animated shape path mask in AE

[Arn Sweatman]

For the life of me I can not figure out how to make a simple animated shape path into a mask.

I'm just trying to do a simple eye blink.   I brought in my art for AI, converted the eyeball layer into a shape layer then animated a blink.   The pupil layer is below the mask with the appropriate track matte setting.  But it (the animated shape layer) refuses to function as an animated mask.  It *will* mask the first and last keyframe, but not the in-betweens.   =[

Am I missing a step, or is this impossible?

Thx

[Martin_Ritter]

Can you please upload a screenshot of your layer order and setting, as well as altered proberties.

*Martin

[Arn Sweatman]

[Rick Gerard]

I am not sure where Layer 1 came from. I'm assuming it came from a layer I can't see. There are two shape layers, one called eyeball and one called eyeball mask. The eyeball layer (4) shows the opacity as 64% but the white part of the eye does not appear to be anything other than 100%. 

I have to assume that the eyelid mask layer (1) is a filled shape with just two vertices, and I can see that it has been edited. It has been placed above the pupil AI layer (2) and used as an Alpha Track matte. If the Pupil layer is a black circle and the eyeball mask layer is a filled solid then everything on the Pupil layer will be masked by the shape of the animated path. That tells me that if layer 1 changes from the current shape to something like a single line, then back to its current shape the pupil layer will change from the pie shape it is now to a thin line or no line, then back to the pie shape. 

I don't see anything that would make the eyeball layer change shape. You could use set matte on the eyeball layer and point it to the eyeball matte layer.

I would start by turning on the eyeball matte layer and soloing the layer to check the animation. If my assumption that the path is indeed animated is true then you either have to pre-compose the screen left eyeball and screen left pupil layer and use layer 1 as a track matte for the pre-comp or apply set matte to layer 3 something like this (they are all shape layers for illustration):

The eyeball and eyeball matte layers are identical except for the animation. You are seeing all modified properties of all layers so you should be able to duplicate the technique.

[Arn Sweatman]

Hi Rick - I really appreciate the feedback.

In my image you can see where I've keyframed the mask shape changes (the blink).

I have tried pre-comping the animated shape layer (mask).   Sadly with the same result.

If I put a mask on the pupil layer I can achieve what you've shown in your image but, as you know, any mask on a given layer will move relative to that layer.    That's not what I want.

*Layer 1 means nothing and has no effect on this issue, btw.

Thanks again.

[Arn Sweatman]

Here's a zipped file of my AE project.

[Rick Gerard · Accepted solution]

I didn't have time to dig into your comp completely but something weird is going on with the layer you are using as a track matte.

You have two options to fix the problem. The first is pretty easy. Delete the eyeball mask layer (layer 1), duplicate the eyeball layer and drag it on top of the pupil layer, and turn off visibility so that the eyeball 2 layer is now the track matte for the pupil. 

The second option is to delete the eyeball layer, turn off the Alpha trace matte and apply set matte to the pupil layer and set the eyeball layer to the source for the alpha matte.

The eyeball layer in the original comp is getting an alpha channel from somewhere that is masking the ellipse, but the size and scale are wrong. I didn't see anything obvious. It must have happened when you duplicated the eyeball layer. Maybe I'll play with the project a little later, but just deleting the problem track matte layer at the top and replacing it with a copy of the eyeball layer will quickly solve the problem.

[Arn Sweatman]

Hi Rick!!   Thanks again for your help with this.

You were right when you said "something weird is going on with the layer you are using as a track matte".

The TrkMat layer wasn't pointing at the correct layer.    In fact, it wasn't even giving me the option to point to the correct layer!??    I should have done what I did this AM - trash it and start over.    I just did that and it took me 5 minutes to fix using the same steps I (thought I) was using yesterday.     That would have saved me over an hour of fighting with this yesterday.

So to answer my original question - Yes, it is possible to make an animated shape layer a mask.  =]

Thanks again.