Tracking an Additional Feature with Offsets

< Previous | Contents | Manuals Home | Boris FX | Next >

‌Tracking an Additional Feature with Offsets

If you've already got one solid tracker, and need a few other nearby trackers, you can also use offset tracking. For example, you may want to quickly track additional features for detailed 3-D modeling, or may want a track of the corner of an object when a very variable background is moving behind it. Because you are relying on an already- tracked tracker, the additional offset trackers are easy to generate, even if the original tracking was difficult.

To do this, complete 2-D tracking of the easy feature, then click the New+ button (New Offset Tracker) on the Tracker control panel to make (clone) a copy of the selected tracker. If the tracker already has an offset track, you will be asked if you want to remove it, which you should it will be baked into the trackers path.

Rewind to the beginning of the tracker, then drag the offset cursor to the desired feature to be tracked. Work through the shot, periodically adjusting the position of the offset cursor to stay accurately on the desired point to be tracked.

Important! Don't change the underlying tracker, only the offset marker.

That might be every 20 frames, or whenever there is a key on the tracker position how often depends on how much the camera view angle is changing. You may want to use the graph editor to change the key type of the offset channel keys from linear (suitable for temporary offsets), to smooth.

Tip : To monitor the position of the offset marker carefully, click the '5' key to turn on pan-to-follow in the camera view. Zoom into the camera view.

Scrub through the shot to monitor the position of the offset marker. You can stop adding additional keys when the offset position is suitably accurate throughout the entire length of the shot (underlying tracker).

If the offset tracker winds up in the wrong 3-D location compared to the original tracker, it is because you have not set up the offset channel accurately! The relative 3-D location is ENTIRELY determined by what offset keys you set. An offset tracker does not contain as much information as a normal tracker.

Offset tracking is easier for simple camera motions, such as a left to right dolly, even if it bounces quite a bit, versus a complex move that will require many different keys in the offset to get right.

< Previous | Contents | Manuals Home | Boris FX | Next >