Trapcode Particular

Emitter group > Layer Emitter group

This parameter group lets you emit particles from layers. The Emitter Type Layer needs to be selected for this parameter group to be active.

Technical notes for Layer Emitters:

• When the Layer Emitter is 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.
• The layer used as Layer Emitter must have 'Continuous Rasterize' switched off in the Timeline's Layer Switches.

Layer Pop-up

Selects a layer in the comp that will emit particles.

Layer Sampling pop-up

Defines how the layer information should be read.

• Current Time (Legacy): This does the same thing as 'Still,' and is actually only in Particular so it can read from previous versions of the plugin.  It's not advised to use this over Still on account it does the same thing and is an older version of the same functionality.
• Particle Birth Time: Each particle, when birthed, samples its image from the layer emitter and retains that image throughout its lifespan.
• Still: The default mode, which should be used if a still image is used as the Layer Emitter.

Layer RGB Usage pop-up

Defines how to use the values that are sampled from the layer used as the Layer Emitter.

• Lightness - Size: The particle size is affected by the lightness of the Layer Emitter.
• Lightness - Velocity: The particle velocity is affected by the lightness of the Layer Emitter. If lightness is less than 50%, the particle will emit backwards. If lightness is exactly 50%, velocity will be 0. Above 50%, the particles will emit forwards.
• Lightness - Rotation: The particle rotation is affected by the lightness of the Layer Emitter.
• RGB - Size, Vel, Rot: The particles get their size, velocity and rotation from the Red, Green and Blue color channels of the Layer Emitter.
• RGB - Particle Color: The particles get their color from the Red, Green and Blue color channels of the Layer Emitter.
• None: No values are used.
• RGB - Size Vel Rot + Col: The particle size, velocity, rotation and color are affected by the Red, Green and Blue color channels of the Layer Emitter.
• RGB - XYZ Velocity: The particles get their velocity from the Red, Green and Blue color channels of the Layer Emitter.
• RGB - XYZ Velocity + Col: The particles get their velocity and color from the Red, Green and Blue color channels of the Layer Emitter.