Motion Tracking – Position, Rotation & Scale

Topics Covered in This After Effects Tutorial:

Planar Tracking, Tracking Transform Properties, Mocha AE Plugin

Exercise Preview

Exercise Overview

In this comprehensive exercise, you'll master the Mocha AE effect to precisely track a video element's transform properties and seamlessly apply them to another layer. This technique forms the backbone of professional motion graphics work, enabling you to create convincing composites where graphics appear naturally integrated into live-action footage. By the end of this tutorial, you'll have the skills to tackle complex tracking scenarios that would be impossible with After Effects' built-in point trackers alone.

Previewing the Final Video

Before diving into the technical process, let's examine the professional results you'll achieve with proper planar tracking implementation.

1. Let's see a preview of what you'll be creating. If you're currently in After Effects, keep it open but switch to your Desktop.
2. On the Desktop, navigate to Class Files > After Effects Advanced Class> Motion Tracking—Transform > Preview Movie and double-click Logo Replacement.mp4.
3. Also preview Magic Hand.mp4 to see an additional example of this technique in action.

4. Notice the following critical elements:

   • Graphics are seamlessly integrated into the video, matching the perspective and movement perfectly.
   • The graphics follow the surface movement with precise accuracy, maintaining proper scale, rotation, and position throughout the sequence.

5. Replay the video to analyze how the tracking maintains accuracy even through complex camera movements, then close it when you've finished your analysis.

Setting up the Workspace

A properly configured workspace is essential for efficient tracking workflows. Let's optimize your After Effects interface for this advanced technique.

1. In After Effects, go to Window > Workspace > Standard.

2. Choose Window > Workspace > Reset "Standard" to Saved Layout to ensure all panels are in their optimal positions.

3. If the After Effects window does not fill the screen, maximize it for the best tracking experience:

   Mac:	At the top left of the window, click the green button (the third button).
   Windows:	At the top right of the window, click the Maximize button (the middle button).

Getting Started

Now we'll set up a new project specifically optimized for motion tracking work. Proper project organization is crucial when working with tracking data.

1. In After Effects, if you have a project open, choose File > Save to preserve your current work.

2. Choose File > Close Project to start fresh.

3. In your new project, choose File > Save As > Save As and:

   • Name the file Your Name—Logo Replacement.aep and
   • Save it into Desktop > Class Files > After Effects Advanced Class> Motion Tracking—Transform.

Project Setup and Composition Creation

When working with motion tracking, ensuring that your composition settings match your source footage dimensions is absolutely critical. Mismatched settings will result in tracking data that doesn't align properly with your composition space.

For tracking projects created from scratch, follow this essential workflow:

1. Drag your primary video footage (the clip you want to track) into the empty Timeline panel or directly onto the Create a New Composition button. This automatically creates a composition with matching dimensions and frame rate.

2. Rename the layer to something descriptive like "Source Footage" or "Tracking Layer" so you can easily identify it throughout the tracking process.

Applying the Mocha AE Effect

Mocha AE represents one of the most powerful tracking tools available within After Effects. Unlike traditional point trackers, Mocha uses planar tracking technology that analyzes entire regions of pixels, making it significantly more robust for complex camera movements and perspective changes.

1. Select the video layer that contains the element you want to track.

2. In the Effects & Presets panel, type Mocha into the search field to quickly locate the effect.

3. Double-click on the Mocha AE effect to apply it to your selected layer.

4. In the Effect Controls panel, click on the Mocha logo to launch the Mocha interface. This opens the full Mocha application within After Effects.

Understanding Mocha AE's Tracking Workflow

Before diving into the technical steps, it's important to understand that Mocha AE is developed by Boris FX, not Adobe. This means the interface, terminology, and workflow concepts differ significantly from After Effects. Even fundamental concepts like "layers" work differently in Mocha's planar tracking environment.

The core Mocha AE tracking workflow follows this proven sequence:

• Create a spline shape (similar to an After Effects mask) which automatically generates a tracking layer.
• Execute the track across your footage timeline, making real-time adjustments to the layer boundaries or tracking parameters as needed.
• Perform post-tracking refinements and adjustments to ensure maximum accuracy throughout the entire sequence.

Now let's implement this workflow step by step:

1. In Mocha, scrub through your timeline to locate the frame where the element you want to track is most clearly visible and has good contrast with the surrounding areas.

2. Create a spline layer around the element you want to track, ensuring you select an area with sufficient detail and contrast for reliable tracking.

3. Reveal the Planar Surface indicator and verify it's positioned precisely in the center of the element you're tracking. This surface represents the plane that your tracked graphics will align to.

4. If necessary, adjust the Minimum % Pixels Used parameter to optimize tracking performance based on your footage characteristics.

5. Execute the tracking process across your entire timeline, monitoring the results in real-time.

6. Save the Mocha project to preserve your tracking data, then return to the After Effects interface.

Applying Tracking Data to a Layer

Successfully completing the track in Mocha is only half the process. The crucial next step involves transferring that tracking data back into your After Effects composition and applying it to the layers you want to move. This is where many users encounter challenges, but following this precise workflow ensures reliable results.

1. Back in the After Effects interface, create a null object layer that will serve as the recipient for your tracking data.

2. Select your tracked layer and locate the Tracking Data properties in the Effect Controls panel.

3. Click the Create Tracked Data button and press OK to generate keyframe data from your Mocha track.

4. Set the Export Option to Transform to transfer position, scale, and rotation data.

5. Set Layer Export To to target the null layer you created, ensuring the effect targets the Source properties of that layer.

6. Click Apply Export to transfer the tracking data to your null object.

Parenting Layers for Final Integration

The final step involves connecting your graphic elements to the tracked null object through After Effects' parenting system. This relationship ensures that any layers you want to move with the tracked surface will inherit all the motion data seamlessly.

1. Import and add your graphic layer to the composition, positioning it precisely relative to the element you tracked in the original footage.

2. Set the tracking null object as the parent for your graphic layer using the Parent column in the Timeline panel. This creates the hierarchical relationship that drives the motion.

3. Save your project file to preserve all tracking data and layer relationships for future revisions.