Particle System: Ordered Mesh Emission - 2019.3

1. Create Mesh and Particle System

If you are using Unity 2019.2 or below, click here.

1. Create a new plane primitive in the Scene by selecting from the top dropdown menu: GameObject > 3D Object > Plane.

1. Add a new Particle System to the object. In the Inspector with the Plane selected, select Add Component and search for “Particle System.”

1. In the Particle System’s main module (the one at the top), set Ring Buffer Mode to Pause Until Replaced. This will allow new particles to replace the oldest particles if the system tries to emit a new particle while a maximum number of particles are active.

2. Configure Shape Module

1. Under the Shape module, select the dropdown menu to set the Shape to Mesh Renderer. In the Mesh property, reference the Plane object of which this Particle System is a component.

1. Set Type to Vertex, and Mode to Loop. This will make it such that particles will spawn on vertices in the order they’re written in the mesh data. Ping-Pong would also do this, but instead of starting from the first vertex, once the last vertex is reached, the wave would reverse direction toward the first vertex.

1. Set Randomize Direction to .1 and Randomize Position to .5. This makes the system appear more natural by reducing the uniformity of the movement.

1. Set Normal Offset to .5. This will prevent particles from spawning underneath the surface of the mesh on account of the Randomize Position setting we just modified.

The final Shape module settings are shown in (Figure 01).

Figure 01: Settings for the Shape module of the Particle System for creating an ordered mesh particle emission

The plane should now have particles emitting from it in a wave, from one side to the other, as seen in (Figure 02).

Figure 02: Particles emitting from an ordered mesh

3. Conclusion

Ordered mesh particle emission is a tool that allows VFX artists to use meshes to define the position, orientation, and ordering of a sequence of particle emissions. It’s useful for fire, vapor, and other effects in which the order of emissions adds realism to your Scene.