Ground Detection

Determines which WheelFrictionPreset, effects, and sounds apply to each wheel based on surface type.

v13.1+ Changes

No layer setup required. Detection priority:

1. GameObject tags (highest)
2. Terrain texture splatmaps
3. Fallback surface preset

Configuration centralized in GroundDetectionPreset ScriptableObject.

Ground Detection Preset

Contains:

• Surface Maps (texture indices/tags → SurfacePreset)
• Fallback surface
• Particle prefabs

Create: Right-click > Create > NWH > Vehicle Physics 2 > Ground Detection Preset

Surface Maps

Each entry defines:

• Terrain texture indices (0-based, matches Terrain Layer order)
• GameObject tags
• SurfacePreset reference (friction, sound, effects)

Performance

Checks one wheel per update cycle. Configure groundDetectionInterval:

• 0.05s - responsive (player vehicle)
• 0.1s - balanced (default)
• 0.2s - low CPU (AI)

Surface change detection depends on interval and wheel count.

Dominant Surface

Tracks which surface has most wheels in contact. Used for vehicle-wide effects (engine sounds, etc).

Setup

Basic

1. Create or assign GroundDetectionPreset to VehicleController
2. Configure Surface Maps:
   • Terrain: Note texture order in Terrain Layers, assign indices
   • Objects: Tag objects, assign tags to Surface Maps
3. Link each Surface Map to appropriate SurfacePreset

For Terrains

Texture index = order in Terrain Layers (first = 0, second = 1, etc.)

For Objects

Tag objects with surface type ("Asphalt", "Concrete", etc.), match tags in Surface Maps.

Troubleshooting

Wrong surface detected: Check texture indices match Terrain Layer order, verify GameObject tags match Surface Map tags

Delayed changes: Reduce groundDetectionInterval, note design checks one wheel per cycle

No effects/sounds: Verify SurfacePreset has clips/prefabs, check EffectManager/SoundManager enabled

Technical Notes

• No raycasting (uses contact point sampling)
• Thread-safe
• Supports multiple terrains
• Per-wheel surface assignment
• Dominant surface cached