The process of camera tracking

In this section I will explain the basic steps of a typical camera tracking shot. Of course, every project has its own specific requests, and some of these steps don’t necessarily apply to all shots. Nonetheless, this will give a good overview of the process.

Briefing 
Every time I start working on a new project, I like to sit down with the client and have a good briefing of the project. I really want to get the more information possible, so I can evaluate the clients need and give the best service possible.

Information needed 
-Pictures of the set from different angles

-Measurements of the set

-Camera information (Focal length, filmback width and height

-Distortion grid

-Scaling reference of characters and/or objects

Set extension 
In the case of a camera tracking for set extension, I ask the client to give me a picture references of the set, and any other useful information, measurements for example. From these informations, I build the virtual set. This virtual set will be the foundation for all the camera placement for that specific sequence throughout the project.

Camera tracking 
Camera tracking is the discipline of recreating in 3D the movement of the real camera that shot the action. Every shot is different and represents a challenge on its own. There are lots of factors that can help or harm the result.

I have tracked hundreds of shots in the last 6 years, and this experience allows me to track the most difficult shots. Nevertheless, we have to keep in mind that the more accurate information that I get from the client are, the better and faster the results.

The software that I use for camera tracking is the Academy Award 3DEqualizer software from Science D-Vision.

Unwarping 
Once I have solved the camera move, I proceed to unwarping the plate (if it needs to be). Real life cameras introduce some amount of distortion onto the plate. Since 3D cameras are mathematically “perfect”, they don’t introduce any warping, so it is imperative to remove that distortion created by real life cameras before I import the virtual camera in a 3D animation package.

Camera placement 
Now that I have generated the unwarped plate, I can place the virtual camera in the virtual set.

Quality test 
I render the wireframe of the virtual set on top of the plate to confirm that I have a perfect camera tracking. In some cases, I add primitive objects on the ground to help me confirm the accuracy of the tracking.

Final step
Once I have validated the quality of the tracking, I upload the quality test videos and are corresponding 3D files either on my server, or on my clients.

Softwares I use 
3D Equalizer / Boujou / Image modeler / Maya / Shake / Silhouette Roto