I made some grass using Particle System and grouped grass objects (each object is a clump with lots of blades). I didn't do anything to the grass, the only thing that has any keyframes during my animation is a ball rolling through the grass. The "emitting" plane has a collision component and so does the ball.
The problem is, in over half of the frames the whole grass field looks the same, but in some frames it looks like a clump or two disappear and different ones are suddenly visible. It's very annoying and I don't understand how this can happen.
I attach two frames, the first one is the "normal one" and the second is the odd one.
Thanks for any suggestions! Cheers.
PS Look at the middle - far right or at the middle part of the attached pictures. This is where the discrepancies are.