SolidParticleSystem | Babylon.js API documentation

Class SolidParticleSystem

The SPS is a single updatable mesh. The solid particles are simply separate parts or faces of this big mesh. As it is just a mesh, the SPS has all the same properties than any other BJS mesh : not more, not less. It can be scaled, rotated, translated, enlighted, textured, moved, etc. The SPS is also a particle system. It provides some methods to manage the particles. However it is behavior agnostic. This means it has no emitter, no particle physics, no particle recycler. You have to implement your own behavior.

Full documentation here : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/sps_intro

Implements

IDisposable

Constructors

constructor

new SolidParticleSystem(
    name: string,
    scene: Scene,
    options?: {
        autoFixFaceOrientation?: boolean;
        boundingSphereOnly?: boolean;
        bSphereRadiusFactor?: number;
        computeBoundingBox?: boolean;
        enableDepthSort?: boolean;
        enableMultiMaterial?: boolean;
        expandable?: boolean;
        isPickable?: boolean;
        particleIntersection?: boolean;
        updatable?: boolean;
        useModelMaterial?: boolean;
    },
): SolidParticleSystem
Creates a SPS (Solid Particle System) object.
Parameters
- name: string
  (String) is the SPS name, this will be the underlying mesh name.
- scene: Scene
  (Scene) is the scene in which the SPS is added.
- Optionaloptions: {
      autoFixFaceOrientation?: boolean;
      boundingSphereOnly?: boolean;
      bSphereRadiusFactor?: number;
      computeBoundingBox?: boolean;
      enableDepthSort?: boolean;
      enableMultiMaterial?: boolean;
      expandable?: boolean;
      isPickable?: boolean;
      particleIntersection?: boolean;
      updatable?: boolean;
      useModelMaterial?: boolean;
  }
  defines the options of the sps e.g.
  
  updatable (optional boolean, default true) : if the SPS must be updatable or immutable.
  
  isPickable (optional boolean, default false) : if the solid particles must be pickable.
  
  enableDepthSort (optional boolean, default false) : if the solid particles must be sorted in the geometry according to their distance to the camera.
  
  useModelMaterial (optional boolean, default false) : if the model materials must be used to create the SPS multimaterial. This enables the multimaterial supports of the SPS.
  
  enableMultiMaterial (optional boolean, default false) : if the solid particles can be given different materials.
  
  expandable (optional boolean, default false) : if particles can still be added after the initial SPS mesh creation.
  
  particleIntersection (optional boolean, default false) : if the solid particle intersections must be computed.
  
  boundingSphereOnly (optional boolean, default false) : if the particle intersection must be computed only with the bounding sphere (no bounding box computation, so faster).
  
  bSphereRadiusFactor (optional float, default 1.0) : a number to multiply the bounding sphere radius by in order to reduce it for instance.
  
  computeBoundingBox (optional boolean, default false): if the bounding box of the entire SPS will be computed (for occlusion detection, for example). If it is false, the bounding box will be the bounding box of the first particle.
  
  autoFixFaceOrientation (optional boolean, default false): if the particle face orientations will be flipped for transformations that change orientation (scale (-1, 1, 1), for example)
Returns SolidParticleSystem
Example
```
bSphereRadiusFactor = 1.0 / Math.sqrt(3.0) => the bounding sphere exactly matches a spherical mesh.
```
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32406

Properties

billboard

billboard: boolean

If the particles must ever face the camera (default false). Useful for planar particles.

counter

counter: number

This a counter ofr your own usage. It's not set by any SPS functions.

depthSortedParticles

depthSortedParticles: DepthSortedParticle[]

This array is populated when enableDepthSort is set to true. Each element of this array is an instance of the class DepthSortedParticle.

mesh

mesh: Mesh

The SPS mesh. It's a standard BJS Mesh, so all the methods from the Mesh class are available.

name

name: string

The SPS name. This name is also given to the underlying mesh.

nbParticles

nbParticles: number

The SPS total number of particles. Read only. Use SPS.counter instead if you need to set your own value.

particles

particles: SolidParticle[]

The SPS array of Solid Particle objects. Just access each particle as with any classic array. Example : var p = SPS.particles[i];

pickedBySubMesh

pickedBySubMesh: { faceId: number; idx: number }[][]

