What is the Interactivity System?
Transform static 3D objects into engaging interactive experiences! U3D Interactivity Tools let you add professional-grade interactive behaviors to any object with a single click, supporting both single-player and real-time multiplayer scenarios.
Automatic Multiplayer Support
One Click
Every interaction tool includes NetworkObject support!
Choose multiplayer sync when applying tools - behaviors automatically work across all connected players
Powered by Photon Fusion 2 with optimized WebGL performance
Getting Started
- Click on any GameObject in your scene
- Can be primitives, imported models, or complex hierarchies
- Object will auto-get required components (colliders, rigidbodies)
- Works with any Unity-compatible 3D content
- Go to Creator Dashboard → Project Tools → Interactions tab
- Pick the behavior that fits your experience
- Toggle NetworkObject for multiplayer if needed
- Click Apply to add the behavior
- Customize settings in the Inspector
- Connect UnityEvents for custom responses
- Test in Play mode immediately
- Multiplayer tools work in local testing
- Deploy to get full multiplayer experience
Interactive Behaviors You Can Add
Make Grabbable
"Pick up from distance, attach to hand position"
Objects can be picked up from adjustable distances using precise raycast or radius detection. Automatically handles hand attachment and collision management.
Perfect for:
- Interactive props and tools
- Collectible items and treasures
- Building blocks and creative materials
- Key objects for puzzle mechanics
Make Throwable
"Physics-based throwing with auto-sleep"
Must be applied to grabbable objects. Handles camera-direction throwing, physics activation, automatic sleep states, and world bounds recovery.
Great for:
- Sports equipment and game pieces
- Interactive projectiles and toys
- Puzzle elements requiring placement
- Creative building and experimentation
Make Enter Trigger
"Execute actions when players enter area"
Detects U3D players or tagged objects entering trigger zones. Includes cooldown timers, one-time triggers, and separate events for players vs objects.
Perfect for:
- Area activation and lighting systems
- Sound zones and ambient triggers
- Quest checkpoints and progression
- Interactive environment responses
Make Exit Trigger
"Execute actions when players leave area"
Companion to Enter Triggers with identical detection and configuration options. Perfect for cleanup actions and state resets.
Great for:
- Light and sound cleanup systems
- Temporary effect removal
- Security and access control
- Resource management and optimization
Make Parent Trigger
"Player follows object movement (platforms, vehicles)"
Automatically parents players to moving objects when inside trigger area. Essential for elevators, moving platforms, trains, and vehicles.
Essential for:
- Elevators and moving platforms
- Trains, boats, and vehicles
- Rotating or animated structures
- Dynamic world elements
Make Swimmable
"Water volumes with swimming physics"
Create water areas where players can swim with modified movement physics and underwater effects.
Make Climbable
"Surfaces players can climb on"
Enable wall climbing and vertical traversal on designated surfaces with automatic grip detection.
Add Seat
"Sitting animation with movement exit"
Trigger avatar sit animations that players can exit by resuming movement input.
Make Rideable
"Stand on surface, move with object"
Players standing on top move with the object without entering trigger volumes.
Make Steerable
"Player input controls object movement"
Player movement input steers the visual object with smooth acceleration and deceleration.
Make 1x Trigger
"Single-use trigger activation"
Trigger that fires exactly once and then becomes inactive.
Make Toggle
"Switch between two states"
Binary state switching for lights, doors, and interactive elements.
Make Random
"Randomize between multiple GameObjects"
Component with configurable list that randomizes between audio, particles, or other GameObjects on trigger.
Grabbable Objects
Distance-Based Interaction
Grabbable objects support both touch-based grabbing (for VR-like experiences) and distance-based grabbing using camera direction. The system automatically detects U3D players and handles hand attachment.
Setup Options
- Grab Detection Radius: Use radius-based detection or precise raycast
- Distance Configuration: Set minimum and maximum grab distances
- 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
Physics-Based Throwing
Throwable objects must first be made grabbable. When released, they throw 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
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
Parent Triggers (Moving Platforms)
Automatic Player Attachment
Parent triggers solve the classic "moving platform" problem by automatically parenting players to moving objects when they enter the trigger area.
