I shoot a short video, and used a tracking software to integrate a simple 3D object.
I used a Dslr cam, Boujou and Matchmove to track the footage.
I built a the 3D object in Maya (Rendering in Vray and Mental Ray; depending the passes)
and I finaly recompose the final video in Nuke to integrate the 3D object into the scene.
(plus color correction/ grading/ reformat each pass)