Trapcode Particular

Emitter Group > Particles/sec modifier

This parameter lets you emit particles from lights. The Emitter Type Light(s) needs to be selected for this parameter to be active.

The advantages to using Light Emitters rather than the built-in Emitter is that Lights in After Effects are true 3D objects. This means their 3D motion path can be conveniently edited, and many Lights can be used to emit multiple Emitters at once. See our tutorial for 'Emitting Particles from Lights' at the bottom of this page.

The Light(s) option in Emitter Type and its related Particles/sec modifier.

Particles/sec Modifier

When Light(s) is active in the Emitter Type popup, Particles/sec Modifier can tell the Light Emitter to emit different amounts of particles at various times. The parameter does this by modifying certain layer properties of the composition Light that is being used. Essentially, particles/sec Modifier is altering the value set in Particles/sec in the Emitter group.

Particles/sec Modifier has four choices. Each choice affects a different Light property, which is located in the Light's layer properties in the Timeline. For example, if you set the popup to Light Intensity and the emitter's Light Intensity value is set to 90%, then the Particle/sec value will be 90% of the set value in the plug-in. In other words, a value of 100 particles/sec would become 90 particles/sec.

  • Light Intensity will affect the Intensity value.
  • Shadow Darkness will affect the Shadow Darkness value. (Notice a pattern here?)
  • Shadow Diffusion will affect the Shadow Diffusion value.
  • None does not change the emission rate based on any of the Light's properties. Useful when light intensity is used for other things (such as actually lighting a scene).

Options Panel > Light Emitter Name

The Light Emitter is recognized with the Light Emitter feature in the Options panel. When a comp Light has the same name as the Options Light Emitter name, that Light will be used to control the particle emission.

Enter a Light Name in the Name field, and use that same name for the Light layer in your Timeline. This will make the Light recognize the Light Emitter.

By default, this Light Name is named 'Emitter' and that is often an easy standard to use. But the Light Name can be changed to anything as long as the Light's layer name matches. More info on the Options Panel page.

Technical Notes

  • When emitting particles from Lights, the particle color comes from the Light's Color layer property. This coloration can be changed with the Color over Life gradient in the Particle group> Set Color parameter.
  • When the Light Emitters are keyframed and the keyframes are edited a lot, the cache sometimes works inappropriately. This will manifest as jerkiness in the animation (the Emitter jumps from one frame to the next). To get rid of the erroneous frames from the cache, use Edit > Purge > Image Caches and re-render.