In Interaction SDK, interactors and interactables both have an optional Data property that takes an object you can read from and write to. That object lets you share additional information with an interactor or interactable, like which hand grabbed an object. In this tutorial, you learn how to use Data to store and read data so a controller will vibrate when it grabs an object.

Before you begin

Complete Getting Started with Interaction SDK.

Example use case

Here’s one example of how you could use Data. Suppose you’re making a ping-pong paddle that should vibrate using haptics when it collides with the ball. The haptic code will live in the interactable (not the interactor), so it can have different parameters depending on the paddle material and collision strength. However, there’s one problem, you don’t know which controller should vibrate! To solve that, you can pass an object with information about the active controller to the interactor’s Data field, and then read that on the interactable side to know which controller should vibrate.

Write data to GameObject

In order to use Data, you need a GameObject to store information. To avoid having to set up controllers, you’ll add this GameObject to the existing HandGrabExamples scene. The additions you make to the scene can be easily reverted once you complete the tutorial.

In Unity, in the Project window, search for HandGrabExamples. Ensure the search filter is set to either All or In Packages, since the default setting only searches your assets.

In the search results, click the HandGrabExamples scene to open it.

Under Hierarchy, locate HandGrabInteractor by selecting OVRCameraRig > OVRInteraction > OVRControllerDrivenHands > LeftHand > HandInteractorsLeft > HandGrabInteractor.

Under Inspector, in the Hand Grab Interactor component, set Data to the Hand Ref component. You do this because Hand Ref contains a public variable defining which hand is active, so linking that component to the Data field lets you access that information later.

Repeat these steps for the HandGrabInteractor under RightControllerHand.

Read data from GameObject

Now that Data contains Hand Ref, the grabbable object can read Data to find out which controller is active and cause that controller to vibrate.

In the Hierarchy, expand Interactables so you can see its children.

Create a copy of the SimpleGrab0NoPose GameObject (the blue cube).

Rename it to CopyCube so you don’t confuse the new cube with the original.

Using the Transform gizmos, reposition CopyCube so it’s separate from the original cube.

Under Project, open the Assets > Scripts folder.

In the Scripts folder, right-click and click Create > C# Script to create a new script. Name the script as ReadData.

Open the ReadData script in your code editor.

Replace the script’s existing code with this code, which will cause whichever controller you grab with to vibrate.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using Oculus.Interaction;
 using Oculus.Interaction.Input;

 public class ReadData : MonoBehaviour
 {
     OVRInput.Controller leftController = OVRInput.Controller.LTouch;
     OVRInput.Controller rightController = OVRInput.Controller.RTouch;

     private void StartHaptics(Handedness handedness) {
         if (handedness == Handedness.Left && OVRInput.IsControllerConnected(leftController)) {
             OVRInput.SetControllerVibration(0.9f, 0.5f, leftController);
         }
         if (handedness == Handedness.Right && OVRInput.IsControllerConnected(rightController)) {
             OVRInput.SetControllerVibration(0.9f, 0.5f, rightController);
         }
     }

     public void HandlePointerEvent(PointerEvent pointerEvent) {
         HandRef handData = (HandRef)pointerEvent.Data;
         Handedness handedness = handData.Handedness;
         StartHaptics(handedness);
     }
 }

Under Hierarchy, select CopyCube > HandGrabInteractable. This is the object that will read Data.

Under Inspector, add the ReadData script to HandGrabInteractable.

Under Hierarchy, select CopyCube and then, in the Inspector, select the Pointable Unity Event Wrapper component.

In the Pointable Unity Event Wrapper component, in the When Select section, add ReadData’s HandlePointerEvent function.

Prepare to launch your scene by going to File > Build Settings and clicking the Add Open Scenes button.

Your scene is now ready to build.

Select File > Build And Run.

When the scene loads, grab the cube using one or both of your controllers. When you grab the cube, the controller that grabbed it will vibrate, and the hand visual will shake slightly.