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Create an environmental Particle System

Particle Systems are surprisingly versatile. With just a few changes to a Particle System’s modules, you can produce a wide variety of effects. In this tutorial, you will create a brand new Particle System and configure its modules to create snow or rain in the scene.

By the end of this tutorial, you'll be able to:

Set up a new Particle System in the scene.

Configure a Particle System's main properties, such as lifetime, size, and max particles by modifying the Main module.

Control the location and initial direction of particles by modifying the Shape module.

Control the rate and timing of particles by modifying the Emission module.

Control the appearance of individual particles by modifying the Renderer module.

One of the most common, important use cases for Particle Systems is also one of the simplest to achieve: weather effects. With just a few edits, your scene can quickly transform from a clear blue sky to a thunderstorm or a snowy blizzard.

Rather than being emitted from a single source in front of the user, these effects completely surround and immerse the user.. 

In this tutorial, you will use some of the core features of Particle Systems to create a weather effect in your scene.

Overview

In order to create a weather effect like rain or snow, the first thing you need to do is create a new Particle System object and position it in the sky aiming downward toward the ground.

Open the CreativeCore_VFX_ProjectFiles in Unity Editor, if you haven’t already done so.

 and open the TutorialScene_VFX_Outdoor scene.

By default, this will create a Particle System shooting big white dots into the air somewhere in your scene.

it as FX_Snow or FX_Rain, depending on what you choose to make.

FX is a shorthand for Effects. Other common abbreviations you might come across are SFX, which stands for Special Effects. Depending on the industry and type of project you work on, you might see one of these names more commonly than the others. It’s generally good practice to make clear in the name of your object that it is, in fact, a particle effect. 

If you’re making snow or rain, you will want to position the system in the sky facing downward.

  In the GameObject’s Transform component, set its 

so that it’s centered above the fire and set its 

so that the particles are shooting downward from above.

 to run your application and preview your Particle System. It should already be looking a lot like a weather effect, with white dots floating down across the screen. 

Those particles don’t have the right size or speed, though. We’ll address that next.

Add and position a new Particle System

A Particle System is controlled by a bunch of different modules, each one controlling a different aspect of the system. The first module we’ll edit is the main module, which includes some of the most important particle properties, such as size, speed, and lifetime. 

Ensure the main module is expanded by selecting its name (in this case, FX_Snow). 

Since the main module doesn’t look like any of the other modules, it can be easy to miss:

It is slightly taller than the other modules and includes an icon of the particle texture.

The name of the main module takes the name of the GameObject it’s on (e.g. FX_Snow).

It is required and cannot be toggled on or off with a checkbox like the other modules.

To change the size of the particles, reduce the

 property in the main module to 0.1 for tiny raindrops or snowflakes.

It’s called Start Size instead of just Size since you have the ability to change their size over time if you want. Below you can see the difference between a Start Size of 1.0 and a Start Size of 0.1. 

Change the speed of the particles to more accurately reflect your chosen weather effect. Reduce the 

 property from 5 to around 1 for the snow or increase it to around 10 for rain. 

The particles will now appear to be moving at the appropriate speed. However, if you decreased their speed, they’re probably not going fast enough to make it through your entire scene. 


If you increase the Start Speed, they will probably go so fast that they survive way longer than necessary after passing through the ground.

To address this problem, you need to change the particles’ lifetime: 

 property from 5 seconds to however long it takes for the particles to move through the camera’s field of view. The particles should make it all the way to the ground, but not much farther than that.

 to preview your application in Game view, you’ll notice a pretty big problem: when your application begins, you need to wait patiently for the particles to generate and slowly fall from the sky. But what if you want it to already be snowing or raining when the application starts? 

Now when the scene starts, it will be pre-populated with a full cycle of particles. As a VFX artist constantly testing and retesting your effects, this setting would also save you a lot of time. 

Next, we will move away from the main module to make the particles move downward in the same direction. 

Configure the main module properties

The first two modules after the main module, which are both enabled by default on new Particle Systems, are the 

These modules work together to control how many particles are emitted (

Let’s start by changing the shape of the source of the particles to a flat, rectangular, cloud-like shape.

 module to expand it and notice the cone-like shape that appears in Scene view, then change the 

It should now look like a box in the sky, but still far too small to simulate a large cloud or weather system.

 If you do not see the outline of the shape, you may need to enable 

 in the top-right corner of the Scene view.

 Increase the size of the box by changing the 

The box should appear as a square volume large enough to cover the camera’s field of view directly above the firepit. 

You will notice that the particles are now more sparse, making it look like a lighter weather effect. That is because the same number of particles are being generated as before, but from a much larger area.

We need to increase the emission rate of this Particle System. 

 property from 10 to a number between 150-1000 particles per second, depending on how strong a weather effect you are trying to produce. 

You’ll notice that with high enough emission rates, you may start to get strange breaks in the generation of particles.

This happens if the number of particles on the screen reaches the maximum limit allowed for the system. 

 property from 1,000 to 10,000. This should clear up any pauses in particle emissions.

At this point, it will be tempting to crank the 

 limit up to 1,000,000 in order to create the craziest weather phenomenon the world has ever seen. Resist that temptation! A big part of a VFX artist’s job is making sure their effects are optimized, and adding a crazy number of particles would likely decrease the app’s performance.

