In After Effects, you typically add keyframes to animate properties over time. While you don't usually add several keyframes for the exact same property at the exact same time instance (as a property can only have one value at any given moment), you can certainly add keyframes for multiple properties across multiple layers, or add keyframes sequentially for a single property at different times. Working with multiple keyframes effectively often involves adding them strategically and then manipulating them together.
Adding Keyframes
Adding keyframes is fundamental to animation in After Effects. You add keyframes to mark a specific value for a property (like Position, Scale, Rotation, Opacity, etc.) at a specific point in time. After Effects then interpolates (transitions) between these keyframe values to create motion or change.
Here's how adding works:
- For a Single Property: You enable the stopwatch icon next to the property name. This automatically adds the first keyframe at the current time. Moving the Current Time Indicator (CTI) to a new time and changing the property's value automatically adds a new keyframe at that time. You can also manually add a keyframe at the CTI by clicking the diamond icon next to the property name when the stopwatch is active.
- For Multiple Properties on One Layer: You can enable the stopwatch for several properties (e.g., Position, Scale, and Opacity) on a single layer. Moving the CTI and changing the values for any of these properties will add a keyframe for that specific property at that time.
- For Multiple Properties Across Multiple Layers: You can select multiple layers and multiple properties across those layers. At a given time, you can add keyframes simultaneously for all selected properties by Alt-clicking (Windows) or Option-clicking (Mac) the stopwatch icon next to any of the selected properties (if the stopwatch is already active). This adds a keyframe for that property on all selected layers where it exists.
So, while you don't click a single button to scatter multiple keyframes for one property across time, you do add multiple keyframes frequently for animation across different properties, layers, and over sequences of time.
Working with Multiple Keyframes
Once you have added several keyframes, whether for a single property over time or across multiple properties/layers, you'll often need to work with them together. This involves selecting, moving, copying, pasting, or adjusting their timing or interpolation.
Selecting Multiple Keyframes
A crucial skill when working with animation is being able to select groups of keyframes. This allows you to edit them collectively.
According to After Effects documentation:
- To select a single keyframe, simply click its diamond icon.
- To select multiple keyframes, you can either Shift-click on individual keyframes to add them to your selection or drag a marquee (selection box) around the keyframes you want to select.
- If a keyframe is already selected, Shift-clicking it will deselect it.
Using these methods, you can quickly select several keyframes scattered across the timeline for one property, or even select multiple keyframes across different properties and layers if they are visible in your timeline view.
Why Select Multiple Keyframes?
Selecting multiple keyframes allows you to:
- Move Them in Time: Shift a whole section of animation forward or backward on the timeline.
- Move Them in Value: Adjust the values of all selected keyframes simultaneously (e.g., slightly move all position keyframes up).
- Copy and Paste: Duplicate animation segments to other parts of the timeline or other layers.
- Apply Easing: Add Easy Ease or other spatial/temporal interpolation methods to a group of keyframes.
- Scale Time: Stretch or compress the timing of a sequence of keyframes.
Effectively adding keyframes and then knowing how to select and manipulate multiple keyframes together is key to creating complex and polished animations in After Effects.
Summary Table: Keyframe Actions
| Action | Description | How It's Done (Typical) |
|---|---|---|
| Adding a Single Keyframe | Marks a property's value at a specific time. | Enable stopwatch, change value at CTI, or click diamond icon at CTI. |
| Adding Multiple Keyframes (Across Properties/Layers) |
Adding keyframes to several properties or layers simultaneously at one time. | Select layers/properties, use Alt/Option + click stopwatch at CTI (if active). |
| Adding Sequential Keyframes (For one property) |
Adding keyframes for the same property at different times. | Move CTI, change value (adds new keyframe). Repeat as needed. |
| Selecting Multiple Keyframes | Choosing several existing keyframes to edit them together. | Shift-click keyframes or drag a marquee box around them (using reference info). |
Understanding both how to add keyframes and how to select and work with multiple keyframes afterward is essential for efficient animation workflows in After Effects.
