Niagara - Birds Flying Case Study. Unreal 5.4

As part of my flying birds project in Unreal Engine, I dove into Niagara for the first time—and wow, there’s a lot to take in. I wanted something simple: birds flying across the sky, spawning randomly, moving naturally, and (very important) staying performance-friendly. No heavy character blueprints, just one efficient system.

Here are a few key things I learned and noted for myself while working through it—hopefully, they help someone else starting out too:

So, I got the base knowledge. Now, what’s next?

Let’s dissect the project together.

1. Know What You Want to Achieve - Plan of Action!

In my case, it was birds—lots of them—flying across the sky at different speeds and altitudes. Having that clear vision helped me determine how to set up the system and what kind of emitter I needed.

I also needed the birds to actually fly—but I’m not an animator, and I didn’t have the time to animate them manually. So I looked for an alternative and found a simple solution: vertex shader animation (which I’ll cover in another blog post!). Honestly, it turned out to be easier than I expected.

With that part solved, I kitbashed and adapted various bird models, applied the shader, and ended up with something like this:

2. CPU vs. GPU Emitters

I went with a CPU Emitter because I needed control over individual birds. GPU is great for lots of particles like dust or sparks, but CPU gave me the flexibility to add logic and variation to each bird.

3. Setting Up the Emitter

I started with a basic Niagara emitter and began adjusting core parameters like spawn rate, particle lifetime, and velocity. To make each bird feel unique and natural, I added randomness to their movement—slightly varying direction, speed, and staggering their spawn times to avoid repetition.

I also researched different bird species and their flight behaviors, using that as reference to fine-tune the flapping frequency in the vertex animation shader. I built a single master shader and created multiple material instances for each bird type, allowing me to reuse the core logic while customizing visual details like color, flapping speed, and shading.

In the Niagara system, I adjusted spawn rate and movement speed based on bird type to better emulate natural flocking behavior. For example, pigeons would appear frequently and in large numbers, while an eagle might only show up occasionally—just like you’d expect in real life.

To keep things efficient, I built one Niagara system and used per-bird settings inside each character Blueprint. This allowed me to leverage instancing and avoid creating multiple emitters for each bird type, keeping the system lightweight and scalable for larger scenes.

4. Stacking Modules – Building Behavior with Logic

One of the most powerful (and fun) aspects of Niagara is how modular it is. Think of it like stacking LEGO bricks—each module adds a new piece of logic or behavior to your particles. For my birds, I started with basic modules like Velocity, Gravity, and Color Over Life, then layered on more specific behaviors:

• I added “Rotate Around Axis” to give the birds subtle motion and stop them from feeling too stiff.

• I used “Scale Mesh Size Over Life” to fade them in and out smoothly, instead of having them suddenly pop into or out of view.

• I also added random float and vector values to inject slight differences between birds—so even though they came from the same system, they didn’t all move the same way.

It’s basically visual scripting with sliders and logic blocks. Super flexible, and once you get the hang of it, surprisingly intuitive.

5. Keep It Light – Performance is Key

As much as I wanted to flood the sky with birds, I had to be careful with performance—especially since this system would be running in a larger open-world environment. I made a few smart trade-offs:

• Kept the spawn count relatively low, especially for the larger bird types.

• Avoided spawning skeletal meshes or using heavy Blueprints for each bird.

• Leaned on instancing and simple mesh particles combined with shader animation to fake complexity.

By simplifying the system and optimizing from the start, I was able to achieve a nice visual result without tanking the frame rate.

6. Customizing and Iterating – Planning What’s Next

While the base setup gave me satisfying results, I’m already planning ways to push it further. Right now, birds spawn within a defined area and fly randomly—but I’d love to guide them more intentionally.

• Spline-based spawning could let me direct flocks along specific paths (like over rooftops or between buildings).

• Volume-based spawning could let different birds appear in different zones—like pigeons in plazas and eagles in mountains.

• I’m also thinking about using blueprint communication or tags to create smarter, more context-aware behavior.

Even though it started as a quick solution, this system has a lot of room to grow—and that’s what makes Niagara so exciting to work with.

This was my intro to Niagara, and honestly, it was way less intimidating once I just started experimenting. I’ll be posting more as I keep refining this system, but for now—This is the end product I got out of this case study!

You can see all the different kind of birds flying at the same time, with different altitudes and speeds. I added a place holder “building” so we can try collisions. Not working so great but for now, I consider this case study mission successful!