Problem: You have a scene with particle effects attached to a plane (Grass, flowers, etc.) where you want to animate these particles without converting them into meshes but when you add multiple keyframes into the timeline, you realize that the particles just keep their positions.
Note: To avoid facing problems such as Blender not running hair simulation, make sure “Hair Dynamics” option is unchecked/disabled. “Regrow” and “Hair Dynamics” option do not play well together.
