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Use match moving software like mocha and bonjour
If you mean rendering a photo there are many options and renderers like Mental Ray or Vray and sure you need to put a camera in the right place where you want to take the shoot and you may use a background in the scene or render your character then go to photoshop and put it in a background you like.
if you mean something else be specific in your question and which3D tool coz they are many.
there are some tools are made only for rendering if you have some characters ready to be rendered.
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