps/engine (0 or 1). Calibration belongs to each model. Cars supply steering and wheelAngle (radians); their optional third update argument accepts additional signals. World explorer passes speed (signed m/s), heading/pitch/roll (radians), throttle (-1–1) and brake (0 or 1).

An interior can also include sources, using the same component/path mappings as model.signals. World explorer resolves these for each vehicle and merges them over the convenience signals, so an asset can bind a gauge to script-owned state or to an individual engine. Other custom hosts pass resolved readings as the aircraft visual's optional fourth update argument or the car visual's third argument. Choose the interior adapter or the automatic model.signals component for a given model; do not let two adapters own the same transform channel.

The createVehicleInteriorVisual(model, spec) wrapper around model signals is exported from @bendyline/molen-client/vehicles. Its update(signals) also accepts custom telemetry names, such as individual engine readings. Its missingNodes reports unresolved bindings; aircraft and vehicle visuals expose it as visual.interior. There is no prescribed instrument count, node naming scheme or panel layout. This animates model transforms; full avionics/display rendering is a separate system. Entity scripts can manage simulation state and interactions.

Legacy explicit controlStick, collective and steeringWheelNode bindings work without interior. New models should use interior.bindings. The implicit needle-*/attitude-ball convention is removed: assets must list instruments explicitly. airspeedGaugeMax remains legacy metadata and no longer drives a gauge.

Exterior views and detail levels

Cockpit and chase views share the GLB. An interior can be a high-detail portion of that model, but is not inherently a separate LOD: an exterior camera looking through a window needs it too. World explorer promotes up to eight nearby dormant cars to their GLBs within 14 meters, retaining detail to 20 meters to avoid repeated swaps. Distant parking proxies remain instanced. Boarding retains that same GLB for the session. Aircraft already keep their full GLBs resident.