Why particles are shaking?

I used neighbor grid to simulate collision between particles. But each particle had a small shake like someone was knocking the table!

Why and how to fix it?

I upload a GIF here.

Adobe Express - CoffeBean - 虚幻编辑器 2025-09-17 16-15-24

Hello @zucchini_ue ,
I found this Epic tutorial that explains particle collisions using Neighbor Grid quite well:

At this minute (33:20) he starts talking about collisions

The video shows how to set up collisions step by step, it might help you compare with your setup and see if that makes the shake disappear.

I also found this other one on YouTube:

It goes into more detail about how the grid works and how to configure it, It’s not exactly what you’re looking for, but it’s interesting because it shows several tricks and details that help you better understand how the system behaves.

Hope it helps!