Is there away to render update the objects that move while the back drop will be in scene? I have a huge scene setup it takes 3 to 4 mins per frame to render on the 1920 x 1080, I have learned many things to reduce render time while keeping good quality but in scene where camera doesn't move, only the character or car etc. I would like to render only updating the movement rather than doing whole picture but keeping the background in the render. When I have a good video editing software I know I can croma key characters etc. But would be nice to able to skip that process if possible.