Understanding Particle System Concepts

Particle systems are a technique used in computer graphics to simulate a variety of phenomena, such as fire, smoke, rain, and explosions. In a game engine, particle systems are used to add realism and visual interest to scenes. The three main functions of particle systems are emission, simulation, and rendering.

Emission is the process of creating and releasing particles from a specific location or object. This is controlled through properties such as emission rate, velocity, and direction. Emission can also be triggered by events, such as collisions or user input.

Simulation refers to the movement and behavior of the particles over time. This can include properties such as gravity, wind, and turbulence, which can be used to create realistic movement patterns. Particles can also be affected by other forces, such as collisions and user-defined behaviors.

Rendering is the process of displaying the particles on the screen. This can be done...

Technical requirements

You can find the project we worked on in this book here:

https://github.com/PacktPublishing/Build-Stunning-Real-time-VFX-with-Unreal-Engine-5

Exploring key particle concepts

In this chapter, we will understand the key functional concepts of particle systems and how they are implemented in the particle systems in Unreal. All particle systems will invariably have some variation of the following functionalities built into them:

• Emission
• Simulation
• Rendering

Each one of these functionalities will have some variables that will be exposed to enable the user to tweak the behavior of the particle system. Most software has this functionality built in a monolithic element with limited ability to customize it. In Unreal, it is built into modules that are stacked on top of each other. The modules have exposed variables, which can be used to tweak the module’s effect on the behavior of the particle system. These modules are roughly grouped into three broad functionality groups: Emission, Simulation, and Rendering.

Figure 2.1: The Niagara Emitter node grouped into three functionalities...

Vector mathematics and matrices and their representation in Niagara

Vector mathematics and matrices are one of those boring subjects in high school mathematics that you may have entirely skipped because you had no idea where you would use them in your daily life. Well, now you know. They are used everywhere in games and particle systems in particular. Let us take some time to brush up on our concepts, starting with vector mathematics.

What is a vector?

Let us ignore all the complicated talk about magnitude and velocity used in the standard definition of a vector and have a look at the bare essentials.

In a two-dimensional space, a vector just holds an x and y value; for example, vector a = (3, 4) where 3 is x and 4 is y.

This representation can be used to define the location or direction of an object. We can also find the speed of an object by finding what is known as the magnitude of the vector. Let us see how a vector is used to define a location and then we will see...

Understanding particle system tools

There are a bunch of tools and off-the-shelf solutions available for creating particle effects. While you need not know all of them, you certainly will encounter some of them in your work as a real-time FX artist. Many studios might do part of a simulation in one of their own custom tools or one of the tools mentioned here. You may need to receive data such as vector fields from one of these tools and incorporate it into your Niagara System. You may also receive references for effects produced by one of these tools and may be required to recreate them in Niagara.

A lot of these tools have been around for quite some time and have shaped the workflows and terminology used by FX teams. Niagara builds on these concepts.

The following are some of the most widely used particle system tools.

Afterburn

Afterburn, developed by Sitni Sati, is a volumetric particle effects plugin. It has been used in VFX for clouds, smoke, explosions, and other...

Summary

In this chapter, we familiarized ourselves with the groups into which Niagara modules can be classified. We learned about namespaces, a feature we will use a lot, and we brushed up on some high-school mathematics about vectors and matrices. We also learned about other particle system tools used in the industry. Let us now move on to the next chapter, where we will come to understand the Niagara architecture in detail.