Particle System Shape Module

This module defines the the volume or surface from which particles can be emitted, and the direction of the start velocity. The Shape property defines the shape of the emission volume, and the rest of the module properties vary depending on the Shape you choose.

All shapes (except Mesh) have properties that define their dimensions, such as the Radius property. To edit these, drag the handles on the wireframe emitter shape in the Scene view. The choice of shape affects the region from which particles can be launched, but also the initial direction of the particles. For example, a Sphere emits particles outward in all directions, a Cone emits a diverging stream of particles, and a Mesh emits particles in directions that are normal to the surface.

The section below details the properties for each Shape.

Shapes in the Shape module

Sphere, Hemisphere

Note: Sphere and Hemisphere have the same properties.

Property	Function
Shape	The shape of the emission volume.
Sphere	Uniform particle emission in all directions.
Hemisphere	Uniform particle emission in all directions on one side of a plane.
Radius	The radius of the circular aspect of the shape.
Radius Thickness	The proportion of the volume that emits particles. A value of 0 emits particles from the outer surface of the shape. A value of 1 emits particles from the entire volume. Values in between will use a proportion of the volume.
Texture	A texture to use for tinting and discarding particles.
Clip Channel	A channel from the texture to use for discarding particles.
Clip Threshold	When mapping particles to positions on the texture, discard any whose pixel color falls below this threshold.
Color affects Particles	Multiply particle colors by the texture color.
Alpha affects Particles	Multiply particle alphas by the texture alpha.
Bilinear Filtering	When reading the texture, combine 4 neighboring samples for smoother changes in particle color, regardless of the texture dimensions.
Position	Apply an offset to the emitter shape used for spawning particles.
Rotation	Rotate the emitter shape used for spawning particles.
Scale	Change the size of the emitter shape used for spawning particles.
Align to Direction	Orient particles based on their initial direction of travel. This can be useful if you want to simulate, for example, chunks of car paint flying off a car’s bodywork during a collision. If the orientation is not satisfactory, you can also override it by applying a Start Rotation value in the Main module.
Randomize Direction	Blend particle directions towards a random direction. When set to 0, this setting has no effect. When set to 1, the particle direction is completely random.
Spherize Direction	Blend particle directions towards a spherical direction, where they travel outwards from the center of their Transform. When set to 0, this setting has no effect. When set to 1, the particle direction points outwards from the center (behaving identically to when the Shape is set to Sphere).
Randomize Position	Move particles by a random amount, up to the specified value. When this is set to 0, this setting has no effect. Any other value will apply some randomness to the spawning positions of the particles.

Cone

Property	Function
Shape	The shape of the emission volume.
Cone	Emit particles from the base or body of a cone. The particles diverge in proportion to their distance from the cone’s center line.
Angle	The angle of the cone at its point. An angle of 0 produces a cylinder while an angle of 90 gives a flat disc.
Radius	The radius of the circular aspect of the shape.
Radius Thickness	The proportion of the volume that emits particles.A value of 0 emits particles from the outer surface of the shape. A value of 1 emits particles from the entire volume. Values in between will use a proportion of the volume.
Arc	The angular portion of a full circle that forms the emitter’s shape.
Mode	Define how Unity generates particles around the arc of the shape. When set to Random, Unity generates particles randomly around the arc. If using Loop, Unity generates particles sequentially around the arc of the shape, and loops back to the start at the end of each cycle. Ping-Pong is the same as Loop, except each consecutive loop happens in the opposite direction to the last. Finally, Burst Spread mode distributes particle generation evenly around the shape. This can give you an even spread of particles, compared to the default randomized behavior, where particles may clump together unevenly. Burst Spread is best used with burst emissions.
Spread	The discrete intervals around the arc where particles may be generated. For example, a value of 0 allows particles to spawn anywhere around the arc, and a value of 0.1 only spawns particles at 10% intervals around the shape.
Speed	The speed the emission position moves around the arc. Using the small black drop-down menu next to the value field, set this to Constant for the value to always remain the same, or Curve for the value to change over time. This option is only available if Mode is set to something other than Random
Length	The length of the cone. This only applies when the Emit from: property is set to Volume.
Emit from:	The part of the cone to emit particles from: Base or Volume.
Texture	A texture to be used for tinting and discarding particles.
Clip Channel	A channel from the texture to be used for discarding particles.
Clip Threshold	When mapping particles to positions on the texture, discard any whose pixel color falls below this threshold.
Color affects Particles	Multiply particle colors by the texture color.
Alpha affects Particles	Multiply particle alphas by the texture alpha.
Bilinear Filtering	When reading the texture, combine 4 neighboring samples for smoother changes in particle color, regardless of the texture dimensions.
Position	Apply an offset to the emitter shape used for spawning particles.
Rotation	Rotate the emitter shape used for spawning particles.
Scale	Change the size of the emitter shape used for spawning particles.
Align to Direction	Orient particles based on their initial direction of travel. This can be useful if you want to simulate, for example, chunks of car paint flying off a car’s bodywork during a collision. If the orientation is not satisfactory, you can also override it by applying a Start Rotation value in the Main module.
Randomize Direction	Blend particle directions towards a random direction. When set to 0, this setting has no effect. When set to 1, the particle direction is completely random.
Spherize Direction	Blend particle directions towards a spherical direction, where they travel outwards from the center of their Transform. When set to 0, this setting has no effect. When set to 1, the particle direction points outwards from the center (behaving identically to when the Shape is set to Sphere).
Randomize Position	Move particles by a random amount, up to the specified value. When this is set to 0, this setting has no effect. Any other value will apply some randomness to the spawning positions of the particles.

