Feathering one side of a mask, do it from the start or can be added later?

Question

Hello After Effects Aficionados,

EZ one for the pros....

I've completed a mask. (around a person's head)

Now, I'd like to feather one side only.

I then go back to my mask, using the feather tool, expand the feather a bit, and add 2 more points to isolate the area I want.

All that works fine.

But, how do I keep those new one sided feather changes thruought the entire animated mask?

When I preview, the feather mask dissapears and seems to only work for a couple frames.

Must I add the 'one sided feathering' at the time of the creation of the mask?

Was really hoping I could just add it in, and somehow it will follow the original mask animation.

Thanks,

Letty

Rick Gerard · Accepted Answer

If you intend to add feathering to a mask. you should add the feather controls before you start animating. It's the same as adding a vertex. Add a new vertex after you start animating and that point will have to be adjusted for every previous keyframe.

By far the easiest way to animate a mask is to make sure that the path you want to animate is selected in the timeline and then use the selection tool (v). When the path is selected the cursor will change to a white tailless arrow that you can use to select a vertex or feather control point, or draw selections around multiple points, or grab line segments to animate them.

You'll also want to use multiple masks for rotoscope work. One for the body, one for the head. Sometimes I even use multiple masks on just the head, it depends on the movement in the frame. I also seldom rotoscope by drawing on the actual footage. I add a solid that I use as a track matte. Changing the blend mode and setting the color of the solid lets me easily see the edges and make adjustments a lot easier than I could if the mask path was on the layer.

Maybe this tutorial will help you streamline your animation process. I plan to update it and make it much more complete soon.

If you embed a screenshot showing us your project we might be able to give you some other ideas that may help simplify the process.

Mylenium · Answer

Your workflow is kinda crooked. AE simply stores all mask info in its compound keyframes, hence any specific changes are only valid for that given keyframe and they don't propagate like if they were a separate property. Technically the behavior is correct - AE interpolates from a feathered keyframe back to an unfeathered one. All that being the case, simply don#t bother with the feathering until you actually are done with tracing the shapes. That's what experienced roto artists do, anyway, geometry first, motion blur etc. later. Sure, you could start over and apply the feather right from the start, but that doesn't really solve your issue quite likely. you still would have to re-tweak it at every keyframe. Also old-schoolers like me would try to avoid such complicated workflows and simply combine multiple masks with uniform feather settings.

Mylenium

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