Tracked mask to expose select portions of underlying video

I have planar tracked base footage with some effects layers over the top, and I have a duplicate of the base footage over the effects layers. I'm trying to mask in select portions of the duplicate base footage to lay over the effects layers. I've tried placing a plane on the top layer, setting it to 3D and parenting it to one of my track points, then added a [Set Matte] effect to the duplicate base footage with the source layer set to the top plane and the Matte Source set to Alpha. My mask stays positioned correctly, but does not expose the underlying footage, it only exposes the plane's base color. I'm new to HitFilm and still learning the interface. If anyone has any suggestions, I sure would appreciate any suggestions.




  • edited September 2016

    It might be an 'order of operations' thing with Mask and Set Matte.

    I suspect someone like @Triem23 will correct me, but first try putting a Grade Layer in there, and pointing the Set Matte on your Effects Layer at that, So...

    1. Effects layer - with Set Matte pointing to Grade Layer
    2. Base Layer - Peekaboo! Shows through Mask cutout
    3. Grade Layer - Flattens what's below
    4. Mask Layer - Visibility off

    Another way is to move the Mask into a composite shot of its own - copy those points across - and point to that.

  • @Palacono, nope you're right. Actually, using a Grade Layer to flatten out the Set Matte source had never occured to me. When @JoshDaviesCEO dropped that in a recent tutorial, I literally facepalmed.

  • edited September 2016

    @Triem23 Noooo. say it isn't so! You'll have to hand back your Oracle trophy. :(

    I prefer to use Grade Layers when I need to see the results of any changes to what they're flattening in real time, rather than in an embedded comp where I can only see that comp. I might later - for neatness or other convenience - move the relevant layer to its own comp when it no longer needs changing. The other advantage of that is for video masks - ink splashes etc. - you can proxy them for speed improvements.

  • I use Grade layers as well, although this trick is handy.

  • "When @JoshDaviesCEO dropped that in a recent tutorial, I literally facepalmed."   @Triem23 which tutorial was it ?

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