This array is populated when the SPS is set as 'pickable' Each key of this array is a submesh index. Each element of this array is a second array defined like this : Each key of this second array is a faceId value that you can get from a pickResult object. Each element of this second array is an object {idx: int, faceId: int}. idx is the picked particle index in the SPS.particles array faceId is the picked face index counted within this particle. It's better to use the method SPS.pickedParticle(pickingInfo) rather than using directly this array. Please read : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/picking_sps

pickedParticles

pickedParticles: { faceId: number; idx: number }[]

This array is populated when the SPS is set as 'pickable'. Each key of this array is a faceId value that you can get from a pickResult object. Each element of this array is an object {idx: int, faceId: int}. idx is the picked particle index in the SPS.particles array faceId is the picked face index counted within this particle. This array is the first element of the pickedBySubMesh array : sps.pickBySubMesh[0]. It's not pertinent to use it when using a SPS with the support for MultiMaterial enabled. Use the method SPS.pickedParticle(pickingInfo) instead. Please read : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/picking_sps

recomputeNormals

recomputeNormals: boolean

Recompute normals when adding a shape

vars

vars: any

This empty object is intended to store some SPS specific or temporary values in order to lower the Garbage Collector activity. Please read : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/optimize_sps#limit-garbage-collection

Accessors

autoUpdateSubMeshes

get autoUpdateSubMeshes(): boolean
If the subMeshes must be updated on the next call to setParticles()

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32778
set autoUpdateSubMeshes(val: boolean): void
Parameters
- val: boolean
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32779

computeBoundingBox

get computeBoundingBox(): boolean
Gets if setParticles() computes or not the mesh bounding box when computing the particle positions.

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32740
set computeBoundingBox(val: boolean): void
Tells to setParticles() to compute or not the mesh bounding box when computing the particle positions.
Parameters
- val: boolean
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32706

computeParticleColor

get computeParticleColor(): boolean
Gets if setParticles() computes the particle colors or not. Default value : true. The SPS is faster when it's set to false. Note : the particle colors are stored values, so setting computeParticleColor to false will keep yet the last colors set.

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32724
set computeParticleColor(val: boolean): void
Tells to setParticles() to compute the particle colors or not. Default value : true. The SPS is faster when it's set to false. Note : the particle colors are stored values, so setting computeParticleColor to false will keep yet the last colors set.
Parameters
- val: boolean
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32695

computeParticleRotation

get computeParticleRotation(): boolean
Gets if setParticles() computes the particle rotations or not. Default value : true. The SPS is faster when it's set to false. Note : the particle rotations aren't stored values, so setting computeParticleRotation to false will prevents the particle to rotate.

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32718
set computeParticleRotation(val: boolean): void
Tells to setParticles() to compute the particle rotations or not. Default value : true. The SPS is faster when it's set to false. Note : the particle rotations aren't stored values, so setting computeParticleRotation to false will prevents the particle to rotate.
Parameters
- val: boolean
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32689

computeParticleTexture

get computeParticleTexture(): boolean
Gets if setParticles() computes the particle textures or not. Default value : true. The SPS is faster when it's set to false. Note : the particle textures are stored values, so setting computeParticleTexture to false will keep yet the last colors set.

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32730
set computeParticleTexture(val: boolean): void
Parameters
- val: boolean
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32696

computeParticleVertex

get computeParticleVertex(): boolean
Gets if setParticles() calls the vertex function for each vertex of each particle, or not. Default value : false. The SPS is faster when it's set to false. Note : the particle custom vertex positions aren't stored values.

