You can track a mask in your scene from the GMask object's Tracking tab. You can track the mask vertices using the Tracker, or track shapes using the GMask object's own shape tracker.
To apply shape tracking to a mask:
- Select the mask you want to track.
- Open the Tracking tab.
- Under Shape Tracking, set the Use Media field to assign the front and matte clip.
- Under Tracking, adjust the fields as needed.
- Select an option from the Track Direction box to determine if the frames before or after the current frame will be used for
analysis.
TipWhen tracking a shape that cuts off during analysis (for example, a person walking into or out of the frame), begin shape
tracking when the whole shape is apparent, and track in the direction of the frames at which the shape begins to disappear.
- Click the Shape Track button to perform the shape tracking analysis.
- To perform additional analysis in a different direction from the first frame of the analysis, toggle the Forward and Backward
box and click Shape Track again.
Vertices Tracking Settings
- Tracker menu button
-
Opens the Tracker menu where you apply tracking data to selected vertices.
- Tracking View box
-
When the current node is attached to a Source node, select to track the media in the Source Front, Source Matte or Source
Result view.
- Camera box
-
Specify which camera to take into account when working with a GMask. Select Auto Frame when the GMask is co-planar with the
image. When the GMask is under a Perspective Grid node, or is not under the image, select a specific camera to view the scene
from the same perspective in Result (F4) or Object (F8) view.
- Camera field
-
Displays the active camera number. Non-editable.
Shape Tracking Settings
- Shape Track button
-
Click to generate tracking data. Tracking information is stored in the Axis node to which the mask is attached.
- Shape Track Progress field
-
Displays the progress of the tracking operation. Non-editable.
- Use Media field
-
Displays the layer number (as defined in the Media list) of the media that will be tracked. Editable.
- Track Axis Hierarchy button
-
Enable to overwrite and store tracking information in the topmost Axis node in the schematic hierarchy.
- Transform Type box
-
Select the type of shape tracking to perform.
- Track Direction box
-
Select to track the image sequence forward or backward from the current frame.
Trackers Settings
- Size field
-
Displays the area in pixels of each tracker. Editable.
- Maximum Number field
-
Displays the number of trackers to use in the analysis. Editable.
- Motion Tolerance field
-
Set a value to determine the tolerance level of acceptable changes in the pixel environment. If an external object passes
in front of the tracked object, a low tolerance value ensures that the motion of an external object does not get tracked through
the analysis. Editable.
- Filtering field
-
Displays the level of smoothing to apply to the shape tracking animation curve. Editable.
