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Overview

This category affects the location of the particles that will be placed in the game world. By default, new born particles are always placed in the same location as the Particle Emitter or their parent particle location (learn more about parent-child relationships here: SecondGen). Some of the location features also allows the changing of velocities or the changing of particle location, even after a particle has been spawned.

A very important aspect to take into account is the fact that these features can be combined with each other. Using the right type of combination(s) allows you to create striking and advanced effects.

The following options are available under the Location category:  

Beam

Spawn particles in a consecutive line forming a beam between a source and a destination. This feature is best used paired with Spawn:Count (Spawn) and Render:Ribbons (Render).

PropertyDescription
SourceStart location of the beam.
DestinationEnd location of the beam.

Both source and destination are internally treated as targets which have the following properties:

Target PropertyDescription
Source drop-down menu

The location that the target uses as a source (not to be confused with beam source, which is the location at which the beam starts).

  • Self: Uses the new born particle position itself as a source.
  • Parent: Uses the parent position (or emitter position if there is no parent present) as a source.
  • Target: Particle emitter's target position (usually another game entity) as a source. For more information on targeting, see Key Concepts about Emitter Targets.
OffsetAdditional offset applied to the source in localspace (X, Y and Z).

BindToCamera

This feature allows the new born particles to spawn relative to the camera instead of its parent or emitter. All other Location and Velocity features will then be relative to the camera. Useful for certain types of screen effects.

PropertyDescription
Spawn OnlyIf enabled, spawns new born particles relative to the camera, but then they will behave like regular particles. If enabled, particles will be permanently attached to the camera.

Box

This feature allows the new born particles to be randomly but uniformly placed within a box. This option can also be used to create uniform planes and uniform lines by collapsing one or two axes.

PropertyDescription
DimensionLet's you configure the size of the box in X (width), Y (length) and Z (height). Setting a zero value to an axis will collapse that dimension. When a single axis is collapsed it creates a plane. When two axes are collapsed it results in a line.
ScaleAllows you to scale up or down the dimension. This option is useful when used with Modifiers.

Circle

This feature allows the new born particles to be randomly but uniformly placed in a circle around the parent particleThis circle is in the plane XY of the parent. When you rotate the parent the circle will also rotate.

PropertyDescription
RadiusSpecifies the radius of the circle in meters. By default, it spawns the particles on the perimeter of a circle until Modifiers are used. When the Random modifier is set to 100%, particles can be uniformly spawned within the circle instead of spawning around the perimeter.
VelocitySpecifies initial particle velocity in meters per second. Positive values make particles move in an XY plane outwards from the center. Negative values make particles move in an XY plane inwards toward the center.
Axis ScaleEnables the scaling of X and Y axes individually. Use this to create ellipses instead of circles.
AxisSpecifies which axis, relative to the parent particle or emitter that should be perpendicular to the circle's plane. For example, if Y axis value is set to (0, 1, 0) the circle will be displayed in the XoZ plane.

Geometry

This feature allows the new born particles to be randomly but uniformly distributed along a mesh geometry. 

Icon

When parent particles are not meshes or the component does not have SecondGen category, then the emitter needs to be linked to another entity that has a mesh.

PropertyDescription
Source

Specifies the geometrical source of locations, The following options are available:

  • Render: Receives location details from the mesh used to render linked entity.
  • Physics: Receives location details from the linked physical entity.
Location

Specifies the location from where the particles should be emitted. The following options are available:

  • Vertices: Grabs the positions from the mesh vertices. Note: Might not work when the source is set to physics and the mesh does not have any vertices (like perfect spheres).
  • Edges: Locates new particles along the edges of the source mesh. Note: Might not work when the source is set to physics and the mesh does not have any edges (like perfect spheres).
  • Surface: Uniformly places the new particles along the surface of the source mesh.
  • Volume: If the source is Physics and the mesh is a well defined geometric shape (like spheres, boxes or capsules), uniformly distributes particles inside the defined volume. When the mesh source is Render or the physics mesh is a triangle soup, uniformly spawns particles within the third degree simplex that connects the origin of the source mesh. This type of distribution works well if the source mesh is strictly convex and contains its origin.
OffsetBy default, places the particles exactly on the mesh. Offset displaces the particles using the normal. This property is defined in meters.
VelocitySpecifies the initial particle velocity in meters per second. Its orientation is the same as the normal.
Orient ParticlesRotates the particle in Euler space so that the forward vector of the particle matches the normal of the spawning location. Given enough particles, they can recreate the underlying mesh almost perfectly. For more information on Euler angles, see Roatet3D section under Angles.

Noise

This feature displaces the particle location using a potential vector field based on a simplex noise. This feature can distort and randomly shape the other location features while maintaining their geometric features without getting fuzzy or diffused.

PropertyDescription
AmplitudeSpecifies how far particles can move away from their original location (in meters).
SizeNoise uses Simplex Noise to generate a vector field, which is similar to Perlin Noise, but can be more efficient in some cases. This type of noise creates a uniform grid of vertices in space and sets a random value to each vertex. The actual displacement added to the particle is interpolated from this grid. Size therefore, specifies the distance between these vertices in this grid. If size is too small, noise will start to get more random, fuzzy and diffuse. If size is too large, particles will start to displace mostly to the same direction and no interesting shapes will arise.
RateOne of the main advantages of Simplex Noise is that it is relatively efficient in generating a smooth noise in space, although those can also smoothly evolve over time - Rate controls how fast this evolution takes place. A value of 0 means no evolution and noise will always result in the same shape for particles coming from the same location.
OctavesAdds additional complexity by sampling the noise field multiple times with different sizes. This creates what is known as Fractal Noise. Note: Octaves multiples the number of times the noise is sampled.

Offset

This feature displaces the particles in a given direction in space. While seemingly not a very interesting feature in itself, by combining multiple features together and using Modifiers on the scale parameter it makes the Offset feature one of the most powerful features in the Location toolbox. In fact, most of the location features in this page could in theory be recreated by just using this feature (although not in a very practical way).

PropertyDescription
OffsetSpecifies spatial offset (in meters) to add to each new born.
ScaleScales the size of the offset vector. Can be used with Modifiers to change particle location dynamically.

Omni

This feature causes the effect to be omnipresent (environmental). This is implemented by spawning particles in a volume in front of the camera and wrapping their location into this volume as particles or as the camera moves.

PropertyDescription
VisibilityProvides the maximum visibility range of the effect. This determines the size of the volume in front of the camera.

Sphere

This feature allows the new born particles to be randomly and uniformly distributed on a sphere surface.

PropertyDescription
RadiusSpecifies the radius of the sphere in meters. By default, it spawns particles on the surface of the sphere until Modifiers are used. By using the Random modifier set to 100%, particles can be uniformly spawned in the sphere's volume.
VelocitySpecifies initial particle velocity in meters per second. Positive values allow the particles to move outwards from the center while negative values allow the particles to move inwards toward the center.
Axis ScaleEnables scaling of each axis individually. Use this to create ellipsoids instead of spheres.

GPU Support

All Location features are supported in the GPU pipeline, although there is no support for modifiers on the properties of the features.

 

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