Box

Property	Function
Shape	The shape of the emission volume.
Box	Emit particles from the edge, surface, or body of a box shape. The particles move in the emitter object’s forward (Z) direction.
Emit from:	Select the part of the box to emit from: Edge, Shell, or Volume.
Texture	A texture to be used for tinting and discarding particles.
Clip Channel	A channel from the texture to be used for discarding particles.
Clip Threshold	When mapping particles to positions on the texture, discard any whose pixel color falls below this threshold.
Color affects Particles	Multiply particle colors by the texture color.
Alpha affects Particles	Multiply particle alphas by the texture alpha.
Bilinear Filtering	When reading the texture, combine 4 neighboring samples for smoother changes in particle color, regardless of the texture dimensions.
Position	Apply an offset to the emitter shape used for spawning particles.
Rotation	Rotate the emitter shape used for spawning particles.
Scale	Change the size of the emitter shape used for spawning particles.
Align to Direction	Orient particles based on their initial direction of travel. This can be useful if you want to simulate, for example, chunks of car paint flying off a car’s bodywork during a collision. If the orientation is not satisfactory, you can also override it by applying a Start Rotation value in the Main module.
Randomize Direction	Blend particle directions towards a random direction. When set to 0, this setting has no effect. When set to 1, the particle direction is completely random.
Spherize Direction	Blend particle directions towards a spherical direction, where they travel outwards from the center of their Transform. When set to 0, this setting has no effect. When set to 1, the particle direction points outwards from the center (behaving identically to when the Shape is set to Sphere).
Randomize Position	Move particles by a random amount, up to the specified value. When this is set to 0, this setting has no effect. Any other value will apply some randomness to the spawning positions of the particles.

Mesh, MeshRenderer, SkinnedMeshRenderer

Mesh, MeshRenderer and SkinnedMeshRenderer have the same properties.

