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.

depth1.PNG

emit.PNG

collision.PNG

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.

depth.PNG

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: