Common components and terminology in Unity AR

In this article, I will go over some of the common components and terminology you will come across when developing in Unitys’ AR environment.

When you set up your environment of AR development (in my example I set up ARcore for Android) you will have 4 game objects in the scene, each of which may have several components attached.

· AR Session Origin: this component is the parent object for the AR setup. It contains a camera and any game objects created from detected features such as planes and point clouds, which are placed inside an object called “Trackables”.

· AR Plane Manager: this component can create, update and remove game objects in response to detected surfaces.

· AR Anchor Manager: this component tracks and manages all the current anchors in the scene

· AR Raycast Manager: this component is used to raycast against trackables when they do not have a presence in the Physics world

· Anchor Creator: this component allows the creator of anchors with prefabs attached to be able to identify where the anchors are created

· AR Session: this component controls the life cycle and configuration options for the AR Session. Enabling or disabling this component will start and stop the AR session.

Common Terms

Session space: The space relative to the AR devices’ starting location. A device may report its position as 0,0,0 when the AR session begins. All other objects are then placed relative to this position.

AR Plane/Plane: A flat surface detected by an AR device.

Pose: a position and rotation in 3D space

Anchor: a pose in the world which are periodically updated as an AR device's understanding of the world changes, these can be used to make objects stay in the same position and orientation in the space, object without anchors may appear to drift away from where they are originally placed

Trackable: a feature in the physical environment that a device is able to track, such as a surface

That’s all for now.