Using 1 layer as a mask for multiple layers

[Nathan Quattrini]

i`d prefer to do it in real time so i can get things just right. I thought 6.5 could do it, i`m using 7…. or maybe it was another program :\

[Nathan Quattrini]

haha what i meant was, i want the matte applied while i`m editing them or I can`t tell if it`ll look right. If i precompose, i have to guess what it will look like, guess the edges and render, then try masking, rinse repeat for lots of wasted time. I found out i was thinking of premiere. You can select which video layer you want to use as a matte, instead of limiting track mattes to the track right above. I was hoping AE being more for effects and such could also do this.

[Jason Mcclellan]

You can set up AE with two(or more) composition windows.

You can have the ‘main comp’ with the ‘precomposed comp’ and matte open, and you can have the ‘precomposed comp’ open. Any changes you do in the precomp will appear matted in the main comp.

Jason McClellan
jas.mcclellan@gmail.com

[Nathan Quattrini]

heh nope. Kind of the opposite. Theres a bag that needs to serve as a mask. Easiest related example i can give is an odd shaped golf bag that will have several clubs sitting in it, then they fly out turning etc while doing so. The bag is not big enough to put in the foreground (when the clubs start turning on the way out they would pop out behind the bag etc) and the bag has obvious fore/background elements to the opening, so i can`t just put the bag on the front layer. Right now i have 4 clubs and 4 oversized bag matte copies. Perhaps i could try and split the bag fore and backgrounds cleverly, but again, if the club turns too far it will poke out the back or sides of the bag.

[Charlie R]

The easiest solution seems to me, is to use the plug-in effect ‘set matte’.

The effect is under the ‘channel’ heading in your effects. It is an Adobe plug-in, so everyone should have it (not sure if it is a professional only plug-in or not)

but this plug-in is great, you can use one layer to matte an unlimited number of layers. You apply the plug-in to the layers to be matted and set them all to ‘take matte from layer’ to your matte.

hope this helps
charlie

[Shawn Marshall]

I, too, have been long hoping that Adobe would add the ability for a single matte layer to cut out multiple layers below it (but not every layer below it.) I think Flash can do this. You designate your matte layer, then you can select multiple layers below it to be cut out by the matte.

Yes, you can precompose, or open up multiple windows, but sometimes it would be easier to just do everything in one comp.

The Set Matte plugin might work in some instances, but not for all. Say you have a comp with 30 layers, and three of those layers are photos that you want to animate and dissolve between, and you want the three photos matted by a rectangle that travels across the screen. If you create a solid rectangle and animate it, set matte doesn’t see the movement. It’s just looking at the alpha of the raw layer and ignores any masks or animations. You could precompose your matte layer, but that defeats the purpose.

The obvious solution is to precompose the three photos with their moves and dissolves, then track matte that precomp with the rectangle matte, but there have been times when I’ve had trouble syncing up the precomp moves with the main comp, so it’d be nice to be able to do it all in the main comp.

Shawn Marshall
Marshall Arts Motion Graphics

[Sam Moulton]

put the mask layer at the bottom then click on the transparency switch in the mode/trackmatte column. This works as long as there’s nothing below the layer with the mask.