New Feature: Playlist Center! Pick a topic and let our playlists guide the way—like a learning mixtape.

Start learning with our library of video tutorials taught by experts. Get started

After Effects Apprentice 12: Tracking and Keying
Illustration by John Hersey

Tracking to a corner pin


From:

After Effects Apprentice 12: Tracking and Keying

with Chris Meyer and Trish Meyer

Video: Tracking to a corner pin

In the previous movie, we set up a composition, select the footage that we wish to track and applied the tracker to it. Now we need to set it up for a perspective track. Underneath Track Type, you have a few additional choices we haven't played with. You've already worked with Stabilize and you've already worked with Transform, Raw just creates plain old tracking data that you're going to later copy and paste or use expressions to assign to other parameters, but the two of interest to us now are Parallel corner pin and Perspective corner pin.
Expand all | Collapse all
  1. 9m 2s
    1. Welcome
      2m 38s
    2. The Tracker panel
      4m 24s
    3. Using the exercise files
      2m 0s
  2. 13m 25s
    1. Warp Stabilizer basics
      5m 59s
    2. Warp Stabilizer advanced parameters
      7m 26s
  3. 30m 6s
    1. Setting up a stabilization
      2m 57s
    2. Track points explained
      5m 48s
    3. Performing a track
      5m 11s
    4. Applying a stabilization
      2m 42s
    5. Cleaning up the results of a stabilization
      3m 0s
    6. Performing a motion track
      5m 57s
    7. Applying the results
      4m 31s
  4. 13m 48s
    1. The Radio Waves effect
      4m 16s
    2. Tracking the mountain
      5m 31s
    3. Compositing the effect
      4m 1s
  5. 24m 28s
    1. Perspective tracking overview
      2m 40s
    2. Tracking to a corner pin
      7m 1s
    3. Improving the composite
      5m 39s
    4. Tracking with mocha-AE
      9m 8s
  6. 31m 49s
    1. Tracking in 3D (new in CS6)
      4m 31s
    2. Creating 3D objects (new in CS6)
      5m 12s
    3. Hanging a poster (new in CS6)
      8m 8s
    4. Adding text (new in CS6)
      5m 33s
    5. Using shadow catchers (new in CS6)
      8m 25s
  7. 16m 46s
    1. Tracking dots
      5m 43s
    2. Dealing with obscuration
      5m 12s
    3. Cleaning up the stabilization
      5m 51s
  8. 12m 40s
    1. Basic keying
      7m 20s
    2. Refining the key
      5m 20s
  9. 13m 32s
    1. Quizzler challenges
      3m 35s
    2. Quizzler #1 solution: Stabilization plus masking
      2m 58s
    3. Quizzler #2 solution: Stabilization plus tracking
      2m 50s
    4. Quizzler #3 solution: Copying a camera's motion
      4m 9s
  10. 12m 28s
    1. Tracking for multiple effect points
      4m 44s
    2. Converting to ray-traced 3D (new in CS6)
      7m 44s
  11. 23m 59s
    1. Legacy tracker advice
      8m 14s
    2. Tracking interlaced sources
      5m 59s
    3. Using garbage masks for keying
      4m 51s
    4. Using the Rolling Shutter Repair feature (new in CS6)
      4m 55s

Watch this entire course now—plus get access to every course in the library. Each course includes high-quality videos taught by expert instructors.

Become a member
please wait ...
After Effects Apprentice 12: Tracking and Keying
3h 22m Intermediate Nov 23, 2011 Updated Dec 12, 2012

Viewers: in countries Watching now:

Explore how to use the motion tracker and stabilizer built into After Effects and shows how to handle a variety of shots. Author Chris Meyer leads a quick tour of the third-party software mocha and demonstrates the workflow for The Foundry's KEYLIGHT, both bundled with After Effects. The course also covers tracking a greenscreen shot with a handheld camera and replacing its background.

The After Effects Apprentice videos on lynda.com were created by Trish and Chris Meyer and are designed to be used on their own and as a companion to their book After Effects Apprentice. We are honored to host these tutorials in the lynda.com Online Training Library®.

Topics include:
  • Understanding motion stabilization and keying
  • Performing a track
  • Applying tracking to effects
  • Keying with KEYLIGHT
  • Replacing images
  • Improving the composite
  • Garbage masking
  • Dealing with interlaced footage
Subjects:
Video Motion Graphics Visual Effects
Software:
After Effects
Authors:
Chris Meyer Trish Meyer

Tracking to a corner pin

In the previous movie, we set up a composition, select the footage that we wish to track and applied the tracker to it. Now we need to set it up for a perspective track. Underneath Track Type, you have a few additional choices we haven't played with. You've already worked with Stabilize and you've already worked with Transform, Raw just creates plain old tracking data that you're going to later copy and paste or use expressions to assign to other parameters, but the two of interest to us now are Parallel corner pin and Perspective corner pin.

Parallel corner pin assumes you have a parallelogram with the top and bottom edges of what you're trying to track are supposed to say parallel to each other as well as the left and right sides. Perspective corner pins as well maybe camera is skewed and you can't count on those edges being exactly parallel. If you go ahead and look at this monitor over here, these points are closer to each other than these points, so this line is not parallel to this line. In that case, you need to do a Perspective corner pin where you're looking at each corner of this rectangle independently. Your goal is to eventually map a new rectangle over the one you define here.

