How to Change Angles in After Effects

In After Effects, changing angles typically refers to modifying a layer's rotation or adjusting angle-based properties within effects, cameras, or lights. This can be done manually or dynamically using expressions.

Adjusting Angles Manually

The most common way to change an angle is by adjusting the Rotation property of a layer.

1. Select the layer you want to rotate in the Timeline panel.
2. Press the R key to reveal the Rotation property.
3. Click and drag the value to rotate the layer, or type in a specific angle in degrees. The value is typically represented as revolutions + degrees (e.g., 1x + 45.0° means 1 full rotation plus 45 degrees).

Beyond layer rotation, many effects, camera settings (like Cone Angle), and light properties involve angle values that can be adjusted directly in the Effect Controls panel or the Timeline.

Dynamic Angle Changes with Expressions

For more complex or interactive angle control, expressions offer powerful capabilities. Expressions are small scripts that can link properties together or calculate values based on other data.

As highlighted in resources like the video snippet titled "After Effects: Convert Position to Angle Rotation Expression," expressions are often used to:

• Convert Position to Angle: Calculate a rotation angle based on the relative position of two layers (e.g., making one layer always point towards another). This often involves trigonometric functions like Math.atan2(deltaY, deltaX) which takes differences in y and x coordinates and returns an angle in radians.
• Drive Angles Based on Other Properties: Use the value of one property (which might not even be an angle) to control an angle property on another layer or effect.
• Animate Angles with Logic: Create complex animations based on conditions, time, or external data.

For example, the referenced video snippet discusses applying an expression to achieve a "Convert Position to Angle Rotation" effect. The mention of applying the expression and then being able to "change our angle to roughly 45 degrees" implies that the expression either drives a property that is then manually fine-tuned, or perhaps an input value to the expression (like a target angle or offset) is adjusted to demonstrate the expression's dynamic effect. The exact syntax Plus open bracket x comma y. Semicolon. appears to be part of an expression designed to calculate an angle, likely related to position data, similar to how Math.atan2(y, x) works to find the angle based on coordinate differences.

Key Concepts for Expression-Driven Angles

• Property Linking (Pick Whip): Use the pick whip icon to link an angle property to another property. After linking, you can modify the expression text to perform calculations or transformations.
• Common Functions: Functions like Math.atan2(), Math.cos(), Math.sin() are frequently used to calculate angles from position or other numerical data.
• value Attribute: Refers to the current value of the property the expression is applied to before the expression is evaluated.
• toComp(), fromComp(), toWorld(), fromWorld(): Useful methods for converting coordinates between different layers' spaces or the composition space, essential for calculating relative positions for angle calculations.

By utilizing expressions, you can create dynamic relationships where changing a layer's position automatically updates another layer's rotation angle, as demonstrated conceptually by the referenced video topic.

Steps for Adding an Expression (Example: Simple Rotation)

1. Select the layer.
2. Press R to reveal Rotation.
3. Alt-Click (Windows) or Option-Click (Mac) the stopwatch icon next to Rotation. This adds an expression field.
4. Type your expression in the field. For instance, typing time * 50 will make the layer rotate 50 degrees per second.
5. Click outside the field or press Enter on the numeric keypad to apply.

For converting position to angle, the expression would be more complex, often involving picking the position of a target layer and using Math.atan2.

Summary Table: Methods to Change Angles

Method	Description	Use Case
Manual	Directly adjust the Rotation property value.	Simple, static rotation.
Effect/Property	Adjust specific angle controls within effects, lights, etc.	Configuring effect parameters or scene elements.
Expressions	Use scripts to dynamically calculate or link angles.	Aiming, complex animations, reactive motion.

Expressions provide the greatest flexibility for dynamic angle changes, including converting position data to drive rotation, as indicated by the video reference.