hmmmm. now i have no clue what you're trying to do. at first it sounded like you were trying to get your background to reflect elements in your 3D scene. Now it sounds like you are preparing an animated background for compositing. at anyrate, you're right that these things take lots of time. Rendering multiple times for different passes is normal procedure. Just remember that you can optomize the rendering process by turning off channels that you don't need. Rendering out an alpha channel of a reflective object should take only a fraction of the time it takes to actually ray trace the scene. In fact, you don't even have to have reflections on in the renderer to do it. Make the reflective object whitw with 100% glow, and all other objects black with no glow. Make sure there are no other shader values. Then turn off or kill all your light sources. Ambient too. You should be able to render this in the Z-buffer mode - just make sure you have use actual lighting checked in the options. - and you'll get a white mask of your reflective object on the black background. And it will render just about at real time. It's worth a try. -pix