Particles die behond edge (inverse depthfade?)

Hey all,

I’m creating a particle systems for bugs running rampant in differend directions trough the use of of a vector field.
I want to be able to place this system anywhere on my level which has very flat floors, but many edges.

So my issue here is: I want the particles to either die or dissapear when they go over an edge (they can go a little over it). I’ve seen some demo before where particles were spawned in a cone, and only those near the floor were visible.
However, I’m unable to find whatever I saw there. Does anyone know of it?

I was thinking myself of using a depthfade node in the material editor, but then inversed. So the particles are only visible near an object. If anyone has differend solutions, please tell :smiley:

Answere found, tought it might be nice to share for those who ever had to deal with this problem :slight_smile: