Cineversity

Hello,
I am working on a project where I have particles that interact with geometry (falling both in front and behind it), but I need to render the particles separately and composite them with the original animation in After Effects.  How do I render just the particles so that they still look like they are falling behind the geometry as well as in front of it?  Right now, if I render just the particles, and not the geometry it looks like I am seeing through the geometry to the other side.  I basically need to “block out” the middle ground.  What would my settings be in the composite tag?

Hi AlphaCreative,

A scene file would be nice, to see how the particles do what they do to give a more detailed answer.

Right now, I would think two option would be worth to look into it.

1
You use a PGetData node to get the position of them and based on this you set up a Logic that the particles behind the wall are in a different PGroup. In that way you can use two different Particle Geometry Objects and set up for each a Buffer.

2
If v1 will not work for you, you might project a texture (flat) from the top onto the particle shapes and have the texture (or a gradient) set up in the way that the particles on one side becomes only red as color and the ones behind only green as color (Luminance only, no light). In that way the RGB footage rendered especially for that purpose will hold an alpha channel like information in the green as feel in the red channel

Again, I do not have your set up here, so I might have suggested something that will NOT work for your set up.

All the best
Sassi