Update: 3D Match Moving a.k.a 3D Motion Tracking

I've been in this field for a while but its just now that i got a chance to get my hands on a 3d matchmoving application..PFTrack.Though, its a learning edition and cant use it on any commercial projects,I got an opportunity to understand the concept.It was an exciting experience which [i hope] opened up a wide range of visual FX possibilities for me.

Basically,the process is pretty simple to understand.Its an advanced method of compositing a 3d object onto a realworld scene and matching up with its 3D Data so that the viewer gets the feeling that the object is a part of the actual scene.Usually many of you might be familiar with 2D Tracking.We are able to do that inside almost all the compositing softwares.There we are only playing with the X and Y data but the Z data,i.e the 3D Data is not readily available.Watch these sample videos i found on you tube and you will get a better idea..

2D Tracking Sample:
http://in.youtube.com/watch?v=GmKYLDOMYJc&feature=related

Now as you've noticed,the castle is a 2d object composited on to the scene but there is no 3d data.We wont be able to rotate the camera to see another dimension of the castle,coz its just not there.Now watch this...

3D Tracking Sample:
http://in.youtube.com/watch?v=-LfNcwBgVzg&feature=related

I guess now you got it.You can see all the 3 dimensions of the biped as the camera rotates.BTW this clip is not done in PFTrack,but in Boujou.There are many 3d tracking softwares in the market now,but all of them works on the same principle.

Now about the process.The application analyses the footage and then tracks it with 3D camera solving.We can then export the camera data to a[ny] 3d application where we can setup the scene and render out the animation with the tracked camera data in it.Now you can composite the two layers in a regular compositing software and it will perfecly match.Great Technique. Do some googling and you will get more info on this topic.