From time to time I am able to work on high end TV commercials. I work as vfx composer, but I also take care of one of the most important, yet very underrated steps in the ladder of vfx. Matchmoving.
Many people do not even know what it is. It's because when it's done well, it's invisible. Matchmoving - also called camera tracking - is a method of matching the movement of 3D camera in 3D software - such as maya or max - to it's real life movement on set. Imagine it like this: when camera man walks with the camera on set, the device moves in space, shakes as he walks, rotates as he turns. All of those movements have to be replicated 100% perfectly in 3D software, otherwise your 3D object wouldn't stick to recorded video. I will not go deeply into details, because it would take weeks and would be to boring to keep your attention, but know this If the 3D camera moves even slightly off the path of the real one, you can immediately see it. The 3D object starts to shake or slide all over the footage.
There are different types of commercials in TV. Some of them use little of vfx. Artists have to cover some posters on the walls or logos on the billboards. But there are also those, which need alot of attention. Such as the one a showed you above, where you have complex animations, vfx interacting with footage etc. For the easier ones you can use 2D trackers provided by built in plugins in After Effects, but the more complex it gets, the more powerfull tool you need. In my work I use PFTrack.
Every single shot in the commercial above in which you can see an animal had to be tracked. Some of them where easy, and some really complex. PFTrack looks for pixel movement in the footage and mesures changes between those pixels to specify the camera movement.
There are many ways to help yourself matchmove perfectly. You can measure real distances on set, you can make set photos and generate photomesh, which helps not only tracking but also animators and rendering artists to put the 3D object in a good place. When you have all the help you need, you simply sit down and start counting hours, because tracking is often not a one click task.
It takes about one week to track shots to one commercial. Of course it depends of their complexity. There are some which need way more work, and sometimes you have to do it by hand (frame after frame, hour by hour you rotate 3D space until it sticks), but for me it's relaxing. I like the fact, that if not for mathmovers work, there would be no commercial, no movie, to music clips with vfx in it.
Check out this awesome matchmoving demo reel by Arun Massive VFX:
If only people could see whats really going on behind the scenes of vfx ;)