2017

two-point tracking, you use a second tracker to generate rotation and/or scaling information. The
Stabilizer obtains this information by comparing the position of Tracker2 to that of Tracker1.
■ Tracker1 follows the horizontal and vertical translation of the reference point. You should position
Tracker1 over a point on the pattern that you want to track.
NOTE The position of the axis is synced with the position of Tracker1. Therefore, any existing animation
on the Axis is overwritten by the tracking data.
■ Tracker2 tracks the rotation and/or the change in size of the pattern. In the first frame, the rotation
is always 0 and the scaling factor is always 100%. In subsequent frames, a rotation and/or scaling
factor is added if the relative position of the two trackers changes. You should position Tracker2
over a point that represents the rotation or change in size of the pattern.
NOTE You can fine-tune the tracking data if necessary. See
Tracking Difficult Shots and Correcting Errors
(page 735).
7 Once you are satisfied with the tracking, click Return.
The Axis menu in Action reappears. The tracking data is applied to the Axis media.
Bilinear Surface Tracking
With bilinear tracking, or four-point tracking, you use four trackers in the Stabilizer to generate tracking
data.
■ For anchoring the four corners of a bilinear surface to the background clip.
■ For anchoring the four UV points of the surface to features of the clip.
The bilinear surface then tracked to the horizontal and vertical translation of the reference points.
See
Stabilizer Menu Settings (page 1180) for an overview of the settings and options in the Stabilizer.
To track a bilinear surface:
1 Load front and back clips in Action.
2 Double-click the image node in the schematic to display the Surface menu.
3 Select Bilinear from the Surface Type box.
4 Do one of the following:
■ To track the Vertices relative to the background, click the Vertices tab to display the Stabilizer button
and tracking options.
■ To track the UV points of the surface to features of the clip, click the UV Points tab to display the
Stabilizer button and tracking options.
5 Select a tracking mode. Options are:
■ Each Point: Track the surface using a tracker for each selected vertex or UV point.
■ Pos/Rot: Track the surface using two proxy trackers that extrapolate the position of the selected
vertices or UV points, based on changes in the position and rotation.
■ Pos/Scale: Track the surface using two proxy trackers that extrapolate the movement of the selected
vertices or UV points, based on changes in the position and scaling.
■ Pos/Rot/Scale: Track the surface using two proxy trackers that extrapolate the movement of the
selected vertices or UV points, based on changes in the position, scaling and rotation.
6 Click Stabilizer.
The Stabilizer menu is displayed.
Bilinear Surface Tracking | 731