🌫️ Niagara Systems

Overview

The visual effects pipeline in ImpactFX is built entirely using Unreal Engine’s Niagara visual effects system. Designed with a focus on high-performance and AAA visual fidelity, the particle systems are fully scalable and highly modular.

Instead of monolithic, hard-to-edit systems, ImpactFX treats every particle behavior (smoke, sparks, debris) as an independent module. This allows Technical Artists to easily mix, match, and modify effects across different surfaces without rebuilding everything from scratch.

Modular Architecture: Emitters vs. Systems

To ensure maximum reusability and minimal memory footprint, the VFX library is strictly divided into Emitters and Systems.

• Niagara Emitters (NE_): These are the foundational building blocks. Each emitter serves a single, specific purpose—such as NE_FastSmoke_GPU, NE_Gibs_GPU, or NE_Sparkles_GPU.
• Niagara Systems (NS_): These are the final assets spawned in the world (e.g., NS_Impact_Concrete). A System is simply a container that references multiple NE_ emitters to create a complete, cohesive impact effect.

💡 Developer Benefit: By using isolated Emitters, if you want to update the behavior of the sparks, you only need to edit NE_Sparkles_GPU. That change will automatically propagate to every single System (NS_Concrete, NS_Metal, NS_Brick, etc.) that references it, drastically speeding up iteration times.

CPU vs. GPU Particles

ImpactFX intelligently balances the processing load between the CPU and GPU to maximize frame rates during intense firefights. The naming convention of the emitters explicitly states their processing target:

• GPU Particles (e.g., NE_MudSplash_GPU): Used for massive particle counts, such as dust clouds, sparks, and small debris. These utilize GPU scene depth for cheap collision and perform efficiently even when thousands of particles are on screen.
• CPU Particles (e.g., FragmentDriver_CPU): Reserved for complex logic that requires precise calculations or specific collision events, such as breaking a large rock fragment into smaller splinters upon hitting the ground.

Anatomy of an Impact System

If you open a typical system like NS_Impact_Concrete, you will see how the modular architecture comes together. A standard hard-surface impact usually consists of:

1. Shot Flare: A bright, instantaneous flash at the point of impact.