I dont think there is any 3d program that can totally solve your problem. The 3d is just one element. Yes carrara should be able to generate the objects with the alpha mattes that you need. In order to generate the scenes you speak of, what you need is a compositing program like aftereffects from adobe. if money is a problem then there are two cheaper versions that are free: http://www.lerstad.com/mmstudio/ http://moppi.inside.org/demopaja/ These programs are very hard to use and lack the plug-inns that adobe has but they are free and you can see if you have the skills to pull off what you need. You need to become a chromakey master before you become the 3d master if you want to see your ideals come to life...have fun :)