# API reference — Unity SDK

The public runtime API of the **`AR51.Unity.SDK`** assembly (Unity C#), described from the caller's side — what you call and what you receive. Internal/transport (gRPC) types are named but not detailed.

:::tip[Looking for a specific type?]
The **[Class index](/docs/sdk-api/unity-api/classes)** lists every public type with its own reference page. The sections below are topic groupings.
:::

- **Namespace:** `AR51.Unity.SDK` (plus `.Playback`, `.Recorder`, `.Utilities`, `.Tracker`).
- **Units:** positions are Unity world-space `Vector3` in **meters**; rotations are `Quaternion`; angles in **degrees**. Parameters in meters are usually named `…InMeters`.

:::note[Version]
The shipping SDK version isn't embedded in the source — confirm it from the release tag.
:::

:::note[Unverified items]
Entries marked **⚠️** are inferred from source and should be confirmed before relying on them.
:::

## Sections

| Section | Covers |
|---|---|
| [Connection & services](/docs/sdk-api/unity-api/connection) | `ServiceManager`, `ServiceNames`, camera/render/hand/game services, `CameraFeedClient` |
| [Skeletons & characters](/docs/sdk-api/unity-api/skeletons-and-characters) | `Skeleton`, `Joints`, `Person`, `SkeletonConsumer`, `AR51Character` |
| [Object detection & transforms](/docs/sdk-api/unity-api/object-detection) | `ObjectDetectionConsumer`, `TrackedInstance`, `ObjectTransformConsumer` |
| [Hands, controllers & boundary](/docs/sdk-api/unity-api/hands-controllers-boundary) | adapter interfaces + `HandJointInfo` / `ControllerInfo` data models |
| [Recording, anchors & utilities](/docs/sdk-api/unity-api/recording-utilities) | recording/playback, spatial-anchor components, clocks, helpers |

New to the SDK? Start with the [Connecting guide](/docs/unity-sdk/connecting) for the workflow, then use this reference for the details.