Using the Particles Operator on Layers

Compositing particles involves controlling where particles appear and where they are blocked. In addition to using masks and selections, you can sometimes use a duplicate copy of the layer. If the foreground image has an alpha channel, for example, you can put a copy of it above the layer with particles.

Making Particle Effects Seem 3D

You can animate the number and visibility of particles to make them appear to "go behind" an object. For example, you can make a trail of sparkles twist around a column in a dungeon.

Note: You can also use the 2D Particles layer in a 3D composite and use Z compositing, hinging, parenting, and so on. This example does not cover the topic.

In this example, you need the foreground image or clip to have an alpha channel. There are other techniques as well.

To make particles travel behind an object:

1. In a composite, create a layer for the foreground footage and add the Particles operator.
2. Add the emitter and create a full motion path for it. Rename the layer "Behind" since it is used for behind the object.



3. Copy the layer (including Particles operator) and rename the layer "Front." Enable Preserve Alpha for this emitter (it is disabled for the Behind layer).
4. Animate the Number property to decrease to 0 just before the emitter is to make the "behind crossing" and increase after it reappears.



5. Display the Composite operator in the viewport and play the clip.