Trapcode Particular can make use of Z-depth files which allows you to have access to Z space depth within a 2D layer in After Effects. Most applications can create a Z-Depth image for compositing, however After Effects and Particular cannot really generate one as they stand out of the box.
In a general sense, this is a form of z-depth compositing and it opens up incredible possibilities within After Effects
This doesn’t mean that you can’t create Z-Depth Maps With Trapcode Particular that you can then use with the popular particle plugin right in Ae.
Chris Zwar walks through how you can create really complex scenes entirely in After Effects, by creating and using Z-depth maps with Trapcode Form and Particular.
The problem becomes After Effects itself – even though Ae has a really robust 3rd party SDK, each plugin and effect is essentially an island. Even though Particular works in 3D space, After Effects sees it as one flat layer.
This makes it difficult to create complex composites without Z-depth information. Chris shows how you can build up a very complex scene using just a few basic layers in Ae – through creating and using Z-Depth Maps With Trapcode Particular and Form.
Check out the two part article Advanced Z-Depth Compositing with Particular and After Effects over at provideocoalition.com.