Well, Mod, most mattes are exactly that...mattes. They don't move. For when the situation calls for an animated matte, you have lots of options, you can use stock footage and play it in the background (or create your own), you can also do a little Parralax scrolling like they do in videogames. 3DWorld actually had a neat little tutorial on using Combustion (a compositing program) and it showed you how to add movement to stills in very simple and basic ways that could also be edited over time if required. The same rule for rendering applies here : Getting the image you want requires postwork. There's no way around that, even if we're talking about the moving picture. In the case of the flag, you'd have it on it's own layer and thus be able to scale and stretch it as needed. You could also instead have an animated flag (filmed or made) on it's own layer and still be able to perform whatever compositing (overlay, multiply, adding dust,etc.) you'd need too.