Technically it's easy, but you have to keep the restrictions of both media combined in mind ( video is a 2D format, even the stereoscopic variant ). On the other hand, live-action techniques such as motion-capture and 3D-scanning are common ground these days .. they're not exactly cheap though.
Some blasts from the past using digitized actors:
Time Traveler ( 1991 )
![](http://www.arcade-history.com/images/game/4421_2.png)
Mortal Kombat 3 ( 1995 )
![](http://www.emunova.net/img/dossiers/mortalkombat/mk3-temple-md.png)
Rise of the Triad ( 1995 )
![](http://kahesi.net/pcpelit_kuvat/riseofthetriad.png)