So the particles have movement according to vortex force. That’s all fine. They are set to spawn at a SpawnRate, no bursts. They spawn on a torus shape with Radius = 1500 and Handle Radius = 1500.
Now in the video, I zoom in and out of the scene and everytime I do this, a weird, tight band of particles appears. This happens in PIE and Standalone. My mouse actions shouldn’t have any impact on the spawning, I don’t know how a niagara system (apparently) can be affected by the viewport, maybe.