When they released CS5.5 they added the Warp Stabilizer. I have used it numerous times now, and it can really stabilize a shaky shot quite nicely. While watching a video about the Warp Stabilizer there was a clip showing all the tracking points applied to some footage to do the stabilizing... much like the track points in the new 3D Camera Tracker. It made me wonder when they would take the next step, and add motion tracking.
If you are unfamiliar with motion tracking, it's the process of figuring out what the camera did in a live shot. A camera is then created in a compositing program, or a 3D program, performing the same camera moves. This allows you to add objects that weren't originally there as if they were part of the scene.
This is one of my first tests with the 3D Camera Tracker. It's quite intuitive: you track the footage, then right click one of the points you want to track and apply a null, or solid etc.
For this shot I applied a Null object to the distant background and created a solid parented to that null. I masked out the section I wanted to remove and used it as an alpha matte to remove the background from the footage. So I didn't have a sharp unrealistic edge to the matte, I applied the Turbulent Displace plugin. This gave a grass-like pattern to the edge, blending it nicely with the added virtual set.
You may not realize this, but changing backgrounds in television and movies is done far more often than you know. A lot of scenes for The Avengers were not filmed in New York, so they added New York buildings and landmarks. Even shows that you wouldn't think have any effect shots can have many.
I look forward to doing more with the Camera Tracker and all the other new features, plus the completely new products they've added, Speed Grade for example.
As for the 3D Camera Tracker, I hope to do some more experimenting, and perhaps even do a video tutorial on how I created the above video.