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my mask wont keep up with my shape layer using expressions

Aug 20, 2013 10:20 PM

While trying to have a mask path follow a Shape layers KF position. I am not getting a good track via expressions. I am getting a lag of the mask following the shape layer's path or position KF's.

Pic 1 shows both the shape layer and the mask starting off together. (labeled mask in the spatial Comp) Pic 2 shows the lag. Pic 3 shows the lag. Pic 1 & 3 has the TL exposed


I want the mask path to follow the Shape layers, KF'd path. Along with the Scale up of my second layer of my movie to appear as though it is a shooters P.O.V (magnified) via expression of Mask's expansion expressed to the scale of the duplicate layer.

What I am not doing do get my desired effect? Thanks for help on this..Regards NC




  • Currently Being Moderated
    Aug 21, 2013 12:21 AM   in reply to Netcommercial

    Shape layer coordinates start at the cenbter whereas all other coordinates start in the top left. that aside, you are simply going about this the wrong way. Simply pre-compose the cross-hair and create matching matte in a pre-comp, then use both in the main comp with simplke parenting. You realyl are overcomplicating matters here.



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    Aug 21, 2013 10:39 PM   in reply to Netcommercial

    Again, you are overthinking and overcomplicating matters. Just use those pre-comps. you are too bound to do everything in your working comp. Pre-comps are power, not something to shy away from.



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    Aug 22, 2013 10:45 AM   in reply to Mylenium

    I'm going to redo my previous post and give you a clearer step by step.


    I'm assuming that your subject is moving. The first step is to create a new comp and stabilize the footage. You can use the AE point tracker or Mocha. After stabilizing your subject should be locked in the frame. Now you simply create your Crosshairs graphic and set up a track matte or mask for the source footage.


    Now select your source footage layer and copy it.


    Next, Create a new composition. Paste your source footage in the new comp. It will still be stabilized.


    Go back to the pre-comp and scale up all layers the same amount to give you your magnified view.


    Go back to your main composition and drop the stabilized pre-comp with crosshairs above the original footage. The crosshairs and the original footage should line up and the crosshairs should not move.


    Now it's time to remove the stabilization with a null and an easy expression. Add a null and name it destabilize. Make both the stabilized original footage and the pre-comp children of the destabilize null. Select the null and press P to reveal the position property. Select the stabilized original footage and press A to reveal the anchor point property. Alt/Option click on the destabilize null's position property and pickwhip the position to the anchor point of the stabilized footage.


    All done. The stabilization is removed and the crosshairs track perfectly.



    Poor little duck. He was just looking for a handout....

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  • Currently Being Moderated
    Aug 27, 2013 8:06 AM   in reply to Netcommercial

    I think you are stabilizing the camera movement and not locking to the actor. Check out this quick tutorial on the process and download the project file here. It took me about 10 minutes.



    Something's fishy with the embedded video. If the video appears to be unavailable try clicking on the you-tube link and watch it there.

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    Aug 27, 2013 11:34 AM   in reply to Netcommercial

    You can add scale and position keyframes to target and the track matte in the pre-comp to get your shooters POV there then lock in the track for the subject from that point forward. It's prety simple really. Then the same techniques apply to keep the scope lined up with the shot.

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    Aug 27, 2013 1:48 PM   in reply to Netcommercial

    If you'd like to drop you footage in dropbox I'd be happy to show you how I would do it. I think your scope gets way too big. Try to think how this would look for real then stylize that.


    I would animate the position of the scope in the pre-comp so that it moves around and finds it's mark. From that keyframe forward track the movement of your subject. Then apply your track matte. You'll get the scope scanning the frame looking for the target and then locking on the target. The scope would stay locked on until the end of the shot.


    Then I'd use the same techniques for the main comp and just scale up the pre-comp a bit. I'd probably apply a color correction effect to the background footage to darken it up or drop in a dark gray solid set to overlay and adjust the opacity to darken the footage outside the scope.


    I may scale up the pre-comp a bit.


    As far as styling the scope that's an artistic decision that's up to you. Real scopes have very fine lines. You can find illustrations of the reticle inside a high quality modern scope on Google Images. I'd make it look more like that. You might want to add in some color correction to lighten magnified footage.

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