Lumberyard
User Guide (Version 1.16)

Particles Attribute

In the Particles attribute, specify how to control the particle's basic appearance.

Note

We recommend that you set up the Particles attribute first because it includes the Texture file, which is used for most particles.


                Particles attribute in the
                        Particle Editor.

Particles Attribute Parameters

Name Description
Particle Life Time Specifies the lifetime of individual particles. After an emitter's lifetime has expired, spawned particles live out their own lifetime.

Valid values: 0+

Remain While Visible Indicates that particles do not die until the entire emitter is out of view. This is typically used for emitters that move through space quickly and die to avoid particle pooling and other unintended consequences.

Default value: false

Facing Determines how the sprite or geometry is oriented in space. You can further modify texture orientation using the following rotational parameters.
  • Camera (default) – Faces the viewer, with texture X and Y aligned with screen X and Y. In this mode only, particles are assumed to represent spherical objects and are lit accordingly. In all other modes, particles are lit as flat polygons.

  • CameraX – Rotates about the local y-axis only and faces the camera as much as possible.

  • Free – Rotates freely in 3D. Be sure to give it some rotation. The default orientation is equal to the emitter's orientation.

  • Horizontal– Faces horizontal to the emitter's z-axis.

  • Velocity – Faces the direction of movement.

  • Water – Faces upward and is moved and aligned to the nearest water plane.

  • Terrain – Faces upward and is moved and aligned to the nearest terrain location.

  • Decal – Renders the particle as a deferred decal, projected onto the nearest surface along the entity's y-axis. The Thickness parameter under Collision controls the projection depth. This parameter works only with materials and does not work with textures.

  • Shape – Faces the nearest edge of the emitter shape boundary. You can use this parameter with the following shape types: Circle, Sphere, and Box Emitter.

Default value: Camera

Blend Type Applies to 2D particles only and determines how the sprite blends with the background.
  • Alpha Based – Final color = Particle color * Particle alpha + Background color * (1 – Particle alpha)

  • Additive – Final color = Particle color + Background color

  • Multiplicative – Final color = Particle color * 2 * Background color

  • Opaque – Final color = Particle color

Default value: Alpha Based

Material

Opens the Asset Browser for you to assign a material for the 2D sprite particles. Different shaders are uniquely affected by the lighting and environment.

Default value: Empty

Sorting Method (GPU only) Enables intra-GPU emitter sorting.
  • None – No sorting

  • Bitonic – Sorts using a bitonic sorting algorithm

  • OddEven – Sorts using an odd even merge sorting

Default value: None

Sorting Convergence (GPU only) Sorts convergence per frame for an odd to even merge sort.

Default value: 1

Texture Opens the Asset Browser to specify a texture for the 2D sprite particles. When you pause on the input box, a preview of the texture appears.

Default value: /Editor/Plugins/ParticleEditorPlugin/defaultparticle.dds

Normal Map

(GPU only) Opens the Asset Browser to specify a normal map for the 2D GPU particles.

Glow Map

(GPU only) Opens the Asset Browser to specify a glow map for the 2D GPU particles.

Note

You must specify a positive value for the Emissive Lighting parameter for the glow map to be visible.

Texture Tiling Splits the texture into tiles for variation and animation.
  • Tiles X, Y – The number of tiles that the texture is split into.

    Valid values: 1 to 256

    Default value: 1

  • First Tile – The first of the range of tiles used by the particle.

    Valid values: 0 to 255

    Default value: 0

  • Variant Count – The number of consecutive tiles in the texture from which the particle randomly selects.

    Valid values: 1 to 256

    Default value: 1

  • Anims Frame Count – The number of tiles that compose an animation sequence. You can use Variant Count and Anim Frames Count together. For example, if Variant Count = 2 and Anim Frames Count = 8, the particle randomly chooses between tiles 0 to 7 or 8 to 15, as an animated sequence.

    Valid values: 1 to 256

    Default value: 1

  • Anim Framerate – The number of frames per second for the animation. If 0, the animation runs through one sequence in the particle lifetime.

    Valid values: 0+

    Default value: 1

  • Anim Cycle – This parameter has the following values.

    • Once – Animation plays once and holds on the last frame

    • Loop – Animation loops indefinitely

    • Mirror – Animation alternates cycling forward and backward indefinitely

    Default value: Once

  • Anim Blend – Renders the particle blended between the two adjacent animation frames. This has a performance impact.

    Default value: false

  • Horizontal Flip Chance – Specifies the fraction of particles that are rendered and mirrored in texture X.

