Match Multiple Objects

Match Multiple Objects

In the real world, objects sit in an environment, and if that
environment or the point of view changes, they remain in
place. You knew this. You may not know how to make a 2D
After Effects track re-create it.
The key is to stabilize the background layer and then parent
a camera to that stabilization, restoring the motion.
The motion of the source camera is captured and applied
to a virtual camera so that any elements you add to the
scene pick up on that motion. It’s quite cool.
The AE Camera as a Tracking Tool
Suppose you have an arbitrary number of foreground layers
to match to a background plate: not just objects, but
color corrections, effects with hold-out masks, you name it.
Applying track data to each of those layers individually is
a time-consuming headache, and even parenting them all
to a tracked null may not work properly if there is rotation
or scale data, as that null then becomes the center of those
translations.
Instead, the following method allows you to stabilize the
background scene, add static foreground elements, and
then reapply the scene motion.


1. With the background layer selected, choose Stabilize
Motion (either by context-clicking the layer or by
choosing it from the Animation menu).
2. Stabilize the layer for Position, Rotation, and Scale,
using two points equidistant from the camera.
3. The stabilized layer offsets and rotates in the frame
(Figure 8.13). Return to the fi rst frame of the track
(quite possibly frame 0 of the comp). Turn on the stabilized
layer’s 3D switch.
4. Add a 3D camera (context-click in an empty area of the
Timeline); in the Camera Settings, give it a name like
trackerCam, use the 50mm preset, and click OK.
5. Parent the camera layer to the stabilized layer.