The following are notes on how to animate a cut-out character using After Effects. The information can also be applied to the process of parenting items and using null objects.
Helpful Toolbar Shortcuts:
- Selection Tool = v
- Rotation Tool = w
- Pan Behind Tool = y
Helpful Layer Shortcuts:
- Position = p
- Rotation = r
- Opacity = t
Puppet Design
First of all, design a puppet and assemble it in separate pieces. You could do this by making actual artwork first, by drawing and colouring on paper with pencil crayons and watercolours, or you could produce the elements with software like Adobe Photoshop or Corel Painter. Nonetheless, make sure to leave a transparent region around each puppet piece, and trim the objects closely. Don’t leave too many pixels in the regions outside the artwork, otherwise it you’ll probably find that moving/animating the objects will be a cumbersome process.
Make the pieces as separate files: PSD or PNG with an alpha or matte channel, or TIF or TGA files with an alpha channel will also do. Do not use JPGs, as they don’t support matte channels.
You should name your image files in an organized fashion, to keep track of the pieces, but also to arrange them in ascending order. Depending on the view settings in your software, if you choose “by name,” your files will list in alphabetical order. For example:
- arm_far_lower.png
- arm_far_upper.png
- arm_near_lower.png
- arm_near_upper.png
- foot_far.png
- foot_near.png
- hand_far.png
- hand_near.png
- hat.png
- head.png
- leg_far_lower.png
- leg_far_upper.png
- leg_near_lower.png
- leg_near_upper.png
- pelvis.png
- torso.png
Using After Effects
Arranging the Puppet
Create an After Effects project, or new Comp within an existing project, and make the dimensions large enough to contain the cut-out.
From After Effects, import the puppet pieces. In the Project Window, make a folder and organize the pieces / image files.
In the Timeline, arrange the layers so they are grouped in natural clusters; that is, far arm segments together, near leg parts in a region, etc. Also, begin to layer them in a stacked hierarchy, where uppermost layers are on the top of the Timeline stacking. For example:
- torso.png
- pelvis.png
- hat.png
- head.png
- arm_near_upper.png
- arm_near_lower.png
- hand_near.png
- arm_far_upper.png
- arm_far_lower.png
- hand_far.png
- leg_near_upper.png
- leg_near_lower.png
- foot_near.png
- leg_far_upper.png
- leg_far_lower.png
- foot_far.png
Null Objects
To further organize the pieces and to help you animate the puppet, you should create null objects for the two arms, two legs, and torso/puppet. You might find that you’ll want to create additional nulls later, depending on the complexity of the cut-out and animation.
Referring to the Main Menu, go to Layer > Null Object. A null is meant to be something that you can group or parent other objects to. It isn’t a physical thing, but you can move and animate it (i.e., change position, rotate, scale, etc.) and do so in space as well, by making it a 3D Layer.
Bring the nulls down into the timeline, group them with their respective puppet limbs, and name them accordingly (i.e., click on the layer, press the Enter Key, and give the layer a new name, or click on the layer, context-click, choose “Rename,” and give the layer a new name).
- Leg – near
- Leg – far
- Arm – near
- Arm – far
Final Arrangement of Layers in the After Effects Timeline:
- Puppet (null)
- torso.png
- pelvis.png
- hat.png
- head.png
- Arm – near (null)
- arm_near_upper.png
- arm_near_lower.png
- hand_near.png
- Arm – far (null)
- arm_far_upper.png
- arm_far_lower.png
- hand_far.png
- Leg – near (null)
- leg_near_upper.png
- leg_near_lower.png
- foot_near.png
- Leg – far (null)
- leg_far_upper.png
- leg_far_lower.png
- foot_far.png
Hinges / Pivot Points
To arrange the puppet, you should set the Anchor Points first. These will be the hinge points, like shoulders, elbows, hips, knees, and ankles, etc. To easily move the Anchor Points, use the Pan Behind Tool (key stroke Y).
Important — For upper arms and upper legs, you should set the hinge points at the knees and elbows (not the shoulders and hips) as you might think. The same goes for the lower arms and legs: hinge at the elbows and knees. To pivot the arms and legs, you’ll use the anchor point on the null object.
Once you’ve set the anchor points, switch from the Pan Behind Tool to the Selection Tool (V) and arrange the pieces, so they overlap at the hinge points.
Joining Puppet Parts – Parenting
To help keep track of the elements in the Timeline, you should colour code the layers by selecting Label Colours. Make sure the Label Column is active in the Timeline (i.e., if not, in the Timeline, around the region of the Layer Name Column, context-click and choose Columns > Label). The Label Colour is usually located immediately to the left of the Layer Name — the coloured square. You can also select Label Colours by going to the Main Menu > Edit > Label. Choose a colour of your choice. For example, far arm pieces could be Fuchsia, near arm pieces could be Lavender, torso objects could be Sea Foam, etc.