So I'll select Perspective corner pin and now four track points will appear. I need to assign one onto each corner of this monitor. I'm going to hold Command in Mac, Ctrl on Windows and press plus to zoom in, then hold to Spacebar to pan around. It's very easy to have good intentions with this track, but to go wrong. For example, on my first pass, I said oh, well, let's just tighten things up just in those little bright corners like this. Just pan down quickly, show you what I'm up to and say let's just track these very nearly focused regions, because we've nice cleanly defined corners.

And I'll tighten up my search regions as well so that After Effects doesn't have to look too far. However, with experimentation, I found that this doesn't work very well and I'll quickly demonstrate that to you. I'll click Options under the Luminance track, no need to process, no Fields, Subpixel Positioning fine. No need to Adapt Feature. It doesn't move that much, but if it does change a lot, let's stop so we know something is going wrong. I think this is good so far, I'll zoom out a step, re-center and analyze backwards so that it started on the last frame to the shot.

But watch these four corners. You'll see there is a quite a bit of jumping going on in these shots. The part of that is due to the fact that while tracking, After Effects is displaying the track points for the previous frame while it's analyzing the next frame. So we'll seem to be behind. As I'll drag through here, you can see a lot of jittering going on in those corners where there should not be any movement at all. Well, it's quite common with motion tracking that your first attempt is not going to work, and you will need to try alternate ideas.

In this case, I'm going to undo to get rid of my previous work that I done on this. I can keep undoing or I can just twirl open the layer inside the Timeline panel and delete that Tracker. I start over, Track Motion, type Perspective corner pin. After a lot of trial and error, I've actually found on this shot that I get better results if I just go ahead and use the original size feature regions and place it over those corners. In this case, I'm picking up more information, not just the flickering C or T, but also some additional hints in the shadows and the corners of the Bezel monitor, etcetera.

I will, however, tighten up the search regions a little bit just to cut down on false triggering, like that and like that. Now on a Perspective corner pin shot, the attach points are particularly important. I'm going to zoom in another step here. I really want to make sure that those attach points are beyond the area I want to obscure. Now if this attach point is inside, well, this is where my brand-new layer is going to get pinned and some of the old layers are going to peek out behind it.

I really need to make sure that one, I see the attach point icon and those it also changes to a white arrow, and then put my attach point just outside of that corner, so I make sure I cover up the old display. I hold down the Spacebar and drag to pan around, tweak this out a little bit, come down this corner, tweak that out a little bit and then go over to this corner, and make sure I'm covering the corners well. Now you will notice that due to the bowing of the monitor, the lines in between those corners are not perfectly covering the old display. Don't worry; we're going to tackle that refinement in the next movie.

Right now, we're just trying to get a good track. I zoomed out so I can see the whole display. I double-check my Options and I'm pretty sure luminance is right; I've got good contrast. Well, let's just go ahead and analyze backwards because I am starting again this clip again. With these larger feature regions, I do get a better track. However, as I drag through here, I still see there is a little bit of jittering going on and this is indeed a weakness of the After Effects corner pin tracker.

It does not know that this relationship is supposed to stay somewhat fixed. The shape defined by these corners should not be changing. This is where that third-party tracking tool, mocha, which is bundled with After Effects CS4 and later comes in handy and in the sidebar movie, I will show you how to use mocha on this particular shot. But anyway, we now have our four corner track, now let's look at our Motion Target; the new screen we want to put over this existing screen. In tracking situations, After Effects will look above for layers; there is only one, the Heart Monitor, which you put in earlier.

But if you did not select it correctly, you can select Edit Target and pick which layer you indeed want to corner pin into these four track points. I'll click OK, click Apply. In this case, I don't get an Options dialog, because there is no separation of X and Y, I need to do all four corners accurately, and I'll press 0 to RAM Preview, and now you can see our new display in context over the old monitor. And in fact, it doesn't look anywhere near as bad as we thought is going to look when we are assumed in looking just the track points.

It is very easy to obsess about track quality and frankly, you should obsess about track quality. However, before you toss out your work, at least, preview and see if the shot works. This shot does basically work, but I have some issues, like it could be the old display, peeking out around on corners here, and it could be integrated better into the shot and that's what we'll tackle in the next movie.

Find answers to the most frequently asked questions about After Effects Apprentice 12: Tracking and Keying.


Expand all | Collapse all
please wait ...
Q: This course was updated on 12/12/2012. What changed?
A: We added new chapters on the Warp Stabilizer and the exciting new 3D Camera Tracker, and new movies on the Tracker panel, converting to ray-traced 3D, and rolling shutter repair, all new features introduced in After Effects CS6. In addition, there are new sets of exercise files designed for After Effects CS5.5 and After Effects CS6 and a companion movie that shows our premium subscribers how to use the exercise files.
 
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.
Upgrade now


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ.

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

join now Upgrade now

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed After Effects Apprentice 12: Tracking and Keying.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferencesfrom the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Are you sure you want to delete this note?

No

Notes cannot be added for locked videos.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.