Particles Vfx

Particle Systems in Godot 4.3+

All examples target Godot 4.3+ with no deprecated APIs. GDScript is shown first, then C#.

Related skills: shader-basics for custom particle shaders, 3d-essentials for lighting and environment that affect particles, 2d-essentials for 2D rendering context, tween-animation for code-driven VFX timing, godot-optimization for particle performance tuning.

1. Core Concepts

GPU vs CPU Particles

Rule of thumb: Use GPU particles by default. Switch to CPU particles only for low-end/web targets or when you need CPU-side particle positions (e.g., spawning objects at particle locations).

You can convert between GPU and CPU particles in the editor: select the node → toolbar → Convert to CPUParticles2D/3D (or vice versa).

Particle System Architecture

Copy code
GPUParticles2D/3D
├── Process Material (ParticleProcessMaterial)   ← physics, emission, color
├── Draw Pass 1 (Mesh)                            ← what each particle looks like
└── (Optional) Draw Pass 2-4                      ← additional meshes

Minimal Setup

1. Add a GPUParticles2D (or 3D) node
2. In Inspector → Process Material → New ParticleProcessMaterial
3. Set Amount (number of particles)
4. Configure emission, direction, velocity, gravity
5. (2D) Set Texture for particle appearance
6. (3D) Set Draw Pass 1 mesh (QuadMesh for billboards, or custom mesh)

2. Key Node Properties

GPUParticles2D/3D Properties

One-Shot vs Continuous

gdscriptCopy code
# Continuous emitter (fire, smoke, ambient dust)
$GPUParticles2D.one_shot = false
$GPUParticles2D.emitting = true

# One-shot burst (explosion, impact splash)
$GPUParticles2D.one_shot = true
$GPUParticles2D.emitting = false  # arm it
# Later, trigger:
$GPUParticles2D.restart()
$GPUParticles2D.emitting = true

csharpCopy code
// Continuous
var particles = GetNode<GpuParticles2D>("GPUParticles2D");
particles.OneShot = false;
particles.Emitting = true;

// One-shot burst
particles.OneShot = true;
particles.Emitting = false;
// Trigger:
particles.Restart();
particles.Emitting = true;

Local Billboard Alignment (Godot 4.7+)

GPUParticles3D gains TRANSFORM_ALIGN_LOCAL_BILLBOARD (= 4): each particle's Z axis faces the camera while preserving a given axis — X or Y, chosen via transform_align_axis. For billboarded particles, transform_align_channel_filter selects which custom channel to read to calculate their angle. ParticleProcessMaterial pairs this with per-axis rotation velocity: enable use_rotation_velocity_3d, then set rotation_velocity_3d_min/max (Vector3, on the particle's local axes) and optionally rotation_velocity_3d_curve (per-axis curve over lifetime).

gdscriptCopy code
# 3D only — billboard toward the camera while keeping the Y axis fixed.
# Assumes a ParticleProcessMaterial is assigned (section 1 setup).
$GPUParticles3D.transform_align = GPUParticles3D.TRANSFORM_ALIGN_LOCAL_BILLBOARD
$GPUParticles3D.transform_align_axis = RenderingServer.PARTICLES_ALIGN_AXIS_Y

var mat: ParticleProcessMaterial = $GPUParticles3D.process_material
mat.use_rotation_velocity_3d = true
mat.rotation_velocity_3d_min = Vector3(-2.0, 0.0, 0.0)
mat.rotation_velocity_3d_max = Vector3(2.0, 0.0, 0.0)

csharpCopy code
// Assumes a ParticleProcessMaterial is assigned (section 1 setup).
var particles = GetNode<GpuParticles3D>("GPUParticles3D");
particles.TransformAlign = GpuParticles3D.TransformAlignEnum.LocalBillboard;
particles.TransformAlignAxis = RenderingServer.ParticlesTransformAlignAxis.Y;

var mat = (ParticleProcessMaterial)particles.ProcessMaterial;
mat.UseRotationVelocity3D = true;
mat.RotationVelocity3DMin = new Vector3(-2.0f, 0.0f, 0.0f);
mat.RotationVelocity3DMax = new Vector3(2.0f, 0.0f, 0.0f);

3. ParticleProcessMaterial — Essential Properties

The material drives per-particle behavior: emission shape (Point / Sphere / Box / Ring / Points / Directed Points), direction + spread + initial velocity, gravity, scale and color over lifetime (via scale_curve / color_ramp), damping, radial/tangential acceleration, and angular velocity.

See references/process-material-basics.md for the emission-shape table and GDScript + C# snippets for each property group.

