I came across an interesting problem yesterday, and was helping if anyone could help me solve it. I am trying to add a meteor to a moving scene that was shot in the sky. So I tracked the shot, and added particle world. In order to control he particles, I linked the particle producer position to a null object so I could easily animate the meteor. However, the result was less than convincing. The problem I figured, was that scale of the whole scene was incorrect causing the meteor to look almost the same size in the air as it was on the ground. The velocity was also off. Since the this shot was shot really high in the sky, I changed the scale of the scene significantly. I turned off my particle layer, and re animated my null object, and it looked perfect. When the middle was close to the camera high in the sky, it went past the camera really fast and the particles were big. When particles made it to the ground, they were really small, as the ground was far away. So I turned on my null object, and the particles were no where to be seen. I tried messing around with the scale of the scene with the null object that camera tracker makes, and this is when I found my problem. Adjusting the scale of the scene messes up the position of particle world. When you go to the custom views, the particles are attached to the null, but when you go to active camera, they are not. The more you change the scale of the scene, the further away particle worlds position gets displaced. Essentially, particle world does not maintain its relative position as the scene is scaled. This problem does not happen with particular, I have the demo of it. Particular retains it's relative position in space as the scene is scaled. What can I do about this to get the particles to stick to the null?