Emission and Shapes

Shape, direction, and emission rate combine into the distribution visible in the live Scene.

Emission decides when to spawn particles. Shape decides where they start and which direction supplies their initial speed.

Emission Sources

Source	Behaviour
Emission Rate	Spawn continuously over emitter time.
Distance Rate	Spawn as the emitter travels, useful for footsteps and moving trails.
Burst	Spawn a configured count at a specific cycle time.

Bursts include time, count, cycles, interval, and probability. The emitter tracks each burst cycle so looping emitters do not replay old burst state incorrectly.

Shape Transform

The Shape module adds its own position, rotation, and scale inside the emitter transform. This is useful when the visual emission volume needs a different pivot without adding another Empty object.

Built-in Shapes

Shape	Important controls	Typical use
Dot	none	One origin point.
Box	dimensions and emit-from mode	Volumes, planes, or box surfaces.
Circle	radius, thickness, arc	Rings and radial sprays.
Cone	angle, radius, thickness, arc	Fire, jets, and directional spreads.
Cylinder	radius, thickness, arc	Columns and circular walls.
Sphere	radius, thickness, arc	Explosions, auras, and shells.
Mesh	vertices/triangles from a mesh source	Emit from authored model geometry.
Function	expressions for position/direction	Procedural paths and mathematical volumes.

Arc

Circle-like shapes can restrict their angular range and choose how that range is traversed. Arc modes provide random distribution or ordered progression; loop, ping-pong, spread, and speed controls determine how emission advances.

Radius Thickness

A thickness of 0 emits on the outer surface. Larger values allow points further toward the center. Use a shell for readable outlines and a filled volume for clouds or explosions.

Mesh Sources

Universal mesh sources since 2.2.0

Mesh shapes use the same source model as Model rendering: built-in primitives, OBJ, Minecraft JSON model, or a reusable Mesh Resource. This avoids maintaining separate shape and renderer meshes.

Function Shape

Function Shape evaluates expressions for position and direction. Keep expressions deterministic and guard divisions/square roots against invalid values; a NaN spawn position cannot be rendered or collided safely.