🎆 Niagara VFX Integration - Water-Aware Particle Systems

Deep integration between Oceanology and Unreal Engine's Niagara VFX system enables physically-accurate water-aware particle effects.

Overview

The Niagara Water Data Interface provides direct access to Oceanology's wave simulation data within Niagara particle systems. This enables VFX artists to create effects that respond naturally to water surface dynamics.

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Niagara Data Interface

UOceanologyNiagaraDataInterfaceWater

The core integration component exposes water simulation data to Niagara:

Property	Description
bFindWaterBodyOnSpawn	Automatically locate nearest water body when system spawns
bEvaluateSystemDepth	Sample water depth at system position
bEvaluateSystemDepthPerFrame	Update depth sampling every frame
SourceBodyComponent	Explicit water component reference

Available Functions

// Get complete water data at world position
void GetWaterDataAtPoint(FVectorVMExternalFunctionContext& Context);

// Access wave parameter lookup table
void GetWaveParamLookupTableOffset(FVectorVMExternalFunctionContext& Context);

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Water Data Access

Per-Particle Queries

Each particle can query water state independently:

Data	Description
Wave Height	Current water surface height at particle XY
Wave Normal	Surface normal for orientation
Flow Velocity	Water movement direction and speed
Depth	Distance from surface to ground
Submersion	Particle depth below water surface

Performance Considerations

• CPU simulation only (ENiagaraSimTarget::CPUSim)
• Supports instance data caching
• Automatic water body change detection via SourceBodyChangeId
• Pre-simulate tick for data preparation

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Niagara Function Library

Blueprint Accessible Functions

UCLASS()
class UOceanologyNiagaraWaterFunctionLibrary : public UBlueprintFunctionLibrary
{
    // Set water component for Niagara system
    UFUNCTION(BlueprintCallable, Category = "Oceanology|Niagara")
    static void SetOceanologyWaterComponent(
        UNiagaraComponent* NiagaraComponent,
        UOceanologyWaterComponent* WaterComponent
    );
};

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Use Cases

Spray & Splash Effects

Create spray particles that:

• Spawn at wave crests (high curvature areas)
• Orient along wave normals
• Scale intensity with wave height
• Follow flow velocity

Foam Particles

Dynamic foam that:

• Accumulates in high-turbulence zones
• Dissipates based on water calm areas
• Follows surface flow direction
• Responds to shore proximity

Underwater Bubbles

Bubble systems that:

• Rise toward water surface
• Account for current wave height
• Respond to depth pressure
• Interact with flow velocity

Wake Effects

Boat/character wakes that:

• Sample surface at multiple points
• Generate V-shaped spray patterns
• Scale with movement speed
• Fade with distance

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Integration Example

Setting Up Water-Aware Particles

1. Create Niagara System with Water Data Interface
2. Configure Source - Set SourceBodyComponent or enable auto-find
3. Add Modules - Use water data in particle behavior
4. Sample Per-Particle - Query wave height, normal, velocity

Module Setup

Particle Spawn:
  - Sample Water Height at Particle.Position.XY
  - Set Particle.Position.Z = WaterHeight + Offset

Particle Update:
  - Sample Flow Velocity
  - Add to Particle.Velocity
  - Orient sprite to Water Normal

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Debugging

Editor Visualization

Enable WITH_NIAGARA_DEBUGGER for HUD overlays:

• Water body boundaries
• Sample positions
• Flow vectors
• Depth values

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Upcoming Enhancements

Feature	Status
GPU Simulation Support	Planned
Wave Spectrum Access	Planned
Shore Distance Queries	Planned
Foam Threshold Data	Planned

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Resources

• Discord: Join #vfx-integration for community effects
• Example Systems: Available in plugin Content folder
• Documentation: See Niagara module reference