Property	Function
Shape	The shape of the emission volume.
Mesh	Emits particles from any arbitrary Mesh shape supplied via the Inspector.
MeshRenderer	Emits particles from a reference to a GameObject’s Mesh Renderer.
SkinnedMeshRenderer	Emits particles from a reference to a GameObject’s Skinned Mesh Renderer.
Emission drop-down	Where particles are emitted from. Select Vertex for the particles to emit from the vertices, Edge for the particles to emit from the edges, or Triangle for the particles to emit from the triangles. This is set to Vertex by default.
Mesh	The Mesh that provides the emitter’s shape.
Single Material	Specify whether to emit particles from a particular sub-Mesh (identified by the material index number). If enabled, a numeric field appears, which allows you to specify the material index number.
Use Mesh Colors	Modulate particle color with Mesh vertex colors, or, if they don’t exist, use the shader color property “Color“ or ”TintColor” from the material.
Normal Offset	Distance away from the surface of the Mesh to emit particles (in the direction of the surface normal)
Texture	A texture to be used for tinting and discarding particles.
Clip Channel	A channel from the texture to be used for discarding particles.
Clip Threshold	When mapping particles to positions on the texture, discard any whose pixel color falls below this threshold.
Color Affects Particles	Multiply particle colors by the texture color.
Alpha Affects Particles	Multiply particle alphas by the texture alpha.
Bilinear Filtering	When reading the texture, combine 4 neighboring samples for smoother changes in particle color, regardless of the texture dimensions.
UV Channel	Choose which UV channel on the source mesh to use for sampling the texture.
Position	Apply an offset to the emitter shape used for spawning particles.
Rotation	Rotate the emitter shape used for spawning particles.
Scale	Change the size of the emitter shape used for spawning particles.
Align to Direction	Orient particles based on their initial direction of travel. This can be useful if you want to simulate, for example, chunks of car paint flying off a car’s bodywork during a collision. If the orientation is not satisfactory, you can also override it by applying a Start Rotation value in the Main module.
Randomize Direction	Blend particle directions towards a random direction. When set to 0, this setting has no effect. When set to 1, the particle direction is completely random.
Spherize Direction	Blend particle directions towards a spherical direction, where they travel outwards from the center of their Transform. When set to 0, this setting has no effect. When set to 1, the particle direction points outwards from the center (behaving identically to when the Shape is set to Sphere).
Randomize Position	Move particles by a random amount, up to the specified value. When this is set to 0, this setting has no effect. Any other value will apply some randomness to the spawning positions of the particles.

Mesh details

You can choose to only emit particles from a particular material (sub-Mesh) by checking the Single Material property and you can offset the emission position along the Mesh’s normals by checking the Normal Offset property.

To ignore the color of the Mesh, check the Use Mesh Colors property. To read the texture colors from a mesh, assign the Texture you wish to read to the Texture property.

Meshes must be read/write enabled to work on the particle system. If you assign them in the Editor, Unity handles this for you. But if you want to assign different meshes at run time, you need to check the Read/Write Enabled setting in the Import Settings.

Circle

Property	Function
Shape	The shape of the emission volume.
Circle	Uniform particle emission from the center or edge of a circle. The particles move only in the plane of the circle.
Radius	The radius of the circular aspect of the shape.
Radius Thickness	The proportion of the volume that emits particles. A value of 0 emits particles from the outer edge of the circle. A value of 1 emits particles from the entire area. Values in between will use a proportion of the area.
Arc	The angular portion of a full circle that forms the emitter’s shape.
Mode	Define how Unity generates particles around the arc of the shape. When set to Random, Unity generates particles randomly around the arc. If using Loop, Unity generates particles sequentially around the arc of the shape, and loops back to the start at the end of each cycle. Ping-Pong is the same as Loop, except each consecutive loop happens in the opposite direction to the last. Finally, Burst Spread mode distributes particle generation evenly around the shape. This can be used to give you an even spread of particles, compared to the default randomized behavior, where particles may clump together unevenly. Burst Spread is best used with burst emissions.
Spread	Control the discrete intervals around the arc where particles may be generated. For example, a value of 0 will allow particles to spawn anywhere around the arc, and a value of 0.1 will only spawn particles at 10% intervals around the shape.
Speed	Set a value for the speed the emission position moves around the arc. Using the small black drop-down next to the value field, set this to Constant for the value to always remain the same, or Curve for the value to change over time.
Texture	Choose a texture to be used for tinting and discarding particles.
Clip Channel	Select a channel from the texture to be used for discarding particles.
Clip Threshold	When mapping particles to positions on the texture, discard any whose pixel color falls below this threshold.
Color Affects Particles	Multiply particle colors by the texture color.
Alpha Affects Particles	Multiply particle alphas by the texture alpha.
Bilinear Filtering	When reading the texture, combine 4 neighboring samples, for smoother changes in particle color, regardless of the texture dimensions.
Position	Apply an offset to the emitter shape used for spawning particles.
Rotation	Rotate the emitter shape used for spawning particles.
Scale	Change the size of the emitter shape used for spawning particles.
Align to Direction	Use this checkbox to orient particles based on their initial direction of travel. This can be useful if you want to simulate, for example, chunks of car paint flying off a car’s bodywork during a collision. If the orientation is not satisfactory, you can also override it by applying a Start Rotation value in the Main module.
Randomize Direction	Blend particle directions towards a random direction. When set to 0, this setting has no effect. When set to 1, the particle direction is completely random.
Spherize Direction	Blend particle directions towards a spherical direction, where they travel outwards from the center of their Transform. When set to 0, this setting has no effect. When set to 1, the particle direction points outwards from the center (behaving identically to when the Shape is set to Sphere).
Randomize Position	Move particles by a random amount, up to the specified value. When this is set to 0, this setting has no effect. Any other value will apply some randomness to the spawning positions of the particles.

