Wobble motion tracking

Wobble Motion Tracking

Wobble Across the 8th Dimension is an experiment with motion tracking and blend modes. It is the 43rd video of my #100videoclips project.

The “Across the 8th Dimension” part of the title come from the classic cult film, “Buckaroo Banzai Across the 8th Dimension.” My strange headgear just reminded me of the aliens in that film — although, looking back at clips of the film, there is little resemblance, but I liked the name anyway.

What I Did

It started out as an attempt to trace an outline of me and animate it. I thought the top half would be enough, and after spending quite a bit of time on the face (and taking some liberties with the headgear and shoulder winglets — it’s like Halloween!), I decided to simplify the rest of the outfit.

By the time I got to the hands and arms, I was in total simplification mode. I just wanted to get to the animating!

Jon motion tracking puppet comparison

Not having done any animating like this before, I explored various options, including using the Puppet feature in After Effects. However, I never quite figured it out — it seemed to be extremely complicated for what I wanted to do — so I settled on After Effects Motion Tracking.

Motion tracking lets you pick a point or a pair of points with high contrast and automatically track their movement across time. Once their motion is recorded, you can attach another object to those points, so the attached object follows the motion of the original object.

As it turns out, a face is a good thing to track, since there are lots of high-contrast regions to track.

However, a dark turtleneck is more difficult, although the edge of the dark shirt against the light background does help a little.

For the basic procedure of motion tracking, I think the following tutorial is very good. (There are a few beginner gotchas that he misses, but I’ll point them out below.)

After Effects Motion Tracking How To – Visual Effects 101
by Surfaced Studio

Motion Tracking Basics

Here’s a summary of the steps for motion tracking:

  1. In After Effects, go to the Animation menu and choose Track Motion.
  2. Choose one point if you just want movement, but choose two points (which I always did) to also track angle changes.
  3. Set the tracking point(s) on your video on areas with high contrast.
    • When you try to move the track points, you may accidentally resize one of the two sets of boxes instead. (I did about half the time.) If that happens, undo (Cmd+Z) and zoom in more to be able to click on the space between the two boxes so you can move the entire set (point plus two boxes) as a unit.
    • Note two shortcut keys/moves that are extremely helpful during this whole process:
      • Zoom in: Two-finger scroll on the track pad, or scroll wheel on the mouse.
      • Move your position in the scene: Hold down the space bar while you click and drag around.
  4. Analyze by using the Play forward button
    • If the tracking loses the point along the way (mine always did):
      • Stop the tracking
      • Move the cursor back (click and drag, or Cmd+back arrow) to the last point that was still properly tracked.
      • Move forward one frame (Cmd+fwd arrow), and readjust the position of the boxes and the tracking point to where it is supposed to be.
      • Click on the “Analyze one frame” forward arrow.
      • Go forward one frame at a time for a few frames until you think the analyzer is back on track. Then press the Play arrow (Analyze) again, but stop again and backtrack as needed.
  5. Be sure that Track Type: Transform is selected.
  6. Create a Null object layer (Layer/New/Null object)
    1. Rename the Null object layer (right click on the name of the Null object) to the object you are tracking, so you can keep them straight. You may be creating a lot of these.
  7. In Tracker, choose Edit Target, and select the Null object.
  8. Choose Apply
  9. Select the new object (in the composition timeline) that you want to apply the tracking to.
  10. Get the Pick Whip (little spiral) for the object layer, and drag it to the name of the Null object that you created.
    1. Important note: If the Pick Whip is not showing on your timeline (it wasn’t on mine, and it took forever to figure out how to make it show up): Go to the menu icon in the upper right of the comp timeline window, choose Columns, then Parent. The Pick Whip allows you to “Parent” one layer to another.

Now, the movement of your object should be attached to the movement of your null object, which should follow the points identified by the motion tracking procedure.

If your object still gets a little out of alignment, you can adjust the position of the object itself (not the null object) using keyframing.

  • Mark a Position keyframe just before the object gets off track, and just after it comes back.
  • Then, move the cursor to where the object is furthest off track, and change the position so it is back on track.

After the Motion Tracking

You may notice that much of my festive outfit (the shoulder pads, etc.) isn’t included in the final video. That was for a number of reasons:

  • The shoulder-pad thingy was a single piece, so I tried to track two points on my shoulder. However, my shoulders gyrate wildly, and there is no definitive point to track (only an edge), so I could never get the motion tracking to align well enough.
  • Even worse, the torso and arm pieces really had no reliable points to track, and it was just too difficult.
  • I originally tried to track my head as one piece and my neck as a separate piece, but I ended up just joining them together, and using various blend modes in the final for the headpiece.
  • I did create the little “droplets” pairs (once it was clear that I wasn’t using the rest of my traced outfit), and I carefully tracked them to points along my shoulders to add a little more variety.
  • Other than the headpiece, the rest of my body is just the video of me, although it is obscured by the swirling psychadelica.
    • The swirls are two freehand spirals that I drew in Photoshop and saved as a PNG file with a transparent background.
    • In Premiere Pro, I slowly rotated them in opposite directions.
    • The green spiral has the Spherize and Turbulent Displace effects applied to it. The blue spiral has Turbulent Displace and Radial Shadow.
    • Those effects, along with different blend modes for the layers above (me dancing, and my bobbing drawn/traced head) make for some very funky graphics.
  • In a few scenes, I mixed things up with multiple versions of myself in various configurations.