UM:Ft Basic Tracking
Any Shapes layer inside a CC Layer (including Base) or FX Layer can be used to create a track for a shot.
Before starting, familiarise yourself with the shot you wish to use. Play the shot through and identify the area you wish to track and its behaviour. Pay attention to how the chosen feature moves (including any scaling or rotation), whether it is ever obscured (or partly obscured), whether it stays inside the frame and how other parts of the shot move relative to it.
The tracking process is straightforward :
|•||Draw a shape around the area you want to track (and affect)|
|•||Press the track control to track forwards or backwards|
With the play-head at the required starting frame, we will draw a shape around the feature we wish to track.
In the Shapes/Shape menu :
We draw our shape around the feature we wish to track :
Ellipse shape drawn around our car "feature" we will track
It is often possible to keep the shape simple (rectangle, ellipse). Any matte/mask the track creates will usually be softened such that it properly merges into our shot and does not stand out in an artificial way.
Create the shape to cover the entire feature area of interest with some head-room. Try and extend the shape a bit beyond the feature area.
Once the shape is drawn, the DVO Tracking controls are enabled.
To track the feature forwards to the end of the shot, press the track forwards button (as shown above).
If the Feature Points button is enabled, two or more feature points will appear inside the shape as we start playing the shot, tracking as we go.
Tracking forwards, feature points used appear in green.
The selected feature tracks until the end of the shot and then stops. The tracking creates a new key-frame for each frame ,displayed in the key-frame box at the bottom of the screen.
A key-frame is created for each frame of the shot we track.
We can now use this tracked shape as a mask.