Linking Geometries across Secondary Layers			Animating Geometries with the Point Tracker
Chapter 15, Secondary Colour Grading

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The Shape Tracker Menu

Tracking an Object using Shape Tracker

The Shape Tracker tool is a 2-dimensional tracking device that allows you to track objects within your shot. It allows you to create a geometry around the object you want to track, analyse the object through the shot, and then grade the geometry.

To use the Shape Tracker you need to define a region of interest (ROI) by drawing a geometry around the object you want to track. The area inside this geometry is where Lustre searches for trackable points. This group of trackable points is called a point cloud. By tracking a cloud instead of a single point, Lustre can track shapes through translation, rotation, and scaling.

In order to track a shape properly, the ROI needs to be large enough so there are enough trackable points in the point cloud. If the ROI is large enough, the object in the shot will be tracked properly. If the object you want to track is small and does not contain enough trackable points, you need to link the smaller graded geometry to a larger tracked geometry.

The Shape Tracker Menu

To track 2D shapes within a shot, you need to enable the Shape Tracker tool and create an ROI.

1. In the Main menu click Colour.

2. Click Secondaries.

   The Secondaries menu with the Shape Tracker menu appears.

   

The Shape Tracker is made up of the following components.

Tracker button-- Enables the tracking option (Point Tracker or Shape Tracker).

Tolerance slider-- Defines the tolerance level of the Shape Tracker analysis. The range is from 0 to 10.

A tolerance level of 0 (low tolerance) means the object that is being tracked does not change in shape throughout the shot. If an external object passes in front of the tracked object, a low tolerance ensures that the motion of the external object does not get tracked through the analysis.

A tolerance level of 10 (high tolerance) means the object which is being tracked has a slight change in shape throughout the shot. For example, there is slight 3D movement from the shape. If you have set the tolerance level to high, external objects that pass in front of the tracked object may be included in the analysis.

Shape button-- Enables the Shape Tracker tool.

Hide button-- When enabled, it hides the selected geometry and grading (if applicable). You can also use the hot key, left Ctrl+H, to hide and show the geometry.

Analyse backward button-- When selected, the Shape Tracker analyses the object within the selected ROI from your insertion point to the beginning of the shot.

Analyse forward button-- When selected, the shape tracker analyses the object within the selected ROI from your insertion point to the end of the shot.

Tracking an Object using Shape Tracker

There are two ways to use the Shape Tracker. If you can create a large enough ROI around the object you want to track, you can use the Shape Tracker to track the object and then grade the same geometry. If the object you want to track and grade is small and it does not have enough trackable points to use the Shape Tracker effectively, you need to track a larger ROI, create a graded geometry of the smaller object, and link the ROI geometry to the graded geometry.

The following procedure is used when the object has a large enough ROI to track.

1. Make sure you are on the first frame of where you want the tracking to start.

2. In the Secondaries menu, enable the Secondary button.

3. Click Show

   

4. Enable the Shape Tracker tool by clicking on Tracker and Shape.

   

5. Create an ROI by drawing either a basic or free-form geometry around the object you want to track. SeeDrawing Basic Geometries and Drawing Free-Form Geometries.

   Note: Make sure your ROI is as large as possible, without including too many non-rigid shapes, in order to give Shape Tracker a sufficient area to analyse.

6. Make sure the geometry you want to track is selected.

   The axis of the geometry should be yellow.

7. Set the tolerance slider between 0-10.

8. Click the analyse backward, or analyse forward button, to analyse the shot segment.

   When the analysis is complete, you can grade the geometry.

   Note: If the analysis stops before the end of the shot or it does not begin at all, the ROI area may be too small to track. Refer to the following procedure below.

The following procedure is used if the object you want to track is small and does not contain enough trackable points.

1. Make sure you are on the first frame of where you want the tracking to start.

2. In the Secondaries menu, enable the Secondary button.

3. Click Show.

   

4. Enable the Shape Tracker tool by clicking on Tracker and Shape.

   

5. Create an ROI by drawing a basic geometry around a large area in the shot. See Drawing Basic Geometries.

   Note: Depending upon your shot, the large ROI area may or may not contain the smaller object you want to track.

6. Make sure the geometry you want to track is selected.

   The axis of the geometry should be yellow.

7. Set the tolerance slider between 0-10.

8. Click the analyse backward, or analyse forward button, to analyse the shot segment.

   The analysis is now complete.

9. Click Hide.

   The tracked geometry is now hidden.

10. Create a geometry around the object you want to grade.

11. Grade this new geometry.

12. Press ~ (the tilde key) to enter the Schematic view.

    You should see the axis and geometry of the tracked shape and the graded shape.

    

    Geometry of graded shape

    Axis of graded shape

    Axis of ROI

    Geometry of ROI

    
    

13. Position your cursor over the edge of the circle representing the ROI axis and left-click and drag a line to the edge of the circle representing the graded shape axis.

    

    The graded shape is now linked to the ROI and therefore follows its tracked path.

14. Press ~ to return to the Player view.