Final Cut Pro or After Effects?  This is an effect, so you might need software that lets you do the effect.

Now, you could do it in Poser (or whatnot) with some creative mixing.  For instance, you could fade the Poser character in using transparency/alpha.  Have them run in synch and have the Poser animated figure overlay the video, then fade in.  If the camera moved at all, you'll need to do camera matching to keep the view synchronized.  Hopefully the Poser figure completely covers the real actor or you will need to do some frame-by-frame editing.  This is why the pros use green-screens, lighting balls, and position markers.

But it really depends on the type of transition you are trying to create.

Robert

C makes it easy to shoot yourself in the foot. C++ makes it harder, but when you do, you blow your whole leg off.

 -- Bjarne Stroustrup

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