Configuration Options
- Player Detection: Support for U3D players and tagged objects
- World Position: Keep world position when parenting/unparenting
- Retry Logic: Automatic player detection with configurable retry intervals
- Events: Separate events for parenting actions and general trigger activity
Planned Interactive Features
Swimming System
Water volumes will provide modified movement physics, underwater effects, and surface tension simulation for realistic swimming experiences.
Climbing Mechanics
Wall climbing system will detect climbable surfaces and provide grip-based vertical traversal with automatic hand placement and stamina management.
Advanced Interaction Tools
Seat systems for avatar animations, rideable surfaces for dynamic platforms, and steerable objects for vehicle-like controls will expand creative possibilities.
Best Practices for Interactive Experiences
Object Selection
- Start with simple primitives to test behaviors
- Apply interactive tools to parent objects, not individual meshes
- Consider object scale - tiny objects are hard to grab
- Use clear visual indicators for interactive elements
User Experience
- Provide clear feedback when objects are interacted with
- Use UnityEvents to connect interactions to visual and audio responses
- Test grab distances - too far feels unnatural, too close is frustrating
- Consider accessibility - not all players can perform complex motions
Interactive Experience Examples
- Grabbable keys and puzzle pieces: Essential items for progression
- Throwable switches and levers: Physics-based puzzle activation
- Enter triggers for rooms: Area-based sound and lighting changes
- Grabbable building blocks: Free-form construction materials
- Throwable physics objects: Test structural stability
- Parent triggers on platforms: Moving construction elevators
- Enter/Exit triggers: Chapter progression and character dialogue
- Grabbable story artifacts: Interactive props that advance narrative
- Moving platforms: Cinematic moments and scene transitions
- Shared grabbable games: Basketball, chess pieces, collaborative tools
- Throwable sports equipment: Balls, frisbees, interactive challenges
- Area-based activities: Join/leave triggers for different game zones
Troubleshooting
Objects Won't Grab
- Check that object has U3DGrabbable component
- Verify grab distance settings - may be too restrictive
- Ensure player is detected by checking grab detection settings
- Test with radius detection instead of precise raycast
Throwable Objects Not Working
- Verify object has U3DGrabbable component first
- Check that throwable was applied to a grabbable object
- Ensure camera is found - throwable needs camera direction
- Test throw force settings - may be too low to register
Triggers Not Firing
- Confirm trigger collider is enabled and set to "Is Trigger"
- Check player detection settings - may need to enable tag detection
- Verify cooldown timer isn't preventing re-triggering
- Test with "trigger once" disabled to allow repeated activation
Parent Trigger Not Working
- Enable player retry detection - player may not be found initially
- Check both U3D player detection and Player tag detection
- Verify trigger collider encompasses the area where players will stand
- Test world position settings if players appear to teleport
Multiplayer Sync Issues
- Ensure NetworkObject component is added to interactive objects
- Check that objects have proper authority assignment
- Test with multiple players to verify state synchronization
- Verify Fusion 2 is properly configured in your project
Understanding Multiplayer Synchronization
How NetworkObject Integration Works
When you enable "NetworkObject for multiplayer" on any interaction tool:
- Automatic Setup: NetworkObject component is added to your GameObject
- Authority Management: Photon Fusion 2 handles who controls the object
- State Sync: Object state (grabbed, triggered, etc.) syncs across all players
- Event Broadcasting: UnityEvents fire for all players simultaneously
- Physics Sync: NetworkRigidbody handles throwable object physics
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: Sports equipment, games, and contests
- 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, colors, or animations
- Audio Feedback: Play sounds when interactions occur
- Particle Effects: Trigger visual effects for enhanced feedback
- Custom Logic: Connect to your own scripts and systems
Physics Integration
Interaction tools work seamlessly with Unity's physics system:
- Automatic Colliders: Tools add appropriate collider types
- 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
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
Ready to Add Interactivity!
Your interaction system is ready to transform static objects into engaging, multiplayer-synchronized experiences. Select any object and apply interactive behaviors with automatic networking support.
Start creating engaging interactions that work seamlessly across all players!
🎮 Your interactivity system is operational! Apply behaviors to any object and create engaging multiplayer experiences with Unity 6 and Photon Fusion 2.