Interactivity Tools Guide

Getting Started

Interactive Behaviors You Can Add

Object Spawner

Prefab Instantiation

The Object Spawner places a prefab instance at the spawner's scene position when triggered. Assign your prefab in the Inspector and connect an Enter Trigger or interaction event to activate it.

Networked vs Local Spawning

• Local spawn: Instantiates a standard GameObject visible only to the triggering client. Use for visual effects and non-shared props.
• Networked spawn: Sends an RPC to the host, which calls runner.Spawn() so the object appears for all connected players. Requires the prefab to have a NetworkObject component.

Grabbable Objects

Distance-Based Interaction

Grabbable objects support both touch-based grabbing and distance-based grabbing using camera direction. The system automatically detects U3D players and handles hand attachment when the interact button is pressed (R key by default).

Setup Options

• Grab Detection Radius: Use radius-based detection or precise raycast
• Distance Configuration: Set minimum and maximum grab distances
• Offset: Adjust where grabbed object appears relative to hand bone
• Hand Attachment: Specify hand bone name or use player position
• Multi-Grab: Allow multiple objects to be held simultaneously

Safety Features

Grabbable objects include automatic safety recovery. If an object falls through the world or moves too far from spawn, it automatically returns to its original position.

Throwable Objects

Composing with Grabbable

Throwable is designed to compose with Grabbable, not replace it. Applying "Make Throwable" from the dashboard adds both U3DGrabbable and U3DThrowable to the object — Grabbable handles pickup and hold, Throwable handles release physics. Both components remain active on the same object and work together. You can configure each independently in the Inspector.

Physics-Based Throwing

When released, throwable objects launch in the camera direction with configurable force and automatic physics management.

Smart Physics Management

• Auto-Sleep: Objects automatically sleep when velocity drops below threshold
• World Bounds Safety: Automatic recovery if objects go out of bounds
• Grab-Throw Cycling: Seamless transition between grabbed and thrown states
• Impact Detection: Events fire when thrown objects hit surfaces
• Auto Key Remapping: Throw key automatically remaps to avoid conflicts with grabbable and kickable components on the same object

Inspector Fields

• Drop On Release: When enabled, releasing the grab key drops the object straight down instead of throwing it. Use this for objects that should be placed rather than launched — crates you stack, puzzle pieces you set down, and similar.

Kickable Objects

Ground-Level Physics Interaction

Kickable objects use ground-level proximity detection so players can kick objects at their feet. The kick direction follows the camera forward vector with a configurable upward boost, creating natural arcing trajectories.

Setup Options

• Kick Force: Base force multiplier applied on kick
• Upward Boost: Additional upward force for arcing trajectories
• Max Kick Velocity: Velocity cap to prevent objects flying out of bounds
• Detection Radius: Ground-level radius for foot collision detection
• Max Kick Distance: Maximum distance the player can be from the object to kick it

Smart Physics Management

• Auto-Sleep: Objects automatically return to sleep state when velocity drops below threshold or after a configurable timeout
• World Bounds Safety: Automatic position recovery if objects fall through the floor or travel too far from origin
• Grabbable Compatibility: Can coexist with U3DGrabbable on the same object. Interaction keys are automatically remapped to prevent conflicts
• Impact Detection: Events fire when kicked objects collide with surfaces

Events

• OnKicked: Fires when object is successfully kicked
• OnImpact: Fires when kicked object hits something
• OnSleep: Fires when object returns to sleep after kick
• OnEnterKickRange / OnExitKickRange: Fires when player enters or leaves kick proximity
• OnKickFailed: Fires when a kick attempt fails
• OnWorldBoundsReset: Fires when object is reset due to world bounds violation

Climbable Surfaces

Layer-Based Surface Detection

The climbing system uses Unity's layer system to identify climbable surfaces. The player's U3DClimbingController performs a forward sphere-cast to detect walls on the designated Climbable layer, enabling automatic or manual climbing with networked state synchronization.

