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2.3 - Direct and Ray Interactors

In this lesson, you will learn how to implement Direct Interactors and how to switch between interactors on the same controller. By the end of this lesson, the user will be able to grab things directly with their hands, and then toggle a ray to point at things when they need to. 

Rather than using the ray interactors that come by default with the rig, you can set up a “Direct” interactor for one of the controllers.

1.  Remove the Ray Interactor from the right controller:

Remove the three components related to the ray interactor: the XR Interactor Line Visual component, the Line Renderer component, and the XR Ray Interactor component


2.  Enable direct interactions on the right controller:

Add a XR Direct Interactor component to the 

 check box to have the object you pick up replace your hand visual.


3.  Enable detection of the Direct Interactor:

You should now be able to pick up all the grabbable objects in your scene using the hand with the direct interactor.

Add a Direct Interactor to the right controller

Just like you did for the ray interactor, you should add the same haptic and audio feedback for hovering over and selecting objects.

1.  Recall how you set up haptic and audio feedback originally:

 object (which should still have a Ray Interactor component).

In the XR Ray Interactor component, expand the

Note the intensity and duration of your haptic events and the audio clip you selected for your Audio events.


2.  Apply haptic and audio event settings to your new Direct Interactor:

In the XR Direct Interactor component, apply the same haptic and audio event settings to match your other controller.

Your Direct Interactor should now have haptic and audio feedback on hover and select events.

Add haptic and audio feedback to your Direct Interactor

Right now, you can pick up everything with your ray, which doesn’t feel natural. You should only be able to teleport with your ray and pick up objects with your hand directly.

In the top-right corner of the Unity editor, from the Layer dropdown, select 

Add a new “Raycasts” layer in the first available empty slot.


2.  Prevent your ray from interacting with your grabbable objects:

On your controller object’s XR Ray Interactor component, for the 

To do this, you need to first select “Nothing” and then re-select the “Raycasts” layer.

Make sure your grabbable objects do not share the 


3.  Make sure your ray can interact with teleport objects:

For each Teleportation Anchor and Teleportation Area object, in the 


4.  Prevent your hand model from disappearing when you teleport:

In the XR Ray Interactor component, disable the 

Your ray interactor should no longer be able to pick up objects, but should be usable for teleporting.

Prevent ray from picking up objects

In order to be able to pick up objects with both hands, you should have direct interactors on both hands. Then you can just enable the ray when the joystick is moved. To achieve this, you will need to create the Direct and Ray interactors for each hand. 

1.  Make alternative ray controllers for each hand: 

Duplicate the controller with the Ray Interactor 

Renaming these objects “LeftHand Ray” and “RightHand Ray”. 


2.  Control each ray with the correct hand:

 objects, in the XR Controller component, make sure the

 preset is set correctly to Left or Right for each object. 

To edit the preset, in the top-right of the component, click the 

 button and select the appropriate preset for the hand. 


3.  Make the LeftHand Controller behave as a Direct Interactor:

 object, remove the components related to the Ray interactor (the XR Ray Interactor component, the Line Renderer component, the XR Interactor Line Visual component). 

Copy the Direct Interactor and Sphere Collider components from the 

Select the context menu in the top-right of that component and click 

To paste the component on another object, select a context menu of one of the receiving object’s components and click 


4.  Make sure that you only have one hand model for each hand:

 objects, in the XR Controller component, change the 

Each hand should now be able to teleport with their Ray Interactors and grab objects with their Direct Interactors. 

Create a Direct and Ray Interactor for each hand

Now that you have both Direct and Ray Interactors on each hand, you will add the ability to toggle the Ray on and off when a button is pressed.

1.  Add the ability to toggle the left ray:


2.  To be able to detect if a button is pressed:

object, add an On Button Press component.


3.  Specify the button to bind to this action:

In the On Button Press component, in the 

 It is very easy to miss the Action box - look closely).

: Different controllers have different buttons, triggers, and pads on them. If you’re not using an Oculus Quest, you will likely have to choose a different binding path that works with your device. For example, check out the OpenXR controller profiles for the 


4.  Activate the ray when the button is pressed:

 object, since it has the Toggle Ray component.


5.  Deactivate the ray when the button is released:

The ray on the left hand should now only appear while the primary button is touched and disappear when the button is released.

Toggle ray with button press

One controller is working with one button. You can give the player more options of buttons to push depending on their preference, and then apply this functionality to the other hand.

1.  Add an additional binding that detects the thumbstick: 

In the On Button Press component, in the Action box, click the 

 button to add an additional binding to this action.

Follow the same instructions as the previous step to select a binding, but select select 


2.  Add this same ray toggling functionality for your right hand:

Repeat all of the instructions from the previous step, but for your RightHand Controller and RightHand Ray:

and assign the RightHand Controller to the Direct Interactor property.

 and add bindings for the Right Primary Button and Right Thumbstick

The rays on both hands should now only appear while the primary button or thumbstick are touched. 

Add additional binding and repeat for other hand 

Toggle direct interactors on/off with button

Recap

If you want to further develop your skills, explore new concepts, and improve your project, check out some of the optional extension activities below. 

Each one is tagged as [Easy], [Medium], [Difficult], or [Expert] and will also include a [Requires Programming] tag if some coding is required. 

1.  Customize the ray interactor lines [Easy]

Edit the Ray Interactor line colors and transparency colors, including gradients and transparency:

It looks good to make the start of the ray transparent so it doesn’t overlap with your hands.

To customize the colors of the rays, look in the XR Interactor Line Visual components Valid and Invalid color gradient properties

In the Gradient Editor window, use the markers below the color bar to edit the color and the markers above the color bar to edit the transparency (Alpha) value.

2.  Add a functional watering can [Medium]

Add a watering can that generates a water particle when you tilt it:

Use the OnTilt script provided from the Course Library > Scripts > Conditions folder to detect tilting. 

Find a Particle_Water object from the Course Library > Prefabs > Particles folder

Use the ToggleParticle > Play() and Stop() functions to control the particle.

Bonus - Add in pouring sound effect using the PlayContinuousSound script. 

Bonus - Use the OnVelocity script to also add a splashing sound when you shake it - Hint: add a separate audio source for this to not interfere with the pouring sound.

Allow the user to open cabinet doors or chest lids using Unity’s physics hinges:

 and rigidbody to the door, and customize its angular limits

You will need to add an XR Grab Interactable component to the handle and may want to add a 

Make sure your door’s colliders do not overlap any other colliders, which could cause it to get stuck.

Warning: joints are very tricky and can be frustrating. 

Extension Activities

Comp-L2-Prog.VRp: Beginner VR Development

Beginner VR Development

Aaron Sharp

2.3.ext - watering can.mp4

2.3.ext - ray gradients.mp4

2.3.ext - cabinet hinges.mp4

2_3_2_v2.mp4

2_3_1_v2.mp4

2_3_3_v2.mp4

2_3_4_v2.mp4

2_3_5_v2.mp4

2_3_6_v2.mp4

2_3_recap_v1.mp4

By the end of this lesson, you will be able to:

Implement direct interactors on a controller in order to allow a user to pick things directly with their hands.

Understand the need for a variety of interactor types in VR in order to allow the user to interact with the environment in different ways.

Toggle between multiple types of interactors on one controller in order to expand the range of actions a user can do with a single hand (e.g. switch between a ray and direct interactor). 

Games

Film

Automotive

Skill-L2-Prog.VRp-2: Develop a VR app that demonstrates common interactions using Unity's XR interaction toolkit.

Unity Version 2020.3