Edge

Property	Function
Shape	The shape of the emission volume.
Edge	Emit particles from a line segment. The particles move in the emitter object’s upward (Y) direction.
Radius	The radius property is used to define the length of the edge.
Mode	Define how Unity generates particles along the radius of the shape. When set to Random, Unity generates particles randomly along the radius. If using Loop, Unity generates particles sequentially along the radius of the shape, and loops back to the start at the end of each cycle. Ping-Pong is the same as Loop, except each consecutive loop happens in the opposite direction to the last. Finally, Burst Spread mode distributes particle generation evenly along the radius. This can be used to give you an even spread of particles, compared to the default randomized behavior, where particles may clump together unevenly. Burst Spread is best used with burst emissions.
Spread	T the discrete intervals along the radius where particles may be generated. For example, a value of 0 will allow particles to spawn anywhere along the radius, and a value of 0.1 will only spawn particles at 10% intervals along the radius.
Speed	The speed the emission position moves along the radius. Using the small black drop-down next to the value field, set this to Constant for the value to always remain the same, or Curve for the value to change over time.
Texture	A texture to be used for tinting and discarding particles.
Clip Channel	A channel from the texture to be used for discarding particles.
Clip Threshold	When mapping particles to positions on the texture, discard any whose pixel color falls below this threshold.
Color Affects Particles	Multiply particle colors by the texture color.
Alpha Affects Particles	Multiply particle alphas by the texture alpha.
Bilinear Filtering	When reading the texture, combine 4 neighboring samples for smoother changes in particle color, regardless of the texture dimensions.
Position	Apply an offset to the emitter shape used for spawning particles.
Rotation	Rotate the emitter shape used for spawning particles.
Scale	Change the size of the emitter shape used for spawning particles.
Align to Direction	Orient particles based on their initial direction of travel. This can be useful if you want to simulate, for example, chunks of car paint flying off a car’s bodywork during a collision. If the orientation is not satisfactory, you can also override it by applying a Start Rotation value in the Main module.
Randomize Direction	Blend particle directions towards a random direction. When set to 0, this setting has no effect. When set to 1, the particle direction is completely random.
Spherize Direction	Blend particle directions towards a spherical direction, where they travel outwards from the center of their Transform. When set to 0, this setting has no effect. When set to 1, the particle direction points outwards from the center (behaving identically to when the Shape is set to Sphere).
Randomize Position	Move particles by a random amount, up to the specified value. When this is set to 0, this setting has no effect. Any other value will apply some randomness to the spawning positions of the particles.

