Join Mark Christiansen for an in-depth discussion in this video Recognize trackable points, part of After Effects Compositing 06: Tracking and Stabilization.
- In this section and the next one, I want to kind of upend the conventional wisdom about tracking and that conventional wisdom says that you really want as accurate and as automated a track as possible. Well, the truth is, that's just not always realistic, in fact, it's rarely the case that the automated tools give you something that is ready for final. Now, this shot is really pretty great to start with.
And it just has a few flaws that we need to correct with visual effects. The one we planned for was having a grip in shot, although he was a little more in shot than we planned, he actually decided to take his own footage which is what happens when you have a skater as your grip. But more generally, we need to remove him and do a little bit of re-timing so that the chair doesn't move before the landing and so that the rest of the movement happens right at the landing.
So we're going to focus on removing this guy. Now, it would be great if we could just use something like Rotobrush to say, yeah, just select that grip and remove him. But in fact, there are other tracking tools that are simpler and more effective in this case, so I've got this basic roto, and what you can see from that is it's overlapping some things that come in front of it, specifically, just going through the shot, there's the chair and the background to fill in behind it, and then in front of it, there's a table leg, the couch, a hat, and then finally, a parasol.
So in this section, we're going to start by focusing on that couch with the theory that it's going to be much easier to just ignore, making the roto more accurate frame by frame along the edge of that couch and just actually roto in a mask for the couch itself. And that's going to be accomplished 80 to 90 percent with tracking, and then the rest is just going to be some simple hand-key framed roto. So the idea here is to be quick, not worry too much about accuracy although we will fix things that get broken, and then move along.
So no doubt, someday you'll be able to just tell the computer, "Remove that guy," and it will all be done without any effort for you. But since we haven't reached that day yet, I'm going to take you the opposite direction and show you how you can use the tools that are there, and not rely on them to be perfect, but instead plan for them to be imperfect, and leverage what they can do to make your manual work a lot easier.
Here, Mark Christiansen shows how to use the five different After Effects trackers, customizing them to work best in the situations that motion graphics artists encounter most often. He covers the fundamentals, as well as opportunities to think outside the box, especially when an automated approach won't work.
- Why point track?
- Recognizing trackable points
- Offsetting a tracker
- Applying the track to a matte
- Using nulls and third-party scripts to create track mattes
- Tracking and stabilizing objects and planes
- Automated tracking
- Applying 3D tracks