I assume you want to composite the image. Poser is good for this. Making a Poser animation is no small task, especially if you need realistic motions. Some vendors have motion files ready-made, and some will do a custom job for your needs. Expect to spend money. DIY is do-able, but very time-consuming. Poser is good for figures, Bryce is good for terrains. And the links on the right have lots of resources and ideas.