[Darby Edelen]

Here’s another way to try and suppress the spill if you’re using the Intermediate result.

Add another instance of the unkeyed footage above your key. Enable this layer’s “Preserve Transparency” switch and add the Channel Mixer effect to that footage. Change the Channel Mixer “Green” settings to:

Green-Red: 50
Green-Green: 0
Green-Blue: 50

This will replace Green values in your footage with an average of the Red and Blue values.

Finally set the upper layer to the Darken blend mode, this will only replace the Green values where the Green value is greater than the average of Red + Blue values, effectively you’ll clamp the Green values in the footage to the Red + Blue values.

Nothing could possibly have a green tint at this point, but you may not be entirely happy with the result (colors may shift). In that case, change the Green-Red, Green-Blue or even Green-Green values to change the look.

If the Green-Red, Green-Green and Green-Blue values ever combine to more than 100 then you will be adding additional Green into the footage. That may be desirable though.

I’d recommend just playing with the values to see what you like.

Darby Edelen

[Darby Edelen]

You may need to re-import the layer.

When you first import a PSD there are several options that change how AE will treat the file. One of these changes whether the Photoshop layer size or document size determines the size of the layers in AE.

If you’ve imported your layer with “Layer Size” then movement in Photoshop will not be updated when you reload in After Effects.

Darby Edelen

[Darby Edelen]

Yeah, I’ve never seen an issue keying footage with its fields separated.

My list of culprits for causing nasty fringing would be in camera sharpening filters or chroma sub-sampling. Perhaps not separating the fields caused these to become less apparent?

I’d be curious to see the problem if you run across it again.

Darby Edelen

[Darby Edelen]

Most blending modes rely on RGB operations and have no effect on the alpha, so while Screen may work to composite in After Effects, it will never work if you need to export with alpha.

You have to create an alpha from the RGB of the subject if it doesn’t already have alpha. Is this a solid object or something like smoke?

Possible ways to do this would include:

1. Using the Keying > Extract effect.

2. Tinting the footage, applying levels, using this layer as a Track Matte for the original footage. Adjust Levels to taste.

3. Unmult, which is useful for creating alpha from things like smoke (semi transparent objects). Looks like it doesn’t work with CS6 yet, but it’s a free plug-in available here: https://www.redgiantsoftware.com/products/all/knoll-unmult-free/compatibility/

4. Try using Rotobrush if you have CS5 or later.

5. If it’s a still image, do it in a photo editing package like Photoshop.

Darby Edelen

[Darby Edelen]

[keith mcgregor] “It would be best if you tell after effects there are no fields to interpret (separate fields off in interpret footage dialogue tab) while you key, as the resulting fields make edge chatter, pop and swim.”

Is this true? From my understanding of separate fields I would think that setting this to the proper field cadence is important for proper output.

Granted a progressive source would be much better but if the source is interlaced then I believe you’d want to separate the fields.

On to the key!

For your green spill the Despill Bias should do a good job of removing the spill on the subject. Select a color from the face of the woman in the ‘Source’ view. I usually find that I have to reduce the saturation of the selected Despill Bias in order to get a pleasing result (and avoid turning the subject orange).

If the skin tone of the blonde woman still seems off (it likely will) then I’d recommend checking the Hue of the other subjects in your shot. Human skin tone usually falls within a very small range of Hue (the saturation and lightness vary much more). In your image, for example, it looks like the skin tone (sampled from areas without makeup and low green spill) mainly falls from about 25° to 35° in the other two subjects. Therefore I’d use Hue/Saturation to bring the hue of the blonde woman’s skin into about that range.

Darby Edelen

[Darby Edelen]

[Emily Burrow] “So whenever I turn on “contiously rasterize” so my vectors in my precomp are crisp, it just disappears. I can see the outline of the precomp in the main project window but nothing from the actual composition shows up.”

Continuously rasterize/collapse transformations when enabled on a composition will look at the layers inside the composition for their layer switches and transforms to determine how to render them.

Make sure that the layers in your composition are 3D layers and also have continuously rasterize enabled.

Darby Edelen

[Darby Edelen]

In the case of casting a shadow using a light I’d actually recommend using Classic 3D rather than the ray-traced engine. You have more control.

However, I think you’d be best off in this scenario scaling your actor layer down a lot (maybe to 2%) on the y-axis. To start duplicate the actor footage, move the anchor point on the duplicate to where the actor’s feet meet the floor, set the y-scale on this duplicate to 2%-ish (change as you see fit), then add a Generate > Fill effect set to black (or near black, or another color if you want to simulate some ambient light, a dark desaturated blue often works well for outdoor shots for example), add a Fast Blur and crank it up until you’re happy with the result (you could add 2 Fast Blurs, one for the Horizontal Blur and one for the Vertical Blur), finally set the shadow layer to the Multiply blend mode.

You’ll likely need to tweak some things to get this looking right, but it should get you most of the way there. If the talent moves toward or away from the camera then you might need to animate the transforms on the shadow layer. Also if the talent jumps very high you might want to keyframe an increase to the Fast Blur radius when they are in the air.

Also see what it looks like with the shadow layer set to a small negative scale (-2% maybe?). In the end you may want to use 2 shadow layers, one with a small positive and one with a small negative scale.

Darby Edelen

[Darby Edelen]

The right solution will probably depend on what kind of motion you’re looking to create.

If you want all of the layers to follow the same basic motion then I’d recommend animating a Null to define the main motion path. From there you can point each layer to the Null’s position and offset the start in time. When I do this I like to offset the animation on each layer to begin at the layer’s in point. Something like this:


l = thisComp.layer("Null 1");
t = time - inPoint;
l.toWorld(l.anchorPoint, t);

If you then want to add some randomness to the motion path per layer you could do something like add a timeless random value to the result:

seedRandom(index, true);
p = random([-200,-200], [200, 200]);
l = thisComp.layer("Null 1");
t = time - inPoint;
l.toWorld(l.anchorPoint, t) + p;

…Or add the layer’s own position value to the result:


l = thisComp.layer("Null 1");
t = time - inPoint;
l.toWorld(l.anchorPoint, t) + value;

…Or even wiggle the layer’s position value then add it to the result:


p = wiggle(1, 50);
l = thisComp.layer("Null 1");
t = time - inPoint;
l.toWorld(l.anchorPoint, t) + p;

If you’re just looking to create totally random motion then some version of the wiggle() function will probably work for you.

Darby Edelen

[Darby Edelen]

You’ll probably have to set up at least 2 keys. Try and preserve the yellow in one and the blue in the other. I believe the screen balance is the primary way you’d influence that.

I think the Alpha Bias control may also help, but it’s more of a brute force method. You would select the blue or yellow portion (what you want to keep) for the alpha bias and then adjust the saturation until it looks ok.

For the green spill you should choose a despill bias in the range of your subject’s skin tone. Adjust the saturation of the color to try and get a good result. You can also try to use other despill methods like a targeted Hue/Saturation adjustment or the Keying > Spill Supressor effect if you get desperate.

Darby Edelen

[Darby Edelen]

If you wanted to create even more complicated parent/child relationships I believe all you’d need to do is transform the vector into from world space to the layer’s space:

delta = toWorld(anchorPoint) - thisComp.activeCamera.toWorld([0,0,0]);
vec = fromWorldVec(delta);
r = radiansToDegrees(Math.atan2(vec[0],vec[2]));

Interesting side effect of the space transform is that you can also change the keyframed Y-rotation to offset the orientation.

Darby Edelen