Donut

Property	Function
Shape	The shape of the emission volume.
Donut	Emit particles from a torus. The particles move outwards from the ring of the Torus.
Radius	The radius of the main donut ring.
Donus Radius	The thickness of the outer donut ring.
Radius Thickness	The proportion of the volume that emits particles. A value of 0 emits particles from the outer edge of the circle. A value of 1 emits particles from the entire area. Values in between will use a proportion of the area.
Arc	The angular portion of a full circle that forms the emitter’s shape.
Mode	Define how Unity generates particles around the arc of the shape. When set to Random, Unity generates particles randomly around the arc. If using Loop, Unity generates particles sequentially around the arc of the shape, and loops back to the start at the end of each cycle. Ping-Pong is the same as Loop, except each consecutive loop happens in the opposite direction to the last. Finally, Burst Spread mode distributes particle generation evenly around the shape. This can be used to give you an even spread of particles, compared to the default randomized behavior, where particles may clump together unevenly. Burst Spread is best used with burst emissions.
Spread	The discrete intervals around the arc where particles may be generated. For example, a value of 0 will allow particles to spawn anywhere around the arc, and a value of 0.1 will only spawn particles at 10% intervals around the shape.
Speed	The speed the emission position moves around the arc. Using the small black drop-down next to the value field, set this to Constant for the value to always remain the same, or Curve for the value to change over time.
Texture	A texture to be used for tinting and discarding particles.
Clip Channel	A channel from the texture to be used for discarding particles.
Clip Threshold	When mapping particles to positions on the texture, discard any whose pixel color falls below this threshold.
Color Affects Particles	Multiply particle colors by the texture color.
Alpha Affects Particles	Multiply particle alphas by the texture alpha.
Bilinear Filtering	When reading the texture, combine 4 neighboring samples for smoother changes in particle color, regardless of the texture dimensions.
Position	Apply an offset to the emitter shape used for spawning particles.
Rotation	Rotate the emitter shape used for spawning particles.
Scale	Change the size of the emitter shape used for spawning particles.
Align To Direction	Orient particles based on their initial direction of travel. This can be useful if you want to simulate, for example, chunks of car paint flying off a car’s bodywork during a collision. If the orientation is not satisfactory, you can also override it by applying a Start Rotation value in the Main module.
Randomize Direction	Blend particle directions towards a random direction. When set to 0, this setting has no effect. When set to 1, the particle direction is completely random.
Spherize Direction	Blend particle directions towards a spherical direction, where they travel outwards from the center of their Transform. When set to 0, this setting has no effect. When set to 1, the particle direction points outwards from the center (behaving identically to when the Shape is set to Sphere).
Randomize Position	Move particles by a random amount, up to the specified value. When this is set to 0, this setting has no effect. Any other value will apply some randomness to the spawning positions of the particles.

Rectangle

Property	Function
Shape	The shape of the emission volume.
Rectangle	Emits particles from a rectangle. The particles move up from the rectangle.
Texture	A texture to be used for tinting and discarding particles.
Clip Channel	A channel from the texture to be used for discarding particles.
Clip Threshold	When mapping particles to positions on the texture, discard any whose pixel color falls below this threshold.
Color Affects Particles	Multiply particle colors by the texture color.
Alpha Affects Particles	Multiply particle alphas by the texture alpha.
Bilinear Filtering	When reading the texture, combine 4 neighboring samples for smoother changes in particle color, regardless of the texture dimensions.
Position	Apply an offset to the emitter shape used for spawning particles.
Rotation	Rotate the emitter shape used for spawning particles.
Scale	Change the size of the emitter shape used for spawning particles.
Align To Direction	Orient particles based on their initial direction of travel. This can be useful if you want to simulate, for example, chunks of car paint flying off a car’s bodywork during a collision. If the orientation is not satisfactory, you can also override it by applying a Start Rotation value in the Main module.
Randomize Direction	Blend particle directions towards a random direction. When set to 0, this setting has no effect. When set to 1, the particle direction is completely random.
Spherize Direction	Blend particle directions towards a spherical direction, where they travel outwards from the center of their Transform. When set to 0, this setting has no effect. When set to 1, the particle direction points outwards from the center (behaving identically to when the Shape is set to Sphere).
Randomize Position	Move particles by a random amount, up to the specified value. When this is set to 0, this setting has no effect. Any other value will apply some randomness to the spawning positions of the particles.

• 2018–03–28 Page amended with no editorial review

• Functionality of Shape Module updated in Unity 2017.1 NewIn20171

• Texture tinting and selective discarding features (Clip Channel, Clip Threshold, Color affects particles, Alpha affects particles, Bilinear filtering) added to Shape Module in 2018.1 NewIn20181

• Rectangle emission shape added to Shape Module in 2018.1 NewIn20181