Setup Options

• Climbable Layer Mask: Assign surfaces to the Climbable layer (default: layer 6)
• Check Distance: How far forward the player checks for climbable surfaces
• Check Radius: Sphere-cast radius for surface detection
• Auto-Climb: When enabled, players climb automatically on contact while moving. When disabled, requires holding the climb key (Left Control by default)

Climbing Physics

• Climb Speed: Horizontal movement speed along the surface
• Climb Up/Down Speed: Separate vertical speed controls for ascending and descending
• Surface Normal Detection: Movement direction calculated relative to the wall surface for natural traversal

Stamina System

• Stamina Pool: Configurable stamina that drains while climbing
• Drain Rate: How fast stamina depletes during active climbing
• Auto-Recovery: Stamina regenerates at half the drain rate when not climbing
• Exhaustion: Players automatically release the wall when stamina reaches zero

Enter/Exit Triggers

Flexible Player Detection

Trigger systems can detect U3D players specifically, objects with specific tags, or any colliding object. Each offers separate UnityEvents for different detection types.

Advanced Trigger Features

• Cooldown Timers: Prevent rapid re-triggering with configurable delays
• One-Time Triggers: Fire only once per session
• Multiple Event Types: Separate events for players, tagged objects, and general objects
• Authority Management: Proper multiplayer state synchronization

Click Trigger

Camera Raycast Interaction

Click Triggers fire when a U3D player clicks while the camera raycast hits the object. The collider on the object defines the clickable area. Detection range is configurable.

Configuration Options

• Required Tag: Optionally restrict activation to players or objects with a specific tag
• Trigger Once: Deactivates after first successful click
• Cooldown Time: Minimum seconds between activations
• Detect U3D Player / Detect Tagged Objects: Separate flags matching the Enter/Exit Trigger pattern
• Max Click Distance: How far the player can be when clicking
• Events: OnClicked, OnClickFailed fire on each attempt

Trigger Zone

Stateful Occupancy Detection

Trigger Zone tracks how many qualifying objects are currently inside it and fires events when that count crosses zero in either direction. Use it when you need to know whether the zone is occupied right now — not just that something entered or left.

Use Enter/Exit Triggers when you want a fire-and-forget event on each entry or exit. Use Trigger Zone when the state of the zone itself matters — a door that should stay open while anyone is standing in it, or a pressure plate that needs all objects removed before it resets.

Inspector Fields

• Require Tag: Only count objects with this tag toward occupancy. Leave blank to count all colliders.
• Trigger Once: When enabled, OnZoneOccupied fires only the first time the zone is occupied. OnZoneCleared still fires normally.

Events

• OnZoneOccupied: Fires when occupancy goes from zero to one — the zone just became occupied.
• OnZoneCleared: Fires when occupancy returns to zero — the zone is now empty.

Scripting

Call ResetZone() on the component at runtime to clear the occupant count and re-arm a one-time trigger. This is useful for puzzle resets where you need the zone to be re-triggerable after a sequence completes.

Example: Pressure Plate Puzzle

A classic use case — a stone slab that activates a gate while a player stands on it and deactivates the gate when they leave.

1. Select the pressure plate mesh and apply Add Trigger Zone from the dashboard.
2. In the Inspector, set Require Tag to Player so only player characters count.
3. Connect OnZoneOccupied → your gate's Animator.SetBool("Open", true) (or equivalent).
4. Connect OnZoneCleared → your gate's Animator.SetBool("Open", false).

The gate opens the moment a player steps on and closes as soon as the last player leaves. No scripting required beyond wiring the UnityEvents.

Make Rideable

How It Works

Make Rideable adds a U3DRideableController to your object. When a player steps onto the rideable surface, they are carried with it automatically. Movement is driven inside Fusion's deterministic tick so all clients stay in sync — the platform moves and the player rides it within the same frame, with no jitter or lag compensation needed.

Platform Setup

1. Select your platform mesh in the scene and apply Make Rideable from the Creator Dashboard Interactions tab, under Movement.
2. A RideableTrigger child and a Waypoint_0 child are created automatically. The trigger detects when players step on and off. The waypoint marks the starting position.
3. To create a moving platform, duplicate Waypoint_0, rename it Waypoint_1, and move it to the destination. Assign both to the Waypoints array on the U3DRideableController component in the Inspector.
4. Set Loop Mode to Loop or PingPong, adjust Speed, and optionally set a Pause At Waypoint duration.

