Using on animation as a mask for another in After Effects

[dande]

I have rendered out a few animations out of Max. The frames are rendered out as Tiffs with Alphas.

 

Does anybody know if it is possible to use the Alpha of 1 animation as the alpha for another animation. For example if I bring in the footage of 1 animation, ignore the alpha can I use this footage as an alpha for another piece of footage.

 

I have searched the web and I can't any info on this.

 

Thanks

[Corey Beaulieu]

It is... All you have to do is place the animation whose alpha channel you would like to use in the comp that you would like to use it for. You can leave this layer off. Then on the layer whose main pass you want to use, place a "Set Matte". Either type this into a search or I think its under channels. With this you tell the set matte which layer to source from and which channel to source. It's great for multi-mattes, but works just as well for alpha trades.

 

Another method (this one is for alphas only) is to place the alpha layer on top of the main pass layer, both on. In the track matte column (the one next blending modes) switch "none" to "Alpha Matte" or "Alpha Matte Inverted" depending on how you want to use it.

[dande]

Thanks Corey. I'll check that out

[stevenarnold]

Hello Friends,

 

Animating a mask is similar to animating anything else in AE...you just need to turn on keyframing for the mask shape (using the stopwatch icon next to the mask shape property). Once you have done this you can go to a different point on your timeline and change the shape of the mask by moving it's points. AE will blend smoothly from one shape to the next.

Smart Mask Interpolation provides a high level of control for creating mask path keyframes and smooth, realistic animation. After you select the mask path keyframes to interpolate, Smart Mask Interpolation creates intermediate keyframes based on settings you provide. The Info panel displays the progress of the interpolation and the number of keyframes created.

1. Choose Window > Mask Interpolation.

2. Select at least two adjacent mask path keyframes.

3. Set options in the Mask Interpolation panel, and then click Apply.

 

Best Regards

Steven Arnold