Why don't my Niagara effects cull at distance?

You need an Effect Type asset assigned with a Significance Handler. Without it, every system runs at full quality regardless of load. Create a Niagara Effect Type with a SignificanceHandlerDistance and assign per system.

What's Cull Reaction?

On Effect Type: choose what happens to less-significant effects. Kill (full stop), Pause, or Asleep. Kill is harshest but cheapest; Asleep keeps the system around for fast resume.

How do I tune per-system?

Niagara System → System Properties → Significance Index. Higher = kept active under load. Hero VFX 100, ambient 0. The Effect Type's Significance Handler uses this to rank.

Fix: Unreal Niagara Effect Type Significance Cull Disabled

Quick answer: Create a Niagara Effect Type asset with a Significance Handler (Distance is typical). Set Cull Reaction = Kill / Asleep. Assign Effect Type per Niagara System. Tune Significance Index per-system.

100 Niagara systems active. CPU pegged. Distant systems should fade out under load — they don’t. Effect Type isn’t set.

The Symptom

All Niagara systems run at full quality regardless of distance or count. CPU/GPU dies under load.

The Fix

Create a Niagara Effect Type asset.

Right-click in Content Browser → FX → Niagara Effect Type:
  Significance Handler: SignificanceHandlerDistance
  Cull Reaction:        Kill And Resume
  Cull Reaction Per Significance:
    0: Kill And Resume
    1: Pause
    2: Stay Active

Assign on Niagara Systems.

Niagara System → System Properties:
  Effect Type:        EFT_DefaultGameplay
  Significance Index: 10     // hero VFX
                      0      // ambient

Performance Impact

With significance handler active, Niagara culls per-frame based on global significance budget. Distant ambient effects pause; hero effects keep running.

Verifying

Spawn many systems. Console fx.Niagara.Debug.Significance 1. Logs which systems are culled and why. Tune Significance Index until budget fits.

“Effect Type assigned. Handler chooses culling. Hero VFX survive load.”

Related Issues

For Niagara bounds, see Niagara bounds. For Niagara collision events, see collision events.

Effect Type. Significance. Hero priority.