If you apply particular on a layer, you will see that the particules are 3D aware if you have a camera. But if you have layers in your 3D space, the particules won’t intersect with them. Particules are always “in front of” the 3D layers that are below the particules layer in the layer stack.

But, Particular have a visibility option, where you can set a range where your particules are visible or not, let’s say from 0px to 200px in Z space from the camera.

What the script does is sorting your layers in your comp so that the 3D layers stacks on the composition regarding to their Z position, and then duplicate your particule layer between every 3D layers. All thoses instances have their visibility option expressioned to fill the Z range between the front and behind 3D object. Like that your particules are intersecting with your layers.

It’s not a true intersection, it rather an automation of a workaround, but it works great. Plus there are some options if you want to update your particule layer so that every instance get updated too.

Supports Particular from v1.5 and above (including Particular 64bit update for CS5), and works fine with multiple Particular effects on the same layer.