Split personality splines

One big issue you will encounter with motor is that you need to get used to the splines serving two purposes, which is both a blessing and a curse. They serve on the one hand to define the area to track and on the other hand as the ‘roto shape’. This is on the one hand more intuitive than selecting tracking points and linking them to the spline, on the other hand you need to learn how you should position your spline differently in different stages of the process. For example, if I was rotoscoping the headlights of a car I would:

  1. Create a new layer and draw a spline that covers the entire front plane of the car (i.e. the two headlights, the bumber etc.
    Reason: Tracker a larger area will give a more stable track (I am assuming that the headlights are small-ish!)
  2. Track the shot
  3. Delete all layer key frames I may have created during the track
  4. Refine the shape to only cover the one headlight
  5. Either copy the layer or add a second contour to the layer to create a mask for the second headlight, then adjust that shape.

Here your ‘tracking shape’ would look very different from your eventual ‘roto shape’