User Manual

Using Filters to Delete Problem Tracks
The Solve tab includes filters that can be used to select groups of similar tracks by track length,
track error, and solve error. These can be used to quickly select and delete poorly performing
tracks that may be misleading to the resulting camera, leaving a concise list of accurate tracks.
Tracks can be selected using filters and deleted using
the Operations On Selected Tracks buttons.
For instance, it is generally best to run the solver using tracks with longer durations. Since
shorter tracks tend to be less accurate when calculating the camera, you can remove them
using the Filter section in the Inspector.
Increasing the Minimum Track Length parameter sets a threshold that each tracker must meet.
Tracks falling below the threshold appear red. You can then click the Select Tracks Satisfying
Filters button to select the shorter tracks and click Delete from the Options section in the
Inspector.
Exporting a 3D Scene for Efficiency
The Camera Tracker saves all its 2D tracks into the composition, sometimes resulting in a rather
large file on disk. If you are dealing with a large clip with many 2D tracks over a long duration,
the saved composition can reach over a gigabyte in size. Using a Camera Tracker node in a
composition can make it cumbersome to load and operate. While it is possible to use the
Camera Tracker node directly to composite via the 3D output, you’ll achieve better performance
by exporting. Once the quality of the solve is satisfactory, the Export tab can generate a “low
memory” alternative by producing individual Camera 3D, Point Cloud, Ground Plane, and 3D
Renderer nodes.
Before you can export the 3D scene, you must provide a bit more information about it. You’ll do
this using controls found in the Export tab. Cameras do not include tiltmeters, so clips do not
contain metadata that indicates how the camera is tilted or oriented. This is critical information
when recreating the virtual camera. It is also useful to determine the location for the center of
this 3D scene. The Export tab provides various translation, rotation, and scale controls to set
these options.
Unalign the 3D Scene Transforms
By default, the Export tab is set to Aligned in the 3D Scene Transform section. The Aligned
setting locks the orientation and scale of the 3D scene to prevent accidentally changing it. So,
before you can set the ground plane and origin location, you must change the Camera Tracker
to be unaligned using the 3D Scene Transform menu in the Export tab. After you have gone
through the Export settings and configured them how you want, you must set the menu back to
Aligned before exporting.
1601Chapter – 77 3D Camera Tracking