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32736
set computeParticleVertex(val: boolean): void
Tells to setParticles() to call the vertex function for each vertex of each particle, or not. Default value : false. The SPS is faster when it's set to false. Note : the particle custom vertex positions aren't stored values.
Parameters
- val: boolean
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32702

depthSortParticles

get depthSortParticles(): boolean
Gets if setParticles() sorts or not the distance between each particle and the camera. Skipped when enableDepthSort is set to false (default) at construction time. Default : true

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32746
set depthSortParticles(val: boolean): void
Tells to setParticles() to sort or not the distance between each particle and the camera. Skipped when enableDepthSort is set to false (default) at construction time. Default : true
Parameters
- val: boolean
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32712

expandable

get expandable(): boolean
Gets if the SPS is created as expandable at construction time. Default : false

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32751

isAlwaysVisible

get isAlwaysVisible(): boolean
Gets whether the SPS as always visible or not doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/sps_visibility

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32668
set isAlwaysVisible(val: boolean): void
Sets the SPS as always visible or not doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/sps_visibility
Parameters
- val: boolean
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32673

isVisibilityBoxLocked

get isVisibilityBoxLocked(): boolean
Gets if the SPS visibility box as locked or not. This enables/disables the underlying mesh bounding box updates. doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/sps_visibility

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32683
set isVisibilityBoxLocked(val: boolean): void
Sets the SPS visibility box as locked or not. This enables/disables the underlying mesh bounding box updates. doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/sps_visibility
Parameters
- val: boolean
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32678

materials

get materials(): Material[]
The SPS used material array.

Returns Material[]
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32763

multimaterial

get multimaterial(): MultiMaterial
The SPS computed multimaterial object

Returns MultiMaterial
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32773
set multimaterial(mm: MultiMaterial): void
Parameters
- mm: MultiMaterial
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32774

multimaterialEnabled

get multimaterialEnabled(): boolean
Gets if the SPS supports the Multi Materials

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32755

useModelMaterial

get useModelMaterial(): boolean
Gets if the SPS uses the model materials for its own multimaterial.

Returns boolean
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32759

Methods

addShape

addShape(
    mesh: Mesh,
    nb: number,
    options?: { positionFunction?: any; storage?: []; vertexFunction?: any },
): number
Adds some particles to the SPS from the model shape. Returns the shape id. Please read the doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/immutable_sps
Parameters
- mesh: Mesh
  is any Mesh object that will be used as a model for the solid particles. If the mesh does not have vertex normals, it will turn on the recomputeNormals attribute.
- nb: number
  (positive integer) the number of particles to be created from this model
- Optionaloptions: { positionFunction?: any; storage?: []; vertexFunction?: any }
  {positionFunction} is an optional javascript function to called for each particle on SPS creation. {vertexFunction} is an optional javascript function to called for each vertex of each particle on SPS creation {storage} (optional existing array) is an array where the particles will be stored for a further use instead of being inserted in the SPS.
Returns number
the number of shapes in the system
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32523

afterUpdateParticles

afterUpdateParticles(start?: number, stop?: number, update?: boolean): void
This will be called by setParticles() after all the other treatments and just before the actual mesh update. This will be passed three parameters. This does nothing and may be overwritten by the user.
Parameters
- Optionalstart: number
  the particle index in the particle array where to stop to iterate, same than the value passed to setParticle()
- Optionalstop: number
  the particle index in the particle array where to stop to iterate, same than the value passed to setParticle()
- Optionalupdate: boolean
  the boolean update value actually passed to setParticles()
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32830

beforeUpdateParticles

beforeUpdateParticles(start?: number, stop?: number, update?: boolean): void
This will be called before any other treatment by setParticles() and will be passed three parameters. This does nothing and may be overwritten by the user.
Parameters
- Optionalstart: number
  the particle index in the particle array where to stop to iterate, same than the value passed to setParticle()
- Optionalstop: number
  the particle index in the particle array where to stop to iterate, same than the value passed to setParticle()
- Optionalupdate: boolean
  the boolean update value actually passed to setParticles()
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32821

buildMesh

buildMesh(): Mesh
Builds the SPS underlying mesh. Returns a standard Mesh. If no model shape was added to the SPS, the returned mesh is just a single triangular plane.

Returns Mesh
the created mesh
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32424

computeSubMeshes

computeSubMeshes(): SolidParticleSystem
Computes the required SubMeshes according the materials assigned to the particles.

