Raycast Interactions

The HoloMIT SDK’s raycast interaction module allows users to point and select objects at a distance using a visual ray and pointer. It provides hover events and fires actions with ButtonX, based on tag-filtered raycasts.

---

Overview

• Draws a ray from the controller to visualize potential interactable targets.
• Detects hover enter/exit based on the selectableTag and fires HoverEnterEvent/HoverExitEvent.
• Fires a selection event when ButtonX is pressed on a hit collider with a NetworkTrigger.

---

Requirements

• Unity 2022.3 LTS or later
• New Input System (for reading LeftTrigger, LeftGrip, ButtonX)
• XR Interaction Toolkit (for controller tracking)
• HoloMIT Core & EventManager (for NetworkTrigger and hover events)
• InteractionRaycast prefab placed under your player rig
• Project tags defined:
  • Selectable for objects that can be pointed at
  • ObjectDragger for draggable objects (if used)

---

Setup

1. Place InteractionController
   • Add the InteractionRaycast component to your player.
2. Configure the Component
   • On the InteractionController component, assign:
     • lineSelectableMat / lineNotSelectableMat for valid/invalid targets
     • References to LineRenderer and targetMarker for visuals
     • leftHand and rightHand transforms (if not auto-detected)
     • selectableTag (default: “Selectable”) and dragTag (default: “ObjectDragger”)
     • maxDistance and raycastLayers to define range and layers
3. Enable Input Actions
   • InteractionController uses the HoloMITControls asset for trigger and ButtonX bindings.
4. Test Tags and Layers
   • Tag your interactable GameObjects accordingly
   • Verify that the ray and marker appear when pointing

---

Exposed Parameters

Property	Type	Description
lineSelectableMat	Material	Material when the ray hits a selectable object.
lineNotSelectableMat	Material	Material when the ray does not hit a selectable object.
lineRenderer	LineRenderer	Component that draws the ray.
targetMarker	GameObject	Visual indicator at the hit point.
leftHand	Transform	Origin transform for left-hand raycasts.
rightHand	Transform	Optional origin for right-hand raycasts.
selectableTag	string	Tag for hover/select detection (default: Selectable).
dragTag	string	Tag for draggable objects (default: ObjectDragger).
maxDistance	float	Maximum raycast distance (default: 20).
raycastLayers	LayerMask	Layers considered for raycast collisions.

---

Usage

• Activate Ray: Hold the left trigger (while not gripping) to enable the ray and marker.
• Hover: Move the ray over objects tagged Selectable; hover events fire automatically.
• Select: Press ButtonX while pointing at a valid object; its NetworkTrigger will fire.
• Cleanup: Release the trigger to hide the ray and marker.

---

Known Limitations

• Configured only for the left hand by default; extend to both hands if needed.
• No smoothing transitions; the ray appears/disappears instantly.
• Relies on Unity physics and tags; ensure accurate collider and tag setup.
• Does not support drag operations out of the box; additional logic required.

---