API reference — C# API (AR51.Net)

The public API of the AR51.Net .NET library, described from the caller's side: what you call and what you receive. New to AR51.Net? Start with the overview and the quickstart.

Package	NuGet AR51.Net
Version	3.0.302 (3.0.3.2R) — numbered the same as the AR 51 Unity SDK
Namespace	AR51.Net (the only one)
Targets	.NET 8 and .NET 10
Dependencies	Google.Protobuf, Grpc.Net.Client, Microsoft.Extensions.Logging.Abstractions — all managed, no native libraries
Entry point	AR51Client.Create → IAR51Client

Looking for a specific type?

The Class index lists all 52 public types. The table below groups the main ones by area.

Areas

Area	Main types	Covers
Connecting	AR51Client, AR51ClientOptions, IAR51Client, AR51Exception	The entry point. Create one IAR51Client with AR51Client.Create, subscribe to what you need, then call StartAsync.
Skeletons	ISkeletonClient, SkeletonClient, Skeleton, HandPose	Live skeletons of the tracked people: 25 body joints with confidence, hands from hand-tracking headsets, identity and timing.
Object detection	IObjectDetectionClient, ObjectDetectionClient, TrackedObject	Live tracked objects (for example props) with position and rotation. Works exactly like the skeleton client.
Servers	IServerClient	The AR 51 server machines: status, launching and quitting the server program, starting and stopping tracking.
Cameras	ICameraClient, CameraInfo, CameraSettings	Camera list with calibration values, live JPEG preview, image settings and auto-tune.
Calibration	ICalibrationClient, CaptureBounds	Camera calibration and the tracked area (capture bounds).
Recording	IRecordingClient	Recording tracking data and camera video on the servers.
Devices	IDeviceClient	The apps and devices connected to the system: headsets, apps, phones and Mocap Studio.

Conventions at a glance

• Units and axes: meters; left-handed X right, Y up, Z forward (the same axes as Unity). Rotations are System.Numerics.Quaternion.
• Time: CaptureTime is the server's clock in UTC; ReceivedTime is your local clock.
• Threading: every member is safe to call from any thread. SkeletonReceived and ObjectReceived run on the stream's background thread — keep them short. All other events are raised one at a time, in order, on one background thread per client.
• Errors: failed calls throw AR51Exception with an AR51ErrorCode. Cancellation throws OperationCanceledException; use after dispose throws ObjectDisposedException.

Details: Data conventions, threading and errors.

Scope

This reference documents the public contract only. Internal implementation and wire-level types are not published.