Physics, Noise, Lighting, and UV

The UV animation fixture previews tiled frames while its particle and renderer settings remain visible in the editor.

These modules affect different stages of a particle: Physics resolves gravity, friction, and collision, Noise perturbs simulated state, Fixed Light sets the vanilla lightmap value, and UV Animation selects texture frames.

Physics and Collision

Changed 2.2.9

The Physics module adds gravity and friction, and turns on collision through Has Collision. Since 2.2.9, particles collide with block shapes, fluid surfaces, entities, and Collider objects, and the collision is swept, so fast particles no longer pass through thin walls.

• Bounce Rate is restitution: the share of the speed into the surface kept on a bounce.
• Bounce Chance is rolled on every impact; a particle that does not bounce slides along the surface.
• Collided Friction slows only the sliding part of the velocity, and only while the particle touches a surface.
• Avoid invalid curves that can produce NaN position or velocity.

See Particle Collision for every collision option, Collider objects, collision events, performance, and the behaviour changes from 2.2.8.

Noise

Noise can perturb position, rotation, and size. frequency controls how quickly the field changes; quality trades work for smoother variation. Remap converts raw noise into a useful output range.

Use low-frequency noise for smoke drift and high-frequency noise for sparks or electrical jitter. Applying strong noise to both position and velocity-like modules can make motion difficult to predict.

Fixed Light

The Fixed Light module sets the vanilla lightmap value of each particle: a Sky Light and a Block Light function (0–15) over the particle lifetime. It is on by default at 15/15, so particles render full-bright. Turn it off to use the world's light at the particle position. Fixed bright values are useful for magical or emissive-looking effects, while actual HDR emission belongs in the material/shader.

Fixed Light only changes the vanilla lightmap. To make particles cast light, use Light Emission; to light particles by nearby dynamic lights, use Lit by Dynamic Lights on the material. See Dynamic Lights for the whole system.

Light values and material emission solve different problems: light affects Minecraft shading; HDR emission feeds bloom.

UV Animation

UV Animation divides a texture into tiles and chooses a frame over time.

Setting	Meaning
tiles	Columns and rows in the sheet.
animation	Whole sheet or configured animation mode.
frameOverTime	Function that selects progress through frames.
startFrame	Per-particle starting frame offset.
cycle	Number of sheet traversals over the sampling interval.

Use nearest/pixel-art material settings for hard-edged sprite sheets. Incorrect tile counts sample neighbouring sprites or empty texture space.

Performance Checklist

• Collision and high-quality noise are per-particle CPU costs. Enable only the collision targets you need; with Parallel Update on, collision emitters can run on worker threads (see Particle Collision).
• World light (Fixed Light off) queries loaded world positions; keep large systems within reasonable bounds.
• UV animation is cheap, but oversized transparent textures still cost fill rate.
• Test with the real maximum particle count, not only the editor's first seconds.