# Object-detection consumer

`ObjectDetectionConsumer` subscribes to the AR 51 object-detection stream and spawns/updates Unity GameObjects for detected **markers** (simple 3-DoF points) and **6-DoF objects**. It's a singleton component — access it via `ObjectDetectionConsumer.Instance`. Positions are Unity world-space, in meters.

## Setup

Add an `ObjectDetectionConsumer` to your scene and configure it in the Inspector:

- **`Prefabs`** — pool for 6-DoF objects, matched by name to the server object's `Name`.
- **`MarkerItems`** — per-marker-type prefab overrides (`MarkerType` → `Prefab`).
- **Visibility:** `ShowMarkers`, `ShowObjects`, `ShowSkeletonMarkers`, `ShowMarkerItems`.
- **Sizing:** `MarkerSize` (global multiplier), `SkeletonMarkerSize`, `BasketballRadius`.
- **Smoothing (optional):** `EnabledFiltering` (Kalman) with `ProcessNoise` / `MeasurementNoise`, plus `SmoothPositionalFactor`, `SmoothPositionalThreshold` (meters), `SmoothRotationFactor`, `SmoothRotationAngleThreshold` (degrees).

## Reading detections

Subscribe to each frame, or read the current set any time:

```csharp
using AR51.Unity.SDK;

var consumer = ObjectDetectionConsumer.Instance;

consumer.OnObjectDetectionReceived += (s, reply) => {
    // fires once per detection frame, before GameObjects are updated
};

foreach (var inst in consumer.TrackedObjects)      // 6-DoF objects (also: TrackedMarkers, TrackedInstances)
{
    string id   = inst.Id;            // server object id
    Vector3 pos = inst.Position;      // world space, meters
    Color color = inst.Color;
}
```

`TrackedInstance` (a component on each spawned GameObject) is the per-object data model:

| Member | Meaning |
|---|---|
| `Id` | server marker/object id |
| `Type` | `InstanceType.Marker` or `.Object` |
| `ColorName` / `Color` | server type/color label, and resolved Unity color |
| `Position` | current world position (meters) |
| `Radius` | marker radius ⚠️ (units appear to be meters / a scale × `MarkerSize`) |
| `CaptureTime` | server capture timestamp (seconds) |
| `IsSkeletonMarker` | true for skeleton-joint markers |

## Registering a trackable object

Define a new rigid object from a set of marker instances (their color types + positions, recentered to their average):

```csharp
consumer.AddTrackedObject("my-prop", markerInstances);  // TrackedInstance[]
consumer.RemoveTrackedObject("my-prop");
consumer.ResetModels();   // destroy all spawned markers/objects and clear tracking
```

(For the operator-side, point-and-click workflow, see [Mocap Studio → Registering tracked objects](/docs/mocap-studio/tracked-objects).)

## Generic object transforms

For objects whose pose is streamed directly (position/rotation/scale) rather than detected from markers, `ObjectTransformConsumer` maintains matching prefab GameObjects — feed it `ObjectTransform` records (`Id`, `Type`, `Position`, `Rotation`, `Scale`). XR headset poses arrive this way as type `"XR"`.

## Next

- [Unity API reference → Object detection](/docs/sdk-api/unity-api)
- [Connecting](/docs/unity-sdk/connecting)