Particle Collision Question

Hi all, I have a question on creating a mesh collider. So far I use trace sop to trace a texture and extrude it to make it a collider to the particles that are falling from the top.




But the fps is low. The trace sop seems heavy.

Although in the pics it looks like 2D, actually I want the particles to float in 3D space, so I need the collider to have a depth scale so that it can do the effect like below.


I am thinking if there are any other methods instead of using trace and extrude sop to realize the effect as the third pic shows. Maybe I should not use particle sop but use shader stuff? But how to do the collision?

Anyone has experience and suggestions? Thanks in advance! :smiley: