Class reference

GPUParticles3D

Inherits GeometryInstance3D

A 3D particle emitter.

Description

3D particle node used to create a variety of particle systems and effects. GPUParticles3D features an emitter that generates some number of particles at a given rate. Use process_material to add a ParticleProcessMaterial to configure particle appearance and behavior. Alternatively, you can add a ShaderMaterial which will be applied to all particles.

Properties

`int amount = 8`

The number of particles to emit in one emission cycle. The effective emission rate is (amount * amount_ratio) / lifetime particles per second. Higher values will increase GPU requirements, even if not all particles are visible at a given time or if amount_ratio is decreased. Note: Changing this value will cause the particle system to restart. To avoid this, change amount_ratio instead.

`float amount_ratio = 1.0`

The ratio of particles that should actually be emitted. If set to a value lower than 1.0, this will set the amount of emitted particles throughout the lifetime to amount * amount_ratio. Unlike changing amount, changing amount_ratio while emitting does not affect already-emitted particles and doesn't cause the particle system to restart. amount_ratio can be used to create effects that make the number of emitted particles vary over time. Note: Reducing the amount_ratio has no performance benefit, since resources need to be allocated and processed for the total amount of particles regardless of the amount_ratio. If you don't intend to change the number of particles emitted while the particles are emitting, make sure amount_ratio is set to 1 and change amount to your liking instead.

`float collision_base_size = 0.01`

The base diameter for particle collision in meters. If particles appear to sink into the ground when colliding, increase this value. If particles appear to float when colliding, decrease this value. Only effective if ParticleProcessMaterial.collision_mode is ParticleProcessMaterial.COLLISION_RIGID or ParticleProcessMaterial.COLLISION_HIDE_ON_CONTACT. Note: Particles always have a spherical collision shape.

`int draw_order = 0`

Particle draw order. Note: DRAW_ORDER_INDEX is the only option that supports motion vectors for effects like TAA. It is suggested to use this draw order if the particles are opaque to fix ghosting artifacts.

`Mesh draw_pass_1`

Mesh that is drawn for the first draw pass.

`Mesh draw_pass_2`

Mesh that is drawn for the second draw pass.

`Mesh draw_pass_3`

Mesh that is drawn for the third draw pass.

`Mesh draw_pass_4`

Mesh that is drawn for the fourth draw pass.

`int draw_passes = 1`

The number of draw passes when rendering particles.

`Skin draw_skin`

`bool emitting = true`

If true, particles are being emitted. emitting can be used to start and stop particles from emitting. However, if one_shot is true setting emitting to true will not restart the emission cycle unless all active particles have finished processing. Use the finished signal to be notified once all active particles finish processing. Note: For one_shot emitters, due to the particles being computed on the GPU, there may be a short period after receiving the finished signal during which setting this to true will not restart the emission cycle. Tip: If your one_shot emitter needs to immediately restart emitting particles once finished signal is received, consider calling restart() instead of setting emitting.

`float explosiveness = 0.0`

Time ratio between each emission. If 0, particles are emitted continuously. If 1, all particles are emitted simultaneously.

`int fixed_fps = 30`

The particle system's frame rate is fixed to a value. For example, changing the value to 2 will make the particles render at 2 frames per second. Note this does not slow down the simulation of the particle system itself.

`bool fract_delta = true`

If true, results in fractional delta calculation which has a smoother particles display effect.

`float interp_to_end = 0.0`

Causes all the particles in this node to interpolate towards the end of their lifetime. Note: This only works when used with a ParticleProcessMaterial. It needs to be manually implemented for custom process shaders.

`bool interpolate = true`

Enables particle interpolation, which makes the particle movement smoother when their fixed_fps is lower than the screen refresh rate.

`float lifetime = 1.0`

The amount of time each particle will exist (in seconds). The effective emission rate is (amount * amount_ratio) / lifetime particles per second.

`bool local_coords = false`

If true, particles use the parent node's coordinate space (known as local coordinates). This will cause particles to move and rotate along the GPUParticles3D node (and its parents) when it is moved or rotated. If false, particles use global coordinates; they will not move or rotate along the GPUParticles3D node (and its parents) when it is moved or rotated.

`bool one_shot = false`

If true, only the number of particles equal to amount will be emitted.

`float preprocess = 0.0`

Amount of time to preprocess the particles before animation starts. Lets you start the animation some time after particles have started emitting. Note: This can be very expensive if set to a high number as it requires running the particle shader a number of times equal to the fixed_fps (or 30, if fixed_fps is 0) for every second. In extreme cases it can even lead to a GPU crash due to the volume of work done in a single frame.

`Material process_material`

Material for processing particles. Can be a ParticleProcessMaterial or a ShaderMaterial.

`float randomness = 0.0`

Emission randomness ratio.

`int seed = 0`

Sets the random seed used by the particle system. Only effective if use_fixed_seed is true.

`float speed_scale = 1.0`

Speed scaling ratio. A value of 0 can be used to pause the particles.

`NodePath sub_emitter = NodePath("")`

Path to another GPUParticles3D node that will be used as a subemitter (see ParticleProcessMaterial.sub_emitter_mode). Subemitters can be used to achieve effects such as fireworks, sparks on collision, bubbles popping into water drops, and more. Note: When sub_emitter is set, the target GPUParticles3D node will no longer emit particles on its own.

`bool trail_enabled = false`

If true, enables particle trails using a mesh skinning system. Designed to work with RibbonTrailMesh and TubeTrailMesh. Note: BaseMaterial3D.use_particle_trails must also be enabled on the particle mesh's material. Otherwise, setting trail_enabled to true will have no effect. Note: Unlike GPUParticles2D, the number of trail sections and subdivisions is set in the RibbonTrailMesh or the TubeTrailMesh's properties.

`float trail_lifetime = 0.3`

The amount of time the particle's trail should represent (in seconds). Only effective if trail_enabled is true.

`int transform_align = 0`

`bool use_fixed_seed = false`

If true, particles will use the same seed for every simulation using the seed defined in seed. This is useful for situations where the visual outcome should be consistent across replays, for example when using Movie Maker mode.

`AABB visibility_aabb = AABB(-4, -4, -4, 8, 8, 8)`

The AABB that determines the node's region which needs to be visible on screen for the particle system to be active. GeometryInstance3D.extra_cull_margin is added on each of the AABB's axes. Particle collisions and attraction will only occur within this area. Grow the box if particles suddenly appear/disappear when the node enters/exits the screen. The AABB can be grown via code or with the Particles → Generate AABB editor tool. Note: visibility_aabb is overridden by GeometryInstance3D.custom_aabb if that property is set to a non-default value.

Methods

`AABB capture_aabb() const`

Returns the axis-aligned bounding box that contains all the particles that are active in the current frame.

`void convert_from_particles(Node particles)`

Sets this node's properties to match a given CPUParticles3D node.

`void emit_particle(Transform3D xform, Vector3 velocity, Color color, Color custom, int flags)`

Emits a single particle. Whether xform, velocity, color and custom are applied depends on the value of flags. See EmitFlags. The default ParticleProcessMaterial will overwrite color and use the contents of custom as (rotation, age, animation, lifetime). Note: emit_particle() is only supported on the Forward+ and Mobile rendering methods, not Compatibility.

`Mesh get_draw_pass_mesh(int pass) const`

Returns the Mesh that is drawn at index pass.

`void request_particles_process(float process_time)`

Requests the particles to process for extra process time during a single frame. Useful for particle playback, if used in combination with use_fixed_seed or by calling restart() with parameter keep_seed set to true.

`void restart(bool keep_seed = false)`

Restarts the particle emission cycle, clearing existing particles. To avoid particles vanishing from the viewport, wait for the finished signal before calling. Note: The finished signal is only emitted by one_shot emitters. If keep_seed is true, the current random seed will be preserved. Useful for seeking and playback.

`void set_draw_pass_mesh(int pass, Mesh mesh)`

Sets the Mesh that is drawn at index pass.

Signals