Adobe After Effects Forum
Motion tracking on a mask
Motion tracking on a mask
by Laurie Turner on Feb 24, 2009 at 8:28:58 pm

I am trying to blur someones face to protect there idenity. They move around alot and it will take me a long time to key frame the masks position. How do you use tracking to accomplish this?

AE CS3 in Mac OSX



Re: Motion tracking on a mask
by Simon Bonner on Feb 24, 2009 at 8:46:21 pm

Hi Laurie,

If they move around a lot, their face will probably move about too, meaning that using the eyes as track points is out. But perhaps you could track the top of their head, or some item of clothing. The track doesn't have to be fantastic because the obscuration layer won't have to track seamlessly.

If you are new to the motion tracker, check out the tutorial on the topic on my youtube page (

Maltaannon also has a good tutorial on censoring which is definitely worth a look.

Simon Bonner

Re: Motion tracking on a mask
by Laurie Turner on Feb 25, 2009 at 1:10:37 pm

This footage is from a servalience camera. What I did was I put the footage in a comp then added an Adjustment layer where there I put a blur on it. Then I put a mask on the adjustment to make an oval that fit around the head. Could I use motion tracking to get that masked oval to follow the head?

Re: Motion tracking on a mask
by Samuel Hall on Feb 26, 2009 at 2:21:03 pm

You could try creating a null layer, applying any motion tracking data you can get from the person's movement to the null and then parenting your adjustment layer to the null.

Samuel Hall

Re: Motion tracking on a mask
by Laurie Turner on Feb 27, 2009 at 1:14:33 pm

Thank you guys,
Sorry Bonner, I replied after my second questions saying nevermind that you already answered my question with the links you provided. Some reason my reply didn't go through. You're both right. Putting using the null object with the adjustment layer works.
Thanks again for your research and quick replies!