Forgot to mention in the video: if you’re using multiple rock models in your mesh renderer (which is a nice detail to randomize the look) in order for all the meshes to be born randomly, under Initialize Particle module, Mesh Attributes, set Mesh Renderer array Visibility Mode to Random, and assign Mesh Renderer as your Mesh Renderer.

If you don’t do this, only index 0 mesh will be born (so all the pieces will be exactly the same).