Great, glad you figured it out. You actually did what I was going to suggest. I can’t see the videos you posted, but if you want them to move left and right you’d adjust the velocity along the x axis (or z axis) to move positive and negative over it’s life. Using a curve you can have it bounce between positive and negative and it’ll move the particles left and right. This lesson from my latest Weather FX course should explain it a bit better: https://cgcookie.com/lesson/spinning-dust-devils in it I went over how to create a smaller tornado like effect and it was created using a velocity curve that moves positive and negative over the life of the particle to have it bounce back and forth between the x and z axis.