Returns SolidParticleSystem
the solid particle system. Does nothing if called before the SPS mesh is built.
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32625

digest

digest(
    mesh: Mesh,
    options?: {
        delta?: number;
        facetNb?: number;
        number?: number;
        storage?: [];
        uvKind?: number;
    },
): SolidParticleSystem
Digests the mesh and generates as many solid particles in the system as wanted. Returns the SPS. These particles will have the same geometry than the mesh parts and will be positioned at the same localisation than the mesh original places. Thus the particles generated from digest() have their property position set yet.
Parameters
- mesh: Mesh
  ( Mesh ) is the mesh to be digested
- Optionaloptions: {
      delta?: number;
      facetNb?: number;
      number?: number;
      storage?: [];
      uvKind?: number;
  }
  {facetNb} (optional integer, default 1) is the number of mesh facets per particle, this parameter is overridden by the parameter number if any {delta} (optional integer, default 0) is the random extra number of facets per particle , each particle will have between facetNb and facetNb + delta facets {number} (optional positive integer) is the wanted number of particles : each particle is built with mesh_total_facets / number facets {storage} (optional existing array) is an array where the particles will be stored for a further use instead of being inserted in the SPS. {uvKind} (optional positive integer, default 0) is the kind of UV to read from. Use -1 to deduce it from the diffuse/albedo texture (if any) of the mesh material
Returns SolidParticleSystem
the current SPS
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32443

dispose

dispose(): void
Disposes the SPS.

Returns void
Implementation of IDisposable.dispose
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32589

getParticleById

getParticleById(id: number): Nullable<SolidParticle>
Returns a SolidParticle object from its identifier : particle.id
Parameters
- id: number
  (integer) the particle Id
Returns Nullable<SolidParticle>
the searched particle or null if not found in the SPS.
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32606

getParticlesByShapeId

getParticlesByShapeId(shapeId: number): SolidParticle[]
Returns a new array populated with the particles having the passed shapeId.
Parameters
- shapeId: number
  (integer) the shape identifier
Returns SolidParticle[]
a new solid particle array
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32612

getParticlesByShapeIdToRef

getParticlesByShapeIdToRef(
shapeId: number,
ref: SolidParticle[],
): SolidParticleSystem
Populates the passed array "ref" with the particles having the passed shapeId.
Parameters
- shapeId: number
  the shape identifier
- ref: SolidParticle[]
  array to populate
Returns SolidParticleSystem
the SPS
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32619

initParticles

initParticles(): void
This function does nothing. It may be overwritten to set all the particle first values. The SPS doesn't call this function, you may have to call it by your own. doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/manage_sps_particles

Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32785

insertParticlesFromArray

insertParticlesFromArray(
solidParticleArray: SolidParticle[],
): SolidParticleSystem
Inserts some pre-created particles in the solid particle system so that they can be managed by setParticles().
Parameters
- solidParticleArray: SolidParticle[]
  an array populated with Solid Particles objects
Returns SolidParticleSystem
the SPS
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32554

pickedParticle

pickedParticle(
pickingInfo: PickingInfo,
): Nullable<{ faceId: number; idx: number }>
Returns an object {idx: number faceId: number} for the picked particle from the passed pickingInfo object. idx is the particle index in the SPS faceId is the picked face index counted within this particle. Returns null if the pickInfo can't identify a picked particle.
Parameters
- pickingInfo: PickingInfo
  (PickingInfo object)
Returns Nullable<{ faceId: number; idx: number }>
or null
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32597

rebuildMesh

rebuildMesh(reset?: boolean): SolidParticleSystem
Rebuilds the whole mesh and updates the VBO : custom positions and vertices are recomputed if needed.
Parameters
- Optionalreset: boolean
  boolean, default false : if the particles must be reset at position and rotation zero, scaling 1, color white, initial UVs and not parented.
Returns SolidParticleSystem
the SPS.
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32538

recycleParticle

recycleParticle(particle: SolidParticle): SolidParticle
This function does nothing. It may be overwritten to recycle a particle. The SPS doesn't call this function, you may have to call it by your own. doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/manage_sps_particles
Parameters
- particle: SolidParticle
  The particle to recycle
Returns SolidParticle
the recycled particle
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32793

refreshVisibleSize

refreshVisibleSize(): SolidParticleSystem
Visibility helper : Recomputes the visible size according to the mesh bounding box doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/sps_visibility

