keeping a mask stationary while animating the layer its masking

Adobe After Effects

keeping a mask stationary while animating the layer its masking

Posted by Ryan Rapaport on November 16, 2011 at 9:06 am

Hi all,
Not sure if I am just being silly, but i am having real trouble animating a layer that has been masked, and NOT moving that mask, just the layer in question.
i have tired a few things including precomposing the layer and then masking, using the pan behind tool to animate the layer (this looks like exactly what I want while using the tool, but once played back my mask is moving ever so slightly. and no i don’t have a stray keyframe somewhere)
i just don’t get it? anyone able to help me out?
thanks in advance.
cheers
Ryan

Roland R. kahlenberg replied 14 years, 10 months ago 3 Members · 9 Replies
9 Replies

Tudor “ted” jelescu
November 16, 2011 at 10:09 am

draw your mask as a shape on a shape layer above the layer you want to animate and use as track matte.

Tudor “Ted” Jelescu
Senior VFX Artist
Roland R. kahlenberg
November 16, 2011 at 10:30 am

Ted’s given you one option. Another way to do this but within the same comp is to use the Pan Behind Tool.

HTH
RoRK

Intensive AE & Mocha Training in Singapore and Malaysia
Adobe ACE/ACI (version 7) & Imagineer Systems Inc Approved Mocha Trainer
Ryan Rapaport
November 17, 2011 at 7:22 am

thanks:)
works a treat:)
Ryan Rapaport
November 17, 2011 at 7:39 am

Thanks Roland,
I am having trouble animating with pan behind tool.
if I keyframe everything in my comp at 0:00 and move a second in time and using the pan behind tool to animate the layer, the move ends up moving too. not just the layer. Whats weird is that I only see the mask animate once I play the animation. when actually dragging the pan behind tool around it looks perfect. but once played back the mask animates. any idea why that would happen?
Cheers
Ryan
Roland R. kahlenberg
November 17, 2011 at 7:52 am

If you want to animate a layer and yet have its mask stationary then you will have to use a track matte instead of a mask.

The method I mentioned works only if the layer is stationary. As to why the mask moves, well, that has to do with AE’s default Rendering Order where masks are rendered after transforms. Hence any animated anchor point or position will also move the mask.

HTH
RoRK

Intensive AE & Mocha Training in Singapore and Malaysia
Adobe ACE/ACI (version 7) & Imagineer Systems Inc Approved Mocha Trainer
Ryan Rapaport
November 17, 2011 at 7:59 am

ok, i got it:)
thanks for taking the time to explain.
have a great day:)
Roland R. kahlenberg
November 17, 2011 at 8:04 am

No worries Ryan. I made a boo-boo above too – Masks are rendered BEFORE transforms and not after as I mentioned.

HTH
RoRK

Intensive AE & Mocha Training in Singapore and Malaysia
Adobe ACE/ACI (version 7) & Imagineer Systems Inc Approved Mocha Trainer
Ryan Rapaport
November 17, 2011 at 8:08 am

well i think I can forgive you just this once;)
thanks again.
Roland R. kahlenberg
November 18, 2011 at 4:01 am

OK BUT only for as long you aren’t keeping score. 😀

Cheers
RoRK

Intensive AE & Mocha Training in Singapore and Malaysia
Adobe ACE/ACI (version 7) & Imagineer Systems Inc Approved Mocha Trainer

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