The spline should be tracked in addition to the clip being cached to RAM. You can play it back and get an idea as to how the track went. Feel free to change the playback mode in the transport controls to loop or ping-pong your track.
Another trick you can do to check your track is hit the Stabilize button in the View Controls.
Turning on Stabilize will lock the tracked item in place, moving the image to compensate. In the track module, stabilize view is a preview mode to check your track. Actual stabilization output is handled by the Stabilize Module, explained in the Stabilize Overview chapter.
You can check the accuracy of your planar track by turning on the Surface and Grid overlay in the View Control panel. Drag the corners of the Surface overlay (the dark blue rectangle) to match the perspective of your tracked plane. If you play the clip, you should see the surface or grid line up perfectly with the plane you tracked.
The Surface and Grid have no keyframes; they are simply guides that let you check the accuracy of your track. Note that the position of the Surface WILL affect the exported tracking data, so you MUST position the corners of the Surface before exporting tracking data.
Next click on the Surface button under View Controls.
When you turn on the surface you will see the blue box that represents the 4 points of the corner-pin. Right now you will see that it is not lined up with the screen.
By selecting each corner one at a time you can adjust the surface area to cover the area of the screen.
The Grid overlay should line up with the plane you’re tracking and move with it as you cycle through the clip. You can change the density of the grid by adjusting the X and Y grid values in View | Viewer Preferences:
The grid overlay can give you a quick representation of the accuracy of the track.
The Trace feature allows you to see the position of the planar corners over time. Skip allows you to work with only every nth frame, useful on particularly long roto shots where the movement is predictable.
When you track a layer, the mattes of any active layers above the layer itself are subtracted from the matte of the layer and hence influence the area being tracked. To keep your tracking predictable, it is recommended that you keep your tracking layers on the top of the stack unless you specifically wish to use other layers to subtract from the tracking area of layers beneath it.
To monitor what the tracker “sees” as a tracking area, select the Track Matte button in the view control.