Movement Modes

• Waypoints — moves between Transform markers you place in the scene. Markers should be children of the rideable so they move with it if you reposition it in the editor. Their world-space positions are cached at runtime so they don't chase the platform as it moves.
• Rotation — spins the object continuously around a configurable local axis at a fixed speed. No waypoints needed. Use for ferris wheels, turntables, and revolving doors.
• Static — the object doesn't move on its own. Players can still ride it, and Make Steerable will use this mode to take over movement via player input.

Composing the Full Vehicle System

The three Movement tools are designed to layer on top of each other. Make Rideable is the foundation — it handles passenger carrying and self-movement. Make Steerable will extend it so player input drives the object. Add Seat will add snap points for sit animations on top of either. A car, for example, would use Make Rideable in Static mode, Make Steerable for player-driven movement, and Add Seat for the driver and passenger positions.

Planned Interactive Features

Movement Systems

Swimming volumes will provide modified movement physics with avatar animation and underwater effect triggers for realistic swimming experiences.

Movement Tools

Make Steerable will extend Make Rideable so player movement input drives the object directly — W/S for acceleration, A/D for yaw, with a ground-check toggle for wheeled versus free-moving vehicles. Add Seat will place snap points on any object, static or moving, triggering avatar sit animations that players exit by resuming movement input. Together with Make Rideable, these three tools cover everything from park benches to hot air balloons.

Logic and State Tools

Randomized GameObject activation and mutually exclusive selection groups will enable more sophisticated interactive logic without custom scripting.

Object Management

Object destroy triggers for collectibles and breakable items, object reset triggers for puzzle resets, and player reset triggers for out-of-bounds recovery and death zones will round out the interaction toolkit.

Portals

Scene portals will transition players to a different Unity scene. Within-scene portals come in two flavours: one-way portals that teleport players from a source point to a destination, and two-way linked portals that allow travel in either direction between two points.

Interactive Experience Examples

Understanding Multiplayer Synchronization

How NetworkObject Integration Works

When you enable "NetworkObject for multiplayer" on any interaction tool:

1. Automatic Setup: NetworkObject component is added to your GameObject
2. Authority Management: Photon Fusion 2 handles who controls the object
3. State Sync: Object state (grabbed, kicked, triggered, etc.) syncs across all players
4. Event Broadcasting: UnityEvents fire for all players simultaneously
5. Physics Sync: NetworkObject synchronizes physics state across players

When to Enable Multiplayer Sync

• Shared Objects: Items that multiple players should see and interact with
• Cooperative Elements: Puzzles and challenges requiring coordination
• Competitive Interactions: Challenges, games, and contests requiring comparison
• World State Changes: Triggers that affect the environment for everyone

Single-Player vs Multiplayer Mode

All interaction tools work in both modes:

• Without NetworkObject: Faster performance, local-only interactions
• With NetworkObject: Slightly higher overhead, but shared across all players
• Mixed Approach: Some objects networked, others local-only
• Runtime Detection: Tools automatically adapt based on NetworkObject presence

Advanced Configuration

UnityEvent Integration

Every interaction tool provides multiple UnityEvents that you can connect to:

• Visual Responses: Change materials, sounds, effects, or animations
• Game Mechanics: Update UI, scores, game states
• Custom Logic: Connect to your own scripts and systems

Physics Integration

Interaction tools work seamlessly with Unity's physics system:

• Automatic Colliders: Tools add primitive colliders when required
• Rigidbody Management: Smart activation and deactivation for performance
• Physics Materials: Support for custom bounce, friction, and sound
• Joint Compatibility: Works with Unity's joint system for complex mechanics

Automatic Key Remapping

When multiple interaction components share the same object, interaction keys are automatically remapped to prevent conflicts. For example, if both Grabbable and Kickable use the R key, Grabbable remaps to F. If Throwable and Kickable share a key, Throwable remaps to G. Console messages confirm any remapping at startup.

Safety and Recovery Systems

Built-in safety features protect your experience:

• World Bounds: Objects automatically return if they fall out of world
• Distance Limits: Recovery when objects travel too far from spawn
• Auto-Sleep: Physics objects sleep when not in use to save performance
• Smart Drop: Grabbable objects snap to surfaces when released

🎮 Your interactivity system is operational! Apply behaviors to any object and create engaging multiplayer experiences with Unity 6 and Photon Fusion 2.