struct · iOS 27.0+ · SDK 27.1
struct ElementSpawnParametersParameters used to configure the initial state of a particle when it's spawned in the simulation. The values specified become initial values in the Initialization stage, which can read or overwrite the values. ## Usage ```swift let params = ElementSpawnParameters( position: SIMD3<Float>(0, 1, 0), velocity: SIMD3<Float>(0, -1, 0), size: SIMD2<Float>(0.02, 0.02), color: SIMD4<Float>(1, 0.5, 0, 1), lifetime: 2.0 ) ```
get size(): SDKHandlevar size: SIMD2<Float> { get set }The initial size of the particle as a 2D vector representing width and height. For most particle systems, this represents the billboard size in world space units. - `x` component: width of the particle - `y` component: height of the particle Equal values create square particles, while different values create rectangular particles.
set size(value: SDKHandle)var size: SIMD2<Float> { get set }The initial size of the particle as a 2D vector representing width and height. For most particle systems, this represents the billboard size in world space units. - `x` component: width of the particle - `y` component: height of the particle Equal values create square particles, while different values create rectangular particles.
get color(): SDKHandlevar color: SIMD4<Float> { get set }The initial color and alpha (transparency) of the particle. Uses RGBA format where each component ranges from 0.0 to 1.0: - `x` (red): Red color component - `y` (green): Green color component - `z` (blue): Blue color component - `w` (alpha): Transparency (0.0 = fully transparent, 1.0 = fully opaque)
set color(value: SDKHandle)var color: SIMD4<Float> { get set }The initial color and alpha (transparency) of the particle. Uses RGBA format where each component ranges from 0.0 to 1.0: - `x` (red): Red color component - `y` (green): Green color component - `z` (blue): Blue color component - `w` (alpha): Transparency (0.0 = fully transparent, 1.0 = fully opaque)
get lifetime(): numbervar lifetime: Float { get set }The initial lifetime of the particle in seconds. This determines how long the particle will exist before being automatically removed from the simulation. A value of 0 or negative means the particle will be removed immediately or never spawn.
set lifetime(value: number)var lifetime: Float { get set }The initial lifetime of the particle in seconds. This determines how long the particle will exist before being automatically removed from the simulation. A value of 0 or negative means the particle will be removed immediately or never spawn.
static init(position: SDKHandle, velocity?: SDKHandle, size?: SDKHandle, color?: SDKHandle, lifetime?: number): ElementSpawnParametersinit(position: SIMD3<Float>, velocity: SIMD3<Float> = .zero, size: SIMD2<Float> = .init(0.01, 0.01), color: SIMD4<Float> = .init(1, 1, 1, 1), lifetime: Float = 1.0)Creates a new set of particle spawn parameters. - Parameters: - position: The initial 3D position in world space coordinates - velocity: The initial velocity vector in world space units per second (defaults to zero) - size: The initial size as width and height in world space units (defaults to 0.01 x 0.01) - color: The initial RGBA color (defaults to opaque white) - lifetime: The particle lifetime in seconds (defaults to 1.0 second) ## Example ```swift // Create a particle that starts at the origin, moves upward, is red, and lasts 3 seconds let params = ElementSpawnParameters( position: SIMD3<Float>(0, 0, 0), velocity: SIMD3<Float>(0, 2, 0), size: SIMD2<Float>(0.05, 0.05), color: SIMD4<Float>(1, 0, 0, 1), lifetime: 3.0 ) ```
get position(): SDKHandlevar position: SIMD3<Float> { get set }The initial 3D position of the particle in world space coordinates. This determines where the particle will first appear when spawned. The coordinate system follows RealityKit's conventions with Y pointing up.
set position(value: SDKHandle)var position: SIMD3<Float> { get set }The initial 3D position of the particle in world space coordinates. This determines where the particle will first appear when spawned. The coordinate system follows RealityKit's conventions with Y pointing up.
get velocity(): SDKHandlevar velocity: SIMD3<Float> { get set }The initial velocity vector of the particle in world space units per second. This determines the particle's initial direction and speed of movement. The magnitude of the vector represents the speed, while the direction represents the movement direction. A zero velocity means the particle starts stationary.
set velocity(value: SDKHandle)var velocity: SIMD3<Float> { get set }The initial velocity vector of the particle in world space units per second. This determines the particle's initial direction and speed of movement. The magnitude of the vector represents the speed, while the direction represents the movement direction. A zero velocity means the particle starts stationary.
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