ABSTRACT
A common motion tracking task, from corny in-house videos to serious feature films, is to replace a sign or billboard in a shot with something more appropriate to the storyline. The object attach using the motion tracking data can have its own animation – especially if that layer is a precomp. In three-dimensional, it’s easy to render a separate high-contrast pass of just the face that is supposed to receive the tracked image; on a video shoot, perhaps paint this surface green or blue and key it later as the user matte. In either case, set Attach Points slightly outside the area where the image will get matted to so the user have some spill to crop off. As was the case with stabilization, tracking rotation or scale requires having two features to track: One serves as the anchor point, while the other is used as a reference to decide how much the object has rotated or scaled.
