Motion tracking in after effects

1. Tricks of the Trade Assignment

2. What is Motion Tracking?
 When you import a file to after effects, your computer
has no idea what is going on in the footage, it has no
concept of motion or direction unless you define these
things
 What motion tracking does is follow a point(or points)
that you designate through the tracking tool and
extrapolate the motion of that point across the time
that the point is in view
 You can track position, scale and rotation.

3. Why is this useful?
 Motion tracking has many uses. Here are some examples:
 Combining elements filmed separately, such as adding video to the side
of a moving city bus or a star to the end of a sweeping wand.
 Animating a still image to match the motion of action footage, such as
making a cartoon bumblebee sit on a swaying flower.
 Animating effects to follow a moving element, such as making a
moving ball glow.
 Linking the position of a tracked object to other properties, such as
making stereo audio pan from left to right as a car races across the
screen.
 Stabilizing footage to hold a moving object stationary in the frame to
examine how a moving object changes over time, which can be useful in
scientific imaging work.
 Stabilizing footage to remove the jostling (camera shake) of a handheld
camera.

4. How is it done?
 To perform motion tracking in Adobe After effects...you’re
going to need Adobe After effects.
 You’re going to need a video clip, or some sort of clip that
has motion in it
 You can open the Tracker by going to
“Window” and then checking the box that says Tracker,
or by going to “Window” ->”Workplace”->”Motion
Tracking”
• Once you have the tracker window open you can begin the
process

5.  You will now need to drag your video clip on to the
timeline
 Now create a null object
“Layer”->”New”->”Null Object”
• This null object will serve as the storage for our
tracking data
• Now with the tracking window open you need to
define your motion source, which is the clip you
dragged on to the timeline

6. The Tracker
A. Search region B. Feature region C. Attach point
A BC
Feature region
-The feature region defines the element in the layer to be tracked. The feature
region should surround a distinct visual element, preferably one object in the
real world. After Effects must be able to clearly identify the tracked feature
throughout the duration of the track, despite changes in light, background, and
angle.
Search region
-The search region defines the area that After Effects will search to locate the
tracked feature. The tracked feature needs to be distinct only within the search
region, not within the entire frame. Confining the search to a small search
region saves search time and makes the search process easier, but runs the risk
of the tracked feature leaving the search region entirely between frames.
Attach point
-The attach point designates the place of attachment for the target —the layer
or effect control point to synchronize with the moving feature in the tracked
layer.

7.  Hit the track motion button for the tracker to pop up
 Set the track type to transform
 Now you will need to select a point for your tracker
 To run the tracker hit the right or left play buttons(in the
tracking window), you can also use the single frame skip button
to make small changes
 Some tips for getting an accurate track are:
o Pick a point of contrast so that after effects wont get mixed up with
another similar looking point/colour
o Define a small area to track so that the tracker creates a more
smooth and detailed track rather than a sporadic one
o If the tracker gets off course, stop the track and go to the point
where it gets messed up then put it back to the point where it
should be, then run it from that point

8.  Now that you have a path created you will need to hit
“edit target”, and set the target to your null object. This
will put all of the tracking data in to the null object
layer
 With that step done hit apply for the data to be
transferred and leave the default X and Y dimensions
 Now that your tracking data is safely stored in your
null object you can parent the null object to any other
layer you create and that layer will also follow the
motion you just created

9. Stabilizing Footage
 After Effects can track an object's movements, then animate it to move
on the exactly the opposite direction so it appears to be steady
 While previewing the footage, look for items that might make good
features to base your stabilization on: something that has good
contrast, that keeps roughly the same shape and position throughout
the shot, and that isn't obscured by another object.
 This time instead of hitting the “Track Motion” button hit the
“Stabilize” button in the tracking window
 Track a point just like before
 Click apply once your satisfied with the track path and leave the default
X and Y dimensions
 Because of how this is done your background colour might peek
through while your clip moves around the frame, to fix this you can
either change the colour of the background using a solid, or by making
your clip large enough that the sides no longer pass the border