  • Vertical Flip Chance – Specifies the fraction of particles that are rendered and mirrored in texture Y.

    Valid values: 0 to 1

    Default value: 0

  • Anim Curve – Modifies the speed and direction of the animation.

Color

Selects the color and alpha to apply to a particle.

  • Random Between Two Colors – Right-click the color input and choose the option to randomize between two colors and alpha values. Right-click to choose and return to Single Color.

  • Random – Specifies how much a particle's initial color varies from the default.

    Valid values: 0 = no variation | 1 = random black to default

  • Random Hue – Causes the Random color variation to occur separately in the three color channels. If false, the variation is in luminance only.

    Default value: false

  • Strength Over Emitter Lifetime – Defines the color of the particle over the emitter's lifetime. Double-click to open the Gradient Editor.

  • Strength Over Particle Lifetime – Defines the color of the particle over the particle's lifetime. Double-click to open the Gradient Editor.

Alpha clip

(CPU only) Customizes how the particle Alpha value controls opacity or alpha test values. Each parameter has two values that correspond when particle Alpha = 0 and 1. They are interpolated for each particle with its Alpha value and used in the shader with the following equation:

FinalOpacity = saturate( (TextureAlpha - SourceMin) / min(SourceWidth, 1 - SourceMin) ) * Scale

  • Scale – Multiplies the final alpha value. When set to the default value (0, 1) , the particle Alpha directly scales the final opacity.

    Valid values: 0+

  • Source Min – Specifies the minimum source (texture) alpha to render (alpha test); values below the minimum become transparent. When set to the default value (0, 0), there is no alpha test.

    Valid values: 0+

  • Source Width – Specifies the feathering range of alpha clipping. When set to the default value (1, 1), texture alpha is fully used. A value of 0 specifies hard clipping. A value of 1 specifies soft clipping.

    Valid values: 0+

    Default value: 0

    • Default – Alpha controls opacity with no alpha clipping: Scale = (0, 1), Source min = (0, 0), Source width = (1, 1).

    • Hard clipping at texture alpha = C, with no feathering: Scale = (1, 1), Source min = (C, C), Source width = (0, 0).

    • Hard clipping controlled by particle alpha: Scale = (1, 1), Source min = (0, 1), Source width = (0, 0).

    • Feathered clipping with width F, controlled by particle alpha: Scale = (1, 1), Source min = (0, 1), Source width = (F, F).

    • Soft clipping with the test value controlled by particle alpha: Scale = (1, 1), Source min = (0, 1), Source width = (1, 1)

    • Clipping and opacity scale controlled by particle alpha: Scale = (0, 1), Source min = (0, 1), Source width = (1, 1)

Tessellation Enables tessellation, rendering more vertices in the sprite. You must have a minimum of DirectX 11. This parameter is useful when Receive Shadows is set, increasing the resolution of shadows. It is also useful when Tail Length or Connection are set, creating smoother curves in connected particles. This produces more accurate lighting when receiving light from point lights.

Default value: false

Soft Particles Applies rendering that softens the intersection between sprites and nearby objects to prevent unnatural seams. Use sparingly on particles that need it, such as smoke, because this is slightly more expensive. Use the Softness parameter to define the amount of rendering to apply.

Default value: false

Motion Blur (GPU only) Simulates motion blur on GPU particles. Use Blur Strength to set the strength of the blur effect.
Geometry (CPU only) Opens the Asset Browser window to select a 3D object to use for the particles.

Default value: empty

Geometry in Pieces (CPU only) Emits the geometry in pieces, originating at each piece's location in the asset. This applies only if the Geometry asset contains multiple subobjects.
  • Whole – Emits the whole geometry asset as one object.

  • Random Pieces – Emits geometry fragments randomly over the emitter lifetime.

  • All Pieces – Emits geometry pieces in order over the emitter lifetime.

Default value: Whole

This parameter requires that you provide specific names for the nodes in the Maya outliner. The following show examples of acceptable node names:


                                    Node names in the Maya outliner.

In these examples, the groups and individual nodes have a _group suffix. As a result, the Maya exporter assumes there is no geometry. If you receive a "group has no geometry" error, you can safely ignore it.

Geometry No Offset (CPU only) Uses the geometry pivot for centering geometry particles.

Default value: false

Octagonal Shape (CPU only) Renders sprites as octagons instead of quads, reducing pixel cost. Only use with textures that fit within an octagon; otherwise clipping occurs.

Default value: false