Grab Interactions in Unity

Overview

Objects in Unity projects are able to be interacted with in multiple ways by the user, depending on how the objects are implements. A functionality that gives users a more immersive experience and a direct way to interact with the objects in a scene is to make objects grabbable. The Meta Building Blocks in Unity allow for developers to make an object grabbable with a no/low code approach while still allowing for many customizations. To learn more about Unity Meta Building Blocks, please reference this Wiki page.

Requirements

1. Meta Quest 3

   • Device setup for developing: 

     • https://developers.meta.com/horizon/documentation/native/android/mobile-device-setup/

2. Unity installed

   • Additional set up tutorial: Set up Unity for XR development

     • https://developers.meta.com/horizon/documentation/unity/unity-project-setup

3. Meta XR All-in-One SDK installed

   • Add as an asset to your Unity account

   • Once in Unity, navigate to Package Manager and install All-in-One SDK

Steps to make an object grabbable

1. Add an asset into your scene, you can drag and drop the asset into your scene

2. Right click on the asset within the scene list

3. Go to Interaction SDK, then select Add Grab Interaction

4. The Grab Wizard will pop up, set any customizations you would like

   1. Under Add Required Interactor(s), you can select if you wish to use hands, controllers, or both

   2. Under Supported Grab Types, you can select the type of grab

   3. Make sure a Target Transform and Rigidbody is selected, if one is not selected, you can select Fix next to Required Components

For more helpful information, please reference this tutorial: https://www.youtube.com/watch?v=heqAIbxtonE

Default Controller and Hand Commands

• Controller Commands

  • To move object: Press and hold right or left inside trigger on object, move hands and release buttons at location

  • To scale object: Press and hold right + left inside triggers on object while moving hands together and apart

• Hand Commands

  • To move object: Place hand over object + grab or pinch, move object and release hold

  • To scale object: Grab object with both hands 

References and Resources

• Touch Hand Grab Interactions without Building Blocks

  • https://developers.meta.com/horizon/documentation/unity/unity-isdk-touch-hand-grab-interaction

• Grabbing Objects Tutorial with Building Blocks video

  • https://www.youtube.com/watch?v=heqAIbxtonE