Adding Particle Systems

You can now add ray traced particles to your Remix Mods…

Editing in the Remix Runtime

Turn any texture into a particle emitter

In the runtime, assigning a “Particle Emitter” Render Category to any texture will create a particle system.

This is a quick and easy way to see particle effects in game. However there are a couple limitations.

1. All particles will use a single set of global settings

2. Can only be added to textures

Tag a Texture

1. Open the Developer Settings

2. Go to “Game Setup” Tab

3. Click on a texture or right click on an object in the game.

4. Add the “Particle Emitters (optional)” category

Tune Global Particle Settings

1. Open the Developer Settings

2. Go to “Rendering” Tab

3. Change the “Particle System > Global Preset” Settings

For more complex effects, you can build your particle systems in the Remix Toolkit…

Editing in the Remix Toolkit

Creating a Particle System

Right-click on a mesh or a material in the Stage Manager and you will see options to turn the mesh into an emitter or add a new emissive mesh as a child of that Prim.

Right click -> Add -> Particle System

You can also use the action buttons to create or remove particle systems on a prim. They will only be clickable on prims that can be made into a particle system.

Lastly, you can use the “Create Particle System” action in the properties pane.

To see an effect, you’ll need to set the “Spawn Rate Per Second” attribute at a minimum. From there you can dial in the look.

Configuring a Particle System

Particle Parameters

When a prim with the RemixParticleSystemAPI schema applied is selected in the app, you will see all the properties of a particle system in the properties panel.

For a full set of property descriptions see the Remix Particle System Schema.

Particle System Gizmo

1. To select a particle in the viewport, click on the blue spike icon. (Tip: Rectangle select also works to make sure you grab it.)

2. Once it’s selected you’ll see a hologram for hidden emitters or a wireframe outlining visible ones.

Particle Gizmos can be turned on and off in the viewport.

RemixParticleSystemAPI

In order to support defining particle properties on both meshes and materials, we’ve added a USD API Schema that will give those prims that ability.

over "mesh_9858949B5B49CCDC"
{
    over "mesh" (
        active = true
        prepend apiSchemas = ["ParticleSystemAPI"]
    )
    {
        float primvars:particle:initialVelocityFromNormal = 1
        float primvars:particle:spawnRatePerSecond = 100
        token visibility = "inherited"
    }
}

Creating Complex Particle Systems

To get more complicated effects you can use a number of replacement meshes to layer a number of different particle systems on top of each other. For example you can produce realistic looking fire with particles for flames, sparks and smoke.

Controlling Particle look with Material Properties

Particles will take on properties of their emitters material, so you can get interesting effects by modifying those material properties.

Animated Particles using a Sprite Sheet

Create Sprite image sequence and configure it according to these instructions.

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