Jim -- If Carrara is like RDS (which in most cases it is, and which I am still using), you need to add it to your filters tab in your render settings. The thing that kept me confused for a while was that you had to set the first frame of your animation at 0% completion and the last frame of your animation to 100% completion in order to get the blur to work. With some playing, I've determined that you should tick the blur box and depending on your specific animation, the setting for blur should be around 1 or 2. Hope this helps. - Dex