The 3D Camera Tracker in Adobe After Effects is a powerful tool that lets you analyse your footage and extract information about the movement of the real life camera used to film the scene. Assuming the tracking data is spot on, you can then place other visual elements in the 3D space of your scene and they will follow the movement of the camera correctly.
I have afull tutorial on how to use the 3D Camera Tracker in Adobe After Effects as a part of my 3D Integration VFX tutorial series.
As great as the 3D Camera Tracker is, there are a number of common problems that people encounter when trying to track their footage and this tutorial will explain what is going wrong and how you can fix it.
Before we look into why the 3D camera tracker does not work, we first need to understand how it does work.
The 3D Camera Tracker works by analysing your footage frame by frame and detecting features that it can track. A feature is a clearly distinguishable visual shape in your clip that represents a fixed location in space. Moving objects like people and cars are not features and tend to interfere with the 3D camera Tracker.
The tracker will try to find as many features as possible in your footage and track their movement from frame to frame. This generates a cloud of 2 dimensional track points on your footage.
Using this cloud of 2D track points, the 3D Camera Tracker then tries to 'solve the camera'. It will try to infer the 3D position of these track points based on how they move as a group and then derive the movement of the camera from this data.
In the screenshot below you can see that the 2D track points are all the same size as they have no 3D position. On the right side the size of the solved 3D track points represents how far they are from the camera.
Now that we understand the basics of how the 3D Camera Tracker works, let's look at the most common scenarios of why it might fail!