A brush stroke effect....question how to make it do the opposite and write itself back to invisible.

[Stonehedge]

Hi, on one of my comps i have a brush stroke like stock clip.....im using it against a solid...so its a wipe on brush stroke. Ive done it, set a luma key to remove the black bg and its ok.

Now i want the same stroke to unwipe itself. This is where i dont know what to do. I tried laying a dup clip of the same and trying out some blending modes to see if it will do the stroke again, but this time with invisible ink, ie cancelling out the existing bursh stroke below it.

Im imagining i can expand this above clip a little largerand make it into some sort of mask which can wipe out the shrunk (smaller sized) stroke below it. Just a wild guess theoroctically. Dont know how to do it.

Anyone who can point me in the right direction ?

[Finn McNeill]

Have you tried to track matte and invert it? Take you animated brush stroke, duplicate, track matte the bottom layer to the top layer and click invert track matte, maybe this will work? - for this to work properly you will hvae to precomp the existing animated layer before duplicating so the luma key doesn't interfere - make sure to 'move all items to new precomp' when creating one.

[Rick Gerard]

If you used the Pen tool to add a stroke, all you have to do is select the layer and press the 'u' key twice to reveal all modified properties. You should see some keyframes for the brush strokes. Select the property (probably Paint/Brush/Stroke Options/End) to select all keyframes, then right-click or use the Animation Menu to choose the Keyframe Assistant/Time Reverse Keyframes.