Ground Detection

GroundDetection inspector.

Determines which FrictionPreset, effects, and sounds apply to each wheel based on surface type. Continuously samples terrain textures and object tags to switch friction characteristics and rolling resistance in real-time.

Detection Priority

When a wheel contacts a surface:

  1. GameObject tags - Checked first (highest priority)
  2. Terrain texture splatmaps - Sampled if no tag matches
  3. Fallback surface preset - Applied if no matches found (required)

Configuration centralized in GroundDetectionPreset ScriptableObject.

Ground Detection Preset

ScriptableObject containing:

  • Surface Maps - Texture indices/tags mapped to SurfacePresets
  • Fallback surface - Required default when no matches found
  • Particle prefabs - Dust/smoke and chunk effects

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

Required: Must assign fallbackSurfacePreset or ground detection will not function.

Surface Maps

Each entry maps terrain textures or object tags to a SurfacePreset:

  • Terrain texture indices - 0-based, matches Terrain Layer order
  • GameObject tags - String tags assigned to objects
  • SurfacePreset - Defines friction, rolling resistance, sounds, particles

Performance

Checks one wheel per cycle using coroutines (no raycasting overhead). Configure groundDetectionInterval:

  • 0.05s - High responsiveness (player vehicle)
  • 0.1s - Balanced (default)
  • 0.2s - Low CPU (AI vehicles)

Interval is randomized ±20% on initialization to prevent multiple vehicles from updating simultaneously. Detection latency = interval × wheel count.

Dominant Surface

Tracks which surface type has the most wheels in contact. Updated each detection cycle by counting wheels per surface. Used for vehicle-wide effects like engine sounds and UI feedback. Returns null when no wheels are grounded.

Setup

Basic Setup

  1. Create GroundDetectionPreset (Right-click > Create > NWH > Vehicle Physics 2 > Ground Detection Preset)
  2. Assign fallbackSurfacePreset (required)
  3. Configure Surface Maps:
    • For terrains: Note Terrain Layer order, assign texture indices (0-based)
    • For objects: Tag GameObjects, add matching tags to Surface Maps
  4. Assign GroundDetectionPreset to VehicleController > FX > Ground Detection
  5. Each Surface Map links to a SurfacePreset defining friction and effects

Terrain Texture Setup

Texture indices correspond to Terrain Layer order (first layer = 0, second = 1, etc.). Check terrain settings to verify layer order matches your indices.

Object Tag Setup

Tag objects with surface type strings ("Asphalt", "Gravel", etc.). Add matching tags to Surface Maps. Tags have priority over terrain textures.

How It Works

When a surface is detected for a wheel:

  1. WheelController.activeFrictionPreset is updated with the surface's FrictionPreset
  2. Rolling resistance multiplier is applied to the wheel
  3. EffectManager uses the SurfacePreset for particles and skidmarks
  4. SoundManager uses the SurfacePreset for rolling/skidding sounds

Changes take effect immediately but detection latency depends on groundDetectionInterval and wheel count.

Troubleshooting

Wrong surface detected

  • Verify texture indices match Terrain Layer order (0-based)
  • Check GameObject tags exactly match Surface Map tags (case-sensitive)
  • Use Scene view gizmos to see detected surface per wheel

Delayed surface changes

  • Reduce groundDetectionInterval for faster response
  • Note: Only one wheel is checked per cycle (by design)
  • 4-wheel vehicle at 0.1s interval = 0.4s worst-case latency

No effects/sounds

  • Verify SurfacePreset has assigned FrictionPreset
  • Check SurfacePreset has audio clips and particle settings
  • Ensure EffectManager and SoundManager are enabled on VehicleController

Fallback surface errors

  • GroundDetectionPreset requires fallbackSurfacePreset assignment
  • Create a generic SurfacePreset if missing