Our particles still aren’t looking that great. They don’t quite look like snowflakes or raindrops.

To improve the look of the particles, we’ll need to visit the last module in the list: the Renderer

Configure the Shape and Emission modules

The final module we’ll modify, which is also enabled by default, is the 

This module controls how each particle is rendered (how it looks), including its texture.  

Our particles are currently using the default ParticlesUnlit material, which uses the default particle texture. 

It looks OK, but could definitely be made more snowflake- or raindrop-like with a new material.

 module to expand it, then use the circle select icon for the 

The individual particles will now change in appearance.

Let’s take a closer look at that particle material.

In the Inspector, double-click directly on the name of the material from within the Renderer module.

This will select the material in the Project window and show its properties in the Inspector.

There's a lot to know about Materials; luckily, you can learn all about them with our 

 There are, however, just a few things worth noting about this particle material, in case you want to create your own.

 is set to the Particles/Unlit shader. This shader is optimized for particles that don’t need to reflect light. 

 property is set to Transparent, allowing the particle to have some transparency. Without this, the particle would look like a white square.

 texture is set to the Snowflake or Raindrop texture, which have transparent backgrounds. If you wanted to create your own particle texture in a program like Photoshop or Illustrator, you could use that as the Base Map instead.

Configure the Renderer module

With your weather effect now looking really nice, let’s save it as a 

. VFX tend to be very modular, reusable assets, which makes them particularly useful Prefabs. Next time you want there to be a blizzard in a scene, just add in your saved Prefab and let it snow! Later on, you could even make 

 of your Prefab for heavier or lighter weather effects. 

Drag the Particle System object from the Hierarchy into the Prefabs folder in your Project window. This will give it a new blue icon in the Hierarchy and Project window, indicating that it’s been saved as a Prefab.

Save your VFX as a Prefab

Now that you know how to edit a Particle System’s default modules, you can make all kinds of cool environmental effects. With your first effect safely saved as a Prefab, try duplicating, renaming, and modifying the Prefab to create a different weather effect: snow or rain.

Explore: Make other weather effects

In this tutorial, you created an environmental Particle System from scratch, which contributes a lot to the atmosphere of your scene. You created this weather effect using only the modules enabled by default on Particle Systems: the Emission, Shape, Renderer, and main modules. 

In the next tutorial, you will create a burst particle that the user controls with a key press. To do this, you will also experiment with a few new modules. 

Next steps

Create simple particle systems to add dynamic environmental and gameplay effects to your scenes.

Beginner Particles and Visual Effects

ElizabethMidgley

Crea Sistemas de partículas simples para agregar efectos ambientales y de jugabilidad dinámicos a tus Escenas.

Partículas y efectos visuales para principiantes

Anabel Munoz

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Creative Core Pathway Facilitator Kit.zip

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Set up a new Particle System in the scene

Play, pause, stop, and restart a particle system in Scene view by using the Particle Effect window

Create a single burst of particles, rather than a continuous emission over time by using the Bursts section of the Emission module

Explain how individual Particle Systems can be combined to create more complex effects

Locate the Main module of a Particle System

Recall the three modules enabled by default in a Particle System: Emission, Shape, and Renderer

Configure a Particle System's main properties, such as lifetime, size, and max particles by modifying the Main module

Control the location and initial direction of particles by modifying the Shape module

Control the rate and timing of particles by modifying the Emission module

Control the appearance of individual particles by modifying the Renderer module

Add randomness to a Particle System by using the Random Between Two Constants feature

Change the color of a particle over its lifetime by using the gradient editor and the Color Over Lifetime module

Change the size of a particle over its lifetime by using the curve editor in the Size Over Lifetime module

Produce environmental and burst effects by configuring Unity's Particle System object

Configurar un nuevo Sistema de partículas en la Escena.

Reproducir, pausar, detener y reiniciar un Sistema de partículas en la vista de Escena con la ventana Particle Effect (Efecto de partículas).

Crear una sola explosión de partículas, en lugar de una emisión continua en el tiempo mediante el uso de la sección Bursts (Explosiones) en el módulo Emission o Emisión.

Explicar cómo se pueden combinar los Sistemas de partículas individuales para crear efectos más complejos.

Ubicar el módulo principal de un Sistema de partículas.

Recordar los tres módulos habilitados de forma predeterminada en un sistema de partículas: Emission, Shape (Forma) y Renderer (Renderizador).

Configurar las propiedades principales de un Sistema de partículas, como el ciclo de vida, el tamaño y las partículas máximas al modificar el módulo principal.

Controlar la ubicación y dirección inicial de las partículas al modificar el módulo Shape.

Controlar la tasa y el tiempo de las partículas al modificar el módulo Emission.

Controlar la apariencia de las partículas individuales al modificar el módulo Renderer.

Agregar un carácter aleatorio a un Sistema de partículas mediante el uso de la función Random Between Two Constants (Aleatorio entre dos constantes).

Cambiar el color de una partícula durante su ciclo de vida con el Gradient Editor (Editor de gradientes) y el módulo Color Over Lifetime (Color en el ciclo de vida).

Cambiar el tamaño de una partícula durante su ciclo de vida mediante el uso del Editor de curvas en el módulo Size Over Lifetime (Tamaño en el ciclo de vida).

Unity Version 2020.3