Another option is to change your background to a solid colour not in your exisiting palette (gree/ blue screen). Render out you AVI and then import to After Effects/ Premiere and use their compositiing tools to remove the background. Don't forget to make sure your are anti-aliasing your images. Motion blur is helpful to take the edge of animatos that are too sharp. Also you can consider a soft blur or glow in post process to again take the curse off. Good luck. JG