3D Tracking

In an earlier post I took a quick look at the process of Matchmoving, however in retrospect that probably wasn't the best example of matchmoving or 3D tracking process as the movement was only in 2 dimensions. When talking about matchmoving there is a very important difference between 2D and 3D tracking, namely 3D tracking is a much more annoying. 2D tracking is something that can be performed in programs like After Effects and simply relies on the tracker following certain points around the frame. 3D tracking on the other hand is somewhat more complex a process. 3D tracking points are collected via manual track points or auto track points and used to calculate and rebuild a virtual 3D environment with a 3D package such as Maya.


As I have found throughout this latest exercise, it is vitally important to have as much information about your physical camera as possible. The focal length (length of the lens) and the film back (camera aperture or camera censor size) help turn a nightmare track into something a bit more manageable. That and I might also add that Autodesk Matchmover 2011 is a serious pain in the arse. I downloaded a free student licence of Maya 2012 and Matchmover 2012 kindly from Autodesk with a 36 month licence. Anyone interested the address is http://students.autodesk.com/?nd=download_center Make use of being a student and get as much free shit as possible.


But I digress. After downloading and installing Matchmover 2012 the automatic tracking was a breeze. You'll need to break your footage down into an image sequence, I used a Targa sequence which decompiled pretty quick and good quality with Adobes Media Encoder.  Then it's simply a process of upping the quality of your auto track and the length that tracks will stick to the points. Once the track was finished, I solved the camera create 3D points within the scene and added a coordinates system to tell the 3D package which way is up. This is a very important step and helped to line everything up within the Maya axis.

3D Track points within Matchmover after automatic tracking and camera solve. Not the inverted axis with the Y pointing downwards. (Mistake within MM but rectified in Maya).

Once my camera created in Maya it was simply a matter of recreating the lighting of my environment. I used Maya's IBL (image based lighting) to create my environment from within Mental Ray with a full panoramic photo of my living room. This also created reflections within my geometry to help sell the cup. The shadows and reflections on the table were created with a Background shader. This allows a material to only display specular and reflections within the environment. After a bit of tweaking I rendered it out pretty low res and did some colour grading in AE to help tie it all together.

Left middle - perspective view of cup and background shader geometry. Right middle - IBL environment and camera tracks and image plane.

All in all I'm really pleased with the way it came out. Even though it is a very simple shot and piece of geometry, the actual track and coordinates systems proved the can work perfectly and open the door to some much more complex shots to come. Watch this space!

3D Track with geo and grade

Raw Footage.