Per-Axis 3D Scale & Rotation (Godot 4.7+)

Randomize scale and initial orientation per axis instead of uniformly. use_scale_3d enables scale_3d_min/max (Vector3 random scale per particle); use_rotation_3d enables rotation_3d_min/max (Vector3, degrees — works only in 3D).

gdscriptCopy code
mat.use_scale_3d = true
mat.scale_3d_min = Vector3(0.5, 1.0, 0.5)
mat.scale_3d_max = Vector3(1.0, 2.0, 1.0)

mat.use_rotation_3d = true  # 3D only
mat.rotation_3d_min = Vector3(0.0, -180.0, 0.0)  # degrees
mat.rotation_3d_max = Vector3(0.0, 180.0, 0.0)

csharpCopy code
mat.UseScale3D = true;
mat.Scale3DMin = new Vector3(0.5f, 1.0f, 0.5f);
mat.Scale3DMax = new Vector3(1.0f, 2.0f, 1.0f);

mat.UseRotation3D = true;  // 3D only
mat.Rotation3DMin = new Vector3(0.0f, -180.0f, 0.0f);  // degrees
mat.Rotation3DMax = new Vector3(0.0f, 180.0f, 0.0f);

Inheriting Emitter Scale (Godot 4.7+)

particle_flag_inherit_emitter_scale (default false): if true, particles inherit the scale of the emitter node. Has no effect when local_coords is true, since particles in local space are already affected by the emitter's scale.

gdscriptCopy code
mat.particle_flag_inherit_emitter_scale = true

csharpCopy code
mat.ParticleFlagInheritEmitterScale = true;

4. Common VFX Recipes

The recipes most projects need: fire (2D, looped emission with hot-color gradient + scale-down), explosion burst (one-shot, high-amount short-lifetime), dust / footstep puff (one-shot, scale-up + rapid fade).

See references/vfx-recipes.md for ready-to-use GDScript wiring and recommended ParticleProcessMaterial settings for all three.

5. Trails (Forward+ and Mobile only)

Set trail_enabled = true on GPUParticles2D/3D and assign a Mesh (RibbonTrailMesh or TubeTrailMesh). Trails are NOT supported in the Compatibility renderer.

See references/trails.md for the setup and trail-mesh-type comparison.

6. Subemitters

A particle can spawn another particle scene at lifecycle events (birth, collision, death, manual). Configure via ParticleProcessMaterial.SubEmitterMode + subemitter property on the parent particles node.

See references/subemitters.md for trigger modes, scene setup, GDScript and C# (v1.6.0 parity), and limitations.

⚠️ Changed in Godot 4.7: Subemitter velocity inheritance was reworked (GH-118062). With sub_emitter_keep_velocity = true (default false), subemitted particles inherit the parent particle's velocity when they spawn. Subemitter effects authored on earlier versions may look different after upgrading — re-check initial velocity and spread on affected systems.

7. Attractors & Collision (3D)

GPUParticlesAttractor*3D (Box / Sphere / Vector Field) pulls particles toward a region. GPUParticlesCollision*3D (Box / Sphere / SDF / HeightField) lets particles bounce off geometry. Both Forward+/Mobile only; no 2D equivalents.

See references/attractors-and-collision.md for full setup of each attractor and collision type.

8. Turbulence

Set turbulence_enabled = true on ParticleProcessMaterial and tune turbulence_noise_strength (0.5–2.0 typical), turbulence_noise_scale (lower = larger swirls), turbulence_noise_speed (animate the noise field). Cheap effect for "alive" smoke, fire, dust.

9. Flipbook Animation (2D)

Sprite-sheet animated particles via ParticleProcessMaterial.AnimSpeedMin/Max + CanvasItemMaterial.ParticlesAnimHFrames/VFrames for the sheet layout. Particles cycle through frames over their lifetime.

See references/flipbook-animation.md for the full setup with GDScript + C# (v1.6.0 parity).

10. Performance and Common Pitfalls

The biggest wins are the obvious ones: keep amount at the minimum that reads well, set fixed_fps = 30 for ambient systems, always set visibility_rect on 2D particles, and expose amount_ratio as a quality slider. Godot 4.7+ adds request_particles_process() for seeking a paused timeline.

Most "broken particles" reports are one of eleven known causes — invisible (no texture / no draw-pass mesh), vanishing (lifetime too short), one-shot not re-firing (needs restart() first), wrong direction (2D Y is inverted), or a base color silently overriding color_ramp.

Full performance table, the 4.7+ timeline-seek API, dynamic quality scaling (GDScript + C#), and the complete symptom/cause/fix table: references/performance-and-pitfalls.md

11. Implementation Checklist

• Particle amount is set to the minimum needed for the visual effect
• lifetime matches the visual duration — not too short or too long
• one_shot is enabled for burst effects (explosions, impacts)
• preprocess is set for always-visible ambient effects (fire, smoke, dust)
• Emission shape matches the source geometry (sphere for explosions, box for area effects)
• color_ramp fades alpha to 0 at the end so particles don't vanish abruptly
• scale_curve shrinks particles over lifetime for natural fade
• local_coords is set correctly — true for attached effects, false for world-space
• One-shot particles are cleaned up with queue_free after lifetime + margin
• visibility_rect (2D) is set to prevent particles from being culled prematurely
• Dynamic quality scaling uses amount_ratio for player-accessible quality settings
• Performance-heavy features (turbulence, trails) are disabled on low-end targets