I thought Update was enough. Then I saw something called Simulation Stage. And nothing made sense.
This post is part of my daily learning journey in game development.
I’m sharing what I learn each day — the basics, the confusion, and the real progress — from the perspective of a beginner.
On Day 61 of my game development journey, I explored Simulation Stages in Unreal Engine Niagara.
What I Tried
I noticed Simulation Stages inside a GPU emitter.
My particles were already running Spawn and Particle Update every frame. So I didn’t understand why another stage was needed. When I added a Simulation Stage, nothing changed visually at first.
It felt useless.
What Confused Me
Isn’t Update already running every frame?
Why do we need another stage?
What does Iteration Source mean?
Why is this mostly GPU-only?
Why does nothing happen unless I change the iteration count?
It felt like an advanced setting without a clear purpose.
What Finally Clicked
Normal Particle Update runs once per particle per frame.
A Simulation Stage allows additional controlled passes during the same frame.
It’s like adding a custom loop inside the emitter that can run multiple times. On GPU emitters, this works well because the GPU is optimized for parallel processing.
This becomes useful for:
- Fluid-like simulations
- Neighbor-based interactions
- Grid-based calculations
- More complex force behaviors
When I increased the Num Iterations, I finally saw stronger and more noticeable changes.
CPU emitters don’t support Simulation Stages in the same way because they aren’t designed for heavy parallel iterative processing.
Particle Update = single pass per frame.
Simulation Stage = optional extra passes per frame.
It’s not meant for simple fire or smoke. It’s designed for more advanced simulation logic.
Practical Fix
- Use a GPU emitter
- Add a Simulation Stage in the emitter stack
- Set the Iteration Source correctly (Particles or a Data Interface)
- Increase Num Iterations to test visible impact
- Add custom modules inside the Simulation Stage
Performance Note
Higher iteration counts increase GPU cost.
Simulation Stages are powerful, but not lightweight. Use them only when the effect truly needs extra simulation passes.
One Lesson for Beginners
- Simulation Stage is not required for basic effects
- GPU emitters handle iterative logic better
- Iteration count directly affects simulation strength
- Advanced features require performance awareness
- Niagara is more than just simple particle spawning
Understanding Simulation Stages changed how I see Niagara — not just as a VFX tool, but as a real-time GPU simulation system.
Slow progress — but I’m building a strong foundation.
If you’re also learning game development, what was the first thing that confused you when you started?
See you in the next post 🎮🚀
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