After you’ve arranged the various parts and colour-coded them, you can proceed with parenting them. Make sure that the Parent Column is active in the Timeline. To do so, context-click on the Timeline column region and choose “Parent.” From there, use either the “pick whip” to connect the layers, or use the Parent Pull-Down Menu to locate the connections.
Connect the items naturally: arm pieces, leg pieces, torso pieces, head, etc.
- Puppet (null) > torso.png > pelvis.png
- Puppet (null) > hat.png > head.png
- Puppet (null) > Arm – near (null) > arm_near_upper.png > arm_near_lower.png > hand_near.png
- Puppet (null) > Arm – far (null) > arm_far_upper.png > arm_far_lower.png > hand_far.png
- Puppet (null) > Leg – near (null) > leg_near_upper.png > leg_near_lower.png > foot_near.png
- Puppet (null) > Leg – far (null) > leg_far_upper.png > leg_far_lower.png > foot_far.png
Animation
Set the frame counter in the Project Settings so that is reads as “frames” and not “timecode.” To do so, go to the Main Menu > File > Project Settings. Under Display Style, select “Frames.”
In the grand scheme of things, I recommend that you pose and animate the nulls first –that is, the puppet, arms, and legs — as broad strokes, and then you could fine-tune the movement in more detail, like the forearms, hands, and feet, etc. This is where you’d focus on secondary motion and follow-through movement.
To animate, you’ll work with keyframes, obviously, but you should apply more than the default Linear Keyframes. To create rich and convincing movement, you have to apply a full range of motion tempos (such as acceleration and deceleration).
Hold Keyframes
In addition to using Linear and Bezier Keyframes, there’s an advantage to using Hold Keyframes with your animation. Hold Keyframes allow for true frame-by-frame animation with After Effects. The software doesn’t calculate in-betweens. It’s like doing drawn animation, where you create all the poses as well as the in-betweens.
With this particular cut-out animation method, you should prepare the layers with Hold Keyframes for frame-by-frame animation (but you can also convert the keyframes to Linear or Bezier later on.)
To Set Layers/Objects as Hold Keyframes
Shift the Current Time Indicator to the “0” frames point — the absolute beginning of the Timeline. Select the component puppet parts as layers in the Timeline: click on the first layer, hold down the Shift Key and then click on the last. Doing so will select them as a group. Press the “p-key,” to expand “Position.” Referring to the animation features in the layers, while the layers are still selected, click on the Stopwatch on the uppermost layer to make a first keyframe. As the components are all selected, After Effects will set a position keyframe for all of them. However, they will be Linear Keyframes (denoted with diamond shape keyframes on the corresponding layers). Next, to turn the keyframes into Holds, while the layers are still selected as a group, context-click on the top-layer keyframe and choose Toggle Hold Keyframe. Doing so will turn the “diamond-shape” Linear keyframes into “square-shape” Hold Keyframes.
The next step will be to set Holds for Rotation. While the group of layers are still selected, click “p” to collapse Position, and then click the “r-key” to expand Rotation. Just as you did previously, set the Linear and subsequent Hold Keyframes by following the same steps as defined above.
By turning the Rotation and Position into Hold keyframes, you are now able to make adjustments to any of the subsequent moves you make, without interpolation.
To advance from one frame to the next, use the Current Time Indicator to move forward and/or back, but you can also use the Page Down and Page Up keys, to move along the Timeline:
- Page Down Key = Advance one frame (on an extended keyboard with a numeric keypad)
- Page Up Key = Move back one frame (on an extended keyboard with a numeric keypad)
- Current Time Indicator
With keyframes set as Holds, once you advance to a new frame on the Timeline, when you use the Selection Tool (v-key) and Rotation Tool (w-key) to move an object, After Effects will set a new Hold Keyframe. You don’t have to consistently open and close the layer effects to adjust and animate Transform options like Position and Rotation. Simply use the:
- V-key = to grab an object and move it
- W-key = to rotate an object, according to its Anchor Point or Pivot Point / Hinge Point
- Page Down Key = to advance one frame along the Timeline
- Page Up Key = to move back one frame along the Timeline
In fact, quickly selecting the Page Up and Page Down keys is similar to flipping drawings. Click them quickly and watch the Monitor Window and you’ll get a true sense of movement.
Playback the animation from time to time by choosing RAM Preview. To do so, click on “0” (Zero-Key) on the Numeric Keypad. You might have to turn the resolution down to Half, Third, or Quarter.