Debugging and profiling

Symptom ladder

Symptom	Inspect first	Then
Nothing renders	system/component active, emitter enabled, spawn count	bounds, renderer binding, compile errors
Disappears at angle/distance	fixed bounds	scalability/culling, LOD/platform
Particles at origin	parameter binding and coordinate space	invalid data interface/source
Pooled effect keeps old color/target	reset contract	persistent age/emitter state
GPU collision fails off-screen	collision representation	switch method or design fallback
Effect never ends	loop/lifetime/completion	owner cleanup, Auto Deactivate
Hitch on first use	compilation/PSO/assets	prewarm/readiness strategy and packaged capture
Frame time spikes during bursts	system count and spawn multiplication	simulation, renderer, overdraw, collision

Debug procedure

1. Isolate one system and disable all but one emitter.
2. Check compile messages and parameter bindings.
3. Use attribute/parameter watch and Niagara Debugger (Tools -> Debug -> Niagara Debugger).
4. Visualize bounds and collision/debug drawing where supported.
5. Recreate the expected maximum system count and camera overlap.
6. Use the Debug Overview Performance view for system/game-thread comparison.
7. Inspect Shader Complexity for translucent overdraw and use GPU/CPU profiling for actual timing.
8. Compare one change under the same capture conditions.

Track system/emitter instance counts, active particles, tick/simulation time, render cost, material overdraw, collision/events, and memory. A cheap simulation can still be expensive to render; a cheap sprite can still become costly through overlap, sorting, lights, or full-screen coverage.