Adobe 12040118 - After Effects Standard, Руководство

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Layer panels, which makes the tracked feature easier to find and enables subpixel processing and positioning.
After Effects uses one track point to track position, two track points to track scale and rotation, and four points to perform tracking using corner
pinning.
Online resources for motion tracking and stabilization
Curtis Sponsler provides detailed instructions and explanations for tracking and stabilizing motion in a PDF excerpt from his book The Focal Easy
Guide to After Effects .
Chris and Trish Meyer provide a video tutorial on the ProVideo Coalition website that demonstrates and explains the basics of motion tracking.
This video from the After Effects CS5: Learn By Video series shows how to combine motion tracking and the Clone Stamp tool to remove an
object from a scene.
Angie Taylor provides a tutorial on the Digital Arts website that shows how to use tracking data and the Clone Stamp tool to apply copies of an
object in a scene while matching a camera move.
Michele Yamazaki provides a tutorial on the Toolfarm website that shows how to use motion tracking to obscure a logo in motion footage.
Sean Kennedy provides a set of detailed tutorials on the SimplyCG website that demonstrate advanced motion tracking techniques:
Basic 2D tracking
Planar tracking
Motion tracking and compositing computer-generated elements into a scene
Screen tracking and replacement
Sean Kennedy provides a free script, TrackerViz, that makes tracking motion and applying tracking data to masks easier. You can get TrackerViz
and a series of detailed instructions on the
SimplyCG website .
Eran Stern provides a video tutorial on the Artbeats website that demonstrates the use of 3D tracking software that solves for camera movement
so that additional elements can be composited into the scene and appear to honor the same camera movement. This video tutorial uses Pixel
Farm PFHoe, but the techniques can be applied to almost any matchmoving software.
This post on the AE Enhancers forum describes and links to an animation preset from Donat van Bellinghen for scaling a set of Corner Pin effect
points.
This post on the AE Enhancers forum describes and links to a script from Paul Tuersley that takes a stabilized layer, precomposes it, and then
adds expressions that counter the stabilization.
This post on the AE Enhancers forum describes and links to a script from Paul Tuersley that can make a difficult tracking job easier by averaging
multiple sets of tracking data.
Jeff Almasol provides a script on his redefinery website that creates a null layer with an expression that sets the Position property to be the
average of the values of motion tracking track points for the selected layer.
Jörgen Persson provides a script on the After Effects Scripts website with which you can import tracking data from Apple Shake into After Effects.
Mathias Möhl provides useful scripts for motion tracking—including MochaImport, KeyTweak, and Tracker2Mask—on his website . Mathias also
provides video tutorials explaining the use of the scripts.
Motion tracking workflow
The implicit first step of any workflow is to determine the result that you want to achieve before you begin. What type of motion will you track, and
what will you apply the tracking data to?
As with many workflows in the real world, you may have to repeat some of these steps. You can track a layer as many times as desired and apply
any combination of tracking results.
Set up the shot
For motion tracking to go smoothly, you must have a good feature to track, preferably a distinctive object or region.
For best results, prepare the object or region that you are tracking before you begin shooting. Because After Effects compares image data from
one frame to the next to produce an accurate track, attaching high-contrast markers to the object or region lets After Effects more easily follow the
motion from frame to frame. Lightweight, brightly colored balls (such as ping-pong balls) placed on the feature work well, in part because their
appearance is the same from all angles. The number of markers that you use corresponds to the number of points you are tracking. For example,
if you’re tracking four points using the Perspective Corner Pinning option, you’ll track four features, to correspond to the four corners of the layer to
attach. The more markers you add to your subject before shooting, the more features you’ll have for tracking—but the more items you may have to
remove later from the image with the Clone Stamp tool. You don’t need to add a marker for each feature if a distinctive object or region is already
at the appropriate location.
If you’re tracking a large object or the set itself—such as for matchmoving—you can get good results by using a grid of uniformly spaced triangles
of a uniform size as tracking markers.