Tracking an effect

Probably a very basic question but I'm new to FCP X....
How do I track an effect through my video? For instance, I'm using the Alex4D Blurred Coloured Glass plugin on my video and I want it to follow a subject in the video.
How do I get it track with the subject and increase/decrease the time it's on screen?
Thanks,
Newbie

Not a basic question at all. You can do this manually by keyframing the position of the effect, or you can use effects that include automatic tracking options such as SliceX with Mocha.

- Ronny

For the time being, there is no built in solution for automatically tracking an effect as you describe.
The no-cost way is to manually make keyframes to place the effect on the shot.

Slice X is a third party plugin that will allow you to track things through a scene. I have not used it personally, but I have used MOCHA for many projects. MOCHA is the planar tracking system that Slice X uses under the hood. I can say that MOCHA is the best tracker I've ever used. (AE, AVID, Smoke, Inferno) MOCHA has always generated the best tracking data for me.

If you're willing to export the shot and use another app, then Motion 5 has a decent tracker that would most likely do a fine job.

I would certainly try doing it manually. This is how we did it in the old days:

1. Scrub through the shot and find key movement in your subject.
2. Make keyframes where big movements in the subject either begin or end.
3. Go back and check the tweened position of your blur half way between the initial keyframes.
4. Make adjustments as needed.
5. Half these keyframes again.
6. Repeat for all segments as needed.
7. Render, and playback.
8. Fix any sections that look wonky.
9. Save up for Slice X if you need to do this effect often.
10. Go to the FCPX feedback and request motion/planar/3d tracking.