I have tried it, iMovie is rather flexible (the more recent, the more flexible). Any Quicktime-variety animation should cause no problem. I also used AfterEffects to put the Carrara animations in layers and what you have. It works rather good. I bought Final Cut later in the process, actually because I missed the point about non-square pixels and thought my iMovie couldn't cut it. So. It depends on the file format of the Carrara animations... Non-compressed is best, but will eat your harddisk like it is young cheese (?). Good luck!