Apply tracking data to masks?

[Robert Newton]

Wow, James, way to knock the ball out of the park with that answer.

That was EXACTLY the correct way to do what the original questioner was looking for. For animating the mask on a non-transforming object inside a scene – basically keeping a tight roto around an object that isn’t moving – James’s explanation above is THE way to do it.

A great way to highlight an object in a scene.
A great way to blur a single object in a scene.
A great way to color correct an object, like a chair, in a scene.

So many uses. No need for scripts (because the original mask isn’t changing that much, just transforming along x and y.) Thanks James for setting it out step-by-like that.

Robert N.

[Chris Wood]

Hi James, I don’t understand the last part:

now you have footage precomped. bring in footage that you will overlay. track it. apply to new null layer. position tracking pre comp to scale position and rotation on overlay. parent tracking pre comp to new null layer. your done.

Could you clarify please?

I have just pre-comped my footage after following all the instructions above. Now I get confused because you say bring in footage that I will overlay. Is this the pre-comp footage, or the original footage? Bring it into where, into the pre-comp, or bring the pre-comp back into the original composition?

See what I mean? Very confusing.

Thanks.

[Marc Newman]

I was following along and he brushed over a step. But, I’m not going to repeat how it was explained. Instead, I’ll explain what you’ll have as a final result:

One precompiled composition with three layers (in order, top to bottom):

1) A solid color. The actual color doesn’t matter. The point of this layer is to contain one or more masks. The way in which is follows the movement is by setting the parent of this layer to the layer with the transform moves. Note: You could apply the tracking (transform) info to this layer, instead of using a parent, but you don’t really want to do that because you won’t be able to use transform for anything other than this layer.

2) The parent null object “Tracking” layer. This layer doesn’t even need to be visible. It’s just here to provide instruction to the top layer. After applying the tracked motion to this layer the first layer (including the mask) will move, trench, rotate.

3) Your image that will be within the mask (#1). You don’t have to apply any effects to this layer, as it will probably be better/easier to apply the effects in your original composition.

You will also have your original composition, prior to making the precompiled comp. Your original composition will contain (top to bottom):

1) The precompiled composition.

2) The background / outer masks/layer(s). Basically, everything else.

Apply your adjustments to #1, above.

[Mathias Möhl]

If you want to animate the mask with an AE tracker, a very easy and flexible solution is my tool Tracker2Mask:

– You can use as many track points as you want: either move the entire mask with just one track point or add a few more track points to add more precision

– You can either move the entire mask or only move certain vertices (using the “local mode”) of Tracker2Mask

If you prefer the cool construction with the precomp, I would track it in mocha AE (included in AE since CS4) and use MochaImport+ to import the tracking data into AE. It makes this entire precomp rig for you in just one click.

Its shown in this tutorial: https://www.redgiantsoftware.com/videos/redgianttv/item/29/
The tutorial shows it with Red Giant Warp, but if you don’t need motion blur, you can also use AE’s build-in corner pin.

I have a lot of tutorials about both techniques (Tracker2Mask and MochaImport+) on mamoworld.com