Camera Tracking - Nuke 101: Professional Compositing and Visual Effects - page 420

3D tracking only works on stationary objects. Objects that are moving will dis-
tract the solving process, as their movement is not generated from the camera's
movement alone. If there's a moving element in the scene, you should create a
roto for it, feed it into the CameraTracker's Mask input, and then use this prop-
erty to tell the Camera-Tracker node which channel to use as a mask. If you're
not sure where Camera-Tracker's Mask input is, drag the little arrow on the side
of the node ( FIGURE 10.7 ) .
Figure 10.7. Camera-Tracker's Mask input revealed.
For now, you will simply run the tracking process and hope for the best.
3. Click the Track Features button at the bottom of the Properties panel ( FIGURE
10.8 ) .
Figure 10.8. Click the Track Features button to start the tracking process.
TheCameraTrackernodeautomaticallytracksthelengthoftheInputclip.It'sdo-
ing it right now, as you can see from the Progress Bar that displays. If you want
to change the tracking length, change the property called Analysis Range in the
CameraTracker tab ( FIGURE 10.9 ) .
Figure 10.9. The Progress Bar showing the forward tracking stage.