Returns SolidParticleSystem
the SPS.
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32656

removeParticles

removeParticles(start: number, end: number): SolidParticle[]
Removes the particles from the start-th to the end-th included from an expandable SPS (required). Returns an array with the removed particles. If the number of particles to remove is lower than zero or greater than the global remaining particle number, then an empty array is returned. The SPS can't be empty so at least one particle needs to remain in place. Under the hood, the VertexData array, so the VBO buffer, is recreated each call.
Parameters
- start: number
  index of the first particle to remove
- end: number
  index of the last particle to remove (included)
Returns SolidParticle[]
an array populated with the removed particles
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32548

setMultiMaterial

setMultiMaterial(materials: Material[]): void
Sets the SPS MultiMaterial from the passed materials. Note : the passed array is internally copied and not used then by reference.
Parameters
- materials: Material[]
  an array of material objects. This array indexes are the materialIndex values of the particles.
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32769

setParticles

setParticles(
    start?: number,
    end?: number,
    update?: boolean,
): SolidParticleSystem
Sets all the particles : this method actually really updates the mesh according to the particle positions, rotations, colors, textures, etc. This method calls updateParticle() for each particle of the SPS. For an animated SPS, it is usually called within the render loop. This methods does nothing if called on a non updatable or not yet built SPS. Example : buildMesh() not called after having added or removed particles from an expandable SPS.
Parameters
- Optionalstart: number
  The particle index in the particle array where to start to compute the particle property values (default 0)
- Optionalend: number
  The particle index in the particle array where to stop to compute the particle property values (default nbParticle - 1)
- Optionalupdate: boolean
  If the mesh must be finally updated on this call after all the particle computations (default true)
Returns SolidParticleSystem
the SPS.
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32585

setVisibilityBox

setVisibilityBox(size: number): void
Visibility helper : Sets the size of a visibility box, this sets the underlying mesh bounding box.
Parameters
- size: number
  the size (float) of the visibility box note : this doesn't lock the SPS mesh bounding box. doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/sps_visibility
Returns void
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32663

updateParticle

updateParticle(particle: SolidParticle): SolidParticle
Updates a particle : this function should be overwritten by the user. It is called on each particle by setParticles(). This is the place to code each particle behavior. doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/manage_sps_particles
Parameters
- particle: SolidParticle
  The particle to update
Returns SolidParticle
the updated particle
Example
```
: just set a particle position or velocity and recycle conditions
```
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32802

updateParticleVertex

updateParticleVertex(
    particle: SolidParticle,
    vertex: SolidParticleVertex,
    pt: number,
): SolidParticleSystem
Updates a vertex of a particle : it can be overwritten by the user. This will be called on each vertex particle by setParticles() if computeParticleVertex is set to true only.
Parameters
- particle: SolidParticle
  the current particle
- vertex: SolidParticleVertex
  the current vertex of the current particle : a SolidParticleVertex object
- pt: number
  the index of the current vertex in the particle shape doc : https://doc.babylonjs.com/features/featuresDeepDive/particles/solid_particle_system/sps_vertices
Returns SolidParticleSystem
the sps
Example
```
: just set a vertex particle position or color
```
- Defined in .temp/typedoc/docdirectory/doc.d.ts:32813

Class SolidParticleSystem

Implements

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Parameters

Returns SolidParticleSystem

Example

Properties

billboard

counter

depthSortedParticles

mesh

name

nbParticles

particles

pickedBySubMesh

pickedParticles

recomputeNormals

vars

Accessors

autoUpdateSubMeshes

Returns boolean

Parameters

Returns void

computeBoundingBox

Returns boolean

Parameters

Returns void

computeParticleColor

Returns boolean

Parameters

Returns void

computeParticleRotation

Returns boolean

Parameters

Returns void

computeParticleTexture

Returns boolean

Parameters

Returns void

computeParticleVertex

Returns boolean

Parameters

Returns void

depthSortParticles

Returns boolean

Parameters

Returns void

expandable

Returns boolean

isAlwaysVisible

Returns boolean

Parameters

Returns void

isVisibilityBoxLocked

Returns boolean

Parameters

Returns void

materials

Returns Material[]

multimaterial

Returns MultiMaterial

Parameters

Returns void

multimaterialEnabled

Returns boolean

useModelMaterial

Returns boolean

Methods

addShape

Parameters

Returns number

afterUpdateParticles

Parameters

Returns void