Tracking 3D camera movement

The 3D camera tracker effect analyzes video sequences to extract camera motion and 3D scene data. The 3D camera motion allows you to correctly composite 3D elements over your 2D footage.

Analyzing footage and extracting camera motion

1. With a footage layer selected, do one of the following:
   1. Choose Animation > Track Camera, or choose Track Camera from the layer context menu.
      
   2. Choose Effect > Perspective > 3D Camera Tracker.
   3. In the Tracker panel, click the Track Camera button.
      
      The 3D Camera Tracker effect is applied. The analysis and solving phases occur in the background, with status appearing as a banner on the footage and next to the Cancel button.
      
      
2. Adjust the settings, as needed.
   

The 3D solved track points appears as small colored x's. You can use these track points to place content into the scene.

Attaching content into a scene containing a solved camera

1. With the effect selected, select the track point or multiple track points (defining a best-fit plane) to use as the attach point.
   1. Hover between three neighboring unselected track points that can define a plane, a semitransparent triangle appears between the points. A red target appears, showing the orientation of the plane in 3D space.
   2. Draw a marquee-selection box around multiple track points to select them.
2. Right-click above the selection or target, and then choose the type of content to create. The following types can be created:
   • Text
   • Solid
   • Null layer for the center of the target
   • Text, solid, or null layer for each selected point
   • "Shadow catcher" layer (a solid that accepts shadows only) for the created content by using the Create Shadow Catcher command in the context menu.

Moving the target to attach content to different location

To move the target so that you can attach content to a different location, do the following:

1. When above the center of the target, the "move" cursor appears for repositioning the target.
2. Drag the center of the target to desired location.

Once at the intended location, you can attach content by using the commands in the context menu.

Resizing a target

To resize a target, do one of the following:

• Adjust the Target Size property.
• Press Alt-click (Windows) or Option-click (Mac OS) as you drag from the center of the target. When above the center of the target, a cursor with horizontal arrows allows you to resize the target.
  

Selecting and deselecting track points

To select track points, do one of the following:

• Click a track point.
• Click between three adjacent track points.
• Draw a marquee-selection box around multiple points.
• Shift-click or draw a Shift-marquee selection box around the track points to add multiple track points to the current selection.

To deselect track points, do one of the following:

• Alt-click (Windows) or Option-click (Mac OS) selected track points.
• Click away from a track point.
  

Deleting unwanted track points

To delete unwanted track points, do the following:

1. Select the track points.
2. Press Delete or choose Delete Selected Points from the context menu.

After deleting unwanted track points, the camera is resolved. You can delete additional points while resolving takes place in the background. Deleting 3D points deletes the corresponding 2D points, as well.

Creating a "shadow catcher" layer

You can quickly create a "shadow catcher" layer, used to create realistic shadows for the effect. A shadow catcher layer is white solid the same size as the footage, but set to accept shadows only.

To create a shadow catcher layer, use the Create Shadow Catcher, Camera and Light commands in the context menu.

If necessary, adjust the position and scale of the shadow catcher layer so the cast shadow appears as desired. This command also creates a shadow-casting light (a light that is switched on, and casts shadows) if one does not exist in the composition.

Effect controls for the 3D camera tracker

The effect has the following controls and settings:

Starts or stops the background analysis of the footage. During analysis, status appears as a banner on the footage and next to the Cancel button.

Specifies whether the footage was captured with a fixed horizontal angle of view, variable zoom, or a specific horizontal angle of view. Changing this setting requires a resolve.

Specifies the horizontal angle of view the solver uses. Enabled only when Shot Type is set to Specify Angle of View.

Identifies detected features as 3D points with perspective hinting (3D Solved) or 2D points captured by the feature track (2D Source).

Controls if the track points are rendered as part of the effect.

Changes the displayed size of the track points.

Creates the 3D camera. A camera is automatically added when you create a text, solid, or null layer from the context menu.

Advanced controls for the 3D camera tracker effect:

• Solve Method: Provides hints about the scene to help in solving the camera. Solve the camera by trying the following:
  • Auto Detect: Automatically detects the scene type.
  • Typical: Specifies the scene as that which are not purely rotational, or mostly flat.
  • Mostly Flat Scene: Specifies the scene as mostly flat, or planar.
  • Tripod Pan: Specifies the scene as purely rotational.
    
• Method Used: When Solve Method is set to Auto Detect, this displays the actual solve method used.
• Average Error: Displays the average distance (in pixels) between the original 2D source points and a reprojection of the 3D solved points onto the 2D plane of the source footage. If a track/solve was perfect, this error would be 0 and there would be no visible difference if you toggled between 2D Source and 3D Solved track points. You can use this value to tell if deleting points, changing the solve method, or making other changes is lowering this value, and thus improving the track.
• Detailed Analysis: When checked, makes the next analysis phase do extra work to find elements to track. The resulting data (stored in the project as part of the effect) is much larger and slower with this option enabled.
• Auto-delete Points Across Time: With the new Auto-delete Track Points Across Time option, when you delete track points in the Composition panel, corresponding track points (i.e., track points on the same feature/object) are deleted at other times on the layer. You don’t need to delete the track points frame by frame to improve the quality of the track. For example, you can delete track points on a person running through the scene, whose motion should not be considered for the determination of how the camera was moving in the shot.
• Hide Warning Banner: Use when you don't want to reanalyze footage even though there is a warning banner indicating that it be reanalyzed.
  

Ground plane and origin in 3D Camera Tracker effect

You can define a ground plane (reference plane) and origin, for example, the (0,0,0) point of the coordinate system within the 3D Camera Tracker effect.

1. Analyze the scene using the 3D Camera Tracker effect
2. Select a set of tracking points. This action causes the bullseye target to appear, showing the plane defined by the selected tracking points.
3. Optionally drag the target by its center to reposition it along the plane, and place the center is where you want the origin to be.
4. Right-click (Windows) or Control-click (Mac OS) the target and choose Set Ground Plane And Origin.

This action does not have any visible result, but the reference plane and origin of the coordinate system are saved for this scene. Any items that you create from within this instance of the 3D Camera Tracker effect are created using this plane and origin.

Auto-delete Points Across Time

In the Advanced section of the effect properties, there is a new option: Auto-delete Points Across Time.

If this option is on, when you delete track points in the Composition panel, corresponding track points (for example, track points on the same feature or object) are deleted at other times on the layer, so it isn't necessary to delete the track points frame by frame to improve the quality of the track. For example, you can delete track points on a person running through the scene, whose motion should not be considered for the determination of how the camera was moving in the shot. This method works for both 2D Source and 3D Solved track points.

You can delete selected track points with the Delete key or by context-clicking and choosing Delete Selected Points.

Export 3D Camera Tracker data to 3D applications

You can export 3D Camera Tracker data to 3D applications like MAXON CINEMA 4D.

Do the following: