To change an animated shape in After Effects, you primarily manipulate its path property over time using keyframes. This involves converting the shape layer to a Bezier path and then adjusting the vertex positions of the path at different points in time. Here's a detailed breakdown:
Steps to Change an Animated Shape:
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Create a Shape Layer: Begin by creating a shape layer in your After Effects composition using the shape tools (Rectangle, Ellipse, Polygon, Star, etc.).
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Convert to Bezier Path: Right-click on the shape layer in the Timeline panel. Navigate to "Create" and then select "Create Shapes from Vector Layer." This effectively converts your shape into editable paths. Alternatively, if you've already created a shape using the shape tools within a shape layer, you can directly access its path property.
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Access the Path Property: Open the shape layer's properties in the Timeline panel by clicking the arrow next to the layer name, then the arrow next to "Contents," then the arrow next to the shape (e.g., "Ellipse 1"), then the arrow next to "Path." You should see the "Path" property.
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Set the Initial Keyframe: Click the stopwatch icon next to the "Path" property to create your first keyframe. This records the initial shape of your path.
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Move to a New Time: Advance the Current Time Indicator (CTI) in the Timeline panel to the point where you want the shape to change.
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Modify the Shape's Path:
- Select the shape layer in the Composition panel.
- Use the Selection tool (V) to directly manipulate the vertices (points) and handles of the Bezier path. Drag vertices to new positions, adjust handle lengths and angles to change the curves. Adding, deleting, or moving points will alter the shape. You can also use the Pen tool (G) to add or remove vertices, or convert sharp corners to smooth curves and vice versa.
- As you modify the path, After Effects automatically creates a new keyframe for the "Path" property at the current time.
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Add More Keyframes: Repeat steps 5 and 6 to create additional keyframes at different times, further refining the animation of your shape.
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Keyframe Interpolation: You can adjust the interpolation (easing) between keyframes to control the animation's speed and smoothness. Right-click on a keyframe and select "Keyframe Assistant" > "Easy Ease" (or "Easy Ease In" or "Easy Ease Out") for smoother transitions. You can fine-tune the easing in the Graph Editor.
Example:
Imagine you want to animate a circle transforming into a square.
- Create an Ellipse shape.
- Convert the layer to editable shapes if needed.
- Set a "Path" keyframe at 0 seconds. The ellipse's path is now recorded.
- Move the CTI to 2 seconds.
- Using the Selection tool, manipulate the ellipse's path to resemble a square by adjusting the positions of its vertices and handles. A new "Path" keyframe is automatically created at 2 seconds reflecting the square shape.
- Play the animation. The ellipse will smoothly morph into a square over 2 seconds.
Tips and Considerations:
- Complexity: More complex shapes and transformations require more keyframes and finer adjustments.
- Masks: You can also use animated masks to reveal or hide portions of a shape, creating different visual effects.
- Expressions: For more advanced control, you can use expressions to link shape properties to other layers or parameters, creating dynamic and automated animations.
