Track Greenscreen Data from FCP Files with Imagineer mocha for an After Effects Comp
EDIT AND RETIME YOUR FOOTAGE
The spot first had to be edited and retimed because the raw footage’s timings did not match the durations we needed between flips. To do this, place markers on the audio voiceover track at the time when the flips should happen. Then mark in the middle of each flip in the video track. I exported an XML file from Final Cut Pro and imported it into After Effects with an Automatic Duck plug-in. In AE, I used the Time Remap function to synchronize the flips with the voiceover. Also in AE, I did color correction and clean up. There were a few people walking in the background, a few birds flew by, and the scoreboard needed to be corrected. You’ll likely have to do the same with any location greenscreen. Finally, render QuickTime files from AE, which you will use in mocha for tracking.
OPEN MOCHA AND START TRACKING
First, import the file. I usually export a little bit more than I usually need, just to make sure I have all the frames in. In this case, I had one frame extra in the beginning, so I move one frame forward and mark my in point. Next, select the X Spline tool and select the first marker on the first board. Add X Spline to the layer, which will add another spline to the same layer. Then select the second marker and do the same with the third one and fourth one. That’s your first layer.
NAME YOUR LAYERS
Select your first layer and click on Perspective. Use a naming convention that helps you keep track of your many layers. I changed the name of the layer to 0101, which means "first board, first shot." In this shot, we have two flips. Naming things properly always helps you later on.
TRACK MULTIPLE PLANES AT THE SAME TIME TO SAVE TIME
To make my job easier, I decided early on to track multiple planes at the same time. To do this, I duplicated the first layer five times. Click on layer 2, select all splines, then slide it over to the second board. The splines and markers should match up perfectly because the boards are the same size and the markers are the same place on the boards. Change the layer to "0201," meaning second board, first flip. Click on layer 3, select all splines and move to the third board, and rename 0301. Continue in this way over to the sixth board in the row. You may need to make some adjustments along the way, of course, depending on the perspective (see step 6). At one point in this project, I was tracking twelve layers at a time, which honestly is about the max you can do without introducing a little drag to the software and your system.
To put mocha in motion, all you have to do now is press Track Forward. The software will take a few moments to calculate and start tracking.
ADJUST YOUR TRACKS
You’ll see that mocha does an excellent job automatically tracking, but if you want to tweak any drifts that you spot, it’s just another easy step. Select the first layer, click on Surface, and select. The surface will be replaced by an image in After Effects. In this case, I selected more than I needed because I’m going to add some motion blur in After Effects.
Lock all layers except the first one. Turn on visibility and tracking. Next, click on Adjust Track. Now we can reference the four corners of the surface with the closest markers. Click on the Set Master Roll button; this will be your master frame. If you spot any drift, you can click and drag your reference to the right spot. You can see that when you go to the flip section of the shot, you lose the track. But I can adjust those few frames in After Effects later.
EXPORT TO AFTER EFFECTS
Click on the Track tab to export your tracking data. Make sure that first layer is selected and that you are exporting After Effects Corner Pin data.
PREP IMAGES TO COMPOSITE IN PHOTOSHOP PRIOR TO AE IMPORT
I received the high-res images from the art director at the agency. To prep them for After Effects, I dropped each one into Photoshop and split it into 24 identical pieces. I ended up with a Photoshop file with 24 layers and, just in case, I kept the background layer with my full image. I used the same naming convention as before, according to position, for each layer. Export your file as a Photoshop composition into After Effects; this way you’ll have access to all your layers.
START COMPOSITING IN AFTER EFFECTS
Open After Effects and find your file. Take your first Photoshop layer and drag and drop it, on the Create Composition button. Go to your main comp, take the newly created composition, and drop it onto the timeline, to be sure the new layer starts in the right spot. Next, you’ll be able to take the tracking data from mocha and apply it to this layer. Find the file; double-click on it, and copy. Go back to After Effects, select the layer and paste. If it doesn’t end up in the right spot, you can move the anchor points until you can line it up.
TWEAK ANY DRIFTS IN AFTER EFFECTS
To fix any spots where you lose your track, first select the layer. Go to the Effects control and select Corner Pin Effect. Next, open Corner Pin keyframes in the timeline. Move through your frames and adjust each corner point individually, so it goes to the right place. Then move to the next affected frame and do it again. I had about five frames to fix in this project. Select layer and press Option } (right bracket) to bring the end point of the layer to the position bar. Select and delete all remaining keyframes from the Corner Pin effect.
Go to http://www.studiodaily.com/studiomonthly/how_mocha_after_effects.html to watch the full video tutorial, which includes an additional technique for bringing mocha tracking data into your AE comp.
Tools Used: Imagineer mocha, Adobe After Effects and Photoshop, Apple Final Cut Pro, Automatic Duck
Editor and VFX artist
Founder, Formation an Editing Laboratory
Sasa Jokic is a New York-based independent editor and VFX artist. He founded his company, Formation an Editing Laboratory, in 2004. Formation partners with clients and agencies to deliver top-shelf creative commercial editorial and visual effects services. He has an M.A. in film and video editing and grew up and was educated in Serbia. He has been working in post production since 1996.
Sasa Says Keep in Mind…
I do editing and effects work, mostly for television commercials. A few months ago I was approached by an ad agency to do two commercials for Connecticut-based Webster Bank. It was a very challenging and complex project. In the spots, 24 actors hold individual signs that flip to create a seamless graphic about the bank’s services. Each spot featured seven sign flips, totaling 168 separate objects to track. I knew right away, from looking at the boards, that no matter how well the footage was shot, this would involve a huge amount of tracking and compositing work. The whole post process — editorial, color correction and effects — took more than a month. I used Final Cut for editing, mocha for tracking, Photoshop for prepping my composite images, and After Effects for compositing. It could have turned into a huge headache if it weren’t for mocha. The planar tracking technology inside mocha means that I can offer my clients the highest quality compositing, on time and on budget, from a desktop environment. In this tutorial, I’ll walk you through how I did it